That’s a terrific way to destroy a developing sprinter. This issue has been a major pet peave of mine for years. It’s one thing to break down the biomechanics of a sprint race according to what is being seen by an external observer, but that doesn’t necessarily translate into proper coaching cues.
As I have pointed out ad nauseum in the past, there is often a vast difference between what the athlete’s body is objectively doing in space and what the athlete is subjectively feeling while doing it. Coaching cues have to center on what the athlete is feeling.
Many of the biomechanical elements of these different phases of the race are not consciously perceived by the athlete. If you coach the athlete to consciously emphasize them, there is a good chance they will unnecessarily exaggerate certain movements in order to feel them, which will screw up their technique. This is especially true of the horizontal components of the movement patterns.
Contrast the coaching advice in the above article with Charlie’s general cue for running a race: flick the wrist (to clear the blocks) and pump your arms.