There's no doubt that running on a treadmill is most popular during the offseason. Whether you're looking to avoid the winter elements or you're in search of the most efficient workout possible during the busy holiday season, treadmill workouts certainly have their benefits.
While that means that you'll be staying indoors, the good news is that you can do virtually any workout on a treadmill. This includes one of the best workouts a runner can do to boost overall fitness: interval training.
Comprised of short, hard bursts of speed followed by brief periods of rest, intervals can help you maintain and even increase fitness in a short amount of time.
"Interval training translates into an increase in your lactate threshold rate—in other words, being able to run faster for greater periods of time," explains Matt Johnson, the founder and head coach at Runner Academy. Improvements in speed and anaerobic capacity will benefit your winter racing and help to jump start your base building for the spring season.
In addition to fitness gains, intervals can help stave off boredom, because it's no secret that running on a treadmill belt can be akin to watching paint dry.
"You're constantly engaged, thinking about your next interval and recovering after a short burst of high intensity exercise," explains Johnson. "The constant change in pace versus running at one pace for a set amount of time keeps your mind active and engaged rather than staring at the timer and mentally thinking about how much time is left."
To get the most out of interval training, you'll want to chart out your ideal pace, duration and number of intervals to be completed.
"How you approach interval training will vary depending on your current fitness level and the race distance you're training for," says Johnson. "In general, shorter races call for an emphasis on shorter intervals performed at a higher number of repetitions and a faster pace, while longer races call for an emphasis on longer intervals performed at a lower number of repetitions and a slower pace."
In most cases, your intervals should be executed at 98 percent of your max heart rate, with some variability depending on the length of each interval. The pace will feel quite difficult, but not so fast that you aren't able to complete the workout. You should feel like you're capable of completing one extra interval after your workout is complete.
Recent research helps us to pinpoint exactly how long each of our intervals should be. The study, which was conducted at the Mayo Clinic, looked at 37 separate studies that examined interval training and VO2 max. They found that intervals ranging from 3 to 5 minutes were most effective at increasing fitness.
Although you'll occasionally come across workouts that include shorter or longer bouts of intensity, this range was proven to be the most effective. If you're training for a 5K, it's probably best to stick with shorter intervals. If you're training for a marathon, stick to intervals longer in duration.
The number of intervals you complete will depend on your fitness level and the type of race you're training for. As Johnson suggests, increasing the number of repetitions and decreasing the time of each interval is best for shorter distances and the opposite holds true for longer distances. However, there should be some progression to your approach. So while you may start with 4 x 3-minute intervals when training for a 5K, the quantity should be bumped up by every 1 to 2 weeks.