Intra- and intersession reliabilities of the flexor carpi radialis H-reflex while sitting with forearm pronation

Purpose: The flexor carpi radialis H-reflex recordings were more robust when the participants were in a sitting position with forearm pronation than with forearm supination. The reliability of flexor carpi radialis recordings obtained with the participant in sitting posture with forearm supination is well established. However, similar reliability utilizing a sitting posture with forearm pronation has not been established. The purpose of this study was to establish the intra and intersession reliabilities of flexor carpi radialis H-reflex recordings acquired with the participants in a sitting with forearm pronation. Materials and methods: The flexor carpi radialis maximum H-reflex amplitude and latency were recorded unilaterally in twenty participants. The forearm was positioned in either a supination or a pronation position on two separate days. Four traces were recorded, and the intraclass correlation coefficients were calculated. Results: The intrasession intraclass correlation coefficients of the four traces of the flexor carpi radialis H-reflex amplitude during pronation on days 1 (0.96) and 2 (0.94) were more consistent than those acquired during supination on days 1 (0.78) and 2 (0.93). The intersession intraclass correlation coefficients of the average traces of the flexor carpi radialis H-reflex amplitude during pronation between days 1 and 2 were more consistent (0.9) than those during supination (0.55). Conclusions: The flexor carpi radialis H-reflex recordings acquired with the participant in a sitting position are more reliable with forearm pronation than with supination within and between sessions. These results should encourage clinicians and researchers to use this position when examining the neuromuscular function of the upper extremities in healthy individuals and those with neuromuscular disorders.