Explosive Exercise

LIKE MANY BASKETBALL players, I was always keen to jump higher. At 5-foot-6, I didn't hold out much hope for dunking, though I was inspired by a fellow University of Washington player named Bart Hess. Despite being similarly vertically challenged, he was a student favorite during pregame warm-ups for his dunking displays.

Rumor had it Hess' training included holding a weighted barbell on his shoulders and doing squats with his toes on a board and heels on the ground, and for the first time I realized specific exercises might help develop jumping prowess. I tried that and other weight lifting, my improvement culminating in a memorable (for me) practice day when the fingernail of my middle finger nicked one of the loops that hold the net onto the rim.

Several years later, for an article for this magazine, I trained for six months to take the firefighter's physical test. (I was a young and eager reporter; what can I say?) To get ready for carrying a fire hose up and down stairs, I ran and hopped the steps in Husky Stadium with a sand-filled inner tube around my neck. When rec-league basketball came around, a longtime teammate was stunned by one play when I drove past a defender and jumped to shoot over her. "Wow!" my teammate said, "you blew past her! You jumped! You hung in the air!" (You can imagine what my usual game looked like.) It was a short-term high, since I didn't keep up the weighted stair-jumping. But that was my inadvertent introduction to the power of plyometrics.

Sometimes called "jump training," the "shock method" or "powermetrics," "plyometrics" can refer both to a type of movement and, more commonly, to an intense exercise system for developing explosiveness. Specifically, the movement involves "loading" a muscle - stretching it - before contracting it. Running, jumping, hitting and throwing are plyometric movements. Weighted squats, jumping over boxes and throwing weighted balls are examples of plyometric training.

Plyometrics was once known mostly to track-and-field athletes and basketball players, but in recent years it has begun to seep into the fitness and recreational-sports world. Besides helping to develop jumping, it can improve form and strength for throwing and paddling sports, add variety to advanced workout routines and help prevent injuries. Like yoga and Pilates, it helps develop the trunk or "core," a foundation of "functional fitness," a current trend in the exercise world.

"I really think that all athletes need to start with strengthening the core," said Dr. Maxine Weyant, a sports-medicine physician at Seattle Orthopaedic & Fracture Clinic. For example, she said, "Jumping in the air starts with the feet, and the trunk and core add to the momentum." Plyometrics inherently strengthens and coordinates many muscle groups at once.

Most training, Weyant said, occurs in forward and sideways planes, "But most injuries occur in transverse planes." Upper-body plyometrics, usually with weight balls, brings such angled movements into play and replicates daily life better than many exercise machines.

Because of its explosive nature, plyometric training is not something to undertake unless already fairly fit. Even then, progression should be gradual and attention to form and alignment is key, which is why a coach or trainer is often recommended, along with good shoes and a forgiving surface, such as a gym mat or spring-loaded floor. Weyant said beginners might ease in with plyometric jumping in a pool, to lessen impacts.

Resources on plyometric training abound, from books such as Donald Chu's "Jumping into Plyometrics" ($19.95) and "Explosive Power & Strength" ($15.95; 800-747-4457) to videos to a Speed City catalog of equipment (800-255-9930) to Web sites (there's a training program posted at www.spinalhealth.net/plyometrics.html).

A couple years ago, I considered trying some purported jump-enhancing shoes, which elevate the forefoot and leave the heel declined to the ground, like Bart Hess' squats. But my Achilles tendon had been cranky, and I was wary of blowing it out.

"Once you're over 35 or so, the elastic tissues in the body become less elastic," Weyant concurred. "What used to feel sore and get pulled when you were younger is now much more likely to tear. So you're at risk a little bit if you take on more of this stuff."

I wound up sending back the shoes, unused. I still have a couple of heavy balls though. And they're beckoning.

Molly Martin is assistant editor of Pacific Northwest magazine.

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NOTEBOOK

On the shelves

-- "No More Excuses!" by Tawni Gomes ($21.95, Paper Chase Press). Inspired by the Oprah Winfrey / Bob Green "Make the Connection" exercise and diet program, Gomes lost 100 pounds in three years and started www.connectingconnectors.com, an online network of encouragement and inspiration.

-- "Healing Moves: How to Cure, Relieve and Prevent Common Ailments with Exercise," by Carol Krucoff and Dr. Mitchell Krucoff. The couple examines research on the therapeutic power of exercise and presents nine programs for those with medical conditions including diabetes, depression, asthma, arthritis, high cholesterol, heart disease, osteoporosis and cancer.

Magnets and pacemakers

People with pacemakers or heart-defibrillating implants should not use therapeutic magnets within 6 inches of their chests, say scientists who presented results of a study at the North American Society of Pacing and Electrophysiology meeting in May. Though even the highest-strength magnets tested were more than 10 times weaker than claimed, said Dr. Thomas Mattioni of the Arizona Heart Institute in Phoenix, they could cause heart devices to switch off temporarily, which could be life-threatening if the patient went into an irregular heartbeat at the same time. More than 2 million Americans have pacemakers and 250,000 have defibrillators to help their hearts beat properly.