Fig. 5

Scatter diagram representing the changes in muscle hardness and skin temperature on the trapezius muscle under HC conditions: (a) “Cold max” was defined as the maximum cooling temperature from baseline (i.e., the skin temperature at the start of the intervention) during the intervention. (b) “Cold change” was defined as the cumulative cooling change in skin temperature during the intervention duration, which was calculated as the time integral of the cooling temperature change from baseline