Watch yourself run

Most weeks somebody sends me a clip. A start they want me to look over, a few strides shot from the side of the track, a "does this look right to you?" with a video attached.

I get through as many as I can.

But I can't reach all of them, and that's started to nag at me. Because the honest answer is that most people sending me a clip don't need me to watch it.

They need to know how to watch it themselves.

So that's this week. How to film yourself sprinting and actually read what comes back, whether you're coaching someone or you're on your own with a phone and a fence to prop it against.

Start with why the video earns its place at all.

What a sprint feels like and what it looks like are two different things, and the gap between the two is bigger than it has any business being.

An athlete who's reaching out in front and braking on every touchdown will usually swear it feels powerful, like they're really pulling the track back underneath them.

An athlete who pops upright too early out of their drive feels low and aggressive the whole way.

Put either of them on camera and the picture flatly disagrees with the feeling.

That's the case for filming. Not the clip on its own, the second look it gives you.

Feel is a story you tell yourself in the middle of the effort. The camera has no opinion about how it went.

A clip you can't read is worse than no clip, though, and most of the ones I'm sent can't be read.

So before what to look for, how to shoot it.

Film from the side, square on to the runner. The camera wants to sit perpendicular to the track, lens roughly at hip height, looking straight across the lane rather than down it.

Angle it and you lose the one thing you came for, an honest line on where the foot lands relative to the body.

Set it on something solid and let the athlete run through the frame. Don't pan and chase them, because a moving camera smears the exact positions you're trying to judge.

The frame rate setting wrecks more clips than any other.

A phone left on its normal video setting usually films at around thirty frames a second.

Ground contact at top speed is under a tenth of a second. So at that sort of rate you get two or three pictures of the whole contact, and the moment you actually care about lands somewhere in the blur between them.

Switch it to slow motion. Most phones can shoot it in some form now, though how fast they go varies a lot from one phone to the next. The faster it records the better, and from a hundred-odd frames a second upwards it starts to earn its keep.

A single ground contact goes from a smear to a handful of clear frames, more of them the faster your phone shoots, and that on its own is a big step up.

Where the phone runs out of road is the next bit. It shoots the slow motion fine, but the built-in app is clumsy when you try to step through it one frame at a time and stop dead on the touchdown.

You can get close, and for a lot of this close is enough.

If you want it properly frame by frame, free software does it better. Kinovea is the one a lot of coaches use, it's free, and it scrubs cleanly frame to frame, though it runs on a Windows laptop rather than your phone.

There are slow-motion analysis apps built for phones too, if you want to go that far.

Frame it so three or four full strides fit in the shot, get some light on the athlete, and pick one phase per clip.

Film the start from beside the blocks if the start is the question. Film a zone out around thirty to fifty metres if you want the top-end stuff.

Trying to catch the whole run in one pan gives you a clip that shows everything and tells you nothing.

Now what to look at.

Resist the obvious move, which is to watch it through at full speed and decide it looked decent. Full speed is where feel sneaks back in.

The information is in stopping on single frames.

Take the drive first. Through the opening steps you want an aggressive shin angle, the shin pointing forward as it strikes, and the body holding a long forward lean. Somewhere around forty-five degrees off the line of the track in the first couple of steps.

The fault to hunt for is standing up too soon.

Step the clip forward and find the exact stride where the posture rises and the angle softens. It's hard to feel yourself do it, and on camera it's right there.

Then top speed, which is where the most useful frame in the whole video lives.

Stop it at touchdown and look at where the foot lands relative to the hip. You want it coming down under the hip, or just in front and already sweeping back.

What you don't want is the foot striking well out ahead of the body, because that's a brake. Every stride spent reaching is a stride spent slowing yourself down and then building the speed back.

The foot wants to land close to under the centre of mass, not reaching for ground out in front of it.

The shin tells the same story in that frozen frame.

Pointing back or roughly vertical at contact is a pulling action, which is what you're after. Pointing forward, foot leading the knee, is the braking version.

Next to that, look at how long the foot stays down. If you've got it frame by frame you can count the frames of contact and compare left to right.

A heavy, drawn-out contact and a short stiff one look completely different stopped on the screen, even when they feel identical to run.

Two more worth a pass.

Posture, from that same side angle. Hips stacked tall under the shoulders rather than sinking as the run goes on.

And the arms, driving back from the shoulder and not crossing the midline. An arm cutting across is usually a sign of something fighting itself further down.

A few habits stop you fooling yourself once you're watching.

Compare the same checkpoint across two or three reps rather than reading everything into one.

Look hard at left against right. The asymmetry you can't feel is often the one that ends up hurting.

And film yourself fresh, then again tired. The mechanics that hold at rep one and fall apart at rep five are the ones worth knowing about.

And don't try to fix six things at once. Find the checkpoint that's furthest from where it should be, work that one, and leave the rest alone until it changes.

Film it side on, slow it down, and stop it on the frame where the foot meets the track.

You'll learn more from that one still than from a season of running by feel and hoping it looks the way it feels.