The Effects of a Multi-Ingredient Pre-Workout Supplement on Repeated Sprint Ability: A Randomized, Double-Blinded, Placebo-Controlled, Crossover Study

Introduction: Pre-workout supplements have become increasingly popular for exercisers; however, the efficacy of newly marketed supplements may be uninvestigated. The purpose of this study was to assess the effect of a multi-ingredient pre-workout supplement (MIPS) on repeated sprint ability and muscle excitability. Methods:  A total of 20 women (age: 20.95 ± 1.62; mass: 66.23 ± 10.81) and 18 men (age: 22.70 ± 2.94; mass: 84.71 ± 12.76) completed two testing sessions separated by 48 hours and were provided the placebo or MIPS in a randomized order. After ingestion, participants waited 25 minutes before completing ten, 6-second sprints against a resistance of 7.5% of body mass with 45-second rest periods. For each sprint, peak power (PP) was recorded. Surface electromyography was recorded on the vastus lateralis of the subject’s dominant leg to determine muscle activation. The ratio of PP to muscle activation was calculated as muscle excitability. Results: MIPS significantly improved (p=0.005) PP in men on sprint 5 (mean difference ± SD: 62.6 ± 83.3W). In women, MIPS had no effect in PP (p=0.140). Muscle excitability was unaffected by MIPS in men (p=0.255) and women (p=0.501). Conclusions: An acute dose of MIPS does not appear to improve repeated sprint ability nor muscle excitability in men and women.