Abstract
Background The contralateral strength training (CST) effect is a transfer of muscle performance to the untrained limb following training of the contralateral side.
Objective The aim of this study was to explore, in individuals with multiple sclerosis (MS) presenting marked lower limb strength asymmetry, the effectiveness of CST on management of muscle weakness of the more-affected limb following training of the less-affected limb.
Design A single-subject research design was used.
Methods Eight individuals with MS underwent 16 to 18 high-intensity training sessions of the less-affected ankle dorsiflexor muscles. The primary outcome measure of this single-system case series was maximal strength expressed as peak moment and maximal work. Secondary outcome measures were: Six-Minute-Walk Test, Timed “Up & Go” Test, 10-Meter Timed Walk Test, and Multiple Sclerosis Quality of Life–54 questionnaire.
Results After the 6-week intervention, the contralateral more affected (untrained) limb showed a 22% to 24% increase in maximal strength. From pretest-posttest measurements, participants also performed significantly better on the clinical and functional secondary outcome measures. At the 12-week follow-up, the strength levels of the weaker untrained limb remained significantly superior to baseline levels in the majority (5 out of 8) of the outcome parameters.
Limitations Considering the design used, the absence of a control group, and the sample size, these findings should be cautiously generalized and will need confirmation in a properly planned randomized controlled trial.
Conclusions The present proof-of-concept study shows, for the first time, the occurrence of the CST effect on muscle performance of ankle dorsiflexor muscles in people with MS. These preliminary findings reveal new potential implications for CST as a promising rehabilitation approach to those conditions where unilateral muscle weakness does not allow or makes difficult performing conventional strength training of the weaker limb.
Footnotes
Dr Manca, Dr Deriu, and Dr Dragone conceptualized and designed the study. Dr Cabboi, Dr Ortu, Dr Ginatempo, Dr Zarbo, Dr de Natale, and Dr Mureddu collected the data. Dr Manca, Dr Deriu, Dr Bua, and Dr Dragone interpreted the data. Dr Manca, Dr Deriu, and Dr Dragone drafted the manuscript. All authors provided critical review of the manuscript.
The study was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Bioethics Committee of the Local Health Authority (ASL n.1-Sassari, Italy; Prot. number 1160/L/2013).
This work was supported by Fondazione Italiana Sclerosi Multipla (grant FISM 2013/R/11) and by Fondazione Banco di Sardegna (grant FBS 2014/0190). Upon request, the authors can provide any underlying research materials related to the article.
ClinicalTrials.gov identifier: NCT02010398.
- Received May 20, 2015.
- Accepted November 22, 2015.
- © 2016 American Physical Therapy Association
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