HackMotion · Wrist Sensor · Data Mastery
Every wrist data point decoded — the three measurement axes, all five swing positions, tour benchmarks, key diagnostic combinations, fault finder, and session protocols for full swing, short game, and putting.
HackMotion measures what no video, mirror, or coach eye can reliably capture — the precise wrist angles occurring at speeds of 100+ mph through the impact zone. This is the closest thing to a direct readout of clubface position at impact.
HackMotion measures three independent axes of wrist motion simultaneously, across five key swing positions, producing a continuous graph of wrist movement through the entire swing arc.
THREE AXES
① Flexion / Extension
② Radial / Ulnar Deviation
③ Rotation / Pronation-Supination
FIVE POSITIONS
A. Address (P1)
B. Mid-Backswing (P2)
C. Top of Backswing (P4)
D. Impact (P7)
E. Follow-Through (P9)
Of the three axes, flexion/extension is the primary governor of clubface angle. Flexion (bowed) closes the face. Extension (cupped) opens the face. Axes 2 and 3 are secondary for most ball flight problems.
| HackMotion Shows | Mevo Confirms | Ball Flight |
|---|---|---|
| Extension at top (+20°) | Face angle open (+4°) · F2P positive | Slice — starts right, curves right |
| Extension at impact (+10°) | Low smash factor · High spin axis | Open face contact — distance + direction loss |
| Flexion at top (−20°) | Face neutral/closed · F2P near 0 | Controlled draw — ball starts on target |
| High variance shot-to-shot | High F2P variance · Wide lateral std dev | Unpredictable shot shape — main consistency killer |
| Extension at chip impact | Low smash factor · Thin/bladed | Flipping — skulled or chunked short game shots |
HackMotion measures three independent axes simultaneously. Each axis has a distinct role in governing club position. Diagnose in order: Axis 1 first, then 2, then 3.
Axis 1 — Flexion / Extension (PRIMARY)What it measures: The palm-up/palm-down hinging of the wrist. Flexion = back of hand moves toward forearm (bowed). Extension = palm moves toward forearm (cupped).
Sign convention: Negative = flexion (bowed). Positive = extension (cupped). −20° = 20° bowed. +15° = 15° cupped.
What it measures: Side-to-side hinging — toward the thumb (radial) or little finger (ulnar). Radial deviation loads the hinge in backswing; ulnar deviation releases it through impact.
What it measures: Rotational movement around the longitudinal axis of the wrist. Supination (palm toward sky) closes the face through impact. Insufficient supination = blocked shot right. Excessive early supination = hook.
HackMotion captures all three axes continuously, with specific position snapshots corresponding to TPI and PGA coaching positions. The swing graph pattern is as informative as any single snapshot.
The address position is HackMotion's calibration reference. All subsequent readings are relative to how much the wrist has changed from address. A player who addresses at +10° extension and reaches the top at +15° has only added 5° — not 15°. Understanding your address baseline is essential before interpreting any subsequent number.
At P2 (lead arm parallel to ground), the wrist should begin hinging radially while maintaining or slightly increasing flexion from address. If extension is already increasing at P2, the cupped pattern is establishing early and will only worsen at the top.
The top of backswing wrist position is HackMotion's most important single reading. It predicts with high accuracy what the face angle will be at impact — and unlike impact, the top position can be felt and consciously trained.
Impact occurs in 0.5 milliseconds — it cannot be consciously manipulated. It is the result of everything that came before. Use impact data to validate whether backswing and transition changes are reaching the ball. Never attempt to consciously control impact position directly.
Follow-through data confirms whether correct sequencing continues through the entire hitting zone. Watch specifically for the "flip spike" — a sharp extension increase at or just after P7 in the swing graph. This is the most visually obvious fault pattern and directly indicates an early release.
Reference benchmarks for lead wrist data across all three axes at all five positions. Work toward the acceptable range first — not the tour extreme. Find YOUR functional range.
| Position | Axis | Tour Avg | Scratch | 10 HCP Typical | Common Fault |
|---|---|---|---|---|---|
| Address | Flex/Ext | 0° to −5° | 0° to +3° | +3° to +8° | +10°+ (pre-cupped) |
| Mid-BS (P2) | Flex/Ext | 0° to −8° | +3° to −5° | +5° to +12° | +15°+ (early cup) |
| Mid-BS (P2) | Rad/Uln | +15° to +22° | +12° to +20° | +8° to +15° | Below +8° (no hinge) |
| Top (P4) | Flex/Ext | −15° to −25° | −10° to −20° | +5° to +20° | +20°+ (severe cup) |
| Top (P4) | Rad/Uln | +25° to +40° | +20° to +35° | +12° to +22° | Below +12° (lag lost) |
| Impact (P7) | Flex/Ext | −10° to −20° | −5° to −15° | 0° to +10° | +10°+ (flip) |
| Impact (P7) | Rad/Uln | 0° to −5° | 0° to −8° | −5° to −15° | −15°+ (cast) |
| Follow-thru (P9) | Rotation | Rapid supination | Active supination | Stalled supination | No supination (chicken wing) |
| Player | Top Position | Style | Key Note |
|---|---|---|---|
| Dustin Johnson | −40° to −45° (extreme bow) | Power draw | Extreme bow pre-sets closed face — compensates throughout to manage hook |
| Collin Morikawa | −5° to −15° (slight bow) | Controlled fade | Neutral-bow — relies on body rotation. Highly repeatable. Tour's most accurate iron player. |
| Jon Rahm | −10° to −20° (moderate bow) | Draw player | Strong bow at top, body-driven release. Face closes actively through impact. |
| Tiger Woods (peak) | −15° to −20° (moderate bow) | Workable draw/fade | Deliberate and trained over years for maximum repeatability. The benchmark for consistency. |
| Classic amateur | +15° to +25° (cupped) | Slice / weak fade | Most common fault. Open face at impact, low smash factor, positive spin axis. |
| Position | Tour Variance | Scratch | 10 HCP |
|---|---|---|---|
| Top of Backswing (Flex/Ext) | ±2° | ±3–4° | ±6–10° |
| Impact (Flex/Ext) | ±1.5° | ±2–3° | ±5–8° |
| Radial Dev at Top | ±3° | ±4–5° | ±7–12° |
HackMotion can be worn on either wrist. Trail wrist data is a complementary diagnostic — particularly powerful for confirming flip patterns and casting that lead wrist data alone may not fully isolate.
The trail wrist operates in the opposite direction to the lead wrist. Where the lead wrist flexes to close the face, the trail wrist extends to maintain shaft lean. A trail wrist that loses extension at impact = shaft leaning back = face opening + loft adding = smash factor loss.
| Symptom | Lead Wrist Tells You | Add Trail Wrist When |
|---|---|---|
| Slice / strong fade | Primary — Flex/Ext at top is the source | Lead wrist in range but slice persists |
| Distance loss | Check impact flex vs. address (flip test) | Trail wrist extension at impact confirms or denies flip |
| Fat/thin alternating | Check impact variance | Trail wrist deviation timing reveals cast pattern |
| Inconsistent distances | Check top variance | Both wrists — identify which is more variable |
| Hook / over-draw | Check too much flexion at top (−35°+) | Trail wrist extension rate — closing face too fast? |
Expert HackMotion analysis comes from reading relationships between positions and axes — the patterns across the swing graph — not individual snapshots in isolation.
The relationship between top and impact flexion/extension is the single most important HackMotion combination. Impact must ALWAYS be at least as flexed as the top — ideally more flexed. Any reversal = loss of face control through the downswing.
The simplest and most powerful HackMotion diagnostic. If impact is MORE extended than address — you are flipping. Unconditionally. No additional data required to confirm it.
The amount loaded at the top (radial deviation) determines lag potential. The timing of release to ulnar at impact determines how that lag converts to speed. Loading without release = blocked shot. Early release = casting = speed loss.
The mean tells you where you are on average. The variance tells you how reliable that position is. High variance at the top (±10°+) predicts wide Mevo lateral dispersion regardless of what the mean number is. Reducing variance is often more impactful than changing the mean.
These two axes define overall backswing quality. Good flexion (face control) + good radial deviation (lag load) = the backswing has done its job completely. Poor in either means the downswing is compensating from the very start.
| Top Flex | Top Radial | Backswing | Likely Ball Flight |
|---|---|---|---|
| −20° | +32° | Excellent | Controlled draw, full power |
| −8° | +30° | Good lag, marginal face | Mild fade, good distance |
| +18° | +28° | Good lag, open face | Strong fade / slice with power |
| +15° | +12° | Open face + no lag | Slice + distance loss |
Running HackMotion and Mevo simultaneously is the most powerful diagnostic combination in your entire training system. HackMotion identifies the cause; Mevo confirms the effect in ball flight data.
| HackMotion Change | Expected Mevo Response | Pass / Fail |
|---|---|---|
| Top flex +20° → −15° (35° change) | Face angle closes ~20°, F2P reduces, spin axis reduces 8–12° | Pass if both change proportionally |
| Impact flex 0° → −10° | Smash factor rises 0.03–0.05, dynamic loft decreases | Pass — shaft lean confirmed by efficiency gain |
| Top flex improves, impact unchanged | Mevo face angle unchanged, same F2P and spin axis | Fail — change not transferring through downswing |
| Radial dev at top +10° → +28° | Club speed increase 2–4 mph, carry increases | Pass — lag loaded = speed increase |
| Top variance ±12° → ±3° | Mevo lateral std dev reduces, F2P variance narrows | Pass — consistency transfer confirmed |
| Mevo Shows | HackMotion Response | Drill |
|---|---|---|
| High F2P (+5°+) · Positive spin axis | Check top Flex/Ext — likely extended | Biofeedback: top position target |
| Low smash factor (<1.42) | Flip test: impact vs. address flex | Biofeedback: impact flex target |
| High lateral std dev | Check top position variance | Consistency drill: tight tolerance ±3° |
| Low club speed vs. baseline | Check radial deviation at top | Hinge loading — increase radial target |
| Blocked shots right | Check rotation P7–P9 | Supination release drill |
| Pull-hooks left | Check excessive flexion at top (−35°+) | Moderate flexion — reduce by 10–15° |
Start with the ball flight problem. Work to the wrist data root cause. Use alongside the Mevo fault finder — they approach the same problem from different directions.
🔴 Slice / Strong FadeFix: Strengthen grip → reduce address extension → set top target to −10° → biofeedback → validate with Mevo face angle + F2P reduction + spin axis closing.
Fix: Smash Bag + HackMotion simultaneously. Smash Bag builds shaft lean feel; HackMotion quantifies it. Target: impact flexion 5°+ MORE bowed than address. Validate with Mevo smash factor increase.
HackMotion is as valuable in the short game as the full swing. The most common short game fault — the flip — is directly measurable, with tighter tolerances required than the full swing.
| Fault | HackMotion Signature | Fix Protocol |
|---|---|---|
| Bladed / thin chip | Impact ext +8°+. Sharp extension spike at P7. | Biofeedback −5° impact target. G-Force + HackMotion combo. |
| Heavy / chunked chip | Extension at impact + high variance. Arc behind ball. | Weight forward drill. Fix address wrist — cupped setup = cupped impact. |
| Inconsistent distances | Impact variance ±8°+. Face angle varying. | Tight biofeedback ±3°. High volume — 50 chips per session same target. |
| Ball flight too high on chips | Extension adding dynamic loft. Uncontrolled loft. | Target −8° impact flex. Reduces effective loft = lower trajectory. |
HackMotion's putting mode applies the same wrist measurement technology to the stroke, where even 1–2° of wrist variance at impact can produce a miss at 6 feet. The tolerances are tighter than any other application.
HackMotion = wrist angle (cause). ExPutt = face angle at impact (effect). Running both creates the direct validation chain: wrist variance → face angle variance → start direction variance → miss rate.
| Style | Lead Wrist Address | Impact Target | Key Diagnostic |
|---|---|---|---|
| Conventional | 0° to −5° | Match address ±2° | Any extension at impact = open face = misses right |
| Forward press | −10° to −20° | Match address ±2° | High starting flex must hold — any release loses the technique benefit |
| Arm-lock | −15° to −25° | Match address ±1° | Tightest tolerance — any break releases the lock entirely |
| Claw grip | Lead wrist neutral | Lead wrist stays inactive | Confirm lead wrist is not contributing — claw removes it from the equation |
How to structure HackMotion sessions for maximum learning and course transfer. The biofeedback tool is powerful — but only when used in a deliberate phase structure, with clear internalisation tests built in.