Rotational Throws (Shot Put & Discus)
Six-phase analysis of a rotational ring throw: setup, entry, drive, power position, release and recovery, with one annotated snapshot per phase.
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 the throw.
Slightly open side or rear-quarter ring view. All phases. This is our reading of "slightly open side or rear-quarter".
How high, and how it should sit
Framing
The full athlete and implement for the whole throw.
The 50–75% 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 11 ready
All the camera settings
Every setting shows where it came from.
- Camera height
- Around chest-to-shoulder height.
- From published guidance
- Distance
- No published distance exists. Stand back far enough that the full movement (arm circle, stride, follow-through) stays in frame with room to spare. Use the 1x lens and move your feet, not the zoom. Do not crop the feet, the arm path, the release or the recovery.
- Our guidance
- Frame rate
- 60+ fps. 60 fps preferred; higher gives cleaner phase locks. Slow motion saved at normal speed works if you enter the recorded frame rate.
- From published guidance
- Resolution
- 1080p minimum
- 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 light with a clean background.
- From published guidance
- Stability
- Tripod or fixed support, level with the horizon.
- From published guidance
- Calibration
- No calibration is needed for angles. Distances and speeds need a scale (see Calibration).
- From published guidance
Before you start
- Select discus and the athlete’s throwing side before analysis.
- Capture 3-5 clean throws and analyse only clips where the whole throw is visible.
- Coach one issue at a time, then retest.
Cues for the athlete
Plain coaching cues, one thing at a time.
setup
- Sit into the throw from a balanced base.
entry
- Turn the block-side foot first and stay low out of the back.
drive
- Move across the ring rather than up, keeping the centre travelling.
power position
- Land loaded over the throwing foot with the arm long and back.
release
- Keep the centre behind the block, post tall on the front side and release on a clean line.
recovery
- Reverse under control and stay inside the ring.
General
- If several things look wrong, start with entry and drive.
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.