Velocity-Based Training, Without the Hype

For a century, load was the only dial we had. You picked a weight, counted reps, and hoped the stimulus matched the plan. Velocity-based training (VBT) adds a second dial: how fast the bar actually moved.

That matters because the same weight is a different stimulus on different days. A 150 kg squat that flies up at 0.6 m/s is a very different session from one that grinds at 0.3 m/s, even though the number on the bar is identical.

What velocity actually tells you

• Readiness. If your usual warm-up weights are moving slower than baseline, you’re under-recovered today. The bar knows before you do.
• Intent. Training to move a submaximal load as fast as possible drives power adaptations that slow grinding reps can’t.
• Auto-regulation. Instead of “5×5 at 80%”, you stop the set when speed drops past a threshold. Volume adjusts to the athlete, not the spreadsheet.

Mean propulsive velocity ($v_{\text{mpv}}$) is quantified across displacement $\Delta d$ over time $\Delta t$:

$v_{\text{mpv}} = \frac{\Delta d}{\Delta t} \quad \text{where} \quad a(t) \ge -g$

Where the cheap sensors fall short

The linear-position transducers used in labs are accurate but expensive. The wave of sub-$100 accelerometer clips and phone-camera apps democratized VBT, but they trade accuracy for price:

• Camera apps struggle with lighting and framing, and estimate rather than measure.
• Clip sensors drift on lateral bar movement and multi-joint lifts.

None of that makes them useless. It means you should treat their numbers as relative - trends against your own baseline - not absolute truth you can compare to someone else’s setup.

The takeaway

You don’t need VBT to get strong. But if you already grind through fixed percentages, a velocity number is the cheapest way to find out whether today’s plan matches today’s body.