MUSCLE METABOLISM DURING INTENSE INTERMITTENT EXERCISE IN TRAINED WOMEN

PURPOSE: Muscle metabolism during intense intermittent exercise has been well-described in men, but comparable studies are warranted in women. Thus, we examined the acute muscle and systemic physiological responses to a 5v5 soccer game in young women soccer players. METHODS: Trained women soccer players (n = 10; age: 24.5 ± 1.9 years, height: 169 ± 5 cm, weight: 67.0 ± 8.0 kg, muscle mass: 27.8 ± 2.3 kg, fat% 24.8 ± 7.6%) participated in a 5v5 indoor soccer game organized as 4x12-min intervals interspersed with 2-4 min recovery period. Muscle biopsies were obtained from m. vastus lateralis before and immediately after game, and blood was drawn during the game. RESULTS: Muscle lactate increased by 83% (P < 0.01) from pre (4.8 ± 2.3 mmol/kg dw) to post-game (8.8 ± 3.9 mmol/kg dw). Muscle PCr was 73.0 ± 8.3 mmol/kg dw pre-game and was lowered (P < 0.01) by 22% (57.0 ± 12.6 mmol/kg dw) post-game, while no change was observed in muscle ATP. Finally, muscle glycogen declined (P < 0.01) by 23% during the game (343 ± 73 to 265 ± 70 mmol/kg dw). Blood lactate rose (P < 0.05) from 1.8 ± 0.4 mmol/L at pre-game to 2.7 ± 1.2 and 3.1 ± 1.6 mmol/L mid and endgame. Average and peak heart rates were 82 ± 7% and 93 ± 4% of HRmax during the game, while total game distance was 3805 ± 647 m. Game distance was higher (P < 0.05) for the first than three last periods (1017 ± 159 vs. 920 ± 186, 924 ± 171, and 945 ± 168 m, respectively). CONCLUSIONS: Intense intermittent exercise such as a 5v5 soccer game is a demanding exercise training modality for trained women taxing both aerobic and anaerobic energy pathways and significantly lowering muscle glycogen levels.