Muscle temperature and sprint performance during soccer matches - beneficial effect of re-warm-up at half-time

The relationship between quadriceps muscle temperature (T-m) and sprint performance was evaluated during soccer matches in 25 competitive players. In one game, T-m was determined frequently (n=9). In another game, eight players performed low-intensity activities at half-time (re-warm-up, (RW), whereas another eight players recovered passively (CON). T-m was 36.0+/-0.2 degreesC at rest and increased (P<0.05) to 39.4+/-0.2 degreesC before the game and remained unaltered during the first half. At half-time, T-m decreased (P<0.05) to 37.4+/-0.2 degreesC, but increased (P<0.05) to 39.2+/-degreesC during the second half. In CON and RW, T-m and core temperature (T-c) were similar before and after the first half, but 2.1+/-0.1 and 0.9+/-0.1 degreesC higher (P<0.05), respectively, in RW prior to the second half. At the onset of the second half, the sprint performance was reduced (P<0.05) by 2.4% in CON, but unchanged in RW. The decrease in T-m was correlated to the decrease in performance (r=0.60, P<0.05, n=16). This study demonstrates that in soccer, the decline in T-m and T-c during half-time is associated with a lowered sprint capacity at the onset of the second half, whereas sprint performance is maintained when low-intensity activities preserve muscle temperature.