The Reliability of One vs. Three Trials of Pain-free Grip Strength in Subjects with Rheumatoid Arthritis

Study DesignMeasurement Reliability. The purpose of the study was to evaluate the test–retest reliability of one vs. the mean of three trials of pain-free grip strength in participants with rheumatoid arthritis (RA). The study used was a repeated-measures, crossover design. Pain-free grip strength was measured with the Biometric E-Link Evaluation System V900S (Unit 25, Nine Mile Point Ind. Est., Gwent UK NP11 7HZ), pain levels recorded before and after grip tests with visual analog scale. High levels of test–retest reliability (intraclass correlation coefficient ≥ 0.91) were found for both one trial and the mean of three trials of pain-free grip strength testing. Median values of grip strength for both methods produced comparable results. Clinically small but statistically significant increases in pain (p ≤ 0.01) were found. One trial of pain-free grip strength is reliable and may save valuable clinical time while reducing the assessment burden placed on patients with RA.Level of EvidenceN/A.