Standing Data Disproves Biomechanical Mechanism for Balance-Based Torso-Weighting

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• 作者：Ajay Crittendon ; PT ; DPT^a ; Danielle O'Neill ; PT ; DPT^a ; Gail L. Widener ; PT ; PhD^b ; Diane D. Allen ; PT ; PhD^a ; ^{ddallen@sfsu.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Multiple sclerosis ; Postural balance ; Rehabilitation
• 刊名：Archives of Physical Medicine and Rehabilitation
• 出版年：2014
• 出版时间：January 2014
• 年：2014
• 卷：95
• 期：1
• 页码：43-49
• 全文大小：649 K

文摘

To test a proposed mechanism for the effect of balance-based torso-weighting (BBTW) in people with multiple sclerosis (MS) and healthy controls. The mechanism to be tested is that application of light weights to the trunk may result in a biomechanical shift of postural sway in the direction of weighting, mechanically facilitating maintenance of the center of mass over the base of support.

Design

Nonrandomized controlled trial.

Setting

Motion analysis laboratory.

Participants

Participants with MS (n=20; average Expanded Disability Status Scale score, 4.1) and controls matched for sex, age, height, and weight (n=18).

Intervention

Light weights strategically placed according to the BBTW protocol were applied to all participants after at least 3 walking trials and 10 seconds of quiet standing with feet together and eyes open and then eyes closed. Measures were repeated after weighting.

Main Outcome Measure

Forceplate center of pressure (COP) changes >1 standard error of measurement.

Results

With BBTW, people with MS had larger maximum changes in COP than healthy controls in the left-right direction but not in the anterior-posterior direction. COP changes >1 standard error of measurement occurred in the same direction of weighting 20% of the time (95% confidence interval, 5–34), ranging from 10% to 28% across conditions and directions of postural sway. Direction of greatest weight placement did not match the direction of change in the average COP in most participants with MS or the healthy controls in eyes open or eyes closed conditions (P<.001).

Conclusions

If BBTW worked via a biomechanical shift of the center of mass, COP changes should match the direction of greatest weighting with BBTW. Our data allowed us to reject this hypothesis. Future research may explore alternative mechanisms of action underlying this intervention.