Saturday, December 7, 2019

Journal On Selected Areas In Communications -Myassignmenthelp.Com

Question: Discuss About The Journal On Selected Areas In Communications? Answer: Introducation RSA: This cryptographic algorithm was designed by Rivest, Shamir and Adleman in the year 1977. It is a public key encryption standard. This algorithm makes the use of large integer numbers. According to this algorithm an individual will use one public and one private key. The sender will use the receivers public key to encrypt the message that will result in cipher text. The receiver will be able to read the message by decrypting the message using its own private key (Jonsson et al., 2016). RSA has invented the concept of digital signature. This algorithm is based on the problem of factorizing the product of two different large prime integers or numbers. RSA is a secured cryptographic algorithm. DES: Data Encryption Standard is a symmetric key algorithm. It was developed by the research team of IBM. Same keys are used for the purpose of encrypting as well as decrypting messages. Two techniques called diffusion and confusion are used in DES. There are sixteen rounds present in DES (ISLAM AZAD, 2014). The confusion technique uses XOR operation. The size of plain text is 64 bits. The key size used here is 56 bits. The Triple DES is more secure than DES as the message is first encrypted then it is decrypted and again it is encrypted (Barker Barker, 2012). AES: Advanced Encryption Standard was developed after DES and Triple DES. It has a simple design and low cost of memory as compared to DES. The speed of this algorithm is higher than the other algorithms (Karthik Muruganandam, 2014). Size of the plain as well as cipher text is same. It is a symmetric algorithm and uses identical keys for encrypting and decrypting messages unlike RSA. Encryption is done by substitution, shifting and mixing of bits. The message block size used in AES is 128 bits and there are three keys. AES is gives better performance as compared to DES. Security Challenges of WPAN Technologies Security Challenges of Bluetooth Technology: Bluetooth technology allows several wireless devices to connect over a short distance. The mobile phone users can turn on the Bluetooth options in their phones and pair with another device in order to share files and other documents. There are several security challenges that exist in this technology. Malicious codes enter the devices through a file and affect the system. Viruses can damage the system and misuse the valuable information present in the device. Bluesnarfing attack accesses personal photographs and details in an unauthorized manner (Minar Tarique, 2012). When the attacker is able to pair with other devices for the purpose of misusing data then it is called Bluejacking attack (Padgette, 2017). Backdoor hacking is a technique where the attacker accesses the data of a system secretly and the victim remains unaware of this unauthorized access. The private area network created by Bluetooth technology is prone to various security risks and attacks. Incorporating strong security policies will help to prevent such attacks. Security Challenges in ZigBee: ZigBee standard is used in private area networks or PAN. Remote controls, home automation and many other services like the retail services make use of ZigBee. The main security challenge in ZigBee is that the encryption key can get hacked. Sniffing attacks can take place where a monitor or device is able to capture the data exchanges that are taking place in the network (Zillner Strobl, 2015). There are several nodes in the network and one of the nodes can hide its identity for the purpose of attacking the encryption key and the data packets (Wang, Jiang Zhang, 2014). Injection attacks are also possible in ZigBee as the protocols present in ZigBee are not strong. This makes it vulnerable to different types of risks and threats. Critical Reflection on Energy Harvest Energy harvesting focuses on deriving or producing energy form external sources like kinetic energy, wind energy, thermal energy and solar energy. Hydro energy also plays a major role in harvesting energy. Energy can be conserved by this technique of energy harvesting. The wireless networks can store and use the derived energy. According to Ulukus et al. (2015), the nodes present in wireless networks should have the capability to harvest energy on its own. This will enable the nodes and the wireless devices of the network to gain and generate energy continuously. The concept of energy harvesting will benefit the people of future generation. The energy consumption level will fall by adopting this method. A balanced or controlled procedure can also be used for harvesting energy. This will involve the use of human made sources. The efficiency levels of the technologies used will vary. Technical concepts and methods can be applied for harvesting energy continuously. According to Ulukus et al. (2015), Gaussian noise and AWGN channel concept can be used for harvesting energy. The output of this process is the sum of noise and input. Ulukus et al. (2015) presented a concept where the main focus was in the integration of circuits and devices for energy harvesting and transferring purpose. According to Shaikh and Zeadally (2016), WSN technologies have limited energy. Energy efficient and high performance devices can be used for reducing or minimizing this problem. There are two main sources of energy like ambient sources and external sources. Shaikh and Zeadally (2016) said that the ambient sources are the cheapest source of energy. External sources can be explicitly used for the purpose of energy harvesting. Solar based technique can be used for the purpose of harvesting energy where the solar energy is utilized. RF based or radio frequency based techniques can also be used. Wind energy and hydro energy can be used for the purpose of generating electrical power or electricity. Electricity can be generated by using turbines. Falling water can be used for the purpose of harnessing energy. Shaikh and Zeadally (2016) also said that Seebeck effect can be can be applied for converting heat energy into electrical energy. Digital Cellular Handsets Slide note: The Telestra Company is engaged in providing wired telecommunication services across Australia. Their aim is to implement an advanced wireless field of system. Slide note: Cellular handset is a telecommunication device that takes the help of radio waves in order to transmit data wirelessly (Goggin, 2012) Cellular handset is accessible to all and therefore, it would be very beneficial to use it for accessing and displaying standard PC documents. References Barker, W. C., Barker, E. B. (2012). SP 800-67 Rev. 1. Recommendation for the Triple Data Encryption Algorithm (TDEA) Block Cipher. ISLAM, E., AZAD, S. (2014). data encryption standard.Practical Cryptography: Algorithms and Implementations Using C++, 57. Jonsson, J., Moriarty, K., Kaliski, B., Rusch, A. (2016). PKCS# 1: RSA Cryptography Specifications Version 2.2. Karthik, S., Muruganandam, A. (2014). Data Encryption and Decryption by using Triple DES and performance analysis of crypto system.International Journal of Scientific Engineering and Research, 24-31. Minar, N. B. N. I., Tarique, M. (2012). Bluetooth security threats and solutions: a survey.International Journal of Distributed and Parallel Systems,3(1), 127. Padgette, J. (2017). Guide to bluetooth security.NIST Special Publication,800, 121. Shaikh, F. K., Zeadally, S. (2016). Energy harvesting in wireless sensor networks: A comprehensive review.Renewable and Sustainable Energy Reviews,55, 1041-1054. Ulukus, S., Yener, A., Erkip, E., Simeone, O., Zorzi, M., Grover, P., Huang, K. (2015). Energy harvesting wireless communications: A review of recent advances.IEEE Journal on Selected Areas in Communications,33(3), 360-381.

Friday, November 29, 2019

Unless We Accept The Claim That Lenins Coup Detat Gave Birth Essays

"Unless we accept the claim that Lenin's coup d'etat gave birth to an entirely new state, and indeed to a new era in the history of mankind, we must recognize in today's Soviet Union the old empire of the Russians -- the only empire that survived into the mid 1980's" (Luttwak, 1). In their Communist Manifesto of 1848, Karl Marx and Friedrich Engels applied the term communism to a final stage of socialism in which all class differences would disappear and humankind would live in harmony. Marx and Engels claimed to have discovered a scientific approach to socialism based on the laws of history. They declared that the course of history was determined by the clash of opposing forces rooted in the economic system and the ownership of property. Just as the feudal system had given way to capitalism, so in time capitalism would give way to socialism. The class struggle of the future would be between the bourgeoisie, who were the capitalist employers, and the proletariat, who were the workers. The struggle would end, according to Marx, in the socialist revolution and the attainment of full communism (Groiler's Encyclopedia). Socialism, of which "Marxism-Leninism" is a takeoff, originated in the West. Designed in France and Germany, it was brought into Russia in the middle of the nineteenth century and promptly attracted support among the country's educated, public-minded elite, who at that time were called intelligentsia (Pipes, 21). After Revolution broke out over Europe in 1848 the modern working class appeared on the scene as a major historical force. However, Russia remained out of the changes that Europe was experiencing. As a socialist movement and inclination, the Russian Social-Democratic Party continued the traditions of all the Russian Revolutions of the past, with the goal of conquering political freedom (Daniels 7). As early as 1894, when he was twenty-four, Lenin had become a revolutionary agitator and a convinced Marxist. He exhibited his new faith and his polemical talents in a diatribe of that year against the peasant-oriented socialism of the Populists led by N.K. Mikhiaiovsky (Wren, 3). While Marxism had been winning adherents among the Russian revolutionary intelligentsia for more than a decade previously, a claimed Marxist party was bit organized until 1898. In that year a"congress" of nine men met at Minsk to proclaim the establishment of the Russian Social Democratic Worker's Party. The Manifesto issued in the name of the congress after the police broke it up was drawn up by the economist Peter Struve, a member of the moderate "legal Marxist" group who soon afterward left the Marxist movement altogether. The manifesto is indicative of the way Marxism was applied to Russian conditions, and of the special role for the proletariat (Pipes, 11). The first true congress of the Russian Social Democratic Workers' Party was the Second. It convened in Brussels in the summer of 1903, but was forced by the interference of the Belgian authorities to move to London, where the proceedings were concluded. The Second Congress was the occasion for bitter wrangling among the representatives of various Russian Marxist Factions, and ended in a deep split that was mainly caused by Lenin -- his personality, his drive for power in the movement, and his "hard" philosophy of the disciplined party organization. At the close of the congress Lenin commanded a temporary majority for his faction and seized upon the label "Bolshevik" (Russian for Majority), while his opponents who inclined to the "soft" or more democratic position became known as the "Mensheviks" or minority (Daniels, 19). Though born only in 1879, Trotsky had gained a leading place among the Russian Social-Democrats by the time of the Second party Congress in 1903. He represented ultra-radical sentiment that could not reconcile itself to Lenin's stress on the party organization. Trotsky stayed with the Menshevik faction until he joined Lenin in 1917. From that point on, he acomidated himself in large measure to Lenin's philosophy of party dictatorship, but his reservations came to the surface again in the years after his fall from power (Stoessinger, 13). In the months after the Second Congress of the Social Democratic Party Lenin lost his majority and began organizing a rebellious group of Bolsheviks. This was to be in opposition of the new majority of the congress, the Menshiviks, led by Trotsky. Twenty-two Bolsheviks, including Lenin, met in Geneva in August of 1904 to promote the idea of the highly disciplined party and to urge the reorganization of the whole Social-Democratic movement on Leninist lines (Stoessinger, 33). The differences between Lenin and the Bogdanov group of revolutionary romantics came to its peak in 1909. Lenin denounced the otzovists, also known

Monday, November 25, 2019

HD diagnosis and treatment essays

AD/HD diagnosis and treatment essays Attention DeficitHyperactivity Disorder Attention deficit/ hyperactivity disorder (AD/HD) is a diagnosis, which has increased dramatically over the last few years. This issue has both a medical and emotional side to it making discussion of the topic sometimes difficult. There are many children who seem to be uncontrollable both at home and in the classroom. This has teachers and parents clamoring to have these children placed on medication. There are many doctors who feel that this disorder is over diagnosed. They feel that children are being placed needlessly on mind-altering medication. There are many things that may mimic AD/HD. One of the most common is learning disabilities. This is one of the most important things to rule out when considering AD/HD. If a child has difficulty learning he is going to become bored, and is not going to be attentive or cooperative. However, having a learning disability does not mean that the child wouldnt also have AD/HD. It is estimated that up to 40 percent of children with AD/HD also have some other learning disability(Lerner 2). Formal testing for learning disabilities is crucial to make sure it is not playing at least some role if not the entire role in the childs apparent impassivity and inattention . Another thing that may mimic the symptoms of AD/HD is hearing or visual impairment. Anything that is hampering the childs ability to learn is going to result in decreased attention in the classroom. Significant hearing impairment may, unfortunately go unnoticed for years. Therefore, the usual hearing screen performed in the preschool years should be done. Vision problems also can go unnoticed so a vision screen should be done at the doctors office or at school. In 1917 and 1928 it was believed that brain damage was the cause of AD/HD. Terms like Minimal Brain Damage were used to describe children displaying a pattern of hype...

Friday, November 22, 2019

Work Psychology Essay Example | Topics and Well Written Essays - 1000 words

Work Psychology - Essay Example It may comprise of competences and qualifications that a person needs to perform a job. The personal specification and job description that the author refers in this case is that of appointing the European Social Fund Programme Coordinator. This is a particularly vital position in the company and management should be extremely keen during appointment. This is a critical task since it covers the central area of London and requires the person that the management appoints to carry out challenging programmes (Matthewman, Rose, and Hetherington, 2009). The person that the management appoints should have qualities such as the ability to convince, skill, and motivate individuals. They should have relevant qualifications and work experience in the field. This personal specification is sufficient since it provides all the details that match this job. It should incorporate meticulous details of the level of qualification and experience that is necessary. Importance of using job analysis Job an alysis is a valuable method that managers have employed to access information concerning this job of project coordinator. It is a process through which they acquire information concerning responsibilities, skills, and work environment of a job. It is a process that demands them to collect a lot of information to emerge with the right conclusion on the requirements. The process is extremely valuable in preparation of both job specification and description. It enables managers to hire the appropriate coordinator who will facilitate delivery of the European Social Fund programmes in the organization. This leads to proper utilization of the resources of and hence leading to success of the organization. Job analysis aids management to select the best candidate who will deliver the necessary information to young people (Arnold, 2005). This will ensure that the project achieves its target of reaching young people who have many issues that require support. Methods of using job analysis Job analysis is decidedly vital in an organization since it impacts directly on productivity of an organization. The human resource department should be thoroughly keen when deciding the method that an organization should adopt for job analysis. There are various ways of conducting job analysis that managers can adopt. These include conducting interviews, questionnaires, incident investigations, gathering background information, and observation (Matthewman, Rose, and Hetherington, 2009). These methods provide reliable information concerning job description and various specifications for the available job opportunities. The human resources professionals should adopt several of these methods to enhance credibility of the information. The most appropriate method for this job is conducting interviews. This is an ideal method because a panel of interviewers examines the candidates physically. This enables them to acquire all the relevant qualities that they need for the job opportunities ava ilable (Nankervis, Compton, and Morrissey, 2009). Methods of Personnel Selection This is the process that organizations adopt to promote or hire individuals. It mainly focuses on selection of appropriate workers in an organization. The most reliable methods of Personnel Selection that the Organizations should adopt include work sample tests, situational and competency based structural interviews, and cognitive ability. They are the one that are available in this case where selection of a program coordinator is the key issue. These methods are the best since they provide a high level of validity (Nankervis, Compton, and Morrissey, 2009). The management adopts appropriate means of appointing the Program

Wednesday, November 20, 2019

UK Tax System Assignment Example | Topics and Well Written Essays - 3250 words

UK Tax System - Assignment Example Profit margins are small: Higher expenditure and lower selling prices will lead to a lesser bottom-line and so lower dividend payments. This problem can be overcome by working efficiently and effectively to generate high sales and stand up competitively by not lowering the prices of goods. Late payments from customers will seriously influence the cash flow: In this case, credit terms should be discussed beforehand with customers and be kept strict so as to make inflows earliest. Key supplier (s) will gradually be dissatisfied: If payment problems to suppliers arise due to the expansion or new orders being taken, suppliers will be alarmed and dissatisfied with the company. To cure this problem, the company should beforehand discuss the situation with the suppliers and the credit terms should be precisely conveyed so as to prevent future problems. (b) There are a number of short-term finances available to the company to finance its proposed expansion; two of them are discussed as follo ws: Bank Loan, and Bank Overdraft Bank Loan: In the case of this company, bank loan pertains to the short-term period usually equal to or less than a year. The bank according to the credit rating lends the company a certain amount of loan needed and on an interest rate negotiated. Strengths: Amount will be received on one-time basis and the payment will be done in monthly, quarterly or semi annually installments Cost of borrowing is lower than other means such as Bank Overdraft Interest rates are low Reliability and security is always there in terms of getting the money from the bank on time and for a certain period of time contracted upon with the bank Weaknesses: The loan will be secured against the company’s assets The riskier the business is, the higher the interest rate the bank will charge to cover up its risk Arrangement fees, as well as repayment fees, will have to be paid In case of early repayment of loan, an extra charge will have to be paid Bank Overdraft: It is a kind of loan arrangement under which a bank extends credit allotted to a company up to a maximum amount called the overdraft limit against which a customer or company who has current or checking account with the bank can write checks or make withdrawals (Business Dictionary 2011). Strengths: Appropriate for short-term financing Not secured against any asset of the company so the process of obtaining the loan Is expedited Only charged for the amount overdrawn from the bank account and also pertaining only to the period of time the overdraft facility had been used by the company Weaknesses: The bank overdraft amount has to be paid on demand of the bank. This puts the company at a great risk in the case when the bank decides to request the money back at an inconvenient time for the business High-interest rate is charged (c) Capital Gearing Ratio This ratio tells us that how much risk the company is in terms of financial risk and it is used by companies as well as its shareholders to a nalyze the company’s capital structure and leverage (Accounting for Management 2011).

Monday, November 18, 2019

How Police Conduct Themselves in the Public Eye Essay

How Police Conduct Themselves in the Public Eye - Essay Example The concept of â€Å"effectiveness† plays a key role in the analysis offered by Skogan and Frydl (2004), who likewise take a historical approach to evaluating the success of various police reform efforts. As Kelling and Moore (1988) write, â€Å"interpretation is necessary† (p. 1). In other words, a historical approach is defined by interpretations of the facts that emerge from certain cases. Although an interpretative approach is empirically weak, such an approach provides both a descriptive and evaluative view of what problems exist and how the public should fix them. Police have evolved a secondary function in America to serve as a symbol of authority, which they have with the implicit power to deprive individual citizens of their liberty. A normal person knows that if he commits a crime in front of a police officer, that police officer has the authority to take action to lock him in jail or to give him a fine. Even in the threat of depriving people of liberty withou t actually expressing that power, police have a definite authority (Skogan & Frydl, 2004, p. 65). This authority comes from their symbolic place as a representative of authority, which members of the public automatically respond to. ... In the last 50 years in American policing, some of these conflicts have been exacerbated by nationwide media coverage. One of the most remembered incidents involved the beating of Rodney King at the hands of the Los Angeles Police Department. In 1991, an African-American was assaulted by four white police officers. These police officers were later acquitted in 1992, which precipitated the 1992 riots that reflected deep racial mistrust between urban populations and the police in charge of maintaining social order. Of course, the interaction between police and civil rights was nothing new, following major riots in 1964 and 1968. However, Rodney King did represent an opportunity for a more contemporary analysis of how police interact with the public as symbols of authority. In that case, police interacted with the public as authority figures, but the authority figures served no other purpose but to detract from due process and fairness. To some degree, this may have been due to the emer ging category of services that police provide: preventing crime (Skogan & Frydl, 2004, p. 72). By employing nearly deadly force on a suspect, the police seem to be sending a message to the public they deal with; however, in the Rodney King case, the message was extended to the wrong audience. Another new direction in American law enforcement is the widespread use of Taser technology by police officers. Taser technology is a supposedly non-lethal alternative to firearms that subdues suspects before they can pose a bodily threat. A study in 2008 revealed that approximately 90 percent of Taser discharges by police were done in response to unarmed or non-threatening suspects (The Washington Post, 2010). This problem with Tasers reflects a more fundamental problem

Saturday, November 16, 2019

Effect of CR Supplementation on Athletic Performance

Effect of CR Supplementation on Athletic Performance Introduction To succeed in a given sport at any level of competition, athletes must possess specific physiologic, psychologic, and biomechanic traits critical to success in that sport, but they must also receive optimal physical, mental, and biomechanical training to maximise this genetic potential (Williams, Kreider Branch, 1999). However many athletes believe that the combination of genetic traits and optimal training alone are not sufficient to achieve maximum performance, therefore the use of ergogenic aids has become common to improve sports performance beyond the effect of training (Sundgot-Borgen, Berglund Torstveit, 2003). The use of ergogenic aids will allow athletes to gain that competitive advantage over opponents therefore leading to potential success. According to Williams, Kreider Branch, (1999) ergogenic aids are substances or treatments that are theoretically designed to enhance physical power, mental strength or mechanical edge therefore potentially improving athletic performa nce. Given the various demands of team sports such as Soccer, Rugby and Hockey, which require short intermittent bouts of high intensity exercise which are interspersed by low level exercise, it seems feasible the use of ergogenic aids in such sports may enhance and benefit performance to gain that competitive edge over opponents. One ergogenic aid which has become popular among amateur, professional and recreational athletes over recent years is Creatine Monohydrate (Cr). Creatine is a naturally occurring amino acid derivative which is found in skeletal muscle, but is also a normal dietary constituent with a daily requirement of approximately 2 to 3 grams depending on body size (Ostojic, 2001). The majority of creatine in muscles is stored in the form of phosphocreatine (PCr) which serves as an important contributor to energy metabolism during high intensity exercise (Williams, Kreider Branch, 1999). PCr provides the high energy phosphate for adenine diphosphate (ADP) to restore adenine triphosphate (ATP) concentration rapidly via the Cr kinase (CK) reaction (Clarkson, 1996). Hultman, Bergstrom and McLennan-Anderson, (1967) demonstrated that depletion of PCr stores within the muscles can lead to a decline in athletic performance during high intensity exercise, so theoretically increasing PCr stores through Cr supplementation would enhance the ability to maintain high intensity exercise over a prolonged period of time, leading to increases in sporting performance. Ahmun (2005) and Hultman, Soderlund, Timmons, Cederblad, Greenhaff, (1996) demonstrated that the average Cr concentration in human muscle can be increased through Cr supplementation over a 7 day period from 20% pre Cr to 50% post Cr. Since PCr is a substrate for the ATP-PCr energy system which is essential for high intensity exercise of 30 seconds or less it seems logical that the supplementation of Cr would be beneficial to exercise tasks of this duration. Therefore the majority of previous research has focused on bouts of anaerobic performance of To date the effect of Cr supplementation on athletic performance has been widely researched. This includes include positive effects of Cr supplementation over a prolonged period of over 4 weeks which is otherwise known as the maintenance phase (Knehans, Bemben, Bemben and Loftiss, 1998; Larson, Hunter, Trowbridge, Turk, Harbin and Torman, 1998). Also demonstrated have been positive effects of Cr supplementation on exercise performance using a shorter ingestion period known as the loading phase (Stout, Echerson, Noonan, Moore, and Cullen, 1999; Volek, Boetes, Bush, Putukian, Sebastianelli and Kraemer, 1997a). This includes improvements in performance variables such as strength, speed and delaying the onset of fatigue (Okudan and Gokbel, 2004; Volek, Kraemer, Bush, Boetes, Incledon, Clark and Lynch 1997b; Kocak Karli , 2003) Team sports consist of repeated bouts of intermittent high intensity exercise therefore consistently relying on the ATP-PCr energy system which if depleted can have a major factor on performance and the outcome of a game (Ostojic, 2004). One such sport which consists of repeated bouts of high intensity exercise is soccer. Soccer players are required to produce high power outputs and maintain or repeat them with only a few seconds of recovery, (Reilly and Williams, 2003). Such high intensity instances could be the deciding factor of a game, for example sprinting back to make a game saving tackle or sprinting past a defender to the ball to make a shot. One high intensity exercise instance which occurs in a soccer match are bouts of sprinting, which are estimated to consist of 8.1% of a 90 minute match and occur approximately every 90 seconds lasting between two to four seconds in duration (Bangsbo, Norregard Thorso, 1991). Given the fact that there is considerable support for Cr as an ergogenic aid it would be reasonable to suggest that a soccer players sprint performance would benefit from Cr supplementation. However there is minimal research which has looked into the effects of Cr on sprint performance and variables of soccer match play such as agility running, lateral stepping and running backwards( Cox, Mujika, Tumilty and Burke 2002; Ostojic, 2004; Mujika, Padilla, Ibanez, Izquierdo and Gorostiaga, 2000). The aforementioned studies have determined the effects of Cr on elite soccer players, female soccer players and youth soccer players (Ostojic, 2004; Mujika et al., 2000; Smart et al 1998; Cox et al., 2002). However there is no present research that looks into the effects of acute ( Another aspect to consider upon testing the effects of Cr on sprint performance on amateur soccer players is the protocol to be used. Although there have been many protocols which have been designed to measure and simulate soccer performance, plenty of these have failed to adequately simulate the different movement patterns (sprinting, walking, running backwards, lateral stepping) which are involved in a game of soccer (Drust, Reilly and Cable, 2000; Abt, Reaburn, Holmes and Gear, 2003; Thatcher and Batterham, 2004). It seems rational that when assessing components of soccer performance that the protocol that is utilised replicates the different activity patterns and demands of soccer match. If this is not taken into consideration it becomes difficult to determine whether Cr supplementation will have any benefit on soccer performance. Therefore the utilised protocol needs to concisely replicate movement patterns in soccer so that a valid assumption can be made to determine the erogen eity of acute Cr supplementation on sprint performance in amateur soccer players. Thus the purpose of this study is to conduct an investigation that will determine the effect of acute Cr supplementation on sprint performance in Caucasian male amateur soccer players, using a soccer simulation protocol in an accurate, valid and reliable manner with two trials consisting over a 7 day period. Concluding whether or not acute Cr supplementation can be used as an ergogenic aid to improve a footballers sprint performance, therefore recommending to athletes and coaches alike. Literature Review Creatine Monohydrate: Background Creatine monohydrate is one of the most popular sporting supplements in the world today and is used by high school athletes, the elderly, professional and recreational athletes in the hope of improving physical performance (Bemben and Lamont, 2005). It is the most commonly available Cr supplement and the form primarily used in most research studies. Cr monohydrate comes in a number of forms including powder, tablets, gel, liquid, chewing gum and candy (Williams, Kreider and Branch, 1999, p.43). Greenhaff (1997) indicated powdered Cr, ingested with solution to have a quicker absorption rate at raising muscle Cr concentration than using Cr supplementation of a tablet form. Conversely Vuckovich and Michaelis (1999) reported no significant difference in absorption rate between the two different forms. Dosage methods The supplementation dosages of Cr can be broken down into two different phases, otherwise known as the loading phase and maintenance phase. The loading phase that is commonly used in research consists of ingesting daily, 20-30g of Cr in four equal doses of 5-7g dissolved in around 250ml of fluid interspersed throughout the course of the day (preferably morning, noon, afternoon and evening) for a period of 5 to 7 days (Greenhaff, 1997; Kreider, 1997). Hultman et al (1996) utilised a less intense loading method of 3g/day for 28 days and proposed it to be just as effective as the aforementioned loading protocol. However this method places a longer dependency on subjects to comply with the supplementation program, therefore placing more variables into the reliability of results. Following the loading phase, maintenance dosages are considerably lower. Most research investigating the effects of Cr using the maintenance phase, have utilised dosages of 3 to 15g over a 4 to 10 week period (Bemben et al., 2001; Kreider et al., 1998; Stone et al., 1999; Vandenberghe et al., 1997). It is recommended to consume Cr with warm water, as it facilitates the dissolving of the solution and also aid absorption (Harris et al., 1992). It should also be noted that the ingestion of caffeine during Cr supplementation eradicates its potential ergogenic effect (Vandenberghe et al., 1996; Van Leemputte, Vanstapel Hespel, 1997). Vandenberghe et al (1996) demonstrated that a control group that ingested Cr combined with caffeine to have a lessened ergogenic potential compared to a group that ingested Cr without caffein e during repeated bouts of high intensity exercise. Side effects There is no conclusive scientific evidence to suggest that Cr ingestion has any negative side effects utilising the proposed dosage methods ( Larson et al., 1998; Schroder, Terrados Tramullas, 2005). There is further evidence to support this as Kreider et al (1999) found no negative side effects in athletes who had been ingesting Cr for up to 3 years. Poortmans and Francaux (1999) demonstrated similar findings for athletes for taking Cr for up to 5 years. Only undocumented anecdotal reports have reported any adverse negative side effects through Cr supplementation, this includes gastrointestinal distress, muscle cramping and dehydration (Associated press 1997, 1998). Taking dehydration into consideration such anecdotal research can be scrutinised. Oopik, Timpmann and Medijainen, (1995) demonstrated that Cr supplementation increased body mass, while also reporting increases in total body water. Such findings signify that Cr supplementation may prevent dehydration rather than be a cause, due to the fact it can promote water retention. Cr supplementation has been demonstrated to increase body mass by up to 2kg over an acute period of time (Balsom et al., 1995; Becque et al., 1997). This could be recognised as a negative side effect for athletes that compete in weight control sports, as Cr ingestion may impede their ability to make regulated weight in a forthcoming event. This gives a consensus that athletes in such activities need to be made aware that although Cr can promote gains in strength and power, it can increase body mass. Physiology of Soccer Soccer players are frequently required to produce high power outputs and maintain of repeat them with only a few seconds of recovery (Reilly and Thomas, 2003). This includes intermittent bouts of kicking, tackling, turning, sprinting, changing pace and maintaining balance and control of the ball whilst under pressure from an opponent (Wisloff, Helgerud Hoff, 1998). To gain a scientific perspective of the different physiological demands of soccer performance, match and time motion analysis have been utilised (Bangsbo, 1994). This analysis has allowed researchers to determine the overall workload of players during a 90 minute match by calculating total distance covered, and the pattern of activities performed during a game (e.g. sprinting, cruising, walking etc). Movement patterns of Soccer It is estimated that the total distance covered during a 90 minute soccer match varies from 8.7km to 11.5km ( Bangsbo Lindquist, 1992; Ekblom, 1986; Ohashi et al., (1988); Reilly and Thomas, 1976; 1988; Rampini et al., 2007; Wade, 1962). The large variance in distances covered are due in part to the differing styles of play, levels of competition and skill level of the teams that were utilised (Luxbacher, 1997). Reilly (1994) documented the different activity patterns of elite outfield players from the English top division and other major national leagues in Europe and Japan using different methods of match analysis. Results found that a 90 minute match consists of 24% walking, 36% jogging, 20% cruising sub maximally (striding), 11% sprinting, 7% moving backwards and 2% moving in possession of the ball. The categories of sprinting and cruising are defined as high intensity exercise. In terms of distances covered the ratio of low intensity exercise to high intensity exercise during a soccer match is 7 to 1 denoting that the outlay of energy for soccer is predominately aerobic ( Reilly and Thomas, 1976). However the importance for high intensity bouts during soccer match play should not be underestimated. The timing of such a bout could be the defining factor of a game whether in possession of the ball or without the ball. Although work-rate profiles are relatively consistent for players from game to game it is the high intensity exercise which is the most constant feature (Bangsbo, 1994). The number of sprints reported in a soccer game varies greatly from 17 to 62 (Bangsbo et al., 1991; Mohr, Krustrup Bangsbo, 2003). This variance is largely determined by the positional role of the player. Findings by Reilly (1996) demonstrated that midfielders and strikers completed more sprinting bouts than centre backs or full backs therefore relying more on the anaerobic energy system. However if there is not a prolonged recovery period or an individual is not properly conditioned they will not subsequently recovery from high intensity bouts of exercise and fatigue will occur (Reilly, 1996). This is evident as Reilly (1996, p.72) documented that the majority of goals conceded during a soccer match occurred in the final ten minutes of play. A popular theory for this occurrence has been found to be mental fatigue or lapses in concentration from defenders (Reilly, 1996, p.72). However this can theory can be scrutinised as research found that the onset of fatigue in intermittent exercise such as soccer is caused by low muscle glycogen stores (Balsom et al., 1999). Acute Cr supplementation and sprint performance in team sports Athletes in team sports such as soccer, rugby, hockey and American football are required to repeatedly reproduce intermittent bouts of high intensity exercise with minimal recovery. Being able to consistently reproduce such bouts at maximal ability (e.g. sprinting, jumping, running backwards) could be the deciding factor in competition to gain that extra edge of an opponent. During high intensity exercise of an intermittent nature the main contributor of energy is PCr (Williams, Kreider Branch, 1999, p29). Depletion of PCr stores during high intensity exercise has been found to be a factor which has lead to a decline in athletic performance (Hultman, Bergstrom and McLennan-Anderson, 1967). Through the supplementation of Cr, it hypothesised that PCr stores are replenished at a faster rate therefore improving an athletes ability to recover and perform intermittent high intensity bouts of exercise, leading to improved athletic performance (Greenhaff et al, 1993). There have been various studies that have tested this hypothesis by investigating the ergogenic effect of acute Cr supplementation on sprint performance of athletes in team sports (Ahmun et al., 2005; Cornish, Chilibeck Burke, 2006; Izquierdo et al., 2001; Kocak Karli, 2003; Romer et al., 2001; Vandebuerie et al., 1998). However the aforementioned studies have contrasting findings with a quantity of studies finding a significant improvement in sprint performance through Cr supplementation (Izquierdo et al., 2001; Romer et al., 2001; Vandebuerie et al., 1998). On the contrary other studies have found no significant improvements in sprint performance through acute Cr ingestion (Ahmun et al., 2005; Cornish, Chilibeck Burke, 2006; Kocak Karli, 2003). Ahmun et al., (2005) investigated the ergogenic effect of Cr on sprint performance in male rugby players. For this study a Wingate test protocol was utilised prior and post Cr supplementation. Findings of this study were that there was no significant improvement in maximal cycle sprints through Cr ingestion. However in contrast Izquierdo et al., (2001) found that acute Cr supplementation improved sprint times in male hand ball players. For this study subjects were either assigned Cr or placebo over a 5 day period. The protocol that was utilised consisted of repeated sprint runs that were consistent with sprint distances achieved during handball match play. One issue that could have had a determining factor of the non significant results found by Ahmun et al (2005) is the protocol that was utilised. A Wingate test was utilised to test the sprint performance in rugby players, however the relevance of a Wingate test to measure rugby performance is not sports specific there scrutinising the validity of the results. In contrast Izquierdo et al (2001) utilised a protocol which successfully replicated distances found in handball match play therefore maintaining validity. Ahmun et al (2005) also failed to incorporate a dietary analysis into the experimental design of the protocol, therefore whether or not Cr stores within the subjects utilised were full cannot be determined, which gives rationale for results showing no significant improvement. In contrast Izquierdo et al (2001) implemented a dietary examination of subjects that were utilised; this was initiated to determine whether any subjects had ingested Cr or any ergogenic aids prior to baseline testing. This assisted with maintaining validity during research. This can be supported by Romer et al (2001) and Vandebuerie et al (1998) who utilised a protocol containing a dietary analysis and concluded a significant improvement in sprint times within subjects. Cr supplementation and Soccer performance Given the intermittent physical demands of soccer, which requires players to produce high power outputs and maintain or repeat them with only a few seconds of recovery, (Reilly and Williams, 2003) it seems feasible that soccer players would benefit from the supplementation of Cr as an ergogenic aid to improve their overall performance. However research that has investigated the effect on acute Cr supplementation on different variables of soccer performance and predominately sprint performance utilising a soccer simulation protocol is limited (Ostojic, 2004; Mujika et al 2000; Cox et al 2002). The Aforementioned studies have primarily focused on the effects of Cr supplementation on highly trained athletes that are competing at a high standard of competition. However no previous research has looked into the effects of acute Cr supplementation on amateur soccer players. Being as though Cr monohydrate is an immensely popular ergogenic aid not only among professional athletes but also amateur and recreational athletes, the benefit to amateur athletes needs to recognised. Previous research that has looked into the effects of acute Cr supplementation on soccer players using a soccer simulation protocol is discussed below. Ostojic (2004) examined the effects of acute Cr supplementation (3 x 10g doses for 7 days) on 20 young male soccer players (16.6 Â ± 1.9 years). For the testing procedure a double blind method was used and where subjects were either administered either Cr or placebo. Subjects completed two separate trials prior and post to Cr or placebo. The testing procedure consisted of a number of soccer specific skill tests which included a dribble test, sprint-power test, endurance test and a vertical jump test. Results found that there was a significant improvement in a number of the soccer specific tests; this includes superior improvements in sprint times, vertical jump scores and the dribble test. However no significant improvements were made on endurance performance after the two trials. Although a significant improvement was found in vertical jump performance, it is of concern to future researchers to whether the vertical jump test that was utilised during the design is a soccer specific test. During the test subjects were instructed to keep their trunk as straight as possible whilst keeping their hands on their hips to avoid contribution from the arms which doesnt successfully replicate jumping movements in soccer therefore questioning the validity of the vertical jump test as to whether or not it is a measure of soccer specific performance. The age of the subjects in this research can also be scrutinised. Eichner, King, Myhal, Prentice and Ziegenfuss (1999) confirmed that there was insufficient research to determine the acute and chronic side effects of Cr consumption in athletes under the age of 18 therefore places the subjects which were used in the mentioned study under possible risk. Eichner et al (1999) also highlighted that Cr supplementation in young athletes could have a possible degradation of ethics, by where a win at all costs mentality is fostered and an attitude by where ergogenic aids are necessary to win, which is the wrong message to be installing in young athletes. Likewise Mujika, Padilla, Ibanez, Izquerido and Gorostiaga (2000) concluded acute Cr supplementation (20g a day x 6 days) significantly improved sprint performance and found no significant improvement in endurance performance using a soccer simulation protocol. Mujika et al (2000) also documented no increase in vertical jump performance using a similar protocol to Ostojic (2004) which has minimal significance in a soccer simulation study. Mujika et al (2000) tested 19 elite male soccer players who at the time of investigation were highly trained, however only 17 fully completed the testing due to illness or injury. The protocol for this investigation consisted of a circuit of different exercises which consisted of a repeated sprint test (5 and 15m), vertical jump test and an intermittent endurance test. Findings in this study concluded that mean sprint times improved significantly (p This de-training effect is evident for the vertical jump test as no significant improvement between the two trials was found. However if there was a significant de training effect it would have had negative consequences on other testing variables such as sprint performance, this however is not the case as sprint performance significantly improved. Mujika et al (2000) should have took into consideration a possible detraining effect when devising the experimental design as this could have negatively affect the validity of the results. Cox, Mujika, Tumilty and Burke (2002) devised a study which tested Cr supplementation (20g a day) or placebo (20g glucose a day) on 14 elite female soccer players from the Australian institute of sport (AIS) using a soccer simulated protocol. The experimental design consisted of two trials before and after Cr or placebo over a 6 day period. The protocol consisted of fifty five 20m sprints, ten agility runs and a precision ball kicking drill which are separated by recovery walks, jogs and runs. The main findings in this study were that the average 20m sprint time in the Cr group decreased from 3.75 Â ± 0.19 to 3.69 Â ± 0.18s however this decrease in sprint time failed to reach the statistical significance level (p Cox et al (2002) also incorporated a standardised training regime and a controlled diet for the intervention week and also scheduled testing so that it would occur at the same time of day before and after supplementation. In contrast Mujika et al (2000) failed to utilise effective standardised procedures during their experimental design. As previously mentioned Mujika et al (2000) testing procedures took place 3 days after the subjects season had finished therefore training was not standardised due to the fact that subjects had no organised training sessions during the intervention week. Mujika et al (2000) also lacked a familiarisation trial, subjects were only familiarised with the testing procedures prior to arriving for the 1st trial which could substantially affect the results. However although Cox et al (2000) standardised procedures by included a controlled diet for the subjects, it is interesting to note that one of the subjects was a vegetarian, whos Cr content is virtually zero (Greenhaff, 1997). Research has found that vegetarians respond quicker and more effectively to Cr supplementation than those who follow a normal sedentary diet and have natural muscle creatine content (Burke, Chilibeck, Parise, Candow, Mahoney Tamopolsky., 2003; Watt, Garnham Snow, 2004) therefore scrutinising the validity of the results. It may be of future reference to eradicate vegetarians in a experimental design which utilises Cr supplementation due to the diet implications that vegetarians have. Soccer Simulation performance tests To date there has been a number of soccer simulation performance tests which have been utilised to assess and measure different physiological aspects of the game (Bangsbo and Lindquist, 1992; Cox, 2002; Drust, Reilly and Cable, 2000; Nicholas, Nuttall and Williams, 2000). These protocols have been implemented so that they take into consideration different aspects of soccer performance and try to replicate the exercise patterns that are observed during match play, however due to the spontaneity of the soccer it is difficult to assess every physical or metabolic demand (Drust, Reilly and Cable, 2000). Researchers have used different protocols when investigating the metabolic and physical demands of soccer, these can documented into laboratory based protocols (Drust, Reilly and Cable, 2000; Thatcher and Batterham, 2004) and field based protocols (Bangsbo and Lindquist, 1992; Cox, 2002; Nicholas et al 2000). Laboratory based soccer performance protocols Drust, Reilly and Cable (2000) devised a laboratory based protocol on a motorised treadmill what represented the work rates that are observed during soccer match play. For the experimental design 7 male university soccer players (24 Â ± 2 years) were used and the testing consisted of three separate testing blocks which were separated by 6 days. The protocol consisted of the different exercise intensities that are utilised during soccer match play; this consisted of walking, jogging, cruising and sprinting. The speeds at which these exercises were performed on the treadmill were consistent with speeds observed by Van Gool, Van Gervan and Boutmans (1988) during a match analysis. Each testing block consisted of two 22.5 minute cycles which consisted of 23 bouts which were followed by a recovery period of 71 seconds. During each bout the duration of each activity was as follows: walking 35 seconds (s), jogging 50.3s, cruising 51.4s and sprinting 10.5s. However in relevance to this research project it should be noted that the duration covered during the sprint bouts of the protocol of Drust, Reilly and Cable (2000) which is 10.5s does not successfully coincide with match analysis from several soccer studies that have documented the duration of sprint bouts during soccer match play. Research has found that the average sprint time during soccer match play lasts between on average two to four seconds in duration (Bangsbo, Norregard Thorso,1991; Mayhew and Wenger, 1985) therefore concluding in some instances Drust, Reilly and Cables (2000) laboratory based soccer specific protocol can be deemed as in valid as it fails to accurately replicate different soccer performance variables that take place in match play. Another lab based test that was utilised to measure specific variables in soccer performance was devised by Thatcher and Batterham (2004). For this protocol six male professional soccer players were used and the testing consisted of 29 minute exercise bouts on a non motorised treadmill that focused on replicating different speeds, durations, distances and heart rates that occur during soccer match play. Findings from this study suggest that the protocol that was utilised induced a similar physiological load to soccer match play and can be determined as a valid measure of soccer performance. Although lab based soccer specific protocols have been found to replicate some instances of soccer performance it is of consideration of this research project that the limitations and positives of such protocols be noted. The aforementioned lab based failed to perform a re-test procedure to conclude whether their protocols maintained reliability therefore the amount of error in each protocol cannot be determined. Another limitation of lab based testing is that due to tests being performed on treadmills, this limits the subjects to straight-line running only, therefore does not take into consideration lateral movements and agility patterns, which have found to be major characteristics of soccer performance (Bangsbo and Lindquist, 1992). These unorthodox movement patterns need to be taken into consideration when assessing soccer performance as they increase energy expenditure significantly (Nicholas et al., 2000). One positive aspect of lab based protocols are that procedures such as a ir temperature, equipment utilised and humidity can be easily standardised to remain constant throughout performance testing. Field Tests Nicholas et al (2000) devised the Loughborough Intermittent Shuttle test (LIST) to simulate the activity patterns during a game of soccer. The LIST consisted of two separate stages which were known as part A and part B. Part A lasted 70 minutes and consisted of five 15 minute exercise pe Effect of CR Supplementation on Athletic Performance Effect of CR Supplementation on Athletic Performance Introduction To succeed in a given sport at any level of competition, athletes must possess specific physiologic, psychologic, and biomechanic traits critical to success in that sport, but they must also receive optimal physical, mental, and biomechanical training to maximise this genetic potential (Williams, Kreider Branch, 1999). However many athletes believe that the combination of genetic traits and optimal training alone are not sufficient to achieve maximum performance, therefore the use of ergogenic aids has become common to improve sports performance beyond the effect of training (Sundgot-Borgen, Berglund Torstveit, 2003). The use of ergogenic aids will allow athletes to gain that competitive advantage over opponents therefore leading to potential success. According to Williams, Kreider Branch, (1999) ergogenic aids are substances or treatments that are theoretically designed to enhance physical power, mental strength or mechanical edge therefore potentially improving athletic performa nce. Given the various demands of team sports such as Soccer, Rugby and Hockey, which require short intermittent bouts of high intensity exercise which are interspersed by low level exercise, it seems feasible the use of ergogenic aids in such sports may enhance and benefit performance to gain that competitive edge over opponents. One ergogenic aid which has become popular among amateur, professional and recreational athletes over recent years is Creatine Monohydrate (Cr). Creatine is a naturally occurring amino acid derivative which is found in skeletal muscle, but is also a normal dietary constituent with a daily requirement of approximately 2 to 3 grams depending on body size (Ostojic, 2001). The majority of creatine in muscles is stored in the form of phosphocreatine (PCr) which serves as an important contributor to energy metabolism during high intensity exercise (Williams, Kreider Branch, 1999). PCr provides the high energy phosphate for adenine diphosphate (ADP) to restore adenine triphosphate (ATP) concentration rapidly via the Cr kinase (CK) reaction (Clarkson, 1996). Hultman, Bergstrom and McLennan-Anderson, (1967) demonstrated that depletion of PCr stores within the muscles can lead to a decline in athletic performance during high intensity exercise, so theoretically increasing PCr stores through Cr supplementation would enhance the ability to maintain high intensity exercise over a prolonged period of time, leading to increases in sporting performance. Ahmun (2005) and Hultman, Soderlund, Timmons, Cederblad, Greenhaff, (1996) demonstrated that the average Cr concentration in human muscle can be increased through Cr supplementation over a 7 day period from 20% pre Cr to 50% post Cr. Since PCr is a substrate for the ATP-PCr energy system which is essential for high intensity exercise of 30 seconds or less it seems logical that the supplementation of Cr would be beneficial to exercise tasks of this duration. Therefore the majority of previous research has focused on bouts of anaerobic performance of To date the effect of Cr supplementation on athletic performance has been widely researched. This includes include positive effects of Cr supplementation over a prolonged period of over 4 weeks which is otherwise known as the maintenance phase (Knehans, Bemben, Bemben and Loftiss, 1998; Larson, Hunter, Trowbridge, Turk, Harbin and Torman, 1998). Also demonstrated have been positive effects of Cr supplementation on exercise performance using a shorter ingestion period known as the loading phase (Stout, Echerson, Noonan, Moore, and Cullen, 1999; Volek, Boetes, Bush, Putukian, Sebastianelli and Kraemer, 1997a). This includes improvements in performance variables such as strength, speed and delaying the onset of fatigue (Okudan and Gokbel, 2004; Volek, Kraemer, Bush, Boetes, Incledon, Clark and Lynch 1997b; Kocak Karli , 2003) Team sports consist of repeated bouts of intermittent high intensity exercise therefore consistently relying on the ATP-PCr energy system which if depleted can have a major factor on performance and the outcome of a game (Ostojic, 2004). One such sport which consists of repeated bouts of high intensity exercise is soccer. Soccer players are required to produce high power outputs and maintain or repeat them with only a few seconds of recovery, (Reilly and Williams, 2003). Such high intensity instances could be the deciding factor of a game, for example sprinting back to make a game saving tackle or sprinting past a defender to the ball to make a shot. One high intensity exercise instance which occurs in a soccer match are bouts of sprinting, which are estimated to consist of 8.1% of a 90 minute match and occur approximately every 90 seconds lasting between two to four seconds in duration (Bangsbo, Norregard Thorso, 1991). Given the fact that there is considerable support for Cr as an ergogenic aid it would be reasonable to suggest that a soccer players sprint performance would benefit from Cr supplementation. However there is minimal research which has looked into the effects of Cr on sprint performance and variables of soccer match play such as agility running, lateral stepping and running backwards( Cox, Mujika, Tumilty and Burke 2002; Ostojic, 2004; Mujika, Padilla, Ibanez, Izquierdo and Gorostiaga, 2000). The aforementioned studies have determined the effects of Cr on elite soccer players, female soccer players and youth soccer players (Ostojic, 2004; Mujika et al., 2000; Smart et al 1998; Cox et al., 2002). However there is no present research that looks into the effects of acute ( Another aspect to consider upon testing the effects of Cr on sprint performance on amateur soccer players is the protocol to be used. Although there have been many protocols which have been designed to measure and simulate soccer performance, plenty of these have failed to adequately simulate the different movement patterns (sprinting, walking, running backwards, lateral stepping) which are involved in a game of soccer (Drust, Reilly and Cable, 2000; Abt, Reaburn, Holmes and Gear, 2003; Thatcher and Batterham, 2004). It seems rational that when assessing components of soccer performance that the protocol that is utilised replicates the different activity patterns and demands of soccer match. If this is not taken into consideration it becomes difficult to determine whether Cr supplementation will have any benefit on soccer performance. Therefore the utilised protocol needs to concisely replicate movement patterns in soccer so that a valid assumption can be made to determine the erogen eity of acute Cr supplementation on sprint performance in amateur soccer players. Thus the purpose of this study is to conduct an investigation that will determine the effect of acute Cr supplementation on sprint performance in Caucasian male amateur soccer players, using a soccer simulation protocol in an accurate, valid and reliable manner with two trials consisting over a 7 day period. Concluding whether or not acute Cr supplementation can be used as an ergogenic aid to improve a footballers sprint performance, therefore recommending to athletes and coaches alike. Literature Review Creatine Monohydrate: Background Creatine monohydrate is one of the most popular sporting supplements in the world today and is used by high school athletes, the elderly, professional and recreational athletes in the hope of improving physical performance (Bemben and Lamont, 2005). It is the most commonly available Cr supplement and the form primarily used in most research studies. Cr monohydrate comes in a number of forms including powder, tablets, gel, liquid, chewing gum and candy (Williams, Kreider and Branch, 1999, p.43). Greenhaff (1997) indicated powdered Cr, ingested with solution to have a quicker absorption rate at raising muscle Cr concentration than using Cr supplementation of a tablet form. Conversely Vuckovich and Michaelis (1999) reported no significant difference in absorption rate between the two different forms. Dosage methods The supplementation dosages of Cr can be broken down into two different phases, otherwise known as the loading phase and maintenance phase. The loading phase that is commonly used in research consists of ingesting daily, 20-30g of Cr in four equal doses of 5-7g dissolved in around 250ml of fluid interspersed throughout the course of the day (preferably morning, noon, afternoon and evening) for a period of 5 to 7 days (Greenhaff, 1997; Kreider, 1997). Hultman et al (1996) utilised a less intense loading method of 3g/day for 28 days and proposed it to be just as effective as the aforementioned loading protocol. However this method places a longer dependency on subjects to comply with the supplementation program, therefore placing more variables into the reliability of results. Following the loading phase, maintenance dosages are considerably lower. Most research investigating the effects of Cr using the maintenance phase, have utilised dosages of 3 to 15g over a 4 to 10 week period (Bemben et al., 2001; Kreider et al., 1998; Stone et al., 1999; Vandenberghe et al., 1997). It is recommended to consume Cr with warm water, as it facilitates the dissolving of the solution and also aid absorption (Harris et al., 1992). It should also be noted that the ingestion of caffeine during Cr supplementation eradicates its potential ergogenic effect (Vandenberghe et al., 1996; Van Leemputte, Vanstapel Hespel, 1997). Vandenberghe et al (1996) demonstrated that a control group that ingested Cr combined with caffeine to have a lessened ergogenic potential compared to a group that ingested Cr without caffein e during repeated bouts of high intensity exercise. Side effects There is no conclusive scientific evidence to suggest that Cr ingestion has any negative side effects utilising the proposed dosage methods ( Larson et al., 1998; Schroder, Terrados Tramullas, 2005). There is further evidence to support this as Kreider et al (1999) found no negative side effects in athletes who had been ingesting Cr for up to 3 years. Poortmans and Francaux (1999) demonstrated similar findings for athletes for taking Cr for up to 5 years. Only undocumented anecdotal reports have reported any adverse negative side effects through Cr supplementation, this includes gastrointestinal distress, muscle cramping and dehydration (Associated press 1997, 1998). Taking dehydration into consideration such anecdotal research can be scrutinised. Oopik, Timpmann and Medijainen, (1995) demonstrated that Cr supplementation increased body mass, while also reporting increases in total body water. Such findings signify that Cr supplementation may prevent dehydration rather than be a cause, due to the fact it can promote water retention. Cr supplementation has been demonstrated to increase body mass by up to 2kg over an acute period of time (Balsom et al., 1995; Becque et al., 1997). This could be recognised as a negative side effect for athletes that compete in weight control sports, as Cr ingestion may impede their ability to make regulated weight in a forthcoming event. This gives a consensus that athletes in such activities need to be made aware that although Cr can promote gains in strength and power, it can increase body mass. Physiology of Soccer Soccer players are frequently required to produce high power outputs and maintain of repeat them with only a few seconds of recovery (Reilly and Thomas, 2003). This includes intermittent bouts of kicking, tackling, turning, sprinting, changing pace and maintaining balance and control of the ball whilst under pressure from an opponent (Wisloff, Helgerud Hoff, 1998). To gain a scientific perspective of the different physiological demands of soccer performance, match and time motion analysis have been utilised (Bangsbo, 1994). This analysis has allowed researchers to determine the overall workload of players during a 90 minute match by calculating total distance covered, and the pattern of activities performed during a game (e.g. sprinting, cruising, walking etc). Movement patterns of Soccer It is estimated that the total distance covered during a 90 minute soccer match varies from 8.7km to 11.5km ( Bangsbo Lindquist, 1992; Ekblom, 1986; Ohashi et al., (1988); Reilly and Thomas, 1976; 1988; Rampini et al., 2007; Wade, 1962). The large variance in distances covered are due in part to the differing styles of play, levels of competition and skill level of the teams that were utilised (Luxbacher, 1997). Reilly (1994) documented the different activity patterns of elite outfield players from the English top division and other major national leagues in Europe and Japan using different methods of match analysis. Results found that a 90 minute match consists of 24% walking, 36% jogging, 20% cruising sub maximally (striding), 11% sprinting, 7% moving backwards and 2% moving in possession of the ball. The categories of sprinting and cruising are defined as high intensity exercise. In terms of distances covered the ratio of low intensity exercise to high intensity exercise during a soccer match is 7 to 1 denoting that the outlay of energy for soccer is predominately aerobic ( Reilly and Thomas, 1976). However the importance for high intensity bouts during soccer match play should not be underestimated. The timing of such a bout could be the defining factor of a game whether in possession of the ball or without the ball. Although work-rate profiles are relatively consistent for players from game to game it is the high intensity exercise which is the most constant feature (Bangsbo, 1994). The number of sprints reported in a soccer game varies greatly from 17 to 62 (Bangsbo et al., 1991; Mohr, Krustrup Bangsbo, 2003). This variance is largely determined by the positional role of the player. Findings by Reilly (1996) demonstrated that midfielders and strikers completed more sprinting bouts than centre backs or full backs therefore relying more on the anaerobic energy system. However if there is not a prolonged recovery period or an individual is not properly conditioned they will not subsequently recovery from high intensity bouts of exercise and fatigue will occur (Reilly, 1996). This is evident as Reilly (1996, p.72) documented that the majority of goals conceded during a soccer match occurred in the final ten minutes of play. A popular theory for this occurrence has been found to be mental fatigue or lapses in concentration from defenders (Reilly, 1996, p.72). However this can theory can be scrutinised as research found that the onset of fatigue in intermittent exercise such as soccer is caused by low muscle glycogen stores (Balsom et al., 1999). Acute Cr supplementation and sprint performance in team sports Athletes in team sports such as soccer, rugby, hockey and American football are required to repeatedly reproduce intermittent bouts of high intensity exercise with minimal recovery. Being able to consistently reproduce such bouts at maximal ability (e.g. sprinting, jumping, running backwards) could be the deciding factor in competition to gain that extra edge of an opponent. During high intensity exercise of an intermittent nature the main contributor of energy is PCr (Williams, Kreider Branch, 1999, p29). Depletion of PCr stores during high intensity exercise has been found to be a factor which has lead to a decline in athletic performance (Hultman, Bergstrom and McLennan-Anderson, 1967). Through the supplementation of Cr, it hypothesised that PCr stores are replenished at a faster rate therefore improving an athletes ability to recover and perform intermittent high intensity bouts of exercise, leading to improved athletic performance (Greenhaff et al, 1993). There have been various studies that have tested this hypothesis by investigating the ergogenic effect of acute Cr supplementation on sprint performance of athletes in team sports (Ahmun et al., 2005; Cornish, Chilibeck Burke, 2006; Izquierdo et al., 2001; Kocak Karli, 2003; Romer et al., 2001; Vandebuerie et al., 1998). However the aforementioned studies have contrasting findings with a quantity of studies finding a significant improvement in sprint performance through Cr supplementation (Izquierdo et al., 2001; Romer et al., 2001; Vandebuerie et al., 1998). On the contrary other studies have found no significant improvements in sprint performance through acute Cr ingestion (Ahmun et al., 2005; Cornish, Chilibeck Burke, 2006; Kocak Karli, 2003). Ahmun et al., (2005) investigated the ergogenic effect of Cr on sprint performance in male rugby players. For this study a Wingate test protocol was utilised prior and post Cr supplementation. Findings of this study were that there was no significant improvement in maximal cycle sprints through Cr ingestion. However in contrast Izquierdo et al., (2001) found that acute Cr supplementation improved sprint times in male hand ball players. For this study subjects were either assigned Cr or placebo over a 5 day period. The protocol that was utilised consisted of repeated sprint runs that were consistent with sprint distances achieved during handball match play. One issue that could have had a determining factor of the non significant results found by Ahmun et al (2005) is the protocol that was utilised. A Wingate test was utilised to test the sprint performance in rugby players, however the relevance of a Wingate test to measure rugby performance is not sports specific there scrutinising the validity of the results. In contrast Izquierdo et al (2001) utilised a protocol which successfully replicated distances found in handball match play therefore maintaining validity. Ahmun et al (2005) also failed to incorporate a dietary analysis into the experimental design of the protocol, therefore whether or not Cr stores within the subjects utilised were full cannot be determined, which gives rationale for results showing no significant improvement. In contrast Izquierdo et al (2001) implemented a dietary examination of subjects that were utilised; this was initiated to determine whether any subjects had ingested Cr or any ergogenic aids prior to baseline testing. This assisted with maintaining validity during research. This can be supported by Romer et al (2001) and Vandebuerie et al (1998) who utilised a protocol containing a dietary analysis and concluded a significant improvement in sprint times within subjects. Cr supplementation and Soccer performance Given the intermittent physical demands of soccer, which requires players to produce high power outputs and maintain or repeat them with only a few seconds of recovery, (Reilly and Williams, 2003) it seems feasible that soccer players would benefit from the supplementation of Cr as an ergogenic aid to improve their overall performance. However research that has investigated the effect on acute Cr supplementation on different variables of soccer performance and predominately sprint performance utilising a soccer simulation protocol is limited (Ostojic, 2004; Mujika et al 2000; Cox et al 2002). The Aforementioned studies have primarily focused on the effects of Cr supplementation on highly trained athletes that are competing at a high standard of competition. However no previous research has looked into the effects of acute Cr supplementation on amateur soccer players. Being as though Cr monohydrate is an immensely popular ergogenic aid not only among professional athletes but also amateur and recreational athletes, the benefit to amateur athletes needs to recognised. Previous research that has looked into the effects of acute Cr supplementation on soccer players using a soccer simulation protocol is discussed below. Ostojic (2004) examined the effects of acute Cr supplementation (3 x 10g doses for 7 days) on 20 young male soccer players (16.6 Â ± 1.9 years). For the testing procedure a double blind method was used and where subjects were either administered either Cr or placebo. Subjects completed two separate trials prior and post to Cr or placebo. The testing procedure consisted of a number of soccer specific skill tests which included a dribble test, sprint-power test, endurance test and a vertical jump test. Results found that there was a significant improvement in a number of the soccer specific tests; this includes superior improvements in sprint times, vertical jump scores and the dribble test. However no significant improvements were made on endurance performance after the two trials. Although a significant improvement was found in vertical jump performance, it is of concern to future researchers to whether the vertical jump test that was utilised during the design is a soccer specific test. During the test subjects were instructed to keep their trunk as straight as possible whilst keeping their hands on their hips to avoid contribution from the arms which doesnt successfully replicate jumping movements in soccer therefore questioning the validity of the vertical jump test as to whether or not it is a measure of soccer specific performance. The age of the subjects in this research can also be scrutinised. Eichner, King, Myhal, Prentice and Ziegenfuss (1999) confirmed that there was insufficient research to determine the acute and chronic side effects of Cr consumption in athletes under the age of 18 therefore places the subjects which were used in the mentioned study under possible risk. Eichner et al (1999) also highlighted that Cr supplementation in young athletes could have a possible degradation of ethics, by where a win at all costs mentality is fostered and an attitude by where ergogenic aids are necessary to win, which is the wrong message to be installing in young athletes. Likewise Mujika, Padilla, Ibanez, Izquerido and Gorostiaga (2000) concluded acute Cr supplementation (20g a day x 6 days) significantly improved sprint performance and found no significant improvement in endurance performance using a soccer simulation protocol. Mujika et al (2000) also documented no increase in vertical jump performance using a similar protocol to Ostojic (2004) which has minimal significance in a soccer simulation study. Mujika et al (2000) tested 19 elite male soccer players who at the time of investigation were highly trained, however only 17 fully completed the testing due to illness or injury. The protocol for this investigation consisted of a circuit of different exercises which consisted of a repeated sprint test (5 and 15m), vertical jump test and an intermittent endurance test. Findings in this study concluded that mean sprint times improved significantly (p This de-training effect is evident for the vertical jump test as no significant improvement between the two trials was found. However if there was a significant de training effect it would have had negative consequences on other testing variables such as sprint performance, this however is not the case as sprint performance significantly improved. Mujika et al (2000) should have took into consideration a possible detraining effect when devising the experimental design as this could have negatively affect the validity of the results. Cox, Mujika, Tumilty and Burke (2002) devised a study which tested Cr supplementation (20g a day) or placebo (20g glucose a day) on 14 elite female soccer players from the Australian institute of sport (AIS) using a soccer simulated protocol. The experimental design consisted of two trials before and after Cr or placebo over a 6 day period. The protocol consisted of fifty five 20m sprints, ten agility runs and a precision ball kicking drill which are separated by recovery walks, jogs and runs. The main findings in this study were that the average 20m sprint time in the Cr group decreased from 3.75 Â ± 0.19 to 3.69 Â ± 0.18s however this decrease in sprint time failed to reach the statistical significance level (p Cox et al (2002) also incorporated a standardised training regime and a controlled diet for the intervention week and also scheduled testing so that it would occur at the same time of day before and after supplementation. In contrast Mujika et al (2000) failed to utilise effective standardised procedures during their experimental design. As previously mentioned Mujika et al (2000) testing procedures took place 3 days after the subjects season had finished therefore training was not standardised due to the fact that subjects had no organised training sessions during the intervention week. Mujika et al (2000) also lacked a familiarisation trial, subjects were only familiarised with the testing procedures prior to arriving for the 1st trial which could substantially affect the results. However although Cox et al (2000) standardised procedures by included a controlled diet for the subjects, it is interesting to note that one of the subjects was a vegetarian, whos Cr content is virtually zero (Greenhaff, 1997). Research has found that vegetarians respond quicker and more effectively to Cr supplementation than those who follow a normal sedentary diet and have natural muscle creatine content (Burke, Chilibeck, Parise, Candow, Mahoney Tamopolsky., 2003; Watt, Garnham Snow, 2004) therefore scrutinising the validity of the results. It may be of future reference to eradicate vegetarians in a experimental design which utilises Cr supplementation due to the diet implications that vegetarians have. Soccer Simulation performance tests To date there has been a number of soccer simulation performance tests which have been utilised to assess and measure different physiological aspects of the game (Bangsbo and Lindquist, 1992; Cox, 2002; Drust, Reilly and Cable, 2000; Nicholas, Nuttall and Williams, 2000). These protocols have been implemented so that they take into consideration different aspects of soccer performance and try to replicate the exercise patterns that are observed during match play, however due to the spontaneity of the soccer it is difficult to assess every physical or metabolic demand (Drust, Reilly and Cable, 2000). Researchers have used different protocols when investigating the metabolic and physical demands of soccer, these can documented into laboratory based protocols (Drust, Reilly and Cable, 2000; Thatcher and Batterham, 2004) and field based protocols (Bangsbo and Lindquist, 1992; Cox, 2002; Nicholas et al 2000). Laboratory based soccer performance protocols Drust, Reilly and Cable (2000) devised a laboratory based protocol on a motorised treadmill what represented the work rates that are observed during soccer match play. For the experimental design 7 male university soccer players (24 Â ± 2 years) were used and the testing consisted of three separate testing blocks which were separated by 6 days. The protocol consisted of the different exercise intensities that are utilised during soccer match play; this consisted of walking, jogging, cruising and sprinting. The speeds at which these exercises were performed on the treadmill were consistent with speeds observed by Van Gool, Van Gervan and Boutmans (1988) during a match analysis. Each testing block consisted of two 22.5 minute cycles which consisted of 23 bouts which were followed by a recovery period of 71 seconds. During each bout the duration of each activity was as follows: walking 35 seconds (s), jogging 50.3s, cruising 51.4s and sprinting 10.5s. However in relevance to this research project it should be noted that the duration covered during the sprint bouts of the protocol of Drust, Reilly and Cable (2000) which is 10.5s does not successfully coincide with match analysis from several soccer studies that have documented the duration of sprint bouts during soccer match play. Research has found that the average sprint time during soccer match play lasts between on average two to four seconds in duration (Bangsbo, Norregard Thorso,1991; Mayhew and Wenger, 1985) therefore concluding in some instances Drust, Reilly and Cables (2000) laboratory based soccer specific protocol can be deemed as in valid as it fails to accurately replicate different soccer performance variables that take place in match play. Another lab based test that was utilised to measure specific variables in soccer performance was devised by Thatcher and Batterham (2004). For this protocol six male professional soccer players were used and the testing consisted of 29 minute exercise bouts on a non motorised treadmill that focused on replicating different speeds, durations, distances and heart rates that occur during soccer match play. Findings from this study suggest that the protocol that was utilised induced a similar physiological load to soccer match play and can be determined as a valid measure of soccer performance. Although lab based soccer specific protocols have been found to replicate some instances of soccer performance it is of consideration of this research project that the limitations and positives of such protocols be noted. The aforementioned lab based failed to perform a re-test procedure to conclude whether their protocols maintained reliability therefore the amount of error in each protocol cannot be determined. Another limitation of lab based testing is that due to tests being performed on treadmills, this limits the subjects to straight-line running only, therefore does not take into consideration lateral movements and agility patterns, which have found to be major characteristics of soccer performance (Bangsbo and Lindquist, 1992). These unorthodox movement patterns need to be taken into consideration when assessing soccer performance as they increase energy expenditure significantly (Nicholas et al., 2000). One positive aspect of lab based protocols are that procedures such as a ir temperature, equipment utilised and humidity can be easily standardised to remain constant throughout performance testing. Field Tests Nicholas et al (2000) devised the Loughborough Intermittent Shuttle test (LIST) to simulate the activity patterns during a game of soccer. The LIST consisted of two separate stages which were known as part A and part B. Part A lasted 70 minutes and consisted of five 15 minute exercise pe