The neuromuscular system provides communication between the brain and muscles. It’s composed of all the muscles in the body and the nerves serving them. Every movement requires communication between the brain and the muscle; the better this system communicates, the better movement patterns will be performed. This system is controlled by our somatic nervous system, which is comprised of both afferent (sensory) and efferent (motor) nerves. Nerves have cells called neurons; these neurons carry the messages from the brain via the spinal cord. The neurons that carry these messages to the muscles are called motor neurons. Each motor neuron ending sits very close to a muscle fibre. Where they sit together is called a neuromuscular junction. When the nervous system signal reaches the neuromuscular junction, a chemical message is released by the motor neuron. The chemical message, a neurotransmitter called acetylcholine, binds to receptors on the outside of the muscle fibre. That starts a chemical reaction within the muscle, creating a contraction.
A breakdown between the communication of the nerves and muscles is called a neuromuscular disease. Some examples include:
- neuropathies (problems with the nerves), such as Charcot-Marie-Tooth disease or motor neuron disease
- myopathies (problems with the muscles), such as muscular dystrophy
- neuromuscular autoimmune conditions, such as myasthenia gravis or multiple sclerosis
When the nerves are damaged, they don’t carry messages from the brain as they should. In others, the muscles are damaged, and they either cannot receive messages from motor neurons, or they cannot respond as they should.
Either way, the person affected can have problems with tiredness, weakness, muscle pain, wasting and spasms. Often, the symptoms affect the arms and legs more than other parts of the body.
How can exercise/movement, using an external stimulus, be used to help manage and counteract the defected communication between the muscles and nerves?
Regarding Neuropathies: the nervous system in neuroplastic, referring to the ability of the nervous system to change its activity in response to intrinsic or extrinsic stimuli by reorganizing its structure, functions, or connections. Nerves can grow, they can heal, they can improve their ability to send messages. How? By training them specifically, through the anaerobic Alactic energy system, the system which is fuelled by stored ATP and creatine phosphate (CP). The movements that create the highest recruitment of muscle motor units are those of a high velocity nature – aka POWER. By training at this level, it will induce neuroplasticity, even at the neuromuscular junction.
Regarding myopathies: due to the nature of these conditions, that being a dysfunction of the muscle fibre, exercise works by maintaining and improving muscle size and strength, which can be done through resistance training; preventing deterioration and improving functional capabilities.
Improving the way our nerves and muscles communicate can not only benefit those with a neuromuscular disease, it also plays a key role in how athletes break through plateaus: The brain will generally wire movements towards efficiency rather than proficiency. Meaning that if the brain has to pick between power or endurance, it’ll pick endurance. By failing to perform enough specific, high velocity movement, athletes will never break the plateau. How do we break through the plateau? Simple, we need to train specifically more often, and then overload that specificity.
If you would like further information about safe individualised exercise advice speak with an Accredited Exercise Physiologist.