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Introduction: The objective of this study was to determine whether motor evoked potentials (MEPs) elicited with transcranial magnetic stimulation and measured with conventional bipolar electromyography (EMG) are influenced by crosstalk from non-target muscles. Methods: MEPs were recorded in healthy participants using conventional EMG electrodes placed over the extensor carpi radialis muscle (ECR) and high-density surface EMG (HDsEMG). Fifty MEPs at 120% resting and active motor threshold were recorded. To determine the contribution of ECR to the MEPs, the amplitude distribution across HDsEMG channels was correlated with EMG activity recorded during a wrist extension task. Results: While the conventional EMG identified MEPs from ECR in >90% of the stimulations, HDsEMG revealed that spatial amplitude distribution representative of ECR activation was observed less frequently at rest than while holding a contraction (P

INTRODUCTION We investigated the effect of workload and the use of pedal straps on the spatial distribution of neuromuscular activation within the rectus femoris (RF) muscle during pedaling movements. METHODS Eleven healthy men performed submaximal pedaling exercises on an electrically braked ergometer at different workloads and with or without pedal straps. During these tasks, surface electromyograms (SEMGs) were recorded from the RF using 36 electrode pairs, and central locus activation (CLA) was calculated along the longitudinal line of the muscle. RESULTS CLA moved markedly, indicating changes in spatial distribution of SEMG within the muscle, during a crank cycle under all conditions (P