What change in isokinetic knee muscle strength can be detected in men and women with hemiparesis after stroke?

Abstract

Objective: To assess the intra-rater (between occasions) test-retest reliability of isokinetic knee muscle strength measurements in subjects with chronic poststroke hemiparesis and to define limits for the smallest change that indicates real (clinical) improvements for stroke patients. Subjects: Fifty men and women (mean age 589±6.4 years) 6=±46 months post stroke, able to walk at least 300 m with or without a unilateral assistive device. Methods: Maximal concentric knee extension and flexion contractions at 608/s and 1208/s, and maximal eccentric knee extension contractions at 608/s, with the paretic and nonparetic limbs, were performed seven days apart using a Biodex dynamometer. Measures: Reliability of the maximum peak torque measurements was evaluated with the intraclass correlation coefficient (ICC2,1), the Bland and Altman analyses, the standard error of measurement (SEM and SEM%) and the smallest real difference (SRD and SRD%). Results: Test retest agreements were high (ICC2,1 0.89-0.96) with no discernible systematic differences between limbs, angular velocities and modes. The SEM%, representing the smallest change that indicates a real (clinical) improvement for a group of subjects, was relatively small (8-20%). The SRD%, representing the smallest change that indicates a real improvement for a single subject ranged from 26% to 33% for concentric knee extension, from 39% to 55% for concentric knee flexion, and from 22% to 25% for eccentric knee extension. Conclusion: Isokinetic knee muscle strength can be reliably measured and used to detect real improvements following an intervention for single subjects as well as for groups of subjects with chronic mild to moderate hemiparesis after stroke.

No Specific Effect of Whole-Body Vibration Training in Chronic Stroke: A Double-Blind Randomized Controlled Study

“…However, the magnitude of the changes after WBV training was within or very close to the limits of measurement errors, which indicates no real clinical improvement. 15,21 WBV training has been promoted to be an alternative to resistance training. 4 Ten weeks of progressive resistance training (PRT; 80% of 1 Repetition Maximum) after stroke significantly improved knee muscle strength (+14% to +73%) as well as gait performance (+10% to +19%), without any negative effects on muscle tone.…”

“…The same procedure was thereafter repeated with the paretic lower limb.This protocol has been shown to be reliable after stroke 15 and the ICC 2,1 for knee muscle strength measurements at 60°/s ranged from 0.89 to 0.94. The standard error of measurement (SEM%) was 9% to 17% for the concentric knee extension and flexion, respectively.…”

“…15 The participants were seated in the adjustable chair of the dynamometer, without shoes or orthotic device, and were stabilised with straps across the shoulders, waist and thigh throughout the test. Before each measurement the full range of motion (ROM) was set and the Biodex® software applied the gravity correction.…”

“…Our research group has previously performed a reliability study on knee muscle strength after stroke 15 and shown that the measurement errors are generally small. Based on these results, we performed a power calculation; a total of 30 participants would yield an 80% chance of detecting a 20% difference in strength between the intervention group and the control group, with a significance level of p<0.05.…”

Reliability, Concurrent Validity, and Responsiveness of the Fugl-Meyer Assessment (FMA) for Hemiplegic Patients

“…Reliability may also be divided into relative and absolute reliabilities 5) . Relative reliability is determined using the intraclass correlation coefficient (ICC) 6) , and absolute reliability is determined with the standard measurement error (SEM) and smallest real difference (SRD) 7) . Some outcome evaluation tools have a high validity and the interrelationship between widely used valid evaluation tools and FMA, in other words, their concurrent validity, needs to be investigated 8) .…”