That does sound like a great way to boost speed. While I was in JROTC the closest thing to doing that was double-time march for a little bit, then calling quick-time march to go back to a walking pace. Another thing I have been doing with my national guard recruiter is that we run as fast as we can for 60 seconds, then walk for 2 minutes over and over again. But that wears you out after a little bit.