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Knee and elbow 3D strength surfaces: peak torque-angle-velocity relationships
Laura A Frey-Law1, Andrea Laake, Keith G Avin
1Physical Therapy & Rehabilitation Science Graduate Program, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
Journal of Applied Biomechanics
|July 21, 2012
Summary
Human strength capabilities vary by joint and movement, but not by sex. Understanding these three-dimensional (3D) torque-angle-velocity relationships is crucial for accurate digital human modeling.
Area of Science:
- Biomechanics
- Human Physiology
- Kinesiology
Background:
- Three-dimensional (3D) human strength capabilities, encompassing torque-angle and torque-velocity relations, are increasingly studied.
- Limited understanding exists regarding the variation of these strength surfaces across different joints, especially those with similar biomechanical structures.
Purpose of the Study:
- To compare the 3D strength surfaces between the elbow and knee joints in both men and women.
- To investigate the influence of joint biomechanics and sex on human strength capabilities.
Main Methods:
- Peak isometric and isokinetic strength were measured in 54 participants (30 men) using a Biodex System 3 isokinetic dynamometer.
- Normalized peak torque surfaces were analyzed as a function of joint angle and movement velocity.
Main Results:
- Significant variations in normalized peak torque surfaces were observed between flexion and extension within each joint, and between the elbow and knee joints.
- No significant differences in normalized 3D torque surfaces were found between men and women.
Conclusions:
- Underlying joint biomechanics are the primary determinants of 3D strength surface profiles.
- Accurate digital human modeling requires unique representation of torque-velocity-angle relationships for each joint and movement direction.
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