Regular physical activity is crucial when it comes to maintaining -- and building -- muscle mass and bone density. Despite its many benefits, though, exercise is also associated with the development of some side effects, such as leg weakness. In most cases, exercisers can prevent or manage leg weakness by making changes to their pre- or post-exercise routine. Be sure to familiarize yourself with the causes of leg weakness after exercise to ensure optimal results in its treatment.
Low Glycogen Stores
Glycogen is a type of glucose that is stored in the liver and muscles, and is used for fuel during exercise. As with other forms of body fuel, glycogen stores can become depleted during physical activity -- especially when it lasts longer than 60 minutes or is performed at a high intensity. As glycogen stores decrease, exercisers may experience weakness in their legs and other muscle groups. Eating a small snack that contains healthy carbohydrates before an exercise session, or consuming glucose-based substances during extended or intense physical activity, can be an effective way to prevent glycogen depletion.
Dehydration is also associated with leg weakness after exercise, reports the American College of Sports Medicine. In fact, muscles are composed of nearly 80 percent water, so it should come as no surprise that low fluid stores can lead to serious dysfunctions. As dehydration occurs, working muscles experience difficulty contracting in their usual pattern, thus resulting in leg weakness, cramps, and numbness or tingling. Drink at least 8 ounces of water before starting to exercise, and replace each pound of weight lost during activity with another 8 ounces, recommends the American Council on Exercise. In addition, consume at least half of your body weight in fluid ounces over the course of a day to meet minimal dietary requirements.
Over-training syndrome occurs as a result of excessive physical activity and limited recovery time, and may produce leg weakness in individuals who rely excessively on this muscle group, including cyclists and runners. According to Rice University, over-training may be caused by decreases in testosterone, increases in muscular breakdown and changes in immune system function. In most cases, rest is the best form of treatment for individuals who are suffering from over-training syndrome. Depending on the severity of the over-training syndrome, exercisers may need a few days or several weeks to regain leg strength and return to previous levels of performance.
Along with fluid, electrolytes -- like sodium and potassium -- play an important role in muscular contraction. When electrolyte stores are low, then, exercisers may experience weakness in their legs and other muscle groups. While most exercisers get all of the electrolytes that they need with a balanced diet, individuals who engage in extended or intense bouts of activity may need to supplement body stores. Consider the use of electrolyte replacement drinks, such as Gatorade or Powerade, if you exercise more than 60 minutes, live in a very warm climate, or perform high-intensity activity on a regular basis.
- ACSM's Resource Manual for Guidelines for Exercise Testing and Prescription; American College of Sports Medicine
- ACE's Personal Trainer Manual; American Council on Exercise
- U. S. News: The Truth About How Much Water You Should Really Drink
- United States Geological Survey: The Water in You
- Rice University: Overtraining Syndrome