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Knee and ankle joint stiffness in sprint running
Sami Kuitunen1, Paavo V Komi, Heikki Kyröläinen
1Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland. kuitunen@maila.jyu.fi
Medicine and Science in Sports and Exercise
|January 10, 2002
Summary
Sprint running involves regulated joint stiffness. Ankle joint stiffness remained constant, while knee joint stiffness increased with speed, suggesting knee adjustments for optimal performance.
Area of Science:
- Biomechanics
- Human Movement Science
- Sports Physiology
Background:
- Joint stiffness is a key regulated property of the neuromuscular system.
- Understanding joint stiffness regulation is crucial for optimizing athletic performance.
Purpose of the Study:
- To investigate the regulation of ankle and knee joint stiffness during sprint running.
- To analyze how joint stiffness changes with varying running speeds.
Main Methods:
- Ten male sprinters performed sprints at 70%, 80%, 90%, and 100% of their maximum speed.
- Data collected included ground reaction forces, kinematic parameters, and electromyography (EMG).
Main Results:
- Ankle joint stiffness remained constant at approximately 7 N x m x deg(-1) across all speeds.
- Knee joint stiffness significantly increased from 17 to 24 N x m x deg(-1) as running speed increased (P < 0.01).
Conclusions:
- Constant ankle stiffness may be attributed to the dominant role of tendon stiffness in the triceps surae muscle-tendon unit.
- Sprint running performance may be modulated by adjusting knee joint stiffness, highlighting its spring-like behavior.
- Individual mechanical and neural properties likely influence ankle and knee joint stiffness control in complex motor tasks like sprinting.