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Optimal spinal strength normalization factors among male railroad workers
T G Mayer1, R J Gatchel, J Keeley
1Department of Orthopedics, University of Texas Southwestern Medical Center, Dallas.
Spine
|February 1, 1993
Summary
Body weight (BW) is the optimal normalizing factor for trunk strength and lumbar lifting capacity. This finding is crucial for comparing patient data to healthy population benchmarks in occupational health studies.
Area of Science:
- Biomechanics
- Occupational Health
- Ergonomics
Background:
- Quantifying trunk strength and lifting capacity is increasingly important.
- Optimal normalizing factors for strength are not well-established.
- Establishing normative data requires reliable normalization for comparing patient data to uninjured populations.
Purpose of the Study:
- To determine the optimal normalizing factors for isokinetic trunk strength and lifting capacity.
- To compare actual body weight (BW), ideal weight (IW), and adjusted weight (AW) as normalization variables.
- To establish normative data for railroad workers.
Main Methods:
- 160 railroad workers from heavy laboring jobs were assessed.
- Isokinetic trunk strength and lumbar/cervical lifting capacity were measured.
- Three height/weight variables (BW, IW, AW) were analyzed for correlation with strength measures.
Main Results:
- Actual body weight (BW) showed the highest correlation with trunk flexor/extensor strength at 60 and 150 per sec.
- BW demonstrated strong correlations (0.49-0.67) with lumbar isokinetic lifting peak force.
- Cervical lifting correlations were lower and favored adjusted weight (AW).
Conclusions:
- Actual body weight (BW) is the most effective normalizing factor for isokinetic trunk flexor/extensor strength.
- BW is the preferred normalization factor for lumbar (floor-to-knuckle) isokinetic lifting.
- Further research may be needed for optimal normalization of cervical lifting measures.