Understanding Stride Length and Walking Speed: Factors & Optimization

Question
How does walking speed depend on your step speed and stride length?

Answer
Step speed and stride length interact in complex ways to control walking speed. I turns out that each person has an optimum combination of these factors for any given walking speed. A person's body mass, leg length, bone and joint structure, muscle strength and endurance, and technique all go into determining the best combination of stride length and step rate.

Despite this complexity, I can generally simplify it to say that stride length and rate tend to be inversely related. That is: the faster the step speed the shorter the length, and the longer the stride the slower the step speed.

There are, of course, limits to both. Too long a stride results in overstriding, which causes wasted energy that will limit endurance. On the other hand, each person's brain seems to have a stride speed limit that when exceeded causes incoordination. This also causes wasted energy.

One of the benefits of long-term training is that we learn (by doing) the most efficient stride length/rate combinations for different desired walking speeds.