The validity of plantarflexor strength measures obtained through hand-held dynamometry measurements of force.

PURPOSE/BACKGROUND: Hand-held dynamometers are commonly used to assess plantarflexor strength during rehabilitation. The purpose of this study was to determine the concurrent validity of measuring plantarflexion force using a hand-held dynamometer (HHD) as compared to an electromechanical dynamometer as the gold standard. The hypothesis was that plantarflexor forces obtained using a hand-held dynamometer would not show absolute agreement with a criterion standard.

DESIGN

Concurrent validity assessment for a diagnostic strength testing device.

SETTING

Institutional clinic and research laboratory.

PARTICIPANTS

Volunteer sample of healthy university students (N=20, 10 women, 10 men; 25.9±4.1 years).

MAIN OUTCOME MEASURES

Maximal plantarflexion strength was measured using both a HHD and an electromechanical dynamometer (EMD) as a criterion measure.

RESULTS

Plantarflexor force measures with the HHD were significantly different (p<0.01) and not correlated with plantarflexor forces measured using the EMD for either limb (R(2) ≤ 0.09).

CONCLUSIONS

Plantarflexor strength measurements acquired using HHD are different from those acquired using an EMD and are likely influenced by the strength of the examiner.

LEVEL OF EVIDENCE

Prospective cohort study, level II.