Weakness
Weakness can occur in any part of the body in MS, and sometimes affects one side of the body more than the other. There are two main causes of weakness in MS:
1. Primary weakness – resulting from damage to the nerve fibres (demyelination) in the brain and spinal cord that stimulate the muscles. The muscles are not receiving the messages they require to contracture and produce movement. The messages can either be slowed or completely disrupted, resulting in varying degrees of weakness.
2. Secondary weakness – this occurs from deconditioning of the muscles due to lack of use. Due to fatigue, pain, poor balance and other factors; it is common in MS that a person’s activity level is reduced. This can cause the muscles to become weak and deconditioned. For this type of weakness, the research has shown that progressive resistive strength training is effective in reversing deconditioning in multiple sclerosis.
Commonly muscle strength is measured using the “Manual Muscle Testing Scale”, which is a 6 point scale ranging from a score of 0 (nil muscle contraction) to 5 (normal, strong muscle contraction).
Weakness in the hips, knees and ankles can affect a person’s mobility and balance. Weakness in the upper body and arms can affect a person’s ability to carry out activities of daily living and self-care tasks. A physiotherapist can assess and identify sources of weakness and prescribe an appropriate strength training program.
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