Reliability of belt-stabilized handheld or isokinetic dynamometer-based isometric knee-extensor strength-testing when seated with the toes of the contralateral nonexamined side off the floor.
Masahiro Hirano, Munenori Katoh
PMID 39092411WHAT IT FOUND
Belt-stabilized handheld dynamometry is reliable when used repeatedly on the same person in this specific seated position, even if the non-tested foot does not touch the floor.
However, readings from handheld and isokinetic devices are not interchangeable, so do not switch devices mid-plan.
Key findings
01Repeatability of the belt-stabilized handheld dynamometer was excellent (ICC 0.97) and the isokinetic dynamometer was good (ICC 0.88) when measuring twice on the same person.
02Agreement between the handheld and isokinetic devices was poor (ICC 0.66 overall), meaning the two tools produce different strength values in this posture.
03The isokinetic dynamometer recorded higher maximum knee extension strength than the handheld device for the overall group and specifically for female participants.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The study was conducted on healthy university students aged 19–20, so results may not apply to older adults or patients with neurological or musculoskeletal impairments. Only one examiner performed all measurements, so inter-examiner reliability was not assessed. The specific seating setup (upper limbs on the bed, no trunk straps) is just one of many clinical variations; results do not generalize to strapped or different postural positions.
Declared interests
The authors declared no conflicts of interest.
The easy way to misread this
Do not assume that a high reliability score means the handheld device gives the same number as the isokinetic dynamometer. The study found poor agreement between devices, so switching from one to the other during a patient's recovery will look like a sudden change in strength when it is actually just a measurement error.