For non-runners , they can substitute the treadmill for 2 to 3 minute intervals with the jump rope , or they can cycle !
Fitter athletes can ratchet up the intensity throughout the intervals , add more repetitions , or add more exercises during the active rest interval .
For non-runners , athletes can substitute the treadmill for 2 to 3 minute intervals with the jump rope , or they can cycle !
Fitter athletes can ratchet up the intensity throughout the intervals , add more repetitions , or add more exercises during the active rest interval .