How it works
Measured, not inferred.
Every MoCaddieIQ sensor is the same small motion unit: an accelerometer and a gyroscope, a Bluetooth radio, a rechargeable cell, 28 grams. Its position on you is a setting. The app puts them together into one picture of the swing — and is honest about which parts of that picture are measured and which are estimated.
Why a sensor on the club, and two on the wrist
The club sensor
Wrist-only devices infer where the club is from wrist angles, so every "shaft parallel" or "top of swing" they report is a deduction. A sensor in the butt of the grip removes the inference — and it is how we measure tempo, plane, and whether the club came down steeper than it went back, from a single sensor, with no body reference needed.
Hand and forearm
A wrist angle is the difference between two bodies. A hand sensor alone cannot separate wrist hinge from forearm rotation, because both move the hand. So Kit 1 is three sensors, not two: club, hand, forearm.
Back and pelvis
The kinematic sequence — pelvis, then chest, then arm, then club — is the order and timing of peak rotation speed. A gyroscope measures rotation speed directly; a camera has to see a silhouette turn about its own axis, which it barely can. That is why Kit 2 adds the lumbar and upper-back sensors.
Calibrated at address
Every session re-zeroes at your address position, so a strap that sits a centimetre off from last time does not matter. What matters is that a sensor stays put during the swing — which is what the harness and mounts are designed for.
What we measure — and with which kit
| Group | Metrics | Source | Kit |
|---|---|---|---|
| Transition — over-the-top | The plane the club comes down on against the plane it went back on. Steeper = over the top; flatter = shallowed. The Pump drill grades the fix rep by rep. | IMU-DIRECT | Kit 1 |
| Tempo | Backswing and downswing time, the ratio (about 3:1 on Tour), timed from the club | IMU-DIRECT | Kit 1 |
| Swing plane | Plane tilt and on-plane consistency, measured off the club itself | IMU-DIRECT | Kit 1 |
| Swing length & takeaway | Clock-face ladder 7:00–10:00, graded to ±1.5° and coached by voice through earbuds | IMU-DIRECT | Kit 1 |
| Wrist & release | Lead-wrist flexion/extension and deviation (hand minus forearm); cast and release timing | IMU-DIRECT | Kit 1 |
| Club delivery | Face angle, club path, attack angle, shaft lean at impact | ESTIMATE | Kit 1 |
| Kinematic sequence | Firing order and timing: pelvis → thorax → arm → club; flags "out of order" | IMU-DIRECT | Kit 2 |
| Body rotation & posture | Shoulder turn, hip turn, X-factor, early extension, side bend, sway | IMU-DIRECT | Kit 2 |
| Weight shift & balance | Lead/trail distribution, centre-of-pressure path, pressure-shift timing | IMU-DIRECT | Kit 3 |
| Video review | Per-repetition clips with the target line drawn on, jumping straight to the frame the club reached the top | CAMERA | Kit 1 |
IMU-DIRECT: measured straight from the sensors. ESTIMATE: inferred, and labelled as such in the app. CAMERA: needs the phone camera.
Honest limits — we name them
Clubface angle at impact is an estimate
Rotation about the shaft axis is the noisy one for a grip sensor. We estimate it and say so. It is the hardest consumer metric, even for premium systems.
Lead-wrist angle is being validated
The method is documented and the sensor positions exist; the implementation is the defined objective of the feasibility study, benchmarked against a borrowed wrist-only device on the same swings. Until it ships it is a design claim, not a demonstration.
Ground force needs the insoles
Weight shift is never inferred from the motion sensors. It comes from the Kit 3 pressure insoles or not at all.
We do not measure ball flight
Spin, launch and carry are a radar's job. MoCaddieIQ measures the swing; your launch monitor measures the ball. They are better together.