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HAWC offers second phase of strength, conditioning

By Alex Salinas | Joint Base San Antonio-Randolph Public Affairs | Feb. 14, 2013

JOINT BASE SAN ANTONIO-RANDOLPH, Texas — (Editor's note: This is the fourth in a series of articles about circuit training workouts published once a month in the Wingspread.)

The Joint Base San Antonio-Randolph Health and Wellness Center introduced the beginning phase of strength and conditioning exercises in January for its recommended monthly circuit exercises. The next phase incorporates plyometrics, also known as jump training.

"Plyometrics is training that targets our fast-twitch muscle fibers," Keith Prince, HAWC Health Promotions Flight chief, said.

The body is composed of two primary muscle fibers: fast- and slow-twitch muscles. Fast-twitch fibers contract quickly and provide speed and strength, while slow-twitch fibers contract slowly and can be used for longer periods of time.

Sprinters perform well when their fast-twitch muscles are strong, while endurance runners need sturdier slow-twitch muscles.

"Fast-twitch muscles are white in color due to less oxygen flow and offer greater power up front, but can't sustain for very long," Prince said. "As we age, these muscles can diminish if they aren't engaged."

The suggested exercises to work out fast-twitch fibers are squat jumps, skater plyos, medicine ball slams, chest presses and rows.

Squat jumps help increase one's vertical leaping ability with explosive leaps coming out of a squatting position.

Skater plyos are another routine that help build the lower body with lateral movements.

Medicine ball slams require participants to slam a medicine ball to the ground, delivering full body benefits, from the back to the thighs.

People should use one or two workout mats to bounce medicine balls on, Prince said.

Chest presses and rows, which both require TRX Suspension Trainer bands, are total resistance cross-training drills that help strengthen muscles above the torso such as the chest and shoulders.

Medicine balls, workout mats and TRX bands are available at the Rambler Fitness Center.

Each exercise should last 45 seconds for two rounds, with 15- to 20-second rests in between the drills and two-minute breaks in between rounds.

"During the first round, you may not get many repetitions in, so work on your form and technique," Prince said. "Once you've worked out the kinks, pick up the pace for round two. Add a third round for all-out exertion if you're able to."

Fast-twitch muscle improvements help muscles become leaner, which increases one's metabolism, leading to greater calorie burns and changes in body composition.

For more drills, contact the HAWC, Bldg. 999, at 652-2300.