A busy schedule isn't a valid excuse to skip that workout session. Recent research suggests it's possible to get into better shape in less time with sprint interval training.
A study published in the Journal of Clinical and Diagnostic Research found sprint interval training can be more effective in boosting cardiorespiratory fitness for sedentary people than traditional aerobic exercises.
The study compared two groups of sedentary men who completed either a SIT or AE training program over three weeks. The sprint interval training group worked out three days per week, each time running four reps of 60 seconds hard with 90 seconds rest in between each hard run. The aerobic group jogged five days each week for 30 minutes each time. By the end of the three weeks, the SIT group showed a greater improvement in cardiorespiratory fitness than the AE group. The SIT participants not only had slightly better results, they accomplished it in less than a quarter of the time.
Interval training may be just what you need to boost your running fitness. However, before making the jump to speed sessions, it's important for new runners to spend a couple of months building a running base, says Seattle-based coach Beth Baker.
"People get injured when they go too fast too soon," says Baker. "For newer runners who want to get faster, I often recommend they start with kicking for the last 100 to 200 meters at the end of a run."
Once a runner has spent several weeks focusing on their overall fitness, Baker gives athletes their first experience on the track.
"I will have them start with going slow on the curves and faster on the straightaways—maybe at a pace that they can't hold a conversation at," she says. "I always tell people that they aren't going to find that speed right away, but they can start to make progress by getting into fourth gear, back into third gear, and then into fifth gear."
As you gain confidence, you may want to graduate to a more structured interval session like the one in the study.
Kick off your interval training by running hard for 4 x 60 seconds, either on the road or a track, with anywhere from 90 to 120 seconds of rest in between each set. Begin with this session once per week. Increase the time and number of reps of your workout when you finish the fourth sprint feeling like you have more to give. If that's the case, do 5 x 60 seconds and then try 6 x 60 seconds. Reduce your rest time to between 60 to 90 seconds to increase the difficulty.
Avoid injuries by properly warming up and cooling down before and after your interval training session.
"You should do 10 to 15 minutes of really slow running, skipping, and butt kicks to get all your muscles warmed up well before the workout," says Baker. "Afterward, you can jog and do some static stretching."