Spinal muscular atrophy (SMA) is a disorder involving the nerves that control the voluntary muscles. The nerves involved, called motor neurons, are located in the spinal cord. These nerves are required to control muscle movement. Spinal muscular atrophy results in the inability of the muscles to respond to the nerve signals that tell the muscles to move.1 The result is weakness and shrinking (atrophy) of muscles as a result of not being used enough.
SMA causes a reduction in the level of motor function (movement). Over time, the ability to normally use the muscles continues to slowly decline and often leads to immobility (the inability to walk).2
Staying active while living with spinal muscular atrophy can be a challenge for many people, particularly considering that the condition causes weakness in the arms and legs as well as adversely affects the muscles that enable breathing.
Although having to overcome obstacles (such as muscle weakness and fatigue) can seem like a real trial for those with spinal muscular atrophy, being more active may, in turn, strengthen muscles while improving energy and endurance levels.
Many experts claim that being inactive leads to a worsening of symptoms of SMA. But how much activity is recommended? Can a person with SMA overdo it? What does the clinical research say?
Types of Spinal Muscular Atrophy
There are several types of SMA. Some start during infancy, some develop in early childhood, and others primarily impact adults.
When it comes to the impact of physical activity on SMA, study results are usually specific to just one type of the condition. As a result, it's important to identify which variation of SMA one has. There are types linked to chromosome 5 (chromosome-5 related SMA), which are classified into four subtypes. Other rare forms of SMA (non-chromosome-5-related) are caused by a mutation of a different gene. The five different types of SMA include:
SMA type 1 (infantile-onset SMA or Werdnig-Hoffman disease), the most severe type of SMA, begins within the first six months of an infant’s life.
SMA type 2 (intermediate SMA) begins between 6 months and 18 months of age.
SMA type 3 (juvenile SMA, Kugelberg Welander syndrome) impacts children at age 12 months or older (it may also start during the teen years). Muscle weakness is present, but most people with SMA type 3 can walk and stand for limited periods of time.
SMA type 4 (adult SMA) begins during adulthood.
SMA not linked to chromosome 5 includes various forms of SMA, such as Kennedy’s disease, a condition that involves muscles located further from the center of the body than in other forms of SMA.
When people with SMA are inactive, it can lead to worsening of symptoms such as muscle strength, muscle contractures (a tightening or shortening of muscles that results in joint stiffness and the inability to move affected limbs), joint pain, trouble breathing, and more.1
To prevent muscle contractures and lessen other symptoms of SMA, many health care providers recommend engaging in as much physical activity as possible. However, people with SMA should avoid extreme forms of physical activity, and never exercise to the point of experiencing pain or severe discomfort.3
The Muscular Dystrophy Association says that for those with SMA, an increase in physical activity leads to achieving optimal levels of “general physical and psychological health and well-being.”’
The Muscular Dystrophy Association reports that physical activity is important for many reasons, including:3
Protecting the joints from stiffness
Strengthening the joints to help prevent joint injuries
Preserving normal range of motion (flexibility of the joints and the ability to move the extremities normally)
Maintaining good circulation (blood flow)
Allowing for normal exploration of one's environment (particularly for children)
Be sure to consult with your health care provider before starting a new activity or physical exercise. Once you get the stamp of approval from your health care provider, the Muscular Dystrophy Association recommends the following.
ust be prioritized.
Attending regular therapy appointments (with physical and occupational therapists) can help to ensure that joints and muscles are used properly for maximizing function. Consult with therapists about the use of various appliances that can help to optimize the ability to stand and move.
These may include walkers, braces (orthoses), manual powered wheelchairs, powered exoskeletons (a wearable mobile machine made up of a combination of technologies that allow for limb movement), and other types of assistive products.
Your health care provider, therapist, or SMA team may recommend the use of orthotics (supportive braces or splints designed to support, align, or correct the function of movable body parts).
Orthotics may help to promote movement and activity by lessening joint pain, correcting alignment, and lowering the incidence of contractures.
Employing assistive technology may help adults as well as kids in performing work and school tasks by supporting normal movement. The technology may include devices designed to help use a computer, answer a telephone, or help with writing, drawing, or painting.
Assistive technology may also help a person with SMA be able to use everyday equipment such as thermostats, light switches, and more.
Exercise can help improve circulation, reduce muscle stiffness, and maintain flexibility of the joints. In addition, a regular exercise routine has been found to lend itself to promoting a better mood, improving sleep, and more.
A 2019 Cochrane review of studies examined the benefits of specific exercise routines for those with type 3 SMA.2 In the study, the workout regimes were comprised of muscle strengthening and aerobic exercises (but did not involve breathing exercises).
Study participants worked out on a treadmill and stationary cycle and lifted weights. According to the study authors, “’the skeletal muscle training should aim to increase a person's functional performance, muscle strength, cardiopulmonary [heart and lung] exercise capacity, and quality of life, and reduce their levels of fatigue.”
Skeletal muscles are voluntary muscles that are required to move a person’s body voluntarily. Other types of muscles in the body include involuntary muscles (such as those used to make the heart beat continuously).
The 2019 Cochrane review found that in those with type 3 SMA, muscle strength and aerobic capacity may be influenced by skeletal exercise training.2 The study authors explained that physical exercise may also result in lower fatigue levels and overall better quality of life.
But the study authors warn that some of the clinical research evidence is conflicting. This is because there is a point where exercise may over-fatigue the muscles. The authors went on to explain that, at this time, “it is uncertain whether combined strength and aerobic exercise training is beneficial or harmful in people with SMA type 3, because the quality of [study] evidence is very low. We need well-designed and adequately powered studies using protocols that meet international standards in order to improve our understanding of the exercise response in people with SMA type 3."
While you may be eager to begin a fitness routine, it’s best to consult with your health care provider, physical therapist, and other members of your health care team before engaging in a workout program.
A Word From Verywell
When it comes to investing in technology to promote mobility for those with SMA, not everyone can afford the expense. But the Muscular Dystrophy Association can help. The organization has a special national equipment program to help people with disabilities such as SMA acquire wheelchairs and other medical equipment. To learn more, contact the MDA’s Equipment Assistance program.
In conclusion, there are many options when it comes to ways to stay active with spinal muscular atrophy. But it's important to be cautious and consult with your health care team, including your primary care provider, physical therapist, and other team members