Video is the cheapest coach in the sport — if you watch it right. Watched wrong, it is a home movie with commentary. The difference is a protocol: two things per session, the fast kid's lines, short.
The protocol
Two things per session, maximum. The temptation after every session is the full autopsy — every mistake, every line, everything at once. A kid's working memory holds one or two corrections before the session's value collapses into a lecture. Pick the two things with the highest return — the coach's flag from the day, or the obvious pattern the footage confirms — and let the rest go until next time. Over a season, two-per-session is dozens of fixed habits; everything-per-session is a kid who stops wanting to watch video.
Compare to the fast kid's lines, not to their own mistakes. This is the single most useful reframe in video review: footage of your rider's errors teaches what not to do, while footage of the fast rider through the same corner — the onboard or trackside clip every paddock can produce — shows what to do. Where do they tip in, where is the apex, when does the throttle open. Overlay or side-by-side if your tooling allows; memory and a pause button if it does not. The rider learns by copying the reference, not by re-living their own highlight reel of failures.
The angles
On-bike video shows what the rider saw — their lines, their braking points, their head movement — and is the honest mirror. Trackside video — a parent at a corner, phone on a tripod, the camera that sees what the rider cannot — shows body position, bike behavior, the difference between what the rider thinks they are doing and what the bike is doing. The two angles catch different problems; the families with a system run both when they can, and always point the trackside camera at the corner where the homework is, not the pit wall. We spend whole weekends building session video for exactly this use — it is not a highlight reel, it is the review material.
Keeping it short
Ten minutes. A video debrief that runs longer than a session stops being review and starts being film studies. Watch once through for context, once at the homework corner, agree the two things, done. The kid who knows debriefs are short brings attention to them; the kid who braces for a frame-by-frame trial learns to dread the camera. Watch to learn — once — then go ride.