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The torque-angle relationship of shoulder rotator muscles: A systematic review
Heron Baptista de Oliveira Medeiros1, Eduardo Campos Martins1,2, Felipe Neumann1
1Biomechanics Laboratory, School of Sports, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil.
Objective:
To systematically examine how shoulder axial rotation angle influences isometric torque production of the internal and external rotator muscles, and to describe torque-angle curve patterns and their determinants.
Methods:
A systematic review was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, with a protocol registered in PROSPERO. Five databases were searched from inception to September 2026. Studies assessing isometric shoulder rotation torque, or force and moment arm, at three or more shoulder rotation angles in non-injured participants were included. Data extraction focused on torque-angle patterns, testing position, muscle activation, moment arms, limb dominance, and methodological characteristics.
Results:
Twelve studies were included. External rotation torque-angle curves were typically descending or ascending-descending, whereas internal rotation curves were predominantly ascending-descending. Peak torque was generally observed near mid-range positions. Only three studies assessed multiple shoulder positions within the same sample, and none directly evaluated shoulder rotator moment arms. Electromyographic data were limited, and methodological heterogeneity, incomplete bilateral assessment, and limited standardization were common.
Conclusions:
Shoulder rotator torque-angle relationships remain incompletely characterized and appear highly dependent on joint position and testing methodology. Current evidence suggests peak torque production near mid-range rotation, but substantial gaps remain regarding functional testing positions, bilateral comparisons, athletic populations, and underlying biomechanical mechanisms.