Can physical therapy be harmful for ALS?

In general, physical therapy plays a crucial role in ALS by strengthening existing motor functions, alleviating symptoms, and maintaining mobility and participation.

Despite this positive goal, physical therapy may be associated with “side effects.” In particular, in patients with predominantly second-motor-neuron damage (muscle atrophy and paralysis), pre-existing muscle weakness may be exacerbated immediately after physical therapy. This manifests as fatigue and exhaustion following the therapeutic sessions. Additionally, muscle pain (myalgia, “sore muscles”) may occur.

Both of these aftereffects of physical therapy (fatigue and muscle soreness) are signs of overexertion during physical therapy, which can be corrected by adjusting the intensity, duration, and frequency of the therapeutic sessions. Temporary fatigue and occasional muscle pain are not a cause for concern and are a sign of a “training effect.” Persistent fatigue and continuous pain should be considered problematic side effects and should be addressed—in consultation with the physician, therapist, and patient—by adjusting the level of therapeutic exertion.

Due to the wide variation in the course of ALS (different rates of progression and a variable combination of damage to the first and second motor neurons), conducting clinical trials on physical therapy is very complex. As a result, only a very small number of medical studies on physical therapy for ALS have been conducted. Due to the lack of research, no precise exercise limits have been defined to date.

Based on empirical knowledge, physical therapy should aim to utilize up to 80% of an individual’s maximum capacity. Many people are aware of their own bodies and have an internal sense of when they have reached their maximum capacity (100% of their potential) and can also estimate their submaximal capacity (a “perceived” 80% of their individual capacity).

The potential “side effects” relate to muscle strain and do not affect the nervous system. Even in cases of fatigue or muscle pain following physical therapy, there is no further damage to motor neurons. Therefore, a harmful effect of physical therapy—even during physical exertion—can be ruled out.

In the reality of healthcare delivery, overuse of physical therapy is the exception: more often than not, physical therapy is provided with insufficient frequency and duration. A common cause of underutilization of physical therapy is the limited availability of physical therapists with experience in treating neurological patients.

Another limitation may lie in the prescribing practices of physicians, who have an unfounded concern that physical therapy will lead to an overload of patients and therefore prescribe an insufficient number and duration of physical therapy sessions. To overcome both of these problems, a societal shift is necessary—one that can be achieved through the training of additional therapists, improved funding for physical therapy, and further training for medical specialists in the provision of specialized assistive devices and therapeutic interventions, including physical therapy.