Muscle metabolic responses to a 5v5 football game in trained female football players

Purpose The study examined the acute muscle and systemic physiological responses to a 5v5 small-sided game (SSG) of
football in trained female players.
Methods Ten trained female football players (age: 24.5 ± 1.9 years, height: 169 ± 5 cm, weight: 67.0 ± 8.0 kg, fat%:
24.8 ± 7.6%) completed four 12-min periods of play (P1-P4) with 4-min passive recovery. Muscle biopsies were obtained
from m. vastus lateralis pre- and post-game, and analyzed for glycogen, creatine phosphate (CP), ATP, and lactate. Blood
lactate was measured pre-, mid-, and post-game. Heart rate and movement patterns were recorded continuously using chestworn
sensors.
Results Muscle lactate nearly doubled (mean [95CI], 4.8 [2.5, 7.1] to 8.8 [6.5, 11.0] mmol/kg dw; P < 0.01), while blood
lactate rose 57% mid-game and 80% post-game (P < 0.01). Muscle CP declined 22% (P < 0.01), muscle ATP remained
unchanged, and muscle glycogen declined (P < 0.01) from 349 [299, 399] at baseline to 275 [225, 325] mmol/kg dw postgame.
Average and peak heart rates reached 82 [78, 86] % and 93 [89, 97] %HRmax, respectively, while players covered 3805
[3308, 4303] m in total, with greater distance in the first period compared to later periods (P2–P4, P < 0.05).
Conclusion These findings indicate that 5v5 SSG impose a notable muscle metabolic load in trained female players, taxing
both aerobic and anaerobic energy systems despite a relatively low external load. SSG may be a training modality for
improving sport-specific fitness in trained young female players, but intervention studies are required to confirm adaptations.
Inference is limited by the small sample and absence of control for menstrual phase and pre-exercise nutrition.