The 3 Numbers Tim Looks For | FormForge LiftLab

The 3 Numbers Tim Looks For

A physicist's field guide to auditing your lift using nothing more than a phone camera.

Most lifters chase kilos. I want you to chase numbers. After watching too many talented lifters either plateau or get hurt chasing PRs with leaky mechanics, I built this shortlist. These three numbers are objective signals to help you make smarter decisions about your next session.

1. Triple-Extension Speed (TES)

Plain English: How fast your hip + knee + ankle straighten during the power phase. The 'jump' moment. If your bar barely floats, this number is too low.

TES is the mean magnitude of d(hip+knee+ankle)/dt over the power phase (~20% window centred on peak joint-angular velocity).

Reference: 1.52 - 1.67 m/s (Snatch from floor, well-trained)

2. Catch Depth

Plain English: How deep you're willing and able to drop into the catch. Shallow catches mean you'd rather grind a press-out than trust the position.

Maximum knee flexion within the catch window — the 0.3s after bar-contact-with-shoulders or arms-locked-overhead.

Guidepost: ≥110° knee flex for a full squat.

3. Symmetry (Delta)

Plain English: How much your left side and right side disagree, frame by frame. Lower is better. Never a diagnosis, always a flag.

Mean absolute left-right difference for a given joint angle across the rep, expressed in degrees.

Triage: ≤3°Δ is stable. >10°Δ flag for coach review.

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