Extended match time exacerbates fatigue and impacts physiological responses in male soccer players

Purpose: This study evaluated how extended match time (90 + 30 min) affected physiological responses and fatigue in male soccer players.Methods: Twenty competitive players (mean ± SD: age, 20 ± 1 yr; maximal oxygen uptake, 59 ± 4 mL·min⁻¹·kg⁻¹) completed an experimental match with their activity pattern and HR assessed throughout the game, while countermovement jump (CMJ) performance and repeated sprint ability (RSA) were tested and quadriceps muscle biopsies and venous blood samples taken at baseline and after 90 and 120 min of match-play.Results: Less high-intensity running (12%) was performed in extra time in association with fewer intense accelerations and decelerations per minute compared with normal time. Peak sprint speed was 11% lower in extra time compared with normal time, and fatigue also manifested in impaired postmatch repeated sprint ability and countermovement jump performance (all P < 0.05). Muscle glycogen declined from 373 ± 59 mmol⸱kg^-1 dry weight at baseline to 266 ± 64 mmol⸱kg^-1 dw after 90 min, with a further decline to 186 ± 56 mmol⸱kg^-1 dw after extra time (P < 0.05) and with single-fiber analyses revealing depleted or very low glycogen levels in ~75% of both slow and fast twitch fibers. Blood glucose did not change during the first 90-min but declined (P < 0.05) to 81 ± 8 mg⸱dL^-1 after extra time. Plasma glycerol and ammonia peaked at 236 ± 33 mg⸱dL^-1 and 75 ± 21 μmol⸱L^-1 after the extra period.Conclusions: These findings demonstrate exacerbated fatigue following extra time compared with normal time, which seems to be associated with muscle glycogen depletion, reductions in blood glucose levels and hyperammonemia. Together, this points to metabolic disturbances being a major part of the integrated and multifaceted fatigue response during extended soccer match play.