Running is a great sport with a host of health benefits including cardiovascular strength, muscle tone and calorie burn. If building muscle mass is the main objective to your workout routine, however, you may actually want to cut back on running rather than amping up your mileage.
Developing Running Muscles
A certain amount of muscle development occurs with running just by virtue of engaging your muscles in a strenuous activity. Running can certainly build noticeable muscle tone in your legs, buttocks and core, and burning off excess calories can help you shed fat to better reveal those toned muscles beneath. You can build even greater muscle definition by increasing the incline on your treadmill, running stairs or sprinting uphill, but according to exercise physiologist Susan Paul, weight training is required to increase the number of myofilaments, the threadlike structures that make up muscle fibers -- the expansion of which results in substantial muscle growth known as muscle hypertrophy. Depending on your goals, running may be just enough, or you may need to add a weight-training regimen to bulk up the way you want. Your age, nutrition and genetics also come into play when it comes to building muscle and can affect the intensity of work required to see the muscle gain you're seeking. If you aren't seeing the gains you want, consult with a personal trainer who can help you evaluate your needs for protein, calories and specific muscle-building exercises suitable for your body type.