Lou Gehrig's disease, medically known as amyotrophic lateral sclerosis (ALS), is a progressive motor neuron disease that destroys the nerve cells responsible for controlling voluntary muscle movement. Named after legendary baseball player Lou Gehrig, who was diagnosed with the condition in 1939, ALS gradually robs individuals of their ability to move, speak, swallow, and eventually breathe. Although symptoms can be managed, there is currently no cure, and the disease is ultimately fatal. Although ALS is relatively rare, personal trainers may encounter clients living with the disease or working through its early stages. Understanding how ALS affects movement can help you provide safe, supportive exercise while knowing when modifications—or referrals—are appropriate.
Early signs often include muscle twitching, weakness in the hands or feet, cramping, difficulty with fine motor tasks, or slurred speech. As the disease progresses, muscle weakness spreads throughout the body, making everyday activities increasingly difficult. Many people experience frequent tripping or falling, poor posture, difficulty holding their head upright, muscle stiffness, and persistent fatigue. Over time, most voluntary muscles become affected, although bladder and bowel function are typically preserved.
As ALS advances, breathing muscles weaken and some individuals require noninvasive ventilation or, in later stages, a tracheostomy to assist with breathing. Communication may become increasingly difficult, requiring speech-generating devices or other assistive technologies. Swallowing problems can eventually necessitate the use of a feeding tube to prevent malnutrition and dehydration. Some people with ALS also develop cognitive or behavioral changes, including a form of frontotemporal dementia.
Exercise Considerations
Exercise can play an important role in helping people with ALS maintain mobility, reduce joint pain, preserve range of motion, and improve overall quality of life. While exercise cannot slow the progression of the disease, appropriate movement can help minimize discomfort and support independence for as long as possible. Gentle stretching is particularly valuable for reducing muscle cramping and maintaining flexibility, while light aerobic activities such as walking, swimming, or cycling may help improve cardiovascular fitness and respiratory efficiency.
What Trainers Should Avoid
Because muscles progressively weaken in ALS, exercise programs must be approached with caution. High-intensity strength training is generally not recommended, as overworking already compromised muscles may increase fatigue or the risk of injury. Instead, the focus should be on low-impact movement that promotes comfort, mobility, and psychological well-being. It's also important to remind clients that exercise still provides meaningful mental and emotional benefits, even when physical improvements are limited.
Causes and Risk Factors
The exact cause of ALS remains unknown. Approximately 5% to 10% of cases are inherited, while the remaining cases occur sporadically. Researchers continue to investigate genetic mutations, immune system dysfunction, environmental exposures, and other biological factors that may contribute to the disease. For individuals with familial ALS, children have approximately a 50% chance of inheriting the responsible gene mutation.
The Bottom Line
ALS is one of the most devastating neurological diseases because it progressively affects nearly every aspect of voluntary movement while leaving many cognitive functions intact. Most people survive three to five years after diagnosis, although some live much longer. While there is no cure today, ongoing research continues to improve our understanding of the disease and offers hope for more effective treatments in the future.
Dr. Megan Johnson McCullough, is a Doctor of Health and Human Performance. She received her M.A. in Education – Physical Education and Health Science. Megan has been personal training for 14 years and coaching since 2007. Megan is an elite NASM Master Trainer and professional natural bodybuilder. She is certified from the National Academy of Sports Medicine (NASM) and the National Exercise & Sports Trainers Association (NESTA). Megan also holds titles of Corrective Exercise Specialist, Drug & Alcohol Recovery Fitness Specialist, Fitness Nutrition Specialist and Senior Fitness Specialist. Megan is a Wellness Coach as well as a Lifestyle and Weight Management Specialist. Visit www.everybodysfitoceanside.com and www.mindfulbodysrecovery.com.
