Does a well-rounded weight-training workout consist of three exercises for each of the major muscle groups? If not, what is a good regimen? And how often should I work each muscle group?

I hate to give you an ambiguous answer like, "It depends," but different routines suit different people with varying goals. The volume of sets and reps and the intensity of your routine must be determined by what you're trying to achieve. A good basic routine is one that hits all the major muscle groups, but there is no rule that says you have to perform three exercises for each muscle group.

If you're training to increase your overall strength, you can do several multijoint exercises that recruit more than one muscle group at a time. Squats use all of the large muscles of the lower body: glutes, quads, hamstrings and the lower back muscles. Dead lifts employ all of the aforementioned muscle groups, with much more emphasis on the hamstrings and lower back. So both exercises could work for a lower-body workout. Just add some calf raises, and your legs are done. If you are rehabilitating a knee and you must limit the resistance you use, then you would be likely to do several different exercises to strengthen your quads and hamstrings.

The bench press uses your pectoral (chest) muscles, your anterior deltoids (front of the shoulder) and your triceps. If you also do lat pull-downs, which recruit your upper back muscles and biceps, you'll cover all of your major upper-body muscle groups. The heightened stimulus derived from having the fibers of several muscle groups fire together greatly enhances the overall increase in strength.

There are no hard and fast rules about how many exercises to do per muscle group, or how many sets and reps of each exercise to do. What you do must be determined by what you want out of your workout. That's where a trainer or strength coach can help you plan a routine.

In any case, you need a minimum of one day off before revisiting a particular muscle group. Depending on how intensely you train, you might take two or even three days off before bombing a muscle group again.

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