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Updated: May 9, 2026
14:10
Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies
Published on: January 31, 2013
Muscular strains in different modes of load handling
1Occupational Physiology Division, National Institute of Occupational Health, Ahmedabad 380 016, India.
Clinical Biomechanics (Bristol, Avon)
|August 3, 2013
Summary
Optimal load-holding involves specific postures. Trunk-bent, knee-straight positions with loads closer to the body (32-44cm) enhance isometric strength and muscle engagement for better performance.
Area of Science:
- Biomechanics
- Ergonomics
- Human Factors Engineering
Background:
- Understanding how posture affects load-holding capacity is crucial for preventing injuries and optimizing manual handling tasks.
- Previous research has explored various aspects of lifting, but the specific interplay of trunk, knee, and elbow positions with load height and distance requires further detailed analysis.
Purpose of the Study:
- To investigate the influence of ten different load-holding postures on isometric strength and electromyographic (EMG) characteristics of trunk and lower limb muscles.
- To determine optimal load-holding configurations based on load height (LH) and subject-load distance (SLD).
Main Methods:
- Six healthy young males participated in the study.
- Isometric strength and EMG data were collected for trunk and lower limb muscles across ten distinct load-holding postures.
- Variations included straight and bent trunk, knee, and elbow positions, with load heights from 32cm to 125cm and subject-load distances of 12cm and 32cm.
Main Results:
- Maximum voluntary contraction (MVC) was significantly affected by subject-load distance (SLD).
- Higher MVC values were observed with increasing load height (LH) when SLD was 12cm, but the trend reversed at 32cm SLD.
- Trunk-bent/knee-straight postures yielded higher MVCs (31–34 kgf) compared to knee-bent/trunk-straight postures (21–28 kgf), indicating better load-holding capacity in the former.
Conclusions:
- Load-holding operations are most effective in trunk-bent/knee-straight postures when the load is closer to the body (32-44cm height).
- Trunk and lower limb muscles exhibit distinct activation patterns based on trunk posture.
- The hamstrings and quadriceps muscles demonstrate a counter-balanced load-sharing mechanism during knee-bent or straight postures.
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