"I think the key to remaining injury-free is variety," Dr. Carter told POPSUGAR, "which means you may get super into your new workout, but if you do it every day . . . you're going to end up with muscle imbalances and an overuse injury." Variety also works different muscle groups and helps keep things fresh (doing workouts you enjoy makes you want to do them more!). So, change up your routine! Try yoga. Run, but also hit the weights. Remember: you don't want to do too much of any type of workout.