Passive heating following the prematch warm‐up in soccer: examining the time‐course of changes in muscle temperature and contractile function

This study examined changes in muscle temperature, electrically evoked muscle contractile properties, and voluntary power before and after a soccer specific active warm‐up and subsequent rest period. Ten amateur soccer players performed two experimental sessions that involved performance of a modified FIFA 11+ soccer specific warm‐up, followed by a 12.5‐min rest period where participants were required to wear either normal clothing or a passive electrical heating garment was applied to the upper thigh muscles. Assessments around the warm‐up and cool‐down included measures of maximal torque, rate of torque development, muscle temperature (T (m)), and electrically evoked measures of quadriceps contractile function. T (m) was increased after the warm‐up by 3.2 ± 0.7°C (P < 0.001). Voluntary and evoked rates of torque development increased after the warm‐up between 20% and 30% (P < 0.05), despite declines in both maximal voluntary torque and voluntary activation (P < 0.05). Application of a passive heating garment in the cool‐down period after the warm‐up did not effect variables measured. While T (m) was reduced by 1.4 ± 0.4°C after the rest period (P < 0.001), this value was still higher than pre warm‐up levels. Voluntary and evoked rate of torque development remained elevated from pre warm‐up levels at the end of the cool‐down (P < 0.05). The soccer specific warm‐up elevated muscle temperature by 3.2°C and was associated with concomitant increases of between 20% and 30% in voluntary rate of torque development, which seems explained by elevations in rate‐dependent measures of intrinsic muscle contractile function. Application of a passive heating garment did not attenuate declines in muscle temperature during a 12.5‐min rest period.