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Human bilateral deficit during a dynamic multi-joint leg press movement
Dean Hay1, Vinicius Aguiar de Souza, Senshi Fukashiro
1Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komba 3-8-1, Meguro-ku, 153-8902 Tokyo, Japan. w_dean_c_hay@hotmail.com
Human Movement Science
|February 7, 2006
Summary
The bilateral deficit, a reduction in performance during bilateral movements, was confirmed in dynamic leg press jumps. This phenomenon impacts joint power and work, though muscle activation varies.
Area of Science:
- Biomechanics
- Human Movement Science
- Exercise Physiology
Background:
- Bilateral deficit describes reduced performance in bilateral vs. unilateral movements.
- Previous research on bilateral deficit in dynamic conditions is limited and equivocal.
- Biomechanical analyses of dynamic bilateral deficit are lacking.
Purpose of the Study:
- To investigate the presence and extent of bilateral deficit during dynamic multi-joint movements.
- To analyze kinematic, kinetic, and electromyographic (EMG) data during leg press jumps.
- To compare unilateral and bilateral efforts under equal external load conditions.
Main Methods:
- Five male participants performed maximal unilateral and bilateral horizontal leg press jumps.
- Loads were set at 100% (1BW) and 200% (2BW) of relative body weight.
- Kinematic, kinetic, and EMG data were collected and analyzed.
Main Results:
- Significant bilateral deficits were observed in ground reaction impulse (27.7% at 1BW, 13.0% at 2BW).
- Hip joint power and work, along with ankle and knee work, showed significant deficits under both load conditions.
- Electromyographic (EMG) bilateral deficits were found across most muscles, with values ranging from 6.1% to 20.9%.
Conclusions:
- Bilateral deficit is present during dynamic leg press movements.
- The magnitude of bilateral deficit varies across different joints and measures.
- Individual muscle activation and joint kinetics are not uniformly affected by bilateral deficit.