[c0pium]

> you don't have acceleration

If you actually use a treadmill, or watch motion capture, you’ll see that this isn’t the case. It’s a lot of slight accelerations and decelerations. The variation change from person to person, and more experienced runners are able to minimize them, but they’re still present.

Edit: this study is peripherally related https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8160945/

[leereeves]

> It’s a lot of slight accelerations and decelerations

Isn't that always true? If I pay attention to it, I notice a lot of tiny movements of my head, as I just sit here typing.

"You don't have acceleration" is just talking about the big accelerations from 0 mph to roughly 3 mph to 0 mph, not implying that you're completely motionless as if frozen in ice.

[c0pium]

Acceleration is change in velocity and change in time, either can effect the apparent amount of acceleration. The velocity you accelerate to or from is just an implementation detail.