iOS · Boxing · Measured by sound
HandSpeed measures your reaction time and counts every punch on the heavy bag — using nothing but your iPhone's microphone. No sensors. No wearables. Just you and the bag.
median reaction · 14/15 cues answered · reliable ✓
How it works
A punch landing on a heavy bag has an acoustic signature. HandSpeed learns yours, then times everything down to the millisecond.
Ten seconds. Hit your bag a few times — the app learns the sound of your bag in your gym. Music, voices, other bags: ignored.
A cue fires at a random moment. You strike. The mic catches the impact and times your reaction — 2-millisecond resolution, gloves on, hands free.
Median reaction, punches per minute, sprint drop-off — session after session. Your numbers don't lie. Neither does your coach.
The arsenal
Random audio cues, real impacts, millisecond timing. Watch your median drop week after week.
Every clean impact counted — 98%+ accuracy, verified against hand counts. Pace per 10 seconds, best bursts, honest totals.
15/15, tabata, 30/30 — all-out sprints with per-sprint counts and a drop-off score that exposes your engine.
Builds your full session — warm-up to cool-down — from your real numbers, and talks you through every rest. High energy, zero mercy.
Limited beta
Free during beta. Install TestFlight, tap the link, start measuring. Your feedback shapes the app.
Join the TestFlight beta