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Agreement between vertical ground reaction force and ground reaction force vector in five common clinical tests
L N Veilleux1, F Rauch, M Lemay
1Shriners Hospital for Children and Department of Pediatrics, McGill University, Montreal, Quebec, Canada. lnveilleux@shriners.mcgill.ca
Journal of Musculoskeletal & Neuronal Interactions
|December 1, 2012
Summary
Mechanography accurately assesses lower-limb muscle function. Measuring only vertical ground reaction force (GRF) is sufficient for common dynamic tests in healthy adults, as it represents over 99% of total GRF.
Area of Science:
- Biomechanics
- Human Movement Science
- Exercise Physiology
Background:
- Mechanography is a key method for evaluating dynamic lower-limb muscle function.
- Current mechanography often relies on force platforms measuring only vertical ground reaction force (GRF).
- The assumption that non-vertical GRF components are negligible in dynamic tests needs validation.
Purpose of the Study:
- To validate the assumption that only vertical ground reaction force (GRF) is necessary for mechanography.
- To determine the contribution of non-vertical GRF components during common dynamic lower-limb tests.
Main Methods:
- Fifteen healthy adults performed five distinct lower-limb dynamic tests (hopping, jumping, rising).
- Three repetitions of each test were conducted.
- Peak ground reaction force (GRF) and peak vertical GRF were measured and compared.
Main Results:
- Excellent agreement was observed between peak GRF and peak vertical GRF across all tests.
- Peak vertical GRF consistently accounted for over 99% of the total peak GRF.
- Limits of agreement were very small, ranging from 0.05% to 0.4% of average peak force.
Conclusions:
- Measuring only the vertical component of ground reaction force (GRF) is appropriate for these five mechanography tests in healthy individuals.
- This simplification in measurement technique is valid and does not significantly compromise the assessment of dynamic muscle function.
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