Whether you are training for a marathon or just getting into shape, keeping a regular running schedule is important. But doctors at Baylor College of Medicine say if you miss a workout, all is not lost. In fact, it can be beneficial.

Rest days important

"Rest days are important for runners to prevent injury as well as increase muscle strength," said Dr. Jane Corboy, associate professor of family and community medicine at BCM and certified sports medicine physician. "They allow the muscles to replenish glycogen (the energy source used during exercise) as well as allow the muscles to repair minor 'wear and tear' injuries."

Running every day, even while sore, does not weaken the muscles or joints, but it may not allow them to recover enough to adapt to training as well, said Corboy.


Soreness is caused by microscopic tears to the muscle. It is part of adapting to a new activity and plays a role in eventually strengthening and conditioning the muscles, said Corboy.

She adds that doing another hard workout during the peak soreness, usually 24 to 48 hours after the workout that caused it, may result in increasing the inflammation and prolonging the pain. This could prevent gaining as much benefit out of the hard workout as you would if you did it when the muscles had recovered somewhat.

Doing a lighter workout or run may help with soreness but if the muscle is especially stiff, it may be better to do an alternative activity such as swimming or cycling, or take a day off from working out to allow recovery.

Core strength

Corboy also suggests including strength training, particularly of core muscles, in order to avoid injury and improve performance. Having weak core muscles makes the wear and tear of a long run become more and more magnified as the leg muscles fatigue. If the core is "wobbly" so are the hips, knees and ankles, she said.

Corboy suggests talking to your doctor to find out what workouts would be best to add to your running schedule and when rest times are needed.