> There is no control of not doing the 20 sec sprints, so i'm not sure how I can conclude that the sprints give the benefit vs the low intensity work surrounding it.

This.

We cannot tell, from the experiment, how much of a difference each high intensity section in the 10m contributes.

Control would not be safe, going from 500w to idle can cause cardiac problems. Especially with elevated bmi.

Empirically, it’s obviously necessary.