Electromyographic activity in hot (dark columns) and control (white columns) conditions. Left panel, HOT-core: passive hyperthermia in hot ambient conditions. Right panel, HOT-skin: local modification of skin temperature. RMS: Root Mean Square of the EMG signal. RMS/M RMS normalized by the amplitude of a M-wave. All data recorded during maximal voluntary contractions. NS: No significant differences (η2 = 0.01, p ≥ 0.77). $ and* large differences (η2 ≥ 0.18) with $ p = 0.15 and * p < 0.05.