AI Running Form Analyzer

Film 15-20 seconds of easy running on a treadmill from the side and the analyzer reads what a gait lab reads from a camera: cadence, where the foot lands relative to the hip, how much the knee bends at contact, forward lean and vertical bounce. Each number comes with the typical range for recreational runners and a plain flag when something is clearly off. The pose model runs in your browser. The video never leaves your phone or computer.

How to film it

Treadmill, camera square to you at hip height, a few metres back so your whole body stays in frame. Run 3-4 minutes first so your stride settles, then film 15-20 seconds at your normal easy pace with steady light and nothing between you and the camera. Wear fitted clothing: baggy shorts hide the knee and hip and can throw the angles off by a lot. If you change something and refilm, keep the camera where it was. Outdoors works if someone films you running past a fixed camera, but you only get a few usable strides.

What the numbers mean

Cadence. Steps per minute, counted from foot strikes. Most recreational runners land between 160 and 180 at easy pace, and cadence rises with speed and falls with leg length, so it is reported rather than graded. The famous 180 came from counting Olympians at race pace, not from easy running. If yours is low and you land far ahead of the hips, lifting your own number 5-10 percent is the usual first move. The running cadence calculator turns a cadence and pace into stride length.

Foot ahead of hip at contact. The hip to ankle line against the vertical at the moment the foot lands. Landing under the hips reads near zero; the further ahead the foot lands, the bigger the braking force on every step. No study has drawn a line where this becomes a problem, so the tool reports it and flags only a landing clearly ahead of the hips.

Knee bend at contact. In lab cohorts, healthy runners land with about 11-18 degrees of bend at easy pace, and one frame at 30 frames per second can move the number by 7-8 degrees. Reported, not graded. A knee that lands nearly straight usually goes with overstriding.

Forward lean. The hip to shoulder line against the vertical, averaged over the stride. Most runners sit around 4-12 degrees, leaning from the ankles. There is no best value: more lean unloads the knee and loads the hip, so the tool flags only the extremes, upright or folded at the waist.

Vertical bounce. How much the hips rise and fall per stride, as a share of your height and in centimetres when the app knows your height. About 5 percent of height, or 7-12 cm, is typical. Less bounce goes with better running economy in the research. It has no proven link to injury, so read it as an efficiency number, not a risk.

What a phone video cannot tell you

Only the leg nearest the camera is read reliably, and a 2D view measures hip and knee angles to roughly 5-8 degrees in the lab and 9-14 between days, so nothing here is a verdict. Read it as a way to compare your own clips filmed the same way. It cannot see pronation, hip drop or what your form does at kilometre 30. A single clip at easy pace is a snapshot, not a diagnosis. Pain that changes your stride is a job for a physio.

Use it with your coach

In the Movement Rebels app the result goes to your coach, who reads it next to the cadence your Garmin or Apple Health logs on every run. If the video shows you landing far ahead of the hips, the coach can hold a cadence target in your easy runs and check whether it sticks. Read Running Cadence and Form for the drills that move the numbers.