Muscle spasms, also called muscle cramps, are painful, involuntary contractions that occur in your muscle tissue. If you exercise without properly preparing your body or maintaining adequate fluid intake, you significantly increase your chances for developing these contractions. This is true for both casual exercisers and trained athletes who participate in endurance events.
Basics
You can develop a muscle spasm while performing almost any type of exercise, and although they can form in any muscle, they most frequently occur in muscles with ends that span across your joints, including the hamstrings on the backs of your thighs, the quadriceps group on the fronts of your thighs and the gastrocnemius muscles that form your calves. You can develop a spasm in part of a single muscle, throughout a single muscle or in multiple muscles in a given muscle group.
Risks
If you're in your mid-40s or older, natural loss of tissue in your muscles increases your chances for the onset of exercise-related muscle spasms. This is true for several reasons, including reduced muscle durability and response time, as well as reductions in your body's ability to estimate your muscles' water requirements or respond to temperature changes in your local environment. If you're a trained athlete who participates in marathons or triathlons, you may develop spasms during offseason preparations for competitions or at the end of practices or competitions that last for four to six hours or longer.
Exercise-related Causes
While scientists don't know exactly why muscle spasms occur, exercise-related spasms appear to be closely related to muscle fatigue and inadequate muscle stretching. If you don't stretch properly before exercising, you reduce the ability of your muscle tissue to withstand the stresses of your activities. In turn, this reduction of capacity increases your chances of fatiguing your muscles. When fatigue occurs, your muscle don't receive their normal supply of oxygen; without this oxygen, waste products in your muscles can build up and trigger involuntary spasms. You also increase your chances for muscle spasms if sweating during exercise reduces your body's normal amounts of salt and minerals such as magnesium, calcium and potassium.
Treatment and Prevention
You can frequently treat or prevent muscle spasms by gently stretching your spasm-prone muscles before you exercise. Hand massage and applications of heat or cold can also help ease spasming once it begins. Additional steps that can help you prevent muscle spasms include lowering or avoiding caffeine consumption, avoiding exercising right after you eat, increasing your fluid intake after exercise, stretching your muscles before you go to bed, avoiding smoking and avoiding the use of stimulant medications such as pseudoephedrine or ephedrine. Consult your doctor if you have severe spasms, spasms that don't respond well to self-care or spasms that occur frequently after exercise.
