One thing I would like to see further research on is the effect of rest periods in sprint training. When the Tabata study came out in the early 90s, many people followed that protocol of short rest periods. Over the past few years, there have been a number of studies that have a 30-second sprint with 4 minutes or so of rest. So which is better?
One study compared sprint versus interval training in football. The results were similar except sprint training was better in a couple measures. Beyond this study, I haven't found much else.
You would think the metabolic effects of the two would be pretty different. For example, the other week I did Tabata sprints. With Tabata, you are dealing with accumulated fatique and slowly diminishing speed. This week, I did short 20 second sprints with long rest periods (2 minutes or so). With this type of training, you are able to keep your speed higher throughout the workout.
As far as a hunter-gatherer perspective, I would guess that they did short sprints separated by long rest (though I have no evidence to support this). My thought is that humans can't really outsprint other animals. Even with back-to-back sprints, I don't think humans could really catch up to much prey. A sprint/long-rest model would imply that humans mostly tracked their prey with walking, and did occassional sprints to flush out the prey or finally capture it.