Journal article
Gravitational force modulates muscle activity during mechanical oscillation of the tibia in humans
Journal of electromyography and kinesiology, Vol.21(5), pp.847-853
2011
DOI: 10.1016/j.jelekin.2011.06.001
PMCID: PMC3355375
PMID: 21708472
Abstract
Mechanical oscillation (vibration) is an osteogenic stimulus for bone in animal models and may hold promise as an anti-osteoporosis measure in humans with spinal cord injury (SCI). However, the level of reflex induced muscle contractions associated with various loads (
g force) during limb segment oscillation is uncertain. The purpose of this study was to determine whether certain gravitational loads (
g forces) at a fixed oscillation frequency (30
Hz) increases muscle reflex activity in individuals with and without SCI. Nine healthy subjects and two individuals with SCI sat with their hip and knee joints at 90° and the foot secured on an oscillation platform. Vertical mechanical oscillations were introduced at 0.3, 0.6, 1.2, 3 and 5
g force for 20
s at 30
Hz. Non-SCI subjects received the oscillation with and without a 5% MVC background contraction. Peak soleus and tibialis anterior (TA) EMG were normalized to M-max. Soleus and TA EMG were <2.5% of M-max in both SCI and non-SCI subjects. The greatest EMG occurred at the highest acceleration (5
g). Low magnitude mechanical oscillation, shown to enhance bone anabolism in animal models, did not elicit high levels of reflex muscle activity in individuals with and without SCI. These findings support the
g force modulated background muscle activity during fixed frequency vibration. The magnitude of muscle activity was low and likely does not influence the load during fixed frequency oscillation of the tibia.
Details
- Title: Subtitle
- Gravitational force modulates muscle activity during mechanical oscillation of the tibia in humans
- Creators
- Shuo-Hsiu Chang - University of Texas Health Science Center, Houston, TX, United StatesShauna Dudley-Javoroski - Physical Therapy and Rehabilitation Science Department, The Carver College of Medicine, The University of Iowa, Iowa City, IA, United StatesRichard K Shields - Physical Therapy and Rehabilitation Science Department, The Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
- Resource Type
- Journal article
- Publication Details
- Journal of electromyography and kinesiology, Vol.21(5), pp.847-853
- DOI
- 10.1016/j.jelekin.2011.06.001
- PMID
- 21708472
- PMCID
- PMC3355375
- NLM abbreviation
- J Electromyogr Kinesiol
- ISSN
- 1050-6411
- eISSN
- 1873-5711
- Publisher
- Elsevier Ltd
- Language
- English
- Date published
- 2011
- Academic Unit
- Orthopedics and Rehabilitation; Physical Therapy and Rehabilitation Science
- Record Identifier
- 9984047754702771
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