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The Solution

What FORJ Core measures

FORJ Core is FORJ's resistance-training sensor. It attaches to pin-loaded and plate-loaded machines, barbells, dumbbells, and other free weights and records how the load moves — not only how much weight was selected and how many reps were completed. Athletes, coaches, and clinicians use those metrics for velocity-based training, fatigue monitoring, and rehabilitation documentation.

Last updated: 25 August 2026

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What we measure

In most gyms, the only numbers written down are load and reps. FORJ Core adds the kinematics of each repetition, on machines, free weights, plyometrics, and bodyweight movements such as pull-ups and dips:

  • Rep velocity — how fast the load travels, used for velocity-based training and fatigue cut-offs
  • Range of motion — how far the load moves on each rep
  • Rep tempo and consistency — timing of the concentric and eccentric portions across a set
  • Power and force production — output derived from the measured movement of the load
  • Time under tension — how long the load is moving during the set

Coaches, health professionals, hybrid athletes, and gym-goers use the same device: one sensor, live data in the FORJ app, history for the next session.

FAQ

Frequently asked questions

FORJ Core measures rep velocity, range of motion, rep tempo and consistency, power, force production, and time under tension. It also supports limb-symmetry comparisons. A conventional gym log typically records only load and reps.
Movement velocity shows how fast the load is travelling on each rep. That lets coaches prescribe intensity for velocity-based training, stop a set when velocity drops (fatigue), and compare sessions without relying only on the number on the stack.

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