STRENGTH TRAINING—or, as it's now commonly called, resistance training—is on a tear. More research papers were published on the science of resistance training in the decade after 1987 than in all the years prior. Ever since the mushrooming interest in aerobic conditioning in the 1970s, studies have shown that, among other things, the upper bodies of elite runners who did not lift weights atrophied at the same pace as those of nonathletes, that weight lifting helped burn fat by raising resting metabolic rate, and that it offset the effects of aging by stimulating the production of human growth hormone. Studies on "core strength" make up the latest chapter in the story.
"The core is the seat of all power," says Al Vermeil, strength and conditioning consultant for the Chicago Bulls. "Studies have shown that when you sit down to do a lift at a machine, you remove all the stabilizers, the neglected smaller muscles that don't move as much weight but keep you supported, connect your upper and lower body, and keep your joints in position. These are the hips, back, gluteus maximus, and lower abdominal muscles."
While strength is the theme during month two of The Shape of Your Life, the plan incorporates basic muscle-building drills from the first month: push-ups, sit-ups, pull-ups, lunges, bent-over lifts, and others. We've tried to streamline your workload in a few of them. Twisting the sit-up at the top adds a rotational component to the exercise. Doing a wide-grip pull-up transfers the work from your biceps (they look nice, but big bi's are only bit players in most sports) to your back. "Simplicity of tools, but complexity of use," says Vermeil. "You can do everything you need with a medicine ball, dumbbells, a Swiss ball, and your own body weight. I used to train guys entirely with things we found in the woods."
Ultimately, the variety of resistance training that you'll encounter here will do more than make you balanced and powerful. It will introduce strength work as a part of holistic conditioning, encouraging you to approach the weight stack not as a way to get buff—which is both impractical and unsustainable—but as a way to make strength a permanent, functional part of your life.