Validity of the Handheld Dynamometer Compared with an Isokinetic Dynamometer in Measuring Peak Hip Extension Strength

Abstract

Purpose: To determine whether the handheld dynamometer (HHD) is an appropriate tool to assess and quantify peak hip extension strength in prone standing position by (1) evaluating the concurrent validity of the HHD versus an isokinetic dynamometer (IKD), (2) establishing the minimal detectable change (MDC), and (3) determining the validity of single-trial versus multi-trial measures. Method: A convenience sample of 20 healthy adults was recruited for this cross-sectional study. Measures of peak hip extension strength were collected in prone standing position with both the HHD and the IKD and in supine position with the IKD. Results: Values of r were 0.37 for HHD versus IKD prone standing and 0.51 for HHD versus IKD supine. MDC was 14.8 Nm for the HHD, 25.6 Nm for IKD prone standing, and 41.5 Nm for IKD supine. High correlations (r values of 0.92–0.94) were observed between trial 1 and the mean of three trials. Conclusions: The HHD has moderate concurrent validity in measuring peak hip extension strength in the prone standing position in healthy adults. MDC for hip extension strength was lowest using the HHD. Single-trial values showed a high correlation with three-trial mean values.

Using smartphone accelerometer data to obtain scientific mechanical-biological descriptors of resistance exercise training

“…g . in dynamometry, will never be able to achieve synchronization nor sampling frequency equality [ 32 ].…”

“…However, we do not consider this discrepancy to be a limitation, because method-comparison studies with handheld devices versus machines, e.g. in dynamometry, will never be able to achieve synchronization nor sampling frequency equality [32].…”

Algorithmic extraction of smartphone accelerometer-derived mechano-biological descriptors of resistance exercise is robust to changes in intensity and velocity

“…However, we do not consider this discrepancy to be a limitation, because method-comparison studies with handheld devices versus machines, e.g. in dynamometry, will never be able to achieve synchronization nor sampling frequency equality [19].…”

Clinician's Commentary on Keep et al.

“…Keep and colleagues' study, which investigated the validity of hip extensor strength measurements obtained in the prone standing position using HHD, found moderate correlations ( r =0.51) between values obtained with HHD and those obtained with an isokinetic dynamometer. 1 …”

“…Certainly, Keep and colleagues have generated sufficient evidence to demonstrate that HHD in the prone standing position produces a valid measure of hip extensor strength. 1 Furthermore, testing in this position seems to be more functionally relevant, as the patient is in a modified upright position with the hip being tested in flexion. Because most functional deficits will manifest in standing activities (e.g., stair climbing, walking) and will involve hip extensor activation at some degree of flexion, prone standing does seem to be a more logical choice than prone lying.…”