Acute phenylcapsaicin supplementation improves CrossFit® performance: a randomized, triple-blind, placebo-controlled crossover trial.

BACKGROUND

Phenylcapsaicin (PC) may enhance high-intensity exercise performance by reducing perceived exertion, increasing mechanical output, and limiting muscle damage, making it potentially beneficial for CrossFit® (CF) athletes.

OBJECTIVE

To examine the acute effects of PC supplementation on performance, recovery, and metabolic responses during a CF session.

METHODS

This study had a randomized, triple-blind, placebo-controlled crossover design. Fifty CF-trained athletes (50% women) ingested either 2.5 mg of PC or a placebo (PLA) 45 minutes before a standardized CF session, including a warm-up, weightlifting block, and WOD. Delayed-onset muscle soreness (DOMS) was assessed 24- and 48-hours post-session. Countermovement jump (CMJ) was evaluated pre- and post-session, while a deep squat at 70% 1RM was performed post-session. Throughout the session, heart rate, capillary lactate, rating of perceived exertion (RPE), and perceived recovery status (PRS) were monitored.

RESULTS

Compared to PLA, PC improved squat performance at 70% 1RM in both load and repetitions (P ≤ 0.035), attenuated the decline in CMJ (P < 0.001), and maintained weightlifting performance over time (P interaction = 0.011), with significantly higher load in round 9 (P = 0.030). No differences were observed during the WOD (P interaction ≥ 0.826). DOMS was significantly lower in the PC group at both 24 h and 48 h (P = 0.030), while no group differences were found for lactate, RPE, PRS, or heart rate (P interaction ≥ 0.340). Analysis stratified by sex showed that PC reduced CMJ loss in men (P = 0.043) and increased squat load in women (P = 0.021).

CONCLUSION

In conclusion, acute PC supplementation enhances performance and recovery in CF athletes.