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Effect of knee flexion angle on active joint stiffness.
1Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York 10021, USA.
Acta Physiologica Scandinavica
|February 14, 2004
Summary
Active joint stiffness in knee extension is influenced by the angle of knee flexion. Peak stiffness was observed at 70 degrees, impacting maximal voluntary contractions.
Area of Science:
- Biomechanics
- Human Physiology
- Kinesiology
Background:
- Understanding joint mechanics is crucial for optimizing physical performance and injury prevention.
- Active joint stiffness plays a significant role in force transmission and stability during dynamic movements.
Purpose of the Study:
- To investigate the relationship between knee flexion angle and active joint stiffness during maximal voluntary knee extension contractions.
- To determine if knee flexion angle influences the measurement of active joint stiffness.
Main Methods:
- Eighteen healthy subjects (11 male, 7 female) participated in the study.
- Isometric knee contractions were performed at various knee flexion angles (30°, 50°, 70°, 90°, 110°).
- Active joint stiffness was calculated from torque changes during a brief stretch, accounting for gravity and passive tension.
Main Results:
- Knee extension torque exhibited a plateau between 70° and 90° flexion.
- Peak active joint stiffness was identified at 70° knee flexion.
- Stiffness at 70° was significantly higher compared to 30° and 110° flexion angles.
Conclusions:
- Active joint stiffness is angle-dependent in the knee joint.
- Maximum active joint stiffness typically occurs at or before the angle of peak torque production.