The effect of session order on the physiological, neuromuscular, and endocrine responses to maximal speed and weight training sessions over a 24-h period

Athletes are often required to undertake multiple training sessions on the same day with these sessions needing to be sequenced correctly to allow the athlete to maximize the responses of each session. We examined the acute effect of strength and speed training sequence on neuromuscular, endocrine, and physiological responses over 24h. 15 academy rugby union players completed this randomized crossover study. Players performed a weight training session followed 2h later by a speed training session (weights speed) and on a separate day reversed the order (speed weights). Countermovement jumps, perceived muscle soreness, and blood samples were collected immediately prior, immediately post, and 24h post-sessions one and two respectively. Jumps were analyzed for power, jump height, rate of force development, and velocity. Blood was analyzed for testosterone, cortisol, lactate and creatine kinase. There were no differences between countermovement jump variables at any of the post-training time points (p>0.05). Likewise, creatine kinase, testosterone, cortisol, and muscle soreness were unaffected by session order (p>0.05). However, 10m sprint time was significantly faster (mean±standard deviation; speed weights 1.80±0.11s versus weights speed 1.76±0.08s; p>0.05) when speed was sequenced second. Lactate levels were significantly higher immediately post-speed sessions versus weight training sessions at both time points (p