Influencers of relationships between supraspinatus regional indwelling and surface electromyography in arm elevations

The supraspinatus includes two distinct regions. Relationships between regional indwelling electromyography (EMG) and a surface EMG were defined during arm elevation across several factors. Sex, elevation angle and intensity influenced the relationships for both regions, while plane of elevation influenced posterior supraspinatus (p< 0.01). These responses varied, with surface EMG alternately underestimating and overestimating depending on scenario, by up to 53%. These findings should inform EMG measurement modality choices.