This is a common question I receive from individuals interested in strength and toning of their body.
Running is an excellent form of cardiovascular exercise and depending on your level of exertion, can work out the lower limp muscles as well. During any exercise, your muscles get "worn and torn". This is normal and essential for muscle growth. The repair phase of muscle growth you mentioned actually occurs most at night or when you sleep or rest. The repair phase is also imporved if your body has plenty of amino acids (found in protein) to help build up the muscles.
This is why I always recommend any work out routine include a good night sleep with an appropriate amount of protein intake for optimal results.
These Q&A’s are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.