Runners get tired of long, slow distance. Fortunately, there’s speedwork.
When a slow and steady jogger’s routine gets monotonous, interval training — short bursts of fast running followed by slower “recovery” periods — can add variety and fitness benefits.
Breaking a steady pace can be refreshing
“Intervals break up any boredom someone might be experiencing in their workout, ” said Shelly Glover, an exercise physiologist and co-author of The Runner’s Handbook. “If you like a little spice, then interval training is for you.”
For people in a hurry to get fit, interval training also poses a unique advantage over the mellow jog: it doesn’t take much time.
When Dr. Duncan MacDougall his colleagues at Ontario’s McMaster University studied interval training, they found that a set of four to 10- 30-second sprints, performed three times a week for seven weeks, produced a large increase in mens’ aerobic fitness levels.
MacDougall and his colleagues measured fitness levels not only by performance, but also by the increase in mitochondrial enzymes — chemical keys that turn on the fuel-burning centers in the cells.
This study, which was published in the June 1998 issue of the Journal of Applied Physiology, challenged the prevailing view on the aerobic value of interval training.
To make interval training more interesting, you can change direction, run backwards, sideways, or even skip —
Michael Orick, Master Sergeant, USAF (Ret.)
While it was known that practicing short bursts of activity could improve performance on anaerobic activities — short, explosive movements — scientists believed intervals didn’t necessarily change aerobic capacity.
“The thinking was that in order to get a change in mitochondrial enzyme, an athlete has to train at a low intensity for long periods of time, such as 45 minutes a day of jogging seven days a week,” MacDougall said. “But the total time subjects trained in our study was less than 15 minutes a week.”
Interval training is not complex, and it’s not just for runners. Walkers can speed up for short intervals, then slow back down. So can swimmers and cyclists. Aerobics fans can too, and their classes often have pre-set intervals where participants work out near their maximum for a short period of time.
But there is a right and a wrong way to do it, Glover says.
First, you have to warm up before you interval train, in order to avoid injury. Sprinting right off the bat would be like taking your car into fifth gear without warming up the engine.
Glover recommends 10 to 15 minutes of warm up jogging before beginning the intervals, and ten to fifteen minutes of cool down. This means you need to be comfortable running at least 30 to 40 minutes per session before you start interval training.
Fartlek: Not a Dirty Word
An actual interval in running is called a “fartlek.” The word is Swedish, not toilet talk, but people other than the super-serious running types like to call it a “speed interval” or “speedwork” (for obvious reasons).
You can give your interval training a boost by listening to a homemade music tape during the session. Alternate fast-tempo snippets with slower tempo songs —
Sunny Wang, Functional Fitness, Raleigh, N.C.
A fartlek involves “Picking up the pace, then slowing down,” Glover says.
If you’re running alongside a chain link fence, a fartlek would be running two to five fence posts quickly, then two slowly. Otherwise, you could go for 15 seconds fast, then 15 slow, for about ten minutes.
But the time and length of a fartlek depends on your fitness level. In MacDougall’s study, for example, the participants started out going for four 30-second high speed intervals on a stationary bike, then slowed down and biked with no resistance for two to four minutes. Then they gradually worked up to 10 30-second fartleks.
While the study participants did the 30-second bursts at their maximum potential, Glover recommends trying fartleks at speeds in between all-out sprint and a slow jog.
“For some people, it takes a while to learn the gears between sprint and walk, Glover says. “But the longer the interval, the less ‘sprinty’ it is.”
Just as auto racing can increase your odds of getting in an accident, interval training can increase your odds of a running injury.
But injuries can be avoided through an adequate warmup, as well as a full round of stretching, Glover says. This regimen, along with a commitment to pacing yourself and exploring different paces between jog and sprint, can go a long way toward injury prevention.
“People can get hurt doing speedwork because lot of people go at it with not enough preparation or thought,” says Glover. “Running is a patience game.”