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.