Changes in Postural Muscle Dynamics as a Function of Age

Huang, Robert P.; Rubin, Clinton T.; McLeod, Kenneth J.

doi:10.1093/gerona/54.8.b352

Cited by 110 publications

(72 citation statements)

References 17 publications

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“…Thus, in the absence of postural contractions after SCI, neurogenic osteoporosis may develop because pervasive lowmagnitude strains are lost, rather than because a few large strains each day are absent. This hypothesis is supported by the finding that routine postural contractions in the 30 to 50 Hz range decline in older adults (both sexes) [47], a group that undergoes serious bone demineralization over time. In our laboratory, we are investigating the reintroduction of low-magnitude mechanical signals (vibration) as a way to preserve BMD after SCI.…”

Section: Three-dimensional Densitometric Techniques (Such As Periphermentioning

confidence: 83%

“…High-frequency stimulation is known to compromise neuromuscular transmission (a depletion of neurotransmitters at the neuromuscular junction) and therefore it does not adequately challenge other processes known to affect fatigue, notably excitationcontraction coupling [11]. Repetitive stimulation in muscle's normal physiological frequency range (15-50 Hz [47]) may offer a better stimulus for adaptation of muscle fatigue resistance.…”

Section: Muscle Response To Trainingmentioning

confidence: 99%

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Muscle and bone plasticity after spinal cord injury: Review of adaptations to disuse and to electrical muscle stimulation

Dudley-Javoroski

Shields

2008

JRRD

164

141

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Abstract-The paralyzed musculoskeletal system retains a remarkable degree of plasticity after spinal cord injury (SCI). In response to reduced activity, muscle atrophies and shifts toward a fast-fatigable phenotype arising from numerous changes in histochemistry and metabolic enzymes. The loss of routine gravitational and muscular loads removes a critical stimulus for maintenance of bone mineral density (BMD), precipitating neurogenic osteoporosis in paralyzed limbs. The primary adaptations of bone to reduced use are demineralization of epiphyses and thinning of the diaphyseal cortical wall. Electrical stimulation of paralyzed muscle markedly reduces deleterious post-SCI adaptations. Recent studies demonstrate that physiological levels of electrically induced muscular loading hold promise for preventing post-SCI BMD decline. Rehabilitation specialists will be challenged to develop strategies to prevent or reverse musculoskeletal deterioration in anticipation of a future cure for SCI. Quantifying the precise dose of stress needed to efficiently induce a therapeutic effect on bone will be paramount to the advancement of rehabilitation strategies.

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Section: Three-dimensional Densitometric Techniques (Such As Periphermentioning

confidence: 83%

Section: Muscle Response To Trainingmentioning

confidence: 99%

Muscle and bone plasticity after spinal cord injury: Review of adaptations to disuse and to electrical muscle stimulation

Dudley-Javoroski

Shields

2008

JRRD

164

141

View full text Add to dashboard Cite

show abstract

“…Type IIa muscle fibers fire in the range of 20-50 Hz (30), and, albeit small in amplitude relative to the peak signals generated by strenuous activities such as running, these higher-frequency signals are, over time, a predominant component of the mechanical energy in the musculoskeletal system (31). Conditions such as aging reduce these higher-frequency domain signals (32) and suggest that the age- Fig. 4.…”

Section: Discussionmentioning

confidence: 99%

Adipogenesis is inhibited by brief, daily exposure to high-frequency, extremely low-magnitude mechanical signals

Rubin¹,

Capilla²,

Luu³

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

238

198

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Obesity, a global pandemic that debilitates millions of people and burdens society with tens of billions of dollars in health care costs, is deterred by exercise. Although it is presumed that the more strenuous a physical challenge the more effective it will be in the suppression of adiposity, here it is shown that 15 weeks of brief, daily exposure to high-frequency mechanical signals, induced at a magnitude well below that which would arise during walking, inhibited adipogenesis by 27% in C57BL/6J mice. The mechanical signal also reduced key risk factors in the onset of type II diabetes, nonesterified free fatty acid and triglyceride content in the liver, by 43% and 39%, respectively. Over 9 weeks, these same signals suppressed fat production by 22% in the C3H.B6 -6T congenic mouse strain that exhibits accelerated age-related changes in body composition. In an effort to understand the means by which fat production was inhibited, irradiated mice receiving bone marrow transplants from heterozygous GFP ؉ mice revealed that 6 weeks of these low-magnitude mechanical signals reduced the commitment of mesenchymal stem cell differentiation into adipocytes by 19%, indicating that formation of adipose tissue in these models was deterred by a marked reduction in stem cell adipogenesis. Translated to the human, this may represent the basis for the nonpharmacologic prevention of obesity and its sequelae, achieved through developmental, rather than metabolic, pathways. mesenchymal stem cells ͉ obesity ͉ therapeutics ͉ diabetes ͉ vibration

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“…The 30-50 Hz signal, belonging to a relatively high-frequency domain compared with the mechanical signals from muscle contraction, might be critical for maintaining bone mass. 40 Vibration treatment within this frequency domain was found to retard bone loss among postmenopausal women in our previous study, 35 and therefore 35 Hz was chosen as the frequency of interest in this study.…”

Section: Methodsmentioning

confidence: 99%

Low‐magnitude high‐frequency vibration accelerates callus formation, mineralization, and fracture healing in rats

Leung

Shi

Cheung

et al. 2009

Journal Orthopaedic Research

104

130

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Fracture healing is a biological regenerative process that follows a well-orchestrated sequence. Most healing is uneventful and enhancement of normal fracture healing is not commonly done, although it is clinically important in the recovery and regain of functions after fracture. This study investigated the osteogenic effect of low-magnitude high-frequency vibration (LMHFV, 35 Hz, 0.3 g) on the enhancement of fracture healing in rats with closed femoral shaft fracture by comparing with sham-treated control. Assessments with plain radiography, micro-CT as well as histomorphometry showed that the amount of callus was significantly larger (p ¼ 0.001 for callus area, 2 weeks posttreatment); the remodeling of the callus into mature bone was significantly faster ( p ¼ 0.039, 4 weeks posttreatment) in the treatment group. The mechanical strength of the healed fracture in the treatment group at 4 weeks was significantly greater ( p < 0.001). The results showed the acceleration of callus formation, mineralization, and fracture healing in the treatment group. It is concluded that LMHFV enhances healing in the closed femoral shaft fracture in rats. The potential clinical advantages shall be confirmed in the subsequent clinical trials. ß

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Changes in Postural Muscle Dynamics as a Function of Age

Cited by 110 publications

References 17 publications

Muscle and bone plasticity after spinal cord injury: Review of adaptations to disuse and to electrical muscle stimulation

Muscle and bone plasticity after spinal cord injury: Review of adaptations to disuse and to electrical muscle stimulation

Adipogenesis is inhibited by brief, daily exposure to high-frequency, extremely low-magnitude mechanical signals

Low‐magnitude high‐frequency vibration accelerates callus formation, mineralization, and fracture healing in rats

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