Intervals, a training technique that incorporates running at race speed for short, predetermined distances followed by slower-paced intervals, can help runners prepare for longer races. (Tom Shaw/Getty Images / May 12, 2010)

J.A. Abels, 66, is a financial planner by day.

But when he's not working, Abels is a serious Masters track competitor. In fact, he's a national champion, winner of the 2009 indoor 400-meter run in the 65-69 age group.

He ran that 400-meter race in 65.72 seconds. He attributes that victory to one thing: interval training.

"There's no doubt in my mind that interval training is what got me the national championship," the Papillion, Neb., runner said.

Intervals — a training technique that incorporates running at race speed for short, predetermined distances followed by slower-paced intervals — can benefit older runners, whether they're competing in Masters events or just jogging in neighborhood fun runs.

Pete Magill, 48, the 2009 USA Masters 5K national champion in the 45-49 age group and a running coach who lives in South Pasadena, Calif., touts the benefits. "It's inconceivable to me that anyone would attempt to run a good race without (interval training)."

What is interval training?

Interval training teaches your body to go faster. "The only way to get faster is to run faster," said Ross Dunton, 77, a Masters competitor and coach, who lives in Sevierville, Tenn.

With intervals, however, you start running faster in small chunks, in manageable stretches of distance. If your goal is to run a 5K in about 25 minutes — or at about an 8-minute per mile pace — a typical interval training distance would be 400 meters run in about 120 seconds.

This effort would be followed by a 200-meter interval run at a much slower pace. The jog is then followed by another 400-meter run at about 120 seconds.

You would continue in this manner until running 12 of the 400-meter stints at race pace. Overall, including the 200-meter jogging intervals, you'll cover a 7K. Gradually, you can build up to running longer intervals at race pace, with shorter jogging intervals.

How it works

Physiologically, the increased speed helps build the body on a cellular level. The increased effort builds new blood vessels and creates new and more muscle cells. Chris Crowley and Henry S. Lodge explain how the process works in their book "Younger Next Year":

"When you exercise fairly hard, you stress your muscles … You wear out little bits that need to be replaced after each use, requiring lots of fine tuning and minor repairs. This type of injury is called adaptive micro-trauma, and it's critical to your growth and health. It's the signal to your body that it needs to repair the damage — and then some. It needs to make the muscle just a little stronger."

Recovering

Intervals are hard work and require recovery time, so coaches recommend doing one long-distance, aerobic-focused interval workout a week. Magill said runners can add another weekly interval workout using much shorter distances, such as 40 meters or 100 meters. This kind of drill is classified under "speedwork" and is an anaerobic workout.

Magill cautions runners to start interval training slowly to avoid injury. "A lot of people start out way too hard," he said.

To get started, Magill suggests adding 15- to 20-second segments of faster-paced running during regular jogs. After a few weeks, build up to true interval training.

But again, Magill cautions against overdoing it. "When you finish your intervals, if you don't feel like you can run another interval at that pace, you ran too hard," he says.