Muscle strength, the maximal force-generating capacity of a muscle or group of muscles, is regularly assessed in physiological experiments and clinical trials. An understanding of the expected vari...

CORP: Measurement of upper and lower limb muscle strength and voluntary activation

The purpose of this discussion is to review the methods utilized to calculate the intraclass correlation coefficient (ICC) as well as indications on the interpretation and application of the statistic in the assessment of reliability. The index result of the ICC and several examples of clinical and research applications of the ICC are given with respect to the reliability of isokinetic testing. Copyright © 1996 Elsevier Science Ireland Ltd.

The application and interpretation of intraclass correlations in the assessment of reliability in isokinetic dynamometry

BACKGROUND: A single measure to characterize overall muscle strength is advantageous because it saves time and costs of evaluation. For this reason, the back-leg-chest (BLC) strength might be an appropriate single measure in characterizing total body strength. OBJECTIVE: To assess the test-retest reproducibility and smallest real difference (SRD) of the BLC dynamometer in healthy adults and adolescents and to examine whether handgrip, knee-extensor and knee-flexor strength predict BLC strength in healthy adults. METHODS: Forty-five adults and 58 adolescents were recruited. In a first session back-leg-chest strength, handgrip strength, and additionally, in adults, isometric knee-extensor strength, and knee-flexor strength were measured. In a second session, 2–5 days later, BLC strength was measured again for test-retest reproducibility. RESULTS: Inter-session correlations of BLC strength were high (all r’s and ICC’s > 0.92). Bland-Altman-plots showed high agreement. The SRD and SRD% were between 14–26, and 19% and 26% respectively. Strength variables (handgrip, kneeextensor, and knee-flexor strength) explained 87% of the variance in BLC strength. A stepwise linear regression showed that dominant knee extensor and flexor strength were the most important significant predictors of BLC strength (r 2 = 0.86). CONCLUSIONS: This study demonstrated that the BLC dynamometer has reasonably high test-retest reproducibility and hence may serve in some pertinent situations to be an appropriate tool for clinical, basic and applied research.

/pdf/test-retest-reproducibility-and-validity-of-the-back-leg-3hen8nf718.pdf

Test-retest reproducibility and validity of the back-leg-chest strength measurements

[Purpose] Lumbar fusion has been used for spinal disorders when conservative treatment fails. The minimally invasive approach causes minimal damage to the back muscles and shortens the postoperative recovery time. However, evidence regarding functional recovery in patients after minimally invasive lumbar spinal fusion is limited. The purpose of this study was to investigate how trunk control ability is affected after minimally invasive lumbar fusion surgery during the early postoperative phase. [Subjects and Methods] Sixteen patients and 16 age- and sex-matched healthy participants were recruited. Participants were asked to perform a maximum forward reaching task and were evaluated 1 day before and again 1 month after the lumbar fusion surgery. Center of pressure (COP) displacement, back muscle strength, and scores for the Visual Analog Scale, and Chinese version of the modified Oswestry Disability Index (ODI) were recorded. [Results] The healthy control group exhibited more favorable outcomes than the patient group both before and after surgery in back strength, reaching distance, reaching velocity, and COP displacement. The patient group improved significantly after surgery in all clinical outcome measurements. However, reaching distance decreased, and the reaching velocity as well as COP displacement did not differ before and after surgery. [Conclusion] The LBP patients with lumbar fusion surgery showed improvement in pain intensity 1 month after surgery but no improvement in trunk control during forward reaching. The results provide evidence that the back muscle strength was not fully recovered in patients 1 month after surgery and limited their ability to move their trunk forward.

https://www.jstage.jst.go.jp/article/jpts/26/8/26_jpts-2013-619/_pdf

Trunk Control Ability after Minimally Invasive Lumbar Fusion Surgery during the Early Postoperative Phase.

Validity and feasibility of using a seated push-up test among community-dwelling older adults

Although investigations have been performed establishing the reliability of portable instruments designed to measure upper extremity strength, little research exists concerning the reliability of portable back and lower extremity "isometric dynamome­ ters. Therefore, the purpose of this study was to establish the intrarater reliability of one commercially available isometric dynamometer: the TEC isometric back, leg, and chest dynamometer. Subjects consisted of 27 volunteers (14 males and 13 females), with a mean age of 26.3 ± 4.5 years, who reported no back or lower extremity pathologies. Back and leg strength were measured standing in three positions: (1) knees extended, hips flexed, maintaining lumbar lordosis; (2) knees extended, hips flexed, spine flexed; (3) knees flexed, hips flexed, maintaining lumbar lordosis. The testing occurred on two occasions, separated by 1 week. Data analysis using intraclass correlations indicated reliability coefficients for all positions were over 0.97. These results indicate excellent intrarater reliability in each of the three testing positions using the TEC isometric back, leg, and chest dynamometer to evaluate healthy individuals.

Susan Tate

Papers

Intrarater test-retest reliability of an instrument used to measure back and leg strength