Reliability of isokinetic evaluation in passive mode for knee flexors and extensors in healthy children

Abstract

| Background: The isokinetic dynamometer has been considered the gold-standard measurement of muscle performance. However, the reliability for the passive mode in children has not been reported to date. Objectives: The purpose was to evaluate the reliability of the isokinetic dynamometer in passive mode in children. Method: Twenty-one healthy children (ten girls, eleven boys), aged 5 to 12 years (age: 8.5±2.2 years), were evaluated using an isokinetic dynamometer. Each participant was tested twice with a one-week interval and performed five consecutive cycles of knee extension and flexion. The test was performed at 60°/s in the concentric passive mode and the children performed maximal contractions. The measured variables were peak torque, average peak torque, total work, and average power, time to peak torque and angle of peak torque for dominant and non-dominant lower limbs. Reliabilities were determined using intraclass correlation coefficient (ICC 3,1 ), standard error of measurement (SEM and SEM%), and coefficient of variation (CV). Results: We found good reliability in both lower limbs for peak torque, average peak torque, total work and average power of knee flexors and extensors, with ICC 3,1 values greater than 0.80; SEM ranging from 6.7 to 79.2; SEM% ranging from 10.4% to 16.8%; CV lower than 15%. Bland-Altman analysis showed that the bias was low than 10% and limits of agreement (LOAs) ranging from 33.9% to 59.2%, and -28.8% and -52.8%, showing that measures tended to disagree. However, time to peak torque (ICC 3,1 <0.68; SEM > 0.34; SEM%>37.4%; CV>41.7%; bias >24.0%; LOA>101.0%) and angle of peak torque (ICC 3,1 <0.76; SEM>9.3; SEM%>27.6%; CV>15.3%; bias>11.0%; LOA>61.0%) were not reliable. Conclusions: The findings indicate that isokinetic evaluation in passive mode for knee extensors and flexors of dominant and non-dominant lower limbs of children without disabilities was reliable for peak torque, average peak torque, work, and power. However, average time to peak torque and angle of peak torque were not reliable.Keywords: isokinetic evaluation; children; knee; reliability; rehabilitation; movement. HOW TO CITE THIS ARTICLESantos AN, Pavão SL, Avila MA, Salvini TF, Rocha NACF. Reliability of isokinetic evaluation in passive mode for knee flexors and extensors in healthy children. Braz J Phys Ther.

Inter- and intrarater reliability of four single-legged hop tests and isokinetic muscle torque measurements in children

“…The magnitude of the ICCs for isokinetic knee extension and flexion torque in our study are comparable to earlier studies on children [7,14,28], although somewhat lower than reported in adults (0.85 to 0.94) [10,30].…”

“…This indicates that our SEM% values are comparable to previous results in children [7,16,18,28]. Our SRD% values suggest that a change above 14% to 16% for knee extension and 22% to 25% for flexion is necessary to reflect a real change in knee function.…”

Reliability of Ankle–Foot Complex Isokinetic Strength Assessment Using the Isomed 2000 Dynamometer

“…However, the size of the testing sample is comparable to the ones reported by other research papers on reliability in healthy adults [7,10]. Also, it should be borne in mind that the observed findings can be different from earlier findings reported for specific subjects, such as the elderly [17,29] or children [16,19]. Another limitation of the current study might be that only one testing velocity and the concentric mode of action was used for measurement of ankle INV/EV.…”

“…The studies’ results are, however, difficult to interpret and compare due to differences in testing protocols (e.g., testing position and stabilization, testing velocities and modes of muscle action, passive or active mode of testing, gravitational correction application, testing bare feet or with shoes, etc.) [5,7,15,16]. …”

“…Furthermore, reliability reports are specific to the procedures used and should not be generalized to other devices, testing protocols, muscle groups, or specific populations such as elderly or children [4,16,17,18]. To the best of our knowledge, there is only one study on the IsoMed 2000 isokinetic dynamometer that reported reliability for ankle testing specifically for PT of ankle PF (ICC = 0.79); however, the study was conducted on children and in static muscle action [19].…”