Grip strength is more sensitive to changes in elbow position than isolated wrist extension strength in patients with lateral elbow tendinopathy

Study Design: This is an observational study. Introduction: Because isometric wrist extension minimizes the effects of other muscles, the sensitivity of wrist extension strength testing on patients with lateral elbow tendinopathy (LET) should be evaluated. Purpose of the Study: The purpose of the study was to compare the effects of the elbow position on wrist extension and grip strength in patients with LET. Methods: Patients were screened for at least 2 of 5 clinical tests for LET. Between-day intraclass correlation coefficients (ICC_{3, 1}) for healthy individuals were examined for both grip and wrist extension strength at 0° and 90°. To compare the effects of elbow position on wrist extension strength to grip strength, a repeated measure analysis of variance was run using 2 within-group factors, test angles (0° and 90°), and the test type (wrist extension and grip). Results: Nineteen patients with LET and twenty-one healthy participants were included. The between-day intrarater reliability for both wrist extension and grip strength was excellent for the healthy subjects across the 0° and 90° positions (ICC > .95). The analysis of variance yielded a significant interaction between the type of test and the angle of testing (P = .00). Discussion: Both wrist extension strength and grip strength are reliable between-day measures. For patients with LET, there was a significant decrease in grip strength when testing at 0° compared with 90°. Conclusion: In patients with LET, clinicians can expect wrist extension strength at 0° and 90° to be similar. Grip strength testing may be a more relevant clinical test at the initial evaluation.