Acute Effect of a Pre-Workout Supplement on Energy Expenditure During CrossFit® Workouts
Disciplines
Exercise Science | Sports Sciences
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.
Academic department under which the project should be listed
WCHHS - Exercise Science and Sport Management
Primary Investigator (PI) Name
Gerald Mangine
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.