Validity and Reliability of Isometric-Bench for Knee Isometric Assessment

There is a strong need for a new, probably cheaper, smaller, and more portable isometric
dynamometer. With this aim, we investigated the concurrent validity and reliability of a low-cost
portable dynamometer to measure the isometric strength of the lower limb. Seventeen young
participants (age 16.47  0.51 years) were randomly assessed on three dierent days for knee flexion
and extension isometric forces with two dierent devices: a commonly used isokinetic dynamometer
(ISOC) and a portable isometric dynamometer prototype (ISOM). No significant dierences were
observed between the ISOC and the ISOM (all comparisons p > 0.05). Test–retest comparison showed
the ISOM to have high reliability (ICC 0.879–0.990). This study showed that measurements with the
ISOM could be performed without systematic bias and with high reliability. The ISOM is a device
that is able to assess knee isometric strength with excellent concurrent validity and reliability.