Objectives: To determine whether four weeks of Rhodiola rosea (RHO) supplementation improves intermittent exercise performance, post-exercise blood lactate concentrations, and decision-making under fatigue in competitive football players. Methods: Twenty-four male competitive football players completed a randomised, double-blind, placebo-controlled 4-week intervention (RHO vs. placebo). Outcomes included Yo-Yo IR2, repeated-sprint ability (RSA), post-RSA blood lactate (0, 3, 5 min), football-specific technical tests (passing and shooting), a video-based decision-making task (reaction time and accuracy), GPS-derived match running metrics, countermovement jump (CMJ), foot tapping (TAP), and haematological markers. Results: Yo-Yo IR2 performance significantly improved in the RHO group (p = 0.012) and was superior to the placebo group (p = 0.046). For RSA, mean sprint time improved significantly from pre- to post-intervention in the RHO group (p = 0.017), whereas no significant change was observed in the placebo group. Post-intervention, mean sprint time was significantly better in RHO than placebo (p = 0.041), with no between-group difference observed at baseline. Best sprint time showed no between-group difference (p = 0.723). Post-exercise blood lactate concentrations were significantly lower in RHO than placebo at 0, 3, and 5 min (all p < 0.05). Under fatigue, the RHO group demonstrated faster reaction time (p = 0.042) and higher decision accuracy (p = 0.049) than placebo. Additionally, the RHO group showed significant pre- to post-intervention improvements in passing and shooting performance (p < 0.05), with between-group differences observed only for short-pass performance. Match total and high-speed running distances were higher in RHO, accompanied by increases in haemoglobin and haematocrit (p < 0.05). Conclusions: Four weeks of Rhodiola rosea supplementation enhanced high-intensity intermittent performance and decision-making under fatigue, with findings suggesting improved performance maintenance rather than increased peak sprint capacity.

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.