Before diving into the details of sprint mechanics, a coach needs to know how to coach speed, (more than just what the correct mechanics are). Speed can be hard or easy to coach depending on the athlete and situation.
With accomplished, elite athletes, details are more important, but not over-coaching.
For young athletes and beginners, coaching is about repetition and fundamentals, as with any sports skill. Too much detail can overload their circuits, so finding the best word cues to streamline instructions is the hardest part.
What does a young athlete hear when you give instructions? What does what a coach says to these athletes mean? If you have read these writings before, then you may already know that the distance from the ear to the brain to the body part that needs to be fixed is a very long way. To go along with that, CRC (Convert– Revert– Convert) is important to understand.
There have been times when a young athlete has come in and I was able to correct some terrible running form in 20 minutes. That is the conversion from bad form to good form. That individual leaves, sleeps, and does other activities before they come back and they revert back to old habits. A few, but an unknown number of workouts later, they convert permanently to the correct form (CRC).
If you take a survey of coaches at a track meet and have them critique any given sprinter or sprinters, you would probably have a consensus of what the runners did well or did poorly. It has been my observation that although any coach can usually tell you what an athlete is doing wrong, they can't always tell you how to fix it. Many good drills are available, but I think the “why” you do this or that drill is far more important.
We all know that practice makes permanent and that there are many good drills being executed poorly, therefore, permanently wrong habits are born. Understanding the why of sprinting and the details of the associated drills will make you a better coach and in turn produce better athletes.
So the original point is that you need to know how to coach speed if you are going to coach speed.
Here are your takeaways
Learn everything possible about correct speed mechanics and don’t stop learning! This will help you find flaws that others might have missed.
Learn as many drills (for correcting errors) as possible. Every drill may not work for everyone. You are the problem solver, find solutions.
Don’t over coach. TMI is a big mistake. Too much information can overload an athlete's circuit. I call it “flushing out bad technique.” If they aren’t getting it, keep them running and work on one toe or finger at a time. They’ll get it eventually.
Style vs. Technique. You must accept the fact that there are athletes who are just flat-out gifted and can run fast and use a good technique you would never teach. If their unique style is fast, leave it alone, period. My 2002 Male old Olympic Medalist in the Skeleton was like that. His leg cycle was terrible, but it was gold medal fast. I didn’t touch it.