Effects of Combined Caffeine and <i>Rhodiola rosea</i> Supplementation on Repeated Aerial Duel Performance and Neck Neuromuscular Function in Soccer Players.

Abstract

Background: Soccer aerial duels require rapid take-off, repeated-performance maintenance, and effective head-neck control under physically demanding conditions. This study examined the effects of caffeine (CAF), Rhodiola rosea (RHO), and their combination on repeated aerial duel performance and neck neuromuscular function in male collegiate soccer players.Methods: Ninety-six players were randomly assigned, in a double-blind, placebo-controlled, parallel design, to placebo control (CTR), RHO, CAF, or RHO + CAF groups (n = 24 each) for 4 weeks. CAF was acutely administered at 3 mg·kg^-1 before testing, whereas RHO was chronically supplemented at 2.4 g·day^-1. Outcome measures included countermovement jump height, early take-off impulse, repeated heading contact height, ball exit velocity, heading duel success rate, neck maximal voluntary isometric contraction, and session rating of perceived exertion (session-RPE).Results: Significant group × time or group × repetition effects were observed for CMJ height (p = 0.0034), early take-off impulse (p = 0.0007), and post-intervention repeated heading contact height (p < 0.0001), with additional significant effects across heading-specific, neck strength, duel-success, and perceived-load outcomes. CAF was mainly associated with improved take-off-related explosive performance and duel success, whereas RHO was mainly associated with lower perceived exertion and better maintenance of heading contact height during the later repeated trials. Combined RHO + CAF supplementation produced the broadest pattern of benefits across explosive output, ball-contact performance, duel success, and multidirectional neck strength.Conclusions: These findings suggest that, in male collegiate soccer players, CAF and RHO may contribute differently to repeated aerial duel-related performance, and their combination may offer broader sport-specific benefits under repeated high-intensity demands.