Nice! Have you read The Spinal Engine by Serge Gracovetsky?
As for why it's 180. I said to myself, if we didn't have a number such as 180 brainwashed into us already, how might we actually find a number that makes sense physiologically? Well, of course it would be stupid to not at least observe what the best athletes do. It narrows out a lot of bad conclusions.
The answer I believe is in the contraction times of the muscle fibers:
Soleus (predominant slow twitch) contraction time: 160 milliseconds
Gastroc (predominant fast twitch) contraction time: 100 milliseconds
If we allow for one complete cycle of the muscle contraction/relaxation, from firing to maximum force output and back to the resting state, and assume equal time on the ground as in the air for maximal output:resting efficiency, look what we get:
Slow twitch muscle peak output: 60 / .32 = 187 strides per minute
Fast twitch muscle peak output: 60 / .20 = 300 strides per minute
Elite runners and cyclists focused on endurance tend towards a cadence of 187 when around their threshold.
Elite runners and cyclists focused on the sprints tend towards a cadence of 300 in the shortest of the events, such as the 100m.
There you have it. The golden ratio strikes again. I ain't surprised mfers. 300/187 = phi