HEALTH & FITNESS : ATTAINING THE BODY BEAUTIFUL : Interval Training Offers a Big Boost

At some point most athletes want to hoist themselves another rung or two higher on the competitive ladder. For runners, cyclists and swimmers, elapsed time is the measure of success.

In other sports, however, bursts of speed are needed for maximum performance, says Jeff Dilts, fitness manager at the Sports Club/Irvine and a competitive rower and swimmer.

In full-court basketball, for example, a player might sprint up and down the floor 100 times during a game. Racquetball demands 15 or 20 seconds of all-out effort, time after time. Other examples are power lifting and skiing.

The athlete who trains at a single moderate pace will build endurance without building speed. To develop speed, many coaches recommend interval training: using spurts of acceleration during training to get the body used to bursts of faster effort.

The point of interval training is to learn to operate at maximum efficiency and near-maximum effort for longer periods of time.

For the average athlete who is training as much for fitness as for the competitive challenge, a sound program of interval training will usually produce significant improvements in performance. Interval training can be as casual as picking up pace for a block or two on a run, or as complicated as a detailed yearlong training plan with a single race in mind.

Trainers and coaches, however, warn that going overboard with interval training invariably leads to injury. “Because interval training is high intensity, you’re more likely to injure yourself,” Dilts says. “Interval training tends to create more muscle soreness and more muscle damage than lower-intensity training.”

While virtually every athlete improves with interval training, a good plan brings the athlete along gradually. “The idea is to work at high intensity, recover, and then work at high intensity,” Dilts says.

This hard/easy concept applies during the workout itself, and over periods of days, weeks and even years. Dilts recommends a schedule of hard/easy days of training, with intervals one day, then a long, low-intensity workout the next.

What makes extended high-intensity effort so difficult is the buildup of lactic acid in muscles, Dilts says. Lactic acid is a waste product of muscle activity. It causes the burning sensation that you get with hard, prolonged efforts. When lactic acid builds up, the muscle starts to fail and perform less efficiently.

“The goal is to develop the ability for not only the body but the mind to deal with the lactic acid buildup,” Dilts says.

For people just beginning in a sport, an endurance base is more important than speed training, he says: “Interval training is not for the novice. We’re talking about going 80 or 90% of your maximum heart rate.

A conservative method commonly used to determine the maximum recommended heart rate is to subtract your age from 220. An endurance base is built on training at 50% to 60% of one’s maximum heart rate.

Cross-training--working in one sport to develop speed and endurance in another sport--can also increase speed. For example, a distance runner might lift weights to strengthen the upper body.

Cross-training makes sense for the average athlete who wants to achieve overall fitness, Dilts says. Not only is the athlete getting a better physical workout, the variety of activity means that the individual is less inclined to burn out.

However, cross-training will usually be less beneficial for the elite athlete concentrating on one sport.

There’s a wide range of opinion about how intense interval training should be. John Loeschhorn--an elite masters marathoner, owner of Loeschhorn’s for Runners in Mission Viejo and a private coach--is convinced that two to three miles of interval training a week is all a runner needs.

“The idea of speed work is to become very efficient at the race pace you’re running for the 5K and 10K,” Loeschhorn says. “You’ve got to get your body accustomed to running that tempo.

Running faster than that will serve no purpose, says Loeschhorn. “My belief is that you’re not learning anything worthwhile by running 20 seconds a mile faster than your planned race pace. It’s a different stride, a different rhythm.”

If you’re training for a marathon, Loeschhorn suggests running the desired marathon pace for 10% to 15% of your weekly mileage. From experience, he knows that an individual’s optimum marathon pace is about 40% to 50% slower than his 10K pace.

Similar patterns of hard/easy training will help keep a cyclist interested and competitive, year in and year out. Carolyn Follett, a trainer at the Sports Club/Irvine and a competitive cyclist, says proper hard/easy training prevents mental and physical burnout.

She plans the intensity of her interval training so that she peaks for her most important races. In the off-season, her interval training is much less rigorous.