This is probably over the top, and I recognize that. I really enjoy the underlying stuff in running, and I'm home sick for the day, so here we go.
https://journals.physiology.org/doi/full/10.1152/jappl.2000.89.5.1991This is supportive of the idea that faster speed is produced more by greater ground reaction force than just moving the legs faster. However, the assertion that two runners of the same height and weight running at the same speed would have the same cadence, stride length, etc isn't supported. There are many other biomechanics factors that go into that.
https://pubmed.ncbi.nlm.nih.gov/20581720/?utm_source=chatgpt.comThis study had runners run at the same pace but manipulate their cadence 5-10% above and below their natural or preferred. It found that when cadence increased and speed stayed the same:
* step length decreased;
* vertical center-of-mass excursion decreased;
* braking impulse decreased;
* the foot landed closer to the runner's center of mass;
* peak knee flexion changed;
* hip and knee energy absorption changed;
* at +10% cadence, peak vertical ground-reaction force changed
So that's same runner, same speed, different cadence, different stride length, different forces and loading.
https://pubmed.ncbi.nlm.nih.gov/20093666/?utm_source=chatgpt.comThis is slightly different, but the study found that force magnitude, force application time, and stride mechanics are separate variables. So even if one variable is equal in two runners of the same height and weight running at the same speed, the other two variables may not be.
Bringing shoes into all this adds a whole other layer of complexity in that some people respond well to super shoes and some don't respond as much. Also, just about everyone is going to respond to one brand better than another for a multitude of reasons. But the underlying biomechanics and outputs don't support the idea that height, weight, and pace make force and loading equal.
I personally think that none of this really matters that much, too. As much as I love it, the bottom line is just go run. If a shoe feels good and makes someone feel their best on a Tuesday at 5:00 AM, wear it. If a race day shoe does the same on a Sunday morning at 7:00 AM after however many months of hard work, then let it rip.