How to film an athlete so the video is worth analysing
Most unusable clips are unusable for the same four reasons, and none of them are the phone.
Every coach with a phone has a camera roll full of video they cannot do anything with. It is almost never the phone. Modern phones shoot better slow motion than the specialist cameras schools were buying ten years ago. It is where the person stood.
The four rules that do the work
- Stand square to the direction of travel, not down the track. A body filmed at an angle is a body whose joint angles are being measured in the wrong plane.
- Hold the phone at about hip height, landscape, and keep it still. Braced against a fence beats handheld, and a cheap tripod beats both.
- Stand far enough back that the athlete crosses the frame rather than filling it. Close and wide bends the geometry at the edges; further away with the zoom left alone is flatter and truer.
- Put the sun behind you. An athlete backlit against a bright sky is a silhouette, and silhouettes lose limbs against the body.
Frame rate, briefly
Sixty frames a second is enough for posture, running form and most jumps. Two hundred and forty is worth using for a takeoff or a release, where the moment you care about lasts a few hundredths. But high frame rates need light. The same clip that looks sharp outdoors at midday turns to noise in a dim gym, and a noisy clip is a clip nothing can be measured from. If the light is poor, drop back to sixty and keep the picture clean.
What one camera genuinely cannot see
This is worth being blunt about, because it decides how many reps you film. A side-on view cannot see anything that happens across the body. Arms crossing the midline, a hurdle trail leg dragging low, shoulders opening early on a throw, a high jump approach drifting off its arc: all of that is invisible from the side and obvious from the front or from behind.
So film the second rep from a different place. Not a second camera at the same time, just the next attempt from behind. Two angles of two reps beats one angle of ten.
What happens to a good clip
The Film Room takes one clip at a time and analyses it as one of seven events (sprint, block start, hurdles, long jump, triple jump, high jump, and throws), because what counts as a fault is different in each. It reports the measures that belong to that event, and names drills for what it found. All of that depends on the clip being square, steady and lit. Nothing downstream can recover an angle that was wrong when it was shot.
Film the same athlete from the same spot each week and the numbers become comparable to each other, which is more useful than any single reading. Move the camera between sessions and you are measuring your own footwork.
Time your next meet with the phones you already have
Timing, the Film Room and the speed gates are free forever, with no account. A Club plan, $71 a month, puts your meets on your own results page, and one plan covers every phone.
Related
Can you measure sprint speed from a phone video?
You can, to about the accuracy of the two marks you put on the ground, which is better than it sounds and worse than a pair of gates.
Read →What frame rate do you need to film a sprinter?
Ordinary video is fine for checking posture. Ground contact time and cadence need enough frames to actually catch the foot going on and off the track.
Read →Should a high school shot putter glide or spin?
The glide is easier to teach, easier to repeat and good enough to win most high school meets; the spin is worth it only if somebody can genuinely coach it.
Read →Try it: Running form analysis app: skeleton, form check, speed and cadence from a phone clip