An interesting post by Matt Metzgar on variations of Sprint 8, the high-intensity interval training program.
It’s a short post, so go read the whole thing. But here’s Matt’s takeaway:
[The researchers] are saying that traditional sprinting programs may be overkill in a way, and that you could deplete glycogen just as well by doing 1-2 sprints of 15 to 20 seconds.
This I think leads to a real insight: if you cut the number and duration of sprints (but keep the intensity), then I could see how you could be able to do this workout more frequently. So while 3 days per week of 6 to 8 30-second sprints may be too much for many people, 3 days per week of 1 to 2 15-second sprints may produce similar benefits and be more appealing to people.
I have been doing 6x30s in the pool twice a week, but since the back is doing better am thinking about switching and doing my HIIT workouts on the recumbent bike or elliptical. I may give this protocol a try!
Weight Maven is written by Beth Mazur. Beth believes that obesity is more symptom than cause and that the real problem is our Western diet -- especially sugar, refined grains, and industrial oils. Beth writes about nutrition, ancestral health & food policy. And cats! 
