Effort measurement for IME and workers comp

Effort scoring that shows its work.

Flexion scores functional-movement effort for workers compensation, disability, and IME work. Every number is checked against 3D motion capture before it goes in a report.

Flexion is a prototype. No validation study has run yet. The research page shows what has been tested so far and where it breaks.

Grip CV at the 15% cut-off: a flag is strong, a clean result is weak
0.55 Sensitivity misses 45% of low effort 0.94 Specificity flags full effort wrongly 6% of the time 0 1.0
When the grip test flags someone, it is right 94 times in 100. When it comes back clean, it has missed close to half of the people holding back. Most reports quote only the first number.
Shechtman 2001, J Hand Ther 14(3), three trials. PMID 11511013
0.94
Specificity of grip CV at the 15% cut-off. A flag is usually right.
0.55
Sensitivity at the same cut-off. A clean result misses almost half.
39
Within-subject comparisons against 3D motion capture, REHAB24-6

What Flexion does

Three problems in effort measurement that every examiner, claims adjuster, and defense counsel runs into. This is how Flexion handles each one.

Reports both halves of the test

A positive effort flag carries real weight. A clean result clears nobody, because the grip test misses close to half of the people holding back. Flexion puts the sensitivity next to the specificity in every report, so nobody reads a weak rule-out as a clean bill.

Checks every number against 3D motion capture

No movement number goes in a report unless it survives a check against lab-grade ground truth. The research page shows the check being run on real footage, including the places where the phone camera fails it.

Rejects bad camera angles before scoring

A single phone camera invents scatter the body never produced, and calibration does not remove it. So the capture step uses a second camera, a depth signal, or a gate that refuses footage from a bad angle. Refused footage gets no score at all.

The research behind it

Grip strength coefficient of variation is the most common effort test in IME work. Most reports cite the wrong specificity number, and most video effort tools skip the ground-truth check entirely. I pulled the primary data and tested both.

Read the full teardown

What an IME actually proves about effort, and where grip testing falls short

Shechtman 2001, REHAB24-6 motion capture, and the single-camera video trap. Four charts, each with the finding written under it, and the corrected specificity number.

PMID 11511013
Primary source
p 0.006 vs 0.51
Phone gap vs ground truth

If you order or rely on effort findings, write to me.

Examiners, adjusters, defense counsel, FCE clinics. I want to hear how effort gets measured in your work and where the current tests let you down. Arguments welcome.

nick@flexionclaims.com