Low-Dose Caffeine Supplementation Is a Valuable Strategy for Increasing Time to Exhaustion, Explosive Power, and Reducing Muscle Soreness in Professional Male Kickboxers

Abstract

Background

Caffeine is a well-established ergogenic aid that enhances physical performance and recovery. However, its dose-dependent effects on key performance metrics in combat sports like kickboxing remain insufficiently explored.

Objective

This study aimed to evaluate the effects of varied doses of acute caffeine supplementation on performance indices and perceived muscle pain in kickboxing athletes.

Methods

Twelve kickboxing athletes participated in 3 exercise sessions with either caffeine supplementation (3 mg/kg [C3], 6 mg/kg [C6]) or placebo (PLA). A 1-wk washout period occurred between exercise trials. Caffeine was supplemented 60 min before each exercise session. In each session, participants first performed a vertical jump and the Wingate anaerobic tests. After a 45-min rest, they completed the Bruce maximal aerobic treadmill test. Measured performance variables included vertical jump height, Wingate test outcomes (relative power [peak, mean power, and lowest], and fatigue index), maximal oxygen consumption (VO₂max), oxygen consumption at the ventilatory threshold (VT₂), time-to-exhaustion, rating of perceived exertion (RPE), and muscle soreness assessed immediately, at 2 h, and 12 h postexercise.

Results

C3 and C6 significantly increased time-to-exhaustion following treadmill testing (P < 0.05) but had no effect on the Wingate fatigue index (P > 0.05). Compared with PLA, C3 and C6 significantly increased vertical jump (P < 0.05). C3 significantly increased relative peak power (P < 0.05), whereas C6 and PLA did not during the Wingate test (P > 0.05). Muscle soreness after 2 h showed a significant decrease after C6 compared with C3 and PLA (P < 0.05). In contrast, no significant effect was observed for VO_2max, %VO_2max at VT₂, and RPE (P > 0.05) for all treatments.

Conclusions

Acute supplementation of 3 to 6 mg/kg doses of caffeine-induced relative improvements in anaerobic and lower-body muscular power, muscle soreness, and time-to-exhaustion in male kickboxing athletes.