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

The Journal of Spinal Cord Medicine, 2013 · DOI: 10.1179/2045772313Y.0000000092 · Published: January 1, 2013

Spinal Cord Injury Rehabilitation Musculoskeletal Medicine

Simple Explanation

This study investigates how different types of standing exercises affect bone density in people with spinal cord injury (SCI). It compares active-resisted stance, where muscles are stimulated to help with standing, to passive stance, where the person is supported without muscle stimulation. The researchers used a special imaging technique to look at bone density in different areas of the femur (thigh bone). This helped them see if some areas of the bone responded better to the exercises than others. The findings suggest that active-resisted stance is better than passive stance for maintaining bone density after SCI, and that certain areas of the femur may benefit more from this type of exercise.

Study Duration

Up to 3 years

Participants

12 individuals with SCI and 12 non-SCI controls

Evidence Level

Mixed cross-sectional and longitudinal

Key Findings

1
Over 1.5 years, the rate of bone mineral density (BMD) decline was slower in all quadrants of the femur for limbs undergoing active-resisted stance compared to passive stance.
2
After more than 2 years of training, BMD was significantly higher in the active-resisted stance group compared to the passive stance group (P = 0.007).
3
Bone mineral density was preferentially spared in the posterior quadrants of the femur with active-resisted stance.

Research Summary

This study examined the impact of active-resisted versus passive stance on regional bone mineral density (BMD) in individuals with spinal cord injury (SCI) using a novel quadrant analysis of pQCT scans. The results indicated that active-resisted stance was more effective at preserving BMD compared to passive stance over a period of up to 3 years, with a trend toward preferential sparing in the posterior quadrants of the femur. The study highlights the importance of regional BMD assessment to detect subtle changes in bone adaptation that may be masked by traditional whole-bone analysis.

Practical Implications

Rehabilitation Strategies

Active-resisted stance should be considered as a superior method to passive stance in rehabilitation programs for individuals with SCI to mitigate bone mineral density loss.

Targeted Interventions

Rehabilitation strategies might be designed to specifically target the posterior quadrants of the femur to maximize bone preservation benefits.

Advanced BMD Assessment

The regional measurement technique can be used in future research to better understand regional changes in BMD after SCI and to detect subtle changes in bone adaptation.

Study Limitations

1
Small sample size may limit the generalizability of the findings.
2
Increased variation prohibits a complete comparison of all quadrants between the two training groups.
3
The study is limited by the lack of high-resolution CT-based imaging.

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