Supplementary Figure 1

Methods
To calculate overall power, surface EMG data were digitally bandpass filtered from 10-250Hz and then rectified. EEG data were digitally bandpass filtered between 0.5-100Hz (Kenville et al., 2020) prior to power analyses. EEG power was calculated as the squared amplitude of the signal in both the alpha (8-12Hz) and beta frequency (15-35Hz) ranges. Two-way ANOVAs with factors of Protocol and Time were run separately for females and males for alpha and beta power at the Cz electrode. For all other power analyses, data from females and males were pooled for the two-way ANOVAs.

Results
A Protocol by Sex interaction was found for alpha power at the Cz electrode location (F(1,14) = 9.117, p = 0.009). A main effect of Protocol was found for males (F(1,7) = 7.327, p = 0.030). Alpha power was not different between protocols at the beginning of the contractions, but, during the last minute, was higher for the matched-torque than matched-EMG contraction (t(7) = 2.650, p = 0.033). No Protocol by Time or main effect of Time was found for males. For females, alpha power did not have an interaction or main effects.
Beta power at the Cz electrode location had a Protocol by Sex by Time interaction (F(1,14) = 11.235, p = 0.005). For males, there was a Protocol by Time interaction (F(1,7) = 17.368, p = 0.004) and a main effect of Time (F(1,7) = 6.242, p = 0.041), but not a main effect of Protocol. During the final minute of the contraction, beta power was higher for the matched-torque (t(7) = −3.934, p = 0.006), but not the matched-EMG contraction. Females did not have an interaction or main effects.
A Time by Protocol interaction and main effects of Protocol and Time were found for biceps brachii power in both the alpha (Interaction: F(1,15) = 7.071, p = 0.018; Protocol: F(1,15) = 6.895, p = 0.019; Time: F(1,15) = 19.336, p < 0.001;) and beta (Interaction: F(1,15) = 22.284, p < 0.001; Protocol: F(1,15) = 9.605, p = 0.007; Time: F(1,15) = 38.660, p < 0.001) frequency ranges. Power was greater at the end compared to the beginning of the matched-torque contraction for both the alpha (t(15) = −3.649, p = 0.002) and beta (t(15) = −6.341, p < 0.001) ranges. In contrast, power in both the alpha and beta ranges did not increase during the matched-EMG contraction. Alpha and beta power were not different between contraction types during the first minute; however, both alpha (t(15) = 3.947, p = 0.001) and beta (t(15) = 5.405, p < 0.001) power were higher for the matched-torque than matched-EMG contraction during the last minute.
For triceps brachii, alpha power had neither an Interaction nor main effects. Beta power had a main effect of Protocol (F(1,15) = 5.785, p = 0.030), but not an interaction or main effect of Time. Beta power was not different between contractions during the first minute, but was higher during the last minute for the matched-torque compared to matched-EMG contraction (t(15) = 2.857, p = 0.012).