Short range of motion isokinetic testing of wrist flexor and extensor strength in normal subjects and patients with carpal tunnel syndrome.

The purpose of this study was to compare the utility of measuring wrist flexors and extensors strength derived from 'full' range of motion (FRoM): 60 degrees of flexion to 30 degrees of extension, and 3 equally spaced short ranges of motion: SRoM1, 60-30 degrees and SroM2, 30-0 degrees of flexion and SRoM3, 0-30 degrees of wrist extension. Fifteen apparently healthy subjects and 8 patients suffering from unilateral carpal tunnel syndrome (CTS) participated in the study. In all participants, SRoM1 findings closely resembled those obtained from FRoM. In the patient groups, the muscular strength of the uninvolved side was not different from that of the healthy subjects. On the other hand, based on a bilateral comparison (involved vs. uninvolved hand), the mean total weakness (in concentric and eccentric modes) was significantly higher in flexion (56.4 +/- 17.3%) than in extension (39.8 +/- 15.5%) but highly symmetrical between FRoM and SRoM1. Although supporting the interchangeable use of FRoM and SRoM isokinetic testing, this study highlights a hitherto unreported dynamic weakness of the wrist extension-flexion apparatus that may partly account for the general reduction in hand function reported by patients with CTS.