Project Title
Acute Effect of a Pre-Workout Supplement on Energy Expenditure During CrossFit® Workouts
Academic department under which the project should be listed
WCHHS - Exercise Science and Sport Management
Research Mentor Name
Gerald Mangine
Abstract (300 words maximum)
CrossFit® (CF) training involves high-intensity efforts that typically utilize carbohydrates for energy, which is not ideal if fat loss is a goal. Pre-workout supplements typically contain several ingredients known to alter blood flow and substrate utilization, but no study has investigated the acute effect of such formulations on CF performance. PURPOSE: To compare the acute effects of a pre-workout supplement on energy expenditure during CF workouts. METHODS: Men (n=7: 29±7 years, 173±9 cm, 83±17 kg) with CF experience (≥2 years) volunteered for this cross-over design, placebo-controlled study. Across four, weekly experimental visits in randomized order, participants completed pre-exercise assessments of heart rate (HR), quadriceps cross-sectional area (CSA), blood lactate, oxygen uptake (VO2), and respiratory exchange ratio (RER) before consuming the pre-workout supplement (S) or non-caloric placebo (P). They rested 40 minutes and then completed as many repetitions as possible within a 5- or 15-minute circuit of 9-calorie rowing, six barbell thrusters (43.1 kg), and three 0.6-m box jumps. All pre-exercise measures are repeated immediately post-exercise. RESULTS: Repeated measures analysis of variance revealed a trial x time interaction (p2, and CSA. Compared to pre-exercise values, post-exercise elevations (p2 (+2.92 L/min) and quadriceps CSA (+0.88-3.68 cm2). CONCLUSION: A higher RER during the 5-minute trials indicates a greater carbohydrates utilization, but neither this or any other parameter were affected by the supplement. Aside from demonstrating greater carbohydrate utilization during shorter CF-style workouts, these data do not support the use of this supplement for altering substrate utilization for this workout at either duration.
Disciplines
Exercise Science | Sports Sciences
Acute Effect of a Pre-Workout Supplement on Energy Expenditure During CrossFit® Workouts
CrossFit® (CF) training involves high-intensity efforts that typically utilize carbohydrates for energy, which is not ideal if fat loss is a goal. Pre-workout supplements typically contain several ingredients known to alter blood flow and substrate utilization, but no study has investigated the acute effect of such formulations on CF performance. PURPOSE: To compare the acute effects of a pre-workout supplement on energy expenditure during CF workouts. METHODS: Men (n=7: 29±7 years, 173±9 cm, 83±17 kg) with CF experience (≥2 years) volunteered for this cross-over design, placebo-controlled study. Across four, weekly experimental visits in randomized order, participants completed pre-exercise assessments of heart rate (HR), quadriceps cross-sectional area (CSA), blood lactate, oxygen uptake (VO2), and respiratory exchange ratio (RER) before consuming the pre-workout supplement (S) or non-caloric placebo (P). They rested 40 minutes and then completed as many repetitions as possible within a 5- or 15-minute circuit of 9-calorie rowing, six barbell thrusters (43.1 kg), and three 0.6-m box jumps. All pre-exercise measures are repeated immediately post-exercise. RESULTS: Repeated measures analysis of variance revealed a trial x time interaction (p2, and CSA. Compared to pre-exercise values, post-exercise elevations (p2 (+2.92 L/min) and quadriceps CSA (+0.88-3.68 cm2). CONCLUSION: A higher RER during the 5-minute trials indicates a greater carbohydrates utilization, but neither this or any other parameter were affected by the supplement. Aside from demonstrating greater carbohydrate utilization during shorter CF-style workouts, these data do not support the use of this supplement for altering substrate utilization for this workout at either duration.