Creatine monohydrate has been shown to act as a buffer to maintain fast rates of ATP turnover, therefore Creatine availability has been reported to be a main limiting factor during bouts of high-intensity exercise such as sprinting. As a result of recent investigations documenting the ergogenic value of creatine monohydrate supplementation, it has been used as a popular ergogenic aid for many athletes who require fast rates of recovery (Mujika & Padilla, 1997). Creatine is thought to improve performance by facilitating the rate of post-exercise Phosphocreatine (PCr) resynthesis. Given this relationship between PCr resynthesis and recovery of power output, supplementation is most likely to be beneficial to repetitive sprint activities (Glaister, 2006). However, some investigations on the effects of creatine supplementation and its effect on multiple sprint performance report significant improvements, whereas others report no such effect (Mujika, 1996). The main reasons for discrepancies in the results of different investigations are the use of low subject numbers, varied creatine doses, varied test durations, and poor randomization. For these reasons this study will use a high number of subjects in a double blind fashion, with a dosage of 20 grams per day for the first 5 days followed by 5 grams a day for the remainder of the study. The study will continue for a duration of 8 weeks.
Creatine monohydrate supplementation is popular in athletes participating in strength and power sports. Creatine use is thought to be effective for enhancing performance of activities that involve repeated intervals of sprint type exercises with short rest periods. First, an increase in PCr stores should increase the contribution of PCr for the resynthesis and decrease the demand from glycolysis which will result in a smaller accumulation of lactic acid. Then, when PCr is broken down to rephosphorylate ADP, a hydrogen ion is consumed in the reaction. Therefore, an increase in PCr could delay the onset of acidosis and fatigue and thus improve performance in repeated bouts of sprinting (Chilibeck & Cornish, 2006).
A study performed on the sprint performance of 19 highly trained male soccer players using creatine supplementation, consisted of six maximal 15 meter runs with a 30 second recovery period. The results of the study allowed the investigators to conclude that acute Cr supplementation favorably affected repeated sprint performance, however intermittent endurance performance was not affect by Cr (Mujika & Padilla, 1998).
Another study done by Mujika in 1996, involved sprint performance among twenty highly trained swimmers. Unlike the other studies mentioned, this study showed no significant improvements in sprint performance among competitive swimmers, therefore according to these results creatine supplementation cannot be considered as an ergogenic aid (Mujika, 1996).
A study using the 30 second maximal cycle test, also known as the Wingate test, in
conjunction with creatine supplementation also showed no ergogenic benefit. 20 grams of creatine supplementation for 3 days did not increase resting muscle PCr, nor did it affect the single short term maximal cycling performance. A possible explanation for this is that the duration of the test was too short to produce and significant muscular changes (Odland et al., 1997).
Most studies have investigated the effects of creatine supplementation using cycle ergometry, this study will involve actual sprinters performing repeated sprints with relatively short rest periods performing to exhaustion. Also, there is little to no research on the prolonged effects of creatine supplementation, so the length of the study will be 8 weeks.
STATEMENT OF THE PROBLEM:
While many studies exist pertaining the effects of creatine supplementation on strength, power, and endurance, few studies exist investigating the effects of creatine supplementation on sprint performance on trained sprinters. The results of prior studies have noted many discrepancies such as research done by Mujika (1996) and Glaister (2006). Not enough evidence exists on the effects of creatine supplementation on sprint performance specifically the effect it has on trained individuals.
PURPOSE OF THE STUDY:
The purpose of this study is to examine the effects of creatine monohydrate supplementation on sprint performance in 50 NCAA colligate track and field athletes. These participants will go through an eight week supplementation and training period where they will be timed pre and post supplementation on a weekly basis in the 100 and 200 meter runs.
SIGNIFICANCE OF THE STUDY:
Most research on creatine has focused on short-term creatine loading and its effect on high intensity performance capacity. Some studies have investigated the effect of prolonged creatine use during strength training. However, studies on the effects of prolonged creatine supplementation on sprint performance are lacking. Due to this lack of information, this study will provide more data on the effects of prolonged creatine supplementation and its effects on sprint performance.
There will be a significant difference between the group which supplements with creatine and the control group in term of improvements in sprint performance. Improvements will be considered to be an improvement in time trials.
The creatine group will have significant improvements in sprint performance compared to the control group.
There will be more of a significant improvement in the 200 meter sprint times as opposed to the 100 meter sprint times.
N) There will be no significant differences in terms of sprint performance between the creatine group and the control group.
DEFINITION OF TERMS:
Performance Improvement- Performance improvement for sprints will be when one records a better time than a previous test
Fatigue- temporary loss of strength and energy resulting from hard physical work
Exhaustion- extreme fatigue; debilitation: serious weakening and loss of energy
It is assumed that all subjects in the study will not be doing any other training regimen aside from the one included within the study.
It is assumed that all subjects in the study are not using any other supplements during the course of the study.
It is assumed that the all subjects are following protocol of the study and not deviating in any way.
It is assumed that the subjects are training and performing to their maximal efforts.
The study has been delimited to collegiate track and field athletes.
The study has been delimited to athletes who compete in the 100 and 200 meter events.
Subjects are not following protocol correctly.
Subjects are not performing to maximal efforts.
Subjects are taking other supplements during the course of the study.
Subjects change their dietary patterns mid way through the course of the study.
REVIEW OF LITERATURE
Most studies investigating the ergogenic value of creatine supplementation have reported significant increases in strength, power, sprint performance, and accumulation of performed work during multiple sets of maximal effort. These improvements are generally attributed to increase total creatine and phosphocreatine content in working muscles leading to more efficient resynthesis of PCr and enhance quality of training adaptations.
Recent investigations by Mujika and Padilla (2000) have focused on the possible ergogenic value of supplementing the athletesaa‚¬a„? diet with approximately 20 g/d of creatine monohydrate for a week. It has often been shown that this type of creatine supplementation can result in increased total muscle creatine and phosphocreatine concentrations. Some studies have also shown that this elevated intramuscular phosphocreatine can enhance the rate of ATP and phosphocreatine resynthesis after high intensity efforts, causing a delayed onset of muscular fatigue and an increased performance during repeated bouts of high intensity exercise.
A study stimulated by anecdotal reports of gains in strength and lean body mass in conjunction with Cr supplementation investigated the use of lower doses of creatine monohydrate for extended periods during heavy resistance training. Using 16 collegiate football player which were randomly separated into creatine and placebo groups. Cr groups ingested 5 grams of creatine monohydrate while the placebo ingested a placebo capsule, both of which took their capsules for a 10 week period. The results confirmed that 10 weeks of creatine monohydrate supplementing while participating in resistance training program will significantly increase strength and power compared with placebo supplementation. The result also indicates that Cr supplementation over the long term can be effect without a large dose loading phase (Pearson, 1999).
Francaux and Poortmans (1999) used 25 healthy males participating in a 42 day training period followed by a 21 day detraining period. Creatine and placebo were given over a period of 9 weeks. Subjects ingested 21 grams of Cr for 5 days followed by 3 grams per day for 58 days. There were no changes observed in body mass for the control or placebo groups, while the Cr groups had in average increase in body weight by 2 kg. The increase was partially attributed to body water content, however the relative volumes of body water compartments remained constant, thus the gain in body mass cannot be attributed to water retention, but most likely to dry matter growth accompanied with a normal water volume.
It has also been reported that Cr supplementation may improve single effort and repetitive sprint performance, particularly those last from 6- 30 seconds with a 5 min rest for recovery between sprints. A study performed by Dawson et al. found that Cr supplementation significantly increased work performed during the first six 6 second cycle ergometry. These result are supported by a similar study by Schneider who reported at supplementation with Cr was associated with significant improvement in cycle ergometer sprints with 60 second recovery time.
In a study concerning Cr supplementation in professional rugby players, they were directed to take a loading phase consisting of 20 grams per day for 4 days once a month. This loading phase was then followed by a 3 week abstinence period. After the third loading cycle, the players were surveyed on compliance, preferred time and ingestion method, perceived side effects and perceived benefits. The results of this survey included; 35.3% reporting being fatigued less quickly, 29.4% reported quicker recovery from sprint type activities, and 23.5% reported faster recovery from training sessions. The study concluded that Cr supplementation may be useful in sports which require repeated sprint efforts and can be advantageous in both training and performance (Meir, 1995).
It has been suggested by Mujika et al. (2000) that highly trained athletes who participate in sports in which performance relies on repeated efforts could benefit from creatine ingestion by means of an increased ability to perform intermittent high-intensity exercise either during training or competition. There have also been recent reports claiming that most studies not only do not use highly trained athletes as subjects, most of the studies cited above were conducted under laboratory conditions, and none of them assessed the effects of the creatine supplementation on performance during single specific athletic events. Recently reported results suggest that highly trained subjects performing sport-specific activities do not benefit from creatine ingestion (Mujika, 1996).
There have also been a number of studies which report no ergogenic benefit from Cr supplementation. For example, one study by Burke et al. (1996) used male and female swimmers from the Australian National Team who supplemented with Cr for a 5 day period using 20 grams each day. This study did not show any enhancement due to Cr supplementation in 25m,50m, or 100m swims with a 10 min recovery period. Given such a long recovery period, ATP recovery should be recovered with our without Cr supplementation, therefore an increase in performance is not expected. A similar study involving swimmers was conducted by Mujika in 1996. This study also reported no performance increases between Cr and placebo groups, but did report a gain in body weight among the Cr group. This increase in weight could result in a increase in drag force and could alter the efficiency of a swimmers stroke.
A study pertaining to maximal sprint performance on a cycle ergometer after Cr supplementation was conducted by Snow et al. (1998) The subjects were untrained men, who ingested 30 grams of creatine for a 5 day period. The results indicated that this dose of supplementation increase total creatine levels but did not improve sprint exercise performance on the cycle ergometer. These results are supported by similar studies by Finn et al. (2001) and Odland (1997).
A recent study done in 2003, by Delecluse et al. examined the impact of a 7 day, high dosage of Cr supplementation on single and intermittent sprint performance in highly trained sprinters. Each subject ingested 0.35g of Cr per kg of body weight. Maximal sprint performance, degree of fatigue at the end of exercise, and degree of recovery all showed no difference compared to a placebo group.
A review of previous studies concerning the topic of Cr supplementation show that Cr has been show to be a powerful aid in increasing strength and power related to sprint performance. Other studies however, have shown no improvements in strength, power, or overall sprint performance in conjunction with Cr supplementation. These discrepancies in results can possibly be attributed to differences in length of supplementation, exercise criterion, dosages, or subject response.
An email was sent to ten different division one schools asking their coaches if their track team would be willing to participate in an off-season supplementation program within a study that is being conducted at the University of Scranton. Due to the lack of a track and field team, we had to contact other schools in the area and see if there track team would participate. The coach from Lehigh University responded allowing his team to participate in this supplementation program. A written consent was obtained from the all 50 participants after they were thoroughly informed of the purpose and potential risks of participating in the study. All experimental procedures were approved by the Exercise Science Committee of the University of Scranton. All subjects were members of the same team and were competing at a national level at the time of the study.
All of our testing will take place at the University of Scrantonaa‚¬a„?s gym facilities. This study will use a pretest-posttest randomized-groups design. Our subjects will be evenly divided into two groups. One will be the control group, and the other the experimental group. Both the researchers and subjects will lack information as to which group is which. Each group will come in for a pre-training assessment evaluation that will last the first week of the study. Each participant will be timed in the 100 and 200 meter runs to establish prior times and speeds before supplementation begins. All of the timed trials will be supervised by experienced exercise physiologists found in our team here at the University of Scranton.
During weeks two through seven is when supplementation will occur. Creatine (Cr) monohydrate will be administered to the supplementation group. This supplementation group will ingest four 5-g doses of Cr monohydrate per day for 6 days. The control or placebo group will take the same dosage of a carbohydrate solution as the supplementation group. Weekaa‚¬a„?s three to seven will cut back to just one 5-g dose a day for 6 days. By week eight, all supplementation will end. The subjects will be given a three day period of no supplementation and will be timed once again in the 100 and 200 meter runs to see if any significant difference occurred in pre-test times.
During the two to seven week period, all subjects will come in three times a week (Monday, Wednesday, and Friday) and complete the following training regiment, once in the morning and once in the afternoon. All subjects will be expected to continue all off-season training that will be administered by their coaches.
Repeated sprint test (RST). A study conducted by Mujika et. all in 2000 led to believe that the repeated sprint tests were a practical training regimen that could be used within this study. Subjects will perform six maximal 15-m sprints that will have 30 seconds of recovery between each. Each sprint will begin on the blocks, and once the sprint has commenced, subjects will pass through a photocell gate (Newtest OY, Oulu, Finland) placed 0.4 m above the ground, which will start a digital timer. Additional photocell gates will be placed at 5 m and 15 m, which record elapsed and final times.
Intermittent endurance test (IET). This testing procedure was also done by Mujika et. all in 2000 that was also appropriate for the training regimen in this study. This test lasts 16.5 minutes, during which subjects will alternate between forty 15 seconds bouts of high-intensity exercise and thirty-nine 10 second low intensity exercise bouts. During the high-intensity periods, subjects will follow and outlined circuit around Fitzpatrick field, running 40 m forward, and 8.25 m backwards, 95.25 m forward, 8.25 m sideways while facing away from the center of the circuit, and 8.25 m sideways while facing the center of the circuit. During the low-intensity periods, subjects will jog to the center of the circuit and back to the position they reached during previous high-intensity period. The test results in the distance covered during 40 periods of high-intensity running.
Values will be expressed as mean +/- standard deviation. The level of statistical significance will be defined as P < 0.05. All reported values will be from the 50 subjects who completed the study. Pre supplementation versus post supplementation comparisons within the groups will be performed using a one-way ANOVA for repeated measures.