How do you know if a slow start is reaction or drive?
A slow 40 time out of the blocks has two different causes and they need opposite fixes.
A sprinter who is slow out of the blocks could have two completely different problems, and they call for opposite coaching. One is reacting late to the gun. The other is driving badly once they're already moving. Treat the wrong one and you waste a training block.
Two problems wearing one slow time
Reaction is the gap between the gun and the first real push against the blocks. It is mostly nervous system, and the standard fix is false-start practice and gun drills, not strength work. Drive is everything after that: whether the hips climb too early, whether the trunk pops up before step three, whether the back leg fully extends at clearance. That is mechanics, and the fix is wall drives, resisted pushes and falling starts, not reaction training.
Coach the wrong half and nothing changes. An athlete with clean mechanics who is simply slow off the gun does not need their drive angle rebuilt. An athlete who reacts fine but stands up on step two does not need more false-start reps.
Where film helps and where it stops
StatLap's Film Room checks the start once the athlete is moving: drive-phase trunk lean, whether the hips climb instead of pushing out, back-leg extension at clearance. That is the drive half of the problem, and it is genuinely useful for telling a coach whether what they saw with their eyes matches a number.
- Trunk lean in the drive phase, and whether it stands up early
- Whether the hips climb instead of pushing out
- Back-leg extension at clearance
What it does not do is measure reaction. By the time a sprinter's movement is visible on video, part of their response to the gun has already happened, and a single camera has no way to mark the instant the gun fired against the instant the first muscle fired, unless the system is timing the gun sound itself. That gap is why StatLap's timing side, not the Film Room, is the tool for reaction, and why a coach chasing a slow start should ask which tool actually answers the question before changing anything in practice.
What a single 2D camera cannot tell you: the exact instant an athlete decided to move. It can only show you what happened after that decision became visible, which is already a few hundredths of a second late.
Time your next meet with the phones you already have
Timing, the Film Room and the speed gates are free forever. Publishing results to your own page starts at $59 a month.
Related
Why does my sprinter react fast off the gun but still lose the first ten metres?
A quick reaction out of the blocks and a strong drive phase are two different skills, and the block start setting only grades the second one.
Read →Why your sprinter's back leg never fully extends out of the blocks
The rear leg is supposed to finish straight at clearance, and when it does not, the fix is almost never in the leg itself.
Read →How do you know if your sprinter is anticipating the gun?
World Athletics calls a false start under 100 milliseconds for a reason, and a slow-motion clip will tell you roughly where your sprinter actually sits against it.
Read →