TY - JOUR
T1 - Experimentally quantifying the feasible torque space of the human shoulder
AU - Baillargeon, Emma M.
AU - Ludvig, Daniel
AU - Sohn, M. Hongchul
AU - Nicolozakes, Constantine P.
AU - Seitz, Amee L.
AU - Perreault, Eric J.
N1 - Funding Information:
This study was funded by the National Institutes of Health ( R01-NS053813 , T32-EB009406 , T32-GM008152 , and F31-AG057137 ) and the American Society of Biomechanics Grant-In-Aid . The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or American Society of Biomechanics. We would like to acknowledge Timothy Haswell, MS for his technical assistance during protocol development and data collection.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Daily tasks rely on our ability to generate multi-dimensional shoulder torques. When function is limited, strength assessments are used to identify impairments and guide treatment. However, these assessments are often one-dimensional and limited in their sensitivity to diagnose shoulder pathology. To address these limitations, we have proposed novel metrics to quantify shoulder torque capacity in all directions. To quantify the feasible torque space of the shoulder, we measured maximal volitional shoulder torques in 32 unique directions and fit an ellipsoid model to these data. This ellipsoid model was used to quantify overall strength magnitude, strength balance, and the directions in which participants were strongest and weakest. We used these metrics to characterize three-dimensional shoulder strength in healthy adults and demonstrated their repeatability across days. Finally, using musculoskeletal simulations, we showed that our proposed metrics can distinguish between changes in muscle strength associated with aging or rotator cuff tears and quantified the influence of altered experimental conditions on this diagnostic capacity. Our results demonstrate that the proposed metrics can robustly quantify the feasible torque space of the shoulder and may provide a clinically useful description of the functional capacity of the shoulder in health and disease.
AB - Daily tasks rely on our ability to generate multi-dimensional shoulder torques. When function is limited, strength assessments are used to identify impairments and guide treatment. However, these assessments are often one-dimensional and limited in their sensitivity to diagnose shoulder pathology. To address these limitations, we have proposed novel metrics to quantify shoulder torque capacity in all directions. To quantify the feasible torque space of the shoulder, we measured maximal volitional shoulder torques in 32 unique directions and fit an ellipsoid model to these data. This ellipsoid model was used to quantify overall strength magnitude, strength balance, and the directions in which participants were strongest and weakest. We used these metrics to characterize three-dimensional shoulder strength in healthy adults and demonstrated their repeatability across days. Finally, using musculoskeletal simulations, we showed that our proposed metrics can distinguish between changes in muscle strength associated with aging or rotator cuff tears and quantified the influence of altered experimental conditions on this diagnostic capacity. Our results demonstrate that the proposed metrics can robustly quantify the feasible torque space of the shoulder and may provide a clinically useful description of the functional capacity of the shoulder in health and disease.
KW - Aging
KW - Biomechanics
KW - Muscle balance
KW - Musculoskeletal simulations
KW - Rotator cuff tears
KW - Three-dimensional strength
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U2 - 10.1016/j.jelekin.2019.05.014
DO - 10.1016/j.jelekin.2019.05.014
M3 - Article
C2 - 31171406
AN - SCOPUS:85066404898
JO - Journal of Electromyography and Kinesiology
JF - Journal of Electromyography and Kinesiology
SN - 1050-6411
ER -