A weak balance; Balance and falls in patients with neuromuscular disorders.

Muscle strength is a potentially important factor that contributes to postural control. In this article, we consider the contribution of muscle weakness to postural instability and falling. We searched the literature for research supporting muscle weakness as a risk factor for falls in community-dwelling elderly individuals, for evidence that strength training reduces falls, and for supporting pathophysiological evidence. In virtually all studies that included strength testing, muscle weakness was a consistent risk factor for falls in the elderly. Studies that evaluated the merits of muscle strength training often showed a reduction in fall rates, particularly when strength training was a component of multifactorial interventions, although it was unclear whether strength training alone led to a fall reduction. The optimization of fall prevention strategies calls for better insights into the pathophysiological relationship between muscle strength and balance control, which has been addressed by surprisingly few studies. We conclude that muscle weakness is an important risk factor for falls that is potentially amenable to therapeutic intervention, and that future studies should further clarify the role of muscle weakness in balance control and the pathophysiology of falls. A weak balance: The contribution of muscle weakness to postural instability and falls REVIEW CRITERIA For this review we searched PubMed for articles published from 1978 to October 2007. Search terms included combinations of 'falls', 'fall risk', 'exercise', 'intervention', 'stance', balance', 'elderly', and 'muscle weakness'. For finding pathophysiological evidence a combination of 'neuromuscular disease', 'dystrophinopathy', 'muscular dystrophy', 'polio', 'myotonic dystrophy', 'FSHD', 'facioscapulohumeral dystrophy', 'myopathy', 'myotonia', 'neuromyotonia', 'IBM', 'inclusion body myositis', 'myositis', 'myasthenia gravis', 'lambert eaton', 'congenital myasthenic syndrome', 'spinomuscular atrophy', 'neuropathy', 'ALS', 'amyotrophic lateral sclerosis', 'motor', 'posturography', 'stabilography' and 'falls' were used. The titles or abstracts of retrieved citations were reviewed and prioritized by relevant content. Full articles were obtained and references were checked for additional material when appropriate. Studies concerning subjects living in institutions were excluded. Prospective studies were included for table 1, randomized controlled trials for table 2 and 3, and epidemiological, observational or case-control studies for table 4.