Velocity-based training without a $1,000 sensor

Velocity-based training (VBT) is one of the more useful ideas to come out of strength-and-conditioning labs in the last decade: measure how fast the bar actually moves, and you get an objective read on whether a lift is training speed, power, hypertrophy or absolute strength — regardless of what the plan says the percentage should be. The catch has always been the entry price. Real VBT hardware — linear position transducers, accelerometer pucks, camera-based systems — typically runs from a few hundred to a few thousand pounds, which is why it has stayed mostly in university labs and pro sports departments.

The insight: you can infer velocity from what you already log

Bar speed and %1RM are tightly linked — that relationship is exactly what makes VBT hardware useful in the first place. Misi uses that link in reverse. Instead of measuring velocity directly, it infers it from data every lifter already enters: weight, reps and RPE. RPE and reps map to reps-in-reserve using the Zourdos (2016) framework; RIR and reps map to %1RM via the Helms RIR-to-load chart; and %1RM maps to mean concentric velocity through a movement-specific load-velocity regression built from the published profiles for bench, squat, deadlift, overhead press, rows and pull-ups (Conceição 2016; García-Ramos 2018; Sánchez-Medina 2014). Where a personal-best estimated 1RM already exists for that lift, the app skips the RPE step entirely and computes %1RM directly as weight ÷ e1RM — the more accurate path, used whenever it's available.

You do not need a sensor on the bar to know whether a set was fast or a grind. You need the load, the reps, and an honest RPE — Misi already asks for all three.

What the velocity zones actually tell you

The output is one of five zones from the standard Mann/Sands/Stone power-continuum model: Starting Strength (fastest), Speed-Strength, Strength-Speed (peak power output), Hypertrophy, and Absolute/Maximal Strength (slowest). This turns an abstract percentage into a concrete training quality. A hypertrophy-focused session that's supposed to sit in moderate load territory but keeps reading as Absolute Strength zone tells you fatigue has pushed the set heavier than intended — useful information mid-session, not just in a post-workout review.

Velocity loss: the headline metric

The single most actionable VBT number is velocity loss — the percentage drop in bar speed from your fastest set of the session to your current one. Research from Pareja-Blanco (2017) established that a velocity loss beyond roughly 20% is the point where a set stops building the quality it was intended to and starts just accumulating fatigue — the practical 'rack it' signal used in real velocity-based programs. Misi tracks this across every logged set of an exercise within a session and surfaces it live, so you get the same stop signal elite VBT setups use, without owning any of the hardware.

Where it shows up

The velocity readout appears directly in Live Focus Mode as you log each set — a plain m/s figure plus its zone, computed the instant you enter weight, reps and RPE. It only shows for classifiable barbell/dumbbell movement patterns (press, squat, hinge, row, pull); pure isolation work and cardio are left alone, since there is no validated load-velocity profile for a bicep curl.

This does not replace a genuine bar-speed sensor for elite athletes chasing single-percentage-point precision. What it does is put a real, literature-grounded VBT signal in front of every lifter logging honest numbers — turning 'that felt heavy' into an actual velocity-loss percentage you can act on.

Misi is a coaching and wellness platform, not a medical service. Train within your experience level and consult a qualified professional before starting a new resistance-training programme if you have any health concerns.