Reliability of EasyForce Dynamometer for Assessment of Maximal Knee and Hip Strength, and Comparison to Rigid Isometric Dynamometers with External Fixation

Žiga Kozinc, Darjan Smajla, Nebojša Trajković & Nejc Šarabon (2021) Reliability of EasyForce Dynamometer for Assessment of Maximal Knee and Hip Strength, and Comparison to Rigid Isometric Dynamometers with External Fixation, Measurement in Physical Education and Exercise Science, DOI: 10.1080/1091367X.2021.2019037

Link to study online: here.

Aim:

This study aimed to assess intra- and inter-visit reliability of a novel EasyForce dynamometer for assessment of maximal strength in knee extension and flexion, and hip abduction and adduction tasks.

Methods: 

Young healthy participants (n = 50; 25 males, 25 females; age: 23.4 ± 2.1 years) were measured for maximal joint torque with EasyForce dynamometer and rigid isometric dynamometers with external fixation, in two-sessions (5–10 days apart).

 

Figure 1. The positions for EasyForce measurements for knee extension (a), knee flexion (b), hip abduction (c) and hip adduction (d) (1)

Results:

The intra-visit reliability was high (ICC) = 0.84–0.95 knee; 0.90–0.94 hip), with absolute reliability sometimes exceeding the acceptable threshold (CV = 6.9–10.6% knee; 7.8–11.8% hip). Inter-visit reliability was excellent for all tasks (ICC = 0.95–0.97 knee; 0.95–0.96 hip). Although the EasyForce values were different compared to rigid dynamometers, the correlations between the devices were high (r = 0.64–0.75 knee; 0.70–0.75 hip).

Conclusions:

In conclusion, the EasyForce dynamometer provides reliable means of assessing knee (extension and flexion) and hip (abduction and adduction) muscle strength.