PTOTOtherInternational journal of sports physical therapy2025

Validity and Agreement of a Portable Dynamometer in Evaluating Hip Strength and Rate of Torque Development: Influence of Fixation Methods.

Sungwan Kim, Takhyun Yoo, Julie P Burland and 1 others

PMID 40182909

WHAT IT FOUND

Portable dynamometers correlate with lab standards for hip strength, but the pull method is more valid than the push method.

However, portable devices systematically overestimate strength compared to lab standards, so you cannot swap them for tracking patient progress.

Key findings

01The portable dynamometer pull method showed strong correlations with the isokinetic dynamometer for specific hip measures, while the push method showed only moderate correlations.

02Both portable dynamometer methods significantly overestimated hip strength compared to the isokinetic dynamometer, indicating poor agreement for absolute values.

03There were no significant differences in patient discomfort between the push method, pull method, and the isokinetic dynamometer.

STILL TO COME

How it was doneWhat they foundWhat it means for PTsWhat it means for OTs

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What it does not show

The study included only healthy, physically active individuals aged 18-35, so results may not apply to patients with pathology, pain, or sedentary lifestyles. Assessments were limited to hip abduction and extension; findings may not generalize to other hip movements like rotation. The portable dynamometer has a minimum force threshold, requiring pre-tension that may affect the validity of rate of torque development measurements. Soft tissue deformation during the push method may absorb force, reducing validity compared to the pull method.

Declared interests

The authors report no conflicts of interest.

The easy way to misread this

Do not assume that a portable dynamometer reading is equivalent to an isokinetic dynamometer reading. The portable device systematically overestimates hip strength, so switching between devices during a course of care will falsely suggest improvement or decline.

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