Unlike the frog, you'll certainly notice the ever-increasing difficulty of this workout as you reach the half-hour mark. Perfect for those training for a marathon—even those trying for a Boston qualifier—this workout can be used in place of a more traditional marathon or tempo-pace run that would normally be done outside.
More: What Are Threshold and Tempo Runs?
Play iPod Roulette
This challenging workout is perfect for runners who don't have a lot of time, but want to do an intense session on the treadmill. First, you'll need to create a playlist on your MP3 player of 10 to 12 songs that are about 2 to 3 minutes each. The key is to make half of the songs high intensity and half of them calm and mellow.
After a short warm-up, start your playlist on random shuffle. When an intense song plays, increase your pace to about 10K effort. But when a mellow song plays, slow down to a recovery jog. If you're feeling bold, you can run at a higher incline.
More: Ways to Train on Various Inclines
Be cautious with your pace because it's possible you may be running hard for two or more songs in a row—that makes it even more important to choose short songs and a more cautious pace.
While nothing can replace the feeling of the sun on your face and the wind in your hair, these fun treadmill workouts will keep you guessing and working hard when the weather isn't cooperating. Even though you're running inside like a hamster, that doesn't mean you can't spice up your training.
More: 3 Things to Know About Treadmill Training
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