After listening to the great podcast with Justin Williams, I was re-motivated me to go out and work some more on my sprinting.
However, trying the “pull with the opposite hand to the driving foot” technique he described felt totally counterintuitive and made me question if I was doing the right thing.
From trawling the 'net, the only information I could find mentioning this opposing technique was actually from @Pete describing sprint form in podcast 185.
But in the video they did analysing Nate’s sprint technique (here), the only mention was a comment about “pulling in to your hips” (rather than up).
I just don’t think that Justin explained it correctly or quite understood the question.
Physics demands that you pull up with your right hand as you drive down with your right leg.
It’s more of a circular motion than a unidirectional one from what I gather. The analogy of the stairmaster was what made it click for me. The hands are pulling dynamically so while you are pulling up at one point in time, that pull then transitions into pulling into the hip, and the resetting for the next pull. You can kinda see how he does it in this video if you go frame by frame:
