What is the suggested amount of time to rest muscle groups between workouts to prevent injury?
I want to tone (improve shapeliness of existing muscle) my body and workout on average 6 times/wk lifting weights, doing high intensity aerobic classes and doing the elliptical. My typical regimen at the gym involves 45 min of cardio and 6 exercises (15 reps) - 3 exercises of large muscle group (ie chest) and 3 exercises of small muscle group (ie triceps).