Background: While the long-term ergogenic benefits of creatine monohydrate (CrM) supplementation are well-documented, the potential advantages of acute ingestion followed by short-term consumption remain relatively underexplored. This double-blind, randomized crossover study investigated the acute and short-term effects of CrM supplementation on strength performance, heart rate variability (HRV) responses, and recovery of lower limbs strength and muscle soreness in resistance-trained males.
Methods: A total of eleven physically active participants were recruited; however, due to incomplete data, one participant was excluded, and ten participants (age: 21.3 ± 1.9 years) were analyzed. Participants ingested either creatine monohydrate (CrM: 0.3 g·kg-1·d-1) or a placebo (PLA) for three days, with the first day's dose consumed 2 h pre-test and subsequent doses divided into three daily doses. Participants completed two test sessions in a randomized order, separated by a seven-day washout period. Each session included bench press (BP) and back squat (BS) tests performed at 60%, 70%, and 80% of one-repetition maximum (1RM) under either CrM or PLA conditions. Strength performances (repetitions, velocity, power), HRV and peak heart rate (HR), jump tests (Countermovement Jump (CMJ) and Squat Jump (SJ)), and delayed-onset muscle soreness (DOMS) were assessed.
Results: Compared to PLA, CrM supplementation significantly increased repetitions completed at 60-80% 1RM in BP and BS (p ≤ 0.041, d = 0.72-1.6) during both test sessions. CrM reported higher velocity compared to PLA at all intensities (60-80% 1RM) for both exercises and sessions (p ≤ 0.035, d = 0.78-4.09). CrM reduced cardiovascular strain compared to PLA at 60% 1RM during back squat (p = 0.017, d = 1.05). Peak HR increased with intensity for both conditions (d = 1.1-4.28), with CrM showing lower HR at 60% (p = 0.017, d = 1.05) and higher HR at 80% (p = 0.047, d = 0.82) compared to PLA. CrM enhanced post-exercise parasympathetic reactivation in the 1st session demonstrating higher favorable response in RMSSD (p = 0.015, d = 2.99) and HF power (p = 0.022, d = 2.76) compared to PLA. CMJ performance was higher in CrM compared to PLA at 24 h post-1st session and immediately before and after the 2nd session (p ≤ 0.019, d = 1.10-1.93), also DOMS was reduced in upper and lower limbs (p ≤ 0.012, d = 1.15-1.04) immediately before the 2nd session.
Conclusion: These findings demonstrate that even three days of CrM supplementation have the potential to enhance strength performance, reduce physiological stress, and accelerate recovery, suggesting it as an effective ergogenic strategy for athletes seeking immediate performance gains and reduced post-exercise soreness.
Keywords: Creatine; ergogenic effect; performance; recovery; resistance exercise.