What are the signs of physical overexertion in ALS?
One of the most common questions people with ALS ask is about their physical capacity and the risk of overexertion from physical activity.
In general, physical activity—even in the presence of paresis or spasticity—is of great importance for maintaining existing motor skills and reducing the negative effects resulting from reduced activity. Against this backdrop, physical therapy (particularly exercise therapy, gait training, and respiratory therapy) as well as the use of exercise machines are fundamental components of the treatment plan for ALS.
Despite the fundamental importance of physical activity, certain physical limitations must be taken into account when using physical therapy and therapeutic equipment. As with any physical activity, individual physical capacity must be considered. This relates to the cardiovascular system as well as the musculoskeletal system.
When setting goals for physical therapy, it is important to note that “overcoming” ALS through “counter-training” is neither possible nor advisable. The maximum load capacity of muscles in ALS has not yet been scientifically investigated.
A clinical sign of muscle overexertion is the onset of “muscle soreness” (muscle pain, known as myalgia), which results from mechanical overexertion of the muscles. Sore muscles are thought to be caused by “microtraumas,” which are microscopic tears in the muscle fiber structures.
The regular occurrence of muscle pain after physical activity should be understood as a sign of muscle overuse. The irregular occurrence of muscle pain after exercise and physical exertion (several times a month) is not considered a cause for concern.
Muscle pain (myalgia) must be distinguished from tendon and joint pain (arthralgia). Joint pain can occur, particularly at the start of physical therapy, following prolonged periods of low physical activity. Here, it is up to the physical therapist’s expertise and experience to strike an appropriate balance between necessary exertion (with justified stretching pain) and overexertion (with pain resulting from overloading the joints).
Even in cases of joint capsule and tendon pain, the pain should be understood as a signal of overexertion, and physical activity should be adjusted accordingly. When pain occurs, the level of activity should be reduced and only gradually increased over a longer period of time (spanning several weeks and months).