Plyometrics' jumps and other moves can propel you to higher fitness levels

March 20, 2007

NADIA BOROWSKI SCOTT / Union-Tribune

Try plyometrics.

Although it sounds technical, it's actually as simple as child's play. In fact, plyometrics often is part of children's activities. Jumping jacks, skipping, jump-rope and hopscotch are all forms of plyometrics, sometimes called “jump training.”

Traditionally used to develop explosive power and performance in athletes, this form of training is now being incorporated into the exercise regimens of desk jockeys, stroller-pushing moms and even seniors. Plyometric movements can be used by almost anyone looking for stronger, more toned, less injury-prone muscles.

“The real benefit of plyometrics is that it builds power, which is a combination of speed and strength,” says exercise physiologist and biomechanics specialist Anthony Carey, owner of San Diego-based Function First, a corrective exercise studio. “While power (is necessary) in almost every sport, we all need power to get up and down stairs, push a lawn mower, pick up a toddler or go down the ski slopes.”

An exercise is considered plyometric when it involves a very fast dynamic stretch of a muscle immediately before its forceful contraction. An example is a squat-jump. When you squat down, you're lengthening or stretching the leg and gluteal muscles. When you quickly leap up into the air from that crouched position, you're contracting or shortening those muscles. When the stretching-shortening movement is done rapidly, the elastic or rubberbandlike quality of the connective tissue induces a much more powerful contraction than would otherwise be possible. This creates a stronger, more powerful muscle.

Although plyometrics is frequently referred to as “jumping exercise,” it's not just about jumping, although jumping is the most popular form of the exercise. “People need to find the stage of plyometrics most appropriate for their needs,” says Fabio Comana, exercise physiologist for the San Diego-based American Council on Exercise. “There are some forms of plyometrics that don't involve ballistic jumping.”

Although some people may shy away from plyometrics because of sore knees, hips or backs, the movements may actually improve their function if done in a slow progression, on a forgiving surface and under the watchful eye of a fitness expert or physical therapist.

“It's ironic that if a person properly learns how to use plyometrics, it can decrease the impact on the joints because it can train the body to do a better job of shock absorption,” Carey says.

Plyometrics can even be effectively used by many senior citizens who may be starting to lose some mobility, balance and strength with advanced age.

“With power training done at an appropriate level, seniors can get their muscles to react more quickly,” Comana says. “This can improve their quality of life. That can mean the difference between falling and fracturing a hip and not falling.”

If sore or damaged joints limit jumping on padded ground, try jumping in a swimming pool.

University of Maryland researchers found that jumping in water can improve leg strength and vertical jumps almost as much as jumping on the ground. This is because of a decrease in muscle soreness, because legs aren't pounding the ground.

But, for some people, no matter how slow the progression or low the intensity, plyometrics isn't a good idea.

“The reality is that plyometrics could be potentially dangerous for someone with very weakened bones or joints, or someone with a cardiovascular condition,” says Comana, who advises everyone to get a doctor's approval before adding plyometrics to an exercise program. “For some people, plyometrics may be more of a workout than the body can take.”

But if plyometrics does fit your game plan, you've got more to gain than just stronger, more powerful muscles. It also creates stronger, thicker bones, lessening the risk of osteoporosis.

“We know that any load-bearing activity can improve bone mineral density,” Comana says. “Plyometics is even more impactful than most other activities, so there's potential for even greater stimulus to the bone. That's a wonderful thing for women and seniors.”

It also can be a powerful bone-building tool for young people.

An Oregon State University study done in 2000 showed that plyometric training over nine months can improve knee strength and balance and increase the bone mineral density in the lumbar spine and femoral head (leg bone) in adolescent girls.

“When the bones bend slightly, as they do in plyo, it stimulates bone growth,” Carey says. “This can be especially beneficial for adolescents (since these years) are a critical time of bone formation. Plyometrics puts the stress on the growth plates of the bones.”

Before you jump right in, there are a few prerequisites that everyone needs to fulfill before safely trying plyometrics.

You should first check with your doctor, to make sure this type of exercise won't do you more harm than good. You also need some basic strength conditioning and core stability before you start.

“You don't just pull someone off the couch and start plyometrics. It may take four to six weeks of strength training and core conditioning and balance training before you can even begin plyometric training. And, even then, you start out with very simple (plyometric) drills,” Comana says. “But, if you keep at it and have some fun with it, you will see results.”

LOOK BEFOREYOU LEAP

The key to successful plyometric training is slow progression and good form. Exercise pros offer the following tips for safe andeffective jump training:

Before beginning any kind of plyometric training, be sure to check with your doctor to make sure this type of exercise won't be harmful to your health.

When beginning plyometric training, perform movements only under the direction and watchful eye of a fitness professional or physical therapist.

Make sure you've had some basic strength conditioning and core stability training before beginning plyometrics.

Make sure you're stable on two legs. If you can't squat down properly and maintain that stretch, you shouldn't do plyometrics yet.

Find a firm but forgiving surface for plyometrics. Artificial turfs work well, as do spring-loaded wood floors found in many gyms. Cushioned exercise mats are OK as long as they don't slide under your feet. Carpet can be OK as long as there's ample padding beneath. Grass is fine, but it's often not very level. You can even do plyometrics on a swimming pool floor (in water at least waist high). Never perform plyometrics on concrete or asphalt. And, jumping on a trampoline or a Bosu trainer does not give you the benefits of plyometrics, because the bouncy equipment absorbs all the energy.

Wear well-cushioned sneakers with good shock absorption, lateral support and ankle/heel cup stability.

Warm up. Get the body in motion to get the muscles and joints warmed up. You can start with walking, then do some unweighted squats, or stepping up without jumping to “bring heat to the muscles and excite the nervous system,” biomechanist and exercise physiologist Anthony Carey says.

Add plyometrics intervals to your workout. An entire workout of jump training is too much.

When beginning, plyometrics should not be done more than twice a week, because you will probably experience delayed onset muscle soreness 48 to 72 hours after the exercise. Even after you progress, don't do plyometrics more than every other day.

When jumping, land on the balls of your feet with bent knees and a slightly bent torso to absorb the shock. Never land with stiff knees and straight legs. Add plyometric moves to the early part of your exercise program.

– R.J. IGNELZI

SOME PLYOMETRICS STAGE DIRECTION

There are six stages of plyometrics, progressing from low-intensity moves in which you barely come off the ground, to bone-jarring leaps reserved for the likes of Trevor Hoffman. Most people, unless athletically motivated, usually don't need to advance beyond Stage 3.

Stage 1: Jumping in place (jumping jacks, for example). Keeping it basic, you don't have to jump very high. You can also jump in water that's at least waist-deep.

Stage 2 : Standing jumps. Squat-jumps are an example. Start in a crouched position and quickly explode into a jump and then come back down into a squat again. As you become more conditioned, try doing several rapidly in succession for about 10 or 15 seconds. You can either explode straight up or perform a long jump. When you land, come down on the balls of your feet and bend knees to absorb the shock.

Stage 3: Multiple hops and jumps. Hopscotch is an example. Bunny-hop around or over pylons. Travel a distance with your jumps (one leg or two), going back and forth and in different directions rapidly.

Stage 4: Bounding or power skipping. These exaggerated forms of running or skipping use long, stretched-out jump strides and require some skill and strength. Move the arms from the shoulder joint, keeping them bent at an approximate 90-degree angle.

Stage 5: Box drills. This advanced exercise involves jumping onto a box or step, landing in a squat and then jumping back down into a squat. The height of the box can be 6 to 24 inches or more as you advance. Repeat this movement several times.

Stage 6: Depth jumps. Similar to the box drills, this movement uses at least two boxes or steps of even greater height. Starting on top of a box, 36 inches high or more, crouch and jump down, landing in a squat, and then immediately jump back up onto the second box of the same height. Repeat this movement.

Upper-body exercises: Plyometrics can also be used to add power and strength to the upper body, with moves as simple as playing catch with a weighted or medicine ball and advancing to push-ups in which the hands leave the ground.

– R.J. IGNELZI