Rational for High Intensity Interval Training

MY COMMENT: Today my workout was a 5 garbage miles in the morning, then after work 4 x 150 rotations of jump rope, 4 x 60 sec hard on a spin bike, and 4 x 100 meters swimming, followed by 4 x 25 meters with the kickboard and zoomer fins. This is facinating, especially for masters runners.

This is a long video, but listen to the first 10-15 minutes and you'll get the idea. THIS IS FACINATING!