Lower limb body composition is associated to knee passive extension torque-angle response

Area of Science:

• Biomechanics
• Human Physiology
• Sports Science

Background:

• Individual differences in flexibility are influenced by factors like body composition.
• Understanding these factors is crucial for optimizing stretching protocols and injury prevention.

Purpose of the Study:

• To investigate the association between lower limb body composition and anthropometric measures with passive knee extension (PKE) torque-angle (T-A) response.
• To identify specific body composition components that correlate with passive torque, joint angle, and viscoelastic properties during PKE.

Main Methods:

• Twenty-five physically active males with poor flexibility underwent maximal PKE testing at 2°/s.
• Measurements included knee passive T-A, electromyography, viscoelastic stress relaxation (VSR), knee passive stiffness (KPS), and lower limb body composition via DXA.
• Thigh anthropometry was also assessed.

Main Results:

• Thigh skeletal muscle mass, bone mass, and thigh perimeter showed moderate correlations with passive torque, joint angle, and VSR (r values ranging from 0.45 to 0.6).
• Thigh skeletal muscle mass was also significantly correlated with KPS (r=0.42).
• All observed correlations were statistically significant (p<0.05).

Conclusions:

• Passive knee extension T-A response is moderately associated with lower limb body composition.
• Thigh perimeter and skeletal muscle mass are key contributors to knee passive stiffness and viscoelastic stress relaxation.
• Further research is warranted to fully elucidate the determinants of joint flexibility and mechanical responses to stretching.