The effects of a nutritionally enriched coffee drink on repeated flying 40-yd sprint performance

Background

A double-blind, placebo controlled, randomized trial was performed to evaluate the effects of a nutritionally enriched coffee (NEC) drink compared to decaffeinated coffee (DC) on repeated flying 40-yard sprint performance.

Methods

Physically active male and female volunteers (n = 13) completed 24 × 50 yard sprints following NEC and DC (counterbalanced). Sprints were completed in 2 halves (12 sprints per half) with 2 minutes recovery between each sprint and a 10-minute recovery period between halves. Acute-RPE (A-RPE) (0–10 omni scale) was recorded after every sprint and Session RPE (S-RPE) was recorded 20 min after completing each trial. Blood lactate ([LA]) was recorded at baseline and following sprints, 6, 12, 18, and 24. Additionally, a fatigue index (FI) was calculated as a percentage difference between mean sprint time and fastest sprint time.

Results

A 2 (trial) × 2 (treatment) repeated measures ANOVA revealed significantly (p = 0.03) faster (main effect) sprint time for NEC. Post-hoc analyses revealed significantly faster times (p ≤ 0.05) for sprints 1, 3, 4, 6, 8, and 17, while approaching significance at sprints 10 (p = 0.07) and 15 (p = 0.08). No main effect for A-RPE (p = 0.28) or [LA] (p = 0.15) was found. Results from a paired t-test revealed a significantly improved FI (p = 0.04) with NEC but no significant impact on S-RPE (p = 0.72).

Conclusion

Results indicate that caffeine administered in a NEC drink can enhance repeated bouts of acute sprint performance possibly through delayed fatigue as evidenced in a dampened perceived exertion response (faster sprints with similar RPE).