Determine the reliability and validity of hand-held dynamometry measurements in 3 different rater test positions from a mechanically produced external force. We hypothesized that the intra- and inter-rater reliability of the rater non-fixed HHD measurements will be excellent. Further we hypothesize that no differences will exist between measurements taken by a rater (non-fixed) and measurements taken by a fixed HHD.
10 raters took 264 measurements in 3 different rater test positions against 3 different force magnitudes that were randomized and blinded to all raters. The force was created by an external mechanism. The rater’s measurements were compared to measurements taken against a fixed-stabilization device. To establish reliability, precision was assessed by Intraclass Correlation Coefficient (ICC) and Standard Error of Measurement (SEM). To establish validity, error rate was assessed to calculate accuracy.
ICC was found to be excellent at .97 and above. The overall error rate was 15.5% and was significantly influenced by force magnitude.
Hand-held dynamometry measurements have high precision with excellent intra- and inter-rater reliability. Hand-held dynamometry may have a level of inaccuracy, especially against lower force magnitudes.
In clinical practice, providers should be aware that non-fixed hand-held dynamometry may have a degree of inaccuracy. The values obtained with non-fixed hand-held dynamometry were consistently higher compared to the values obtained by fixed hand-held dynamometry. This inaccuracy may be higher when a provider takes measurements from a patient who produces lower forces.
reliability
validity
