Body temperature and physical performance responses are not maintained at the time of pitch-entry when typical substitute-specific match-day practices are adopted before simulated soccer match-play

Objectives: To profile performance and physiological responses to typical patterns of match-day activity for second-half soccer substitutes.Design: DescriptiveMethods: Following a warm-up, 13 male team sports players underwent ~85 min of rest, punctuated with five min rewarm-ups at ~25, ~50, and ~70 min, before ~30 min of simulated soccer match-play. Countermovement jump performance (jump height, peak power output), alongside 15 m sprints, were assessed post-warm-up, and pre- and post-simulated match-play. Core temperature, heart rate, ratings of perceived exertion, and blood glucose and lactate concentrations were measured throughout. Results: Warm-up-induced core temperature elevations (~2.3%, +0.85°C; p<0.001) were maintained until after the first rewarm-up. Thereafter, core temperature was reduced from post-warm-up values until pre-simulated match-play (~1.6%, -0.60°C; p<0.001), where values were similar to pre-warm-up (37.07±0.24°C, p=0.981). Simulated match-play increased core temperature progressively (p≤0.05) but values remained lower than post-warm-up (~5 min; p=0.002) until ~10 min into exercise. From post-warm-up to pre-simulated match-play, sprint times (~3.9%, +0.10 s, p=0.003), jump height (~9.4%, -3.1 cm; p=0.017), and peak power output (~7.2%, -296 W; p<0.001) worsened. Despite increased ratings of perceived exertion and elevated blood lactate concentrations (p≤0.05), sprint times were maintained throughout exercise, whereas peak power increased (~7.8%, +294 W; p=0.006) pre- to post-exercise. Conclusions: At the point of simulated pitch-entry, body temperature and physical performance responses were not maintained from warm-up cessation despite typical substitute-specific match-day practices being employed in thermoneutral conditions. Evidence of performance-limiting fatigue was absent during ~30 min of simulated match-play. These data question the efficacy of practices typically implemented by substitutes before pitch-entry.