Torque and Force Production during Shoulder External Rotation: Differences between Transverse and Sagittal Planes

Abstract

In joints with 3 degrees of freedom, such as the shoulder joint, the association of different movements results in changes in the behavior of the moment arm of the muscles. The capacity of torque production for the same movement can be changed when movements take place in a different plane. The objective of this study is to quantify differences between torque production and resultant force estimated during the shoulder external rotation in two movement planes: the transverse and sagittal planes (with 90° of shoulder abduction). Eight individuals were evaluated using an isokinetic dynamometer and an eletrogoniometer for movements in the transverse plane and six individuals for movements in the sagittal plane. The results showed that the execution of the external rotation in the sagittal plane allowed greater torque magnitudes and resultant force compared with those in the transverse plane, probably owing to a prestretching of infraspinatus and teres minor.

Análise do torque de resistência e da força muscular resultante durante exercício de extensão de quadril no Pilates e suas implicações na prescrição e progressão

“…In general, the results from the present study corroborate the literature, since the maximum FM R were not always reached when the Γ R reached maximum values during HE exercises on the Cadillac 11,12,14,15 . The explanation for this finding is that by definition, the Γ M also depends on the behavior and size of the WMMA involved in the analysis.…”

“…In spite of the limitations from this approach, described on the methodological section of the present study, previous studies, not related to Pilates, showed that a mechanical analysis of the external demand offered by an exercises and the estimative of the resultant muscle effort made from biomechanical techniques, as a representation of the acting strengths through FBD and the use of movement equations, can be used objectively for the prescription of exercises during training and rehabilitation programs [11][12][13][14][15][16] . The analysis and investigation of the biomechanics of Pilates exercises gained great value, given the wide spread of this modality in clinical practice.…”

“…The reason for this is that the sping's strength (given by the constant of strain and the variation of its length) in addition to its respective perpendicular distance (directly determined by the fixation site of the spring) compose the resistance torque (T R ) offered by this exercise, during the exercise range of motion (ROM). Thus, in clinical practice, Γ R assessment (which considers the variations in the constant of strain and the fixation height of the spring) may provide useful quantitative data for progressing the intensity of the program over the course of the treatment and also indicate in which joint position the external load is maximum 11,[13][14][15] , allowing clinicians to prioritize strength gains in specific ranges of motion.…”

“…Another important factor is the mechanical characteristic of the muscles involved in the exercise (perpendicular distance of the muscle), which composes the muscle torque (T M ) which then counteracts the Γ R 13-16 . The muscle perpendicular distance or muscle moment arm is the distance between the action line of the muscle (on tendon insertion) and the joint rotation center 15,16 . The size of the perpendicular distance of a muscle represents a "mechanical advantage" of the muscle in a joint, and its measurement can assist in the understanding of muscle function 17 .…”

Functional torque ratios and torque curve analysis of shoulder rotations in overhead athletes with and without impingement symptoms

“…Few studies have performed such an analysis of shoulder rotation (Timm, 1997;Toledo, Krug, Castro, Ribeiro, & Loss, 2008), which may provide valuable knowledge about how the torque profile can be modified by either throwing training or shoulder injury. Statistical analysis was performed regarding the position where isokinetic peak torque occurred, and no intergroup differences were found in any test condition.…”