We hypothesize that adenosine-5'-triphosphate (ATP) supplementation will be able to enhance motor unit recruitment while simultaneously blunting the decline in power and reaction time that is typically seen during repetitive sprints. This will give researchers a better understanding of the mechanism by which ATP supplementation can augment power, especially under high fatiguing conditions.

Healthy participants of similar training status as previously tested will be enrolled into the study. The participants will be randomly assigned to either placebo supplementation or to 400 mg ATP per day for 14 days. The supplements will be taken in the morning and the last dose will be taken 30 min prior to testing on the last day. Testing will be performed at baseline and after the 14 days of supplementation. Ten successive sprints will be conducted on the Wingate apparatus as this has been previously demonstrated to decrease muscle excitability. After the sprints, muscle excitability, reaction time, and vertical jump power will be measured. In addition a blood sample will be obtained before and after supplementation and complete blood hematology and chemistry analyses will be performed. It is expected that ATP supplementation may help maintain muscle excitability and power after the successive sprint sessions.

Inclusion Criteria:

• Agree to eating a diet approved by a registered dietician consisting of the following by caloric percentages: 15-20% protein, 44-55% carbohydrate, and 25-30% fat.
• Must not have taken performance enhancing supplements for at least 3 months prior to the study start,
• Must be a non-smoker.
• Must not be taking amino acid supplements.
• Must not be using anabolic or catabolic hormones.
• Must not be taking any medications known to influence variables to be measured in the study.

Exclusion Criteria:

• Will not agree to eating a diet approved by a registered dietician consisting of the following by caloric percentages: 15-20% protein, 44-55% carbohydrate, and 25-30% fat.
• Has taken performance enhancing supplements for at least 3 months prior to the study start,
• Is currently a non-smoker.
• Is currently taking amino acid supplements.
• Is currently using anabolic or catabolic hormones.
• Is currently taking medications known to influence variables to be measured in the study.