A Persistent Misconception About Hip Rotation Torques During Elastic Band Sidestepping.

Resisted sidestepping is widely implemented in rehabilitation and strength training, and exercise prescription is often guided by recommendations based on surface electromyography (EMG) patterns and intuitive assumptions about how elastic-band placement and posture influence hip loading. EMG provides valuable insight into neuromuscular strategies, but it does not, by itself, specify the direction or magnitude of joint-level mechanical demand. In this opinion article, we argue that exercise prescription is strengthened when EMG findings are interpreted within a joint-kinetic framework, in which the net external joint moment, calculated via inverse dynamics, defines the mechanical demand imposed by the task. Using resisted sidestepping as the central example and drawing on previously published three-dimensional inverse-dynamics findings, we address a common misconception that placing an elastic band around the forefeet necessarily imposes an external hip moment toward medial rotation that can help target "hip lateral rotator" muscles. Available inverse-dynamics evidence indicates that, under typical execution with slight hip and knee flexion, forefoot-band sidestepping imposes a resultant external hip moment toward lateral rotation, thereby requiring a net internal muscular moment toward medial rotation to maintain alignment and perform the task. We further highlight that posture and resistance configuration modulate how demand is distributed across joint movement planes. Specifically, band placement alters the moment arms of the elastic resistance relative to different hip joint axes and therefore influences how changes in band stiffness are translated into transverse- and frontal-plane hip loading. Thus, band placement, posture, and resistance magnitude should be selected according to the intended joint-level loading objective rather than inferred from EMG patterns alone. Although illustrated with sidestepping, this reasoning is relevant to many resistance and rehabilitation exercises in which EMG-only interpretations, without consideration of external forces and joint kinetics, may lead to incomplete or incorrect inferences about joint loading and musculoskeletal function.