Steps in 400 hurdles

I’m just wondering about what my step pattern should look like. I’ve heard everything from 21 to 18 to the first hurdle and 15 to 17 in between. What’s best for optimal speed/rhythm?

Optimal stride patterning should not be a major issue since you want to maintain speed and pace rhythm without excessive braking between hurdles.

This key more so from H3 thru H7 and so on… Alternate lead leg hurdling should be a major work activity since conditions (such as wind, improved sprint capability, etc.) will more likely dictate alterations throughout the event.