If you are just starting back running, it is a good idea to take a few days in between your workouts. This will allow the lactic acid that builds up in your muscle to dispate. if you do not it could cause fatigue and could cause some problems. After about 2 weeks you should be able to go back to back, but you probably want to take a day of after every 2 to 3 days of back to back running. Stressing the same muscles day to day can cause chronic fatigue and might cause some injuries. GOOD LUCK

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