INTRODUCTION: Knowledge of torque and force production capacity and moment arm patterns throughout the movement, and their influence on the torque produced, are essential for understanding human movement and may be of great use for controlling the overload imposed on the muscle-tendon structure. OBJECTIVE: To present mechanical criteria for progression in internal rotation (IR) and external rotation (ER) exercises of the shoulder in the sagittal plane. METHOD: Six individuals were assessed using an isokinetic dynamometer and an electrogoniometer. From the data collected, the mean torque, mean resultant force and weighted mean moment arm were calculated using the SAD32 and Matlab® software. RESULTS: The angles at which the peak ER and IR torque occurred were -34° and 6º with values of 43 Nm and 69 Nm, respectively. The peaks for ER and IR muscle force were at 35º and -14º, and the values at these angles were 10227 N and 8464 N, respectively. The weighted mean moment arm for ER presented an increasing pattern over the whole range of motion (ROM) and the peak was at the end of the ROM, i.e. at -50º (0.91 cm). The weighted mean moment arm for IR was almost constant with its peak at 50º (0.96 cm). CONCLUSION: The mechanical criteria for progression in internal and external rotation exercises of the shoulder are torque, force and weighted mean moment arm because different overloads on the muscle-tendon structure can be caused according to their patterns over the ROM.
shoulder; exercise; rotation; rehabilitation
