Walk a minute, jog a minute, run a minute. Repeat. For someone with short legs (who is not used to running distances), I've found this is a great alternative. Plus, it breaks up the time so a half-hour on the treadmill doesn't feel so long.
After building up your endurance, you can make your intervals include longer periods of higher intensity and you can actually feel (and see!) the improvement.
Shared by maggie on 2/11/08
Great suggestion. I've read about alternating intensity and it's supposed to help you get the most out of your workout. I run a block/walk a block when I'm cold or in a hurry to get home. It's a fun little "game" that gets me to my door in no time!