THE DANGERS OF DAILY WEIGHT TRAINING: “So his advice is to wait 48 hours between sessions of strenuous weight training that target a particular muscle group. You could focus on upper-body muscles on one day and leg and lower-back muscles the next, if you enjoy visiting the gym daily. But don’t exercise all of the muscles every day.”

You don’t want to get into overtraining, which takes a long time to recover from. As Mark Rippetoe says, your muscles grow during the recovery period, not during the workout.