Exercise as it relates to Disease/The effects of strength training on patients with muscular dystrophy

What is Muscular Dystrophy?
Muscular Dystrophy (MD) is a genetic, degenerative disease characterised by progressive skeletal muscle weakness, defects in muscle proteins and the death of muscle tissue and cells. In affected muscles, tissues become disorganised resulting in a reduction in the concentration of dystrophin. Dystrophin is a protein found in the muscle fibre membrane and has a helical nature allowing it to absorb shock and return back to its original shape after it has been stressed. Dystrophin is an integral protein in linking actin dystroglycans of the muscle cell plasma (the sarcolemma) and also plays an important role in regulating calcium levels.

Who does Muscular Dystrophy affect?
Within Australia, there is approximately 30,000 people suffering some form of the neuromuscular disease. Prognosis for Muscular Dystrophy depends on the type and the progression of the disease. Cases may be mild and progress slowly throughout ones lifespan, and others may quickly suffer severe debilitating effects.

What are the types of Muscular Dystrophy?
Major forms of MD include:

Exercise Prescription
There is an ongoing debate surrounding muscle training and its benefit for patients suffering Muscular Dystrophy. With an absence of effective therapies, patients suffering Muscular Dystrophy are reliant on symptomatic treatment, by which physiotherapy plays a significant role. There is an increased need for research on short and long term effects of muscular training to determine whether endurance, strength or combination exercise is preferred.

Benefits of Strength Training

 * High-resistance strength training can be beneficial for slowly progressive MD (long-term effects undetermined at present).
 * Initial muscular strength and endurance training shows improvements regardless of the type of MD.
 * Increased muscle strength correlates with and increased level of muscle function.
 * Patients with "limb-girdle" and "facioscapulohumeral" dystrophy derive the greatest physical and functional benefit from a strength program.

Exercise Recommendations
Creating an exercise prescription for patients with any form of Muscular Dystrophy requires a primary focus on gaining muscle strength and endurance in the early stages of the disease. Exercise will not cure Muscular Dystrophy, however it is suggested to decrease the speed at which the muscles will waste. It is important that close attention is paid to flexibility in order to prevent contractures.

Exercise Considerations

 * A resistive exercise program in muscular dystrophy is most effective if instituted early in the course of disease.
 * Ensure to allow for adequate rest when undergoing resistance activity.
 * The loss of isometric and isokinetic strength will parallel the loss of functional capacity.
 * Ensure patients “listen to their body” and decrease intensity if muscle cramps are present.
 * Activity specific tasks should be integrated into a program (i.e. wheelchair propulsion) to enhance proficiency of daily living.
 * Every case and strength training adaptations will be different.
 * High-resistance training for rapidly progressive dystrophies is questionable and should only be commenced in the early stages of the disease (when a substantial amount of trainable muscle fibres is present).