Hip Drop Analysis (Pelvic Stability)
Measure pelvic tilt at mid-stance from a rear view on a treadmill, track it across a session and produce a one-minute left/right summary.
How far has this tool been checked?
The measurements were checked against computer-drawn athletes whose true answers are known exactly. That shows the arithmetic and the event rules are right under clean, controlled conditions. It does not measure how well the body-tracking model sees real people (water, loose clothing, crouching, fast limbs) and has not been compared with a lab or a coach’s stopwatch. Treat the numbers as an aid, and use the confidence label beside each value.
Where the camera goes
Seen from above. Angles are measured round from the front of the athlete; 90° is square-on from the side. Reference line: direction of running.
Rear view, directly behind the treadmill. Pelvic tilt at mid-stance, left and right.
How high, and how it should sit
Framing
Pelvis and both legs fully in frame from directly behind.
The 70–90% band is our own guidance. No published source gives a camera distance in metres, so use it as a starting point and adjust until the whole movement fits.
Ready to record?
Tick each item as you set it up. This is a reminder, not a lock.
0 of 10 ready
All the camera settings
Every setting shows where it came from.
- Camera height
- Level with the hips.
- From published guidance
- Distance
- No published distance exists. Stand back until the whole athlete fits with a small margin, so the athlete fills roughly 70-90% of the frame height. Use the 1x lens and move your feet, not the zoom.
- Our guidance
- Frame rate
- 30+ fps (recommended 60). No frame rate is published for video. Our default: 60 fps for cleaner mid-stance frames.
- From published guidance
- Resolution
- 1080p recommended
- From published guidance
- Orientation
- Landscape or portrait both work.
- From published guidance
- Lens and zoom
- Use the 1x lens with no digital zoom. Avoid ultra-wide and fisheye lenses.
- From published guidance
- Lighting
- Bright, even light with a plain background that contrasts with the athlete.
- From published guidance
- Clothing
- Shirt tucked in so nothing covers the waist or hips.
- From published guidance
- Stability
- Tripod or fixed support, level with the horizon.
- From published guidance
- Calibration
- Some existing tools track a resistance band worn just below the waist. Our default uses the left and right hip landmarks instead, and can add band tracking later.
- From published guidance
Before you start
- Warm up for 3 minutes at a comfortable long-run pace before recording.
- Keep treadmill effort the same, because result quality depends on it.
- When retesting, level the camera and repeat the same setup, and retest after 4-6 weeks of routines three times a week.
Cues for the athlete
Plain coaching cues, one thing at a time.
General
- Run steadily and look straight ahead.
- Before runs, warm up with glute bridges, fire hydrants, donkey kicks and standing hip circles.
Why camera position matters
Research behind these rules.
2D angles are only trustworthy when the limb moves in the plane the camera sees. Camera-side joints are measured more accurately than far-side joints, and timing is only as fine as one frame.