Weeks five through eight of The Shape of Your Life focus on functional strength. All the moves (see sidebar) are simple adaptations of standard weight-room lifts. The key difference is that everything takes place on your feet or a stability ball (you can purchase the latter, also called a Swiss ball, at your local sporting goods store). Lifting on a wobbly platform develops your core, a muscle group that transfers strength gains to real sports.

Our regimen stresses quality over quantity, so you'll do only one set, but perform each rep in a slow, smooth manner (five to ten seconds each), placing equal emphasis on both the up and down portions of the lift. Use enough weight to bring you just short of exhaustion after ten reps. When it gets easier, increase the weight, slow down the reps, or both. Each workout, complete a ten-minute warm-up before starting, and mix up the order of the exercises; variety will promote continued muscle growth. In month three, you'll perform a simple cable test that can help measure increases in core strength.

For endurance, continue zone heart-rate training (see sidebar) three days a week. Weeks five and six use intervals to raise your lactate threshold. To maintain the periodized approach laid out in month one, you'll add time (about ten minutes) to your workouts in week seven, and reduce them in week eight to get you rested for the next phase.

Barrier: Your dumbbell routine is stale.
Breakthrough: Tap your imagination.
Using a wobble board or a stability ball, you can invent your own functional lifts. But can't you get hurt making up exercises? "As long as you concentrate on the following, you can't go wrong," says Chuck Wolf, manager for human performance at the USA Triathlon National Training Center. "To protect your lumbar spine, when you twist, make sure your pelvis leads the way. Second, when you bend forward, pull your abs in. This will reduce the risk of spine injury and keep your back straight." Follow his advice and you can spice up your routine. Tired of push-ups? Try them on one arm. Bent-over flies too easy? Try lying on a stability ball.