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Active-resisted stance modulates regional bone mineral density in humans with spinal cord injury
Journal article   Open access   Peer reviewed

Active-resisted stance modulates regional bone mineral density in humans with spinal cord injury

Shauna Dudley-Javoroski and Richard K Shields
The journal of spinal cord medicine, Vol.36(3), pp.191-199
05/01/2013
DOI: 10.1179/2045772313Y.0000000092
PMCID: PMC3654444
PMID: 23809588
url
https://doi.org/10.1179/2045772313Y.0000000092View
Published (Version of record) Open Access

Abstract

Objective In people with spinal cord injury (SCI), active-resisted stance using electrical stimulation of the quadriceps delivered a therapeutic stress to the femur (∼150% of body weight) and attenuated bone mineral density (BMD) decline. In standard densitometry protocols, BMD is averaged over the entire bone cross-section. An asymmetric adaptation to mechanical load may be masked by non-responding regions. The purpose of this study was to test a novel method to assess regional BMD of the femur in individuals with SCI. We hypothesize that there will be regional bone-sparing changes as a result of active-resisted stance. Design Mixed cross-sectional and longitudinal. Setting Research laboratory. Participants Twelve individuals with SCI and twelve non-SCI controls. Intervention Individuals with SCI experienced active-resisted stance or passive stance for up to 3 years. Outcome measures Peripheral quantitative computed tomography images from were partitioned so that femur anatomic quadrants could be separately analyzed. Results Over 1.5 years, the slope of BMD decline over time was slower at all quadrants for the active-resisted stance limbs. At >2 years of training, BMD was significantly higher for the active-resisted stance group than for the passive stance group (P = 0.007). BMD was preferentially spared in the posterior quadrants of the femur with active-resisted stance. Conclusions A regional measurement technique revealed asymmetric femur BMD changes between passive stance and active-resisted stance. Future studies are now underway to better understand other regional changes in BMD after SCI.
Osteoporosis Fractures Spinal cord injuries Bone mineral density Muscle Paralysis Rehabilitation Osteoblasts

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