Spinal Manipulation Impacts Cervical Spine Movement and Fitts' Task Performance: A Single-Blind Randomized Before-After Trial

Abstract Objective The objective of this study was to determine if active cervical range of motion (ROM) and Fitts' task movement time differences occurred after high-velocity low-amplitude cervical spinal manipulation (SM) across various indexes of difficulty. Methods A single-blind randomized before-after trial was performed in a motor performance laboratory. Fifteen volunteers (21-42 years) with asymptomatic palpable intervertebral motion restriction at the C1-C2 level were randomly assigned to an SM group or to a no-intervention (NI) group. A single episode of upper cervical manipulation was performed on the SM group. Active cervical ROM and movement time were measured pre and posttreatment in the SM group and compared to similar measurements in the NI group. Results In the SM group, active cervical ROM into rotation increased after the intervention (pre, 74.75° ± 7.63°; post, 78.50° ± 7.23°; t (7) = −3.07; P < .02). During the second trial, significant group differences were present in the SM group for movement time in direction congruent conditions (F(8,48) = 2.83; P < .02; ηp2 = .320) and direction incongruent conditions (F(8,48) = 2.31; P < .05; ηp2 = .278) but not for the NI group. Conclusions A linear relationship between indexes of difficulty and movement time as predicted by Fitts' law was observed. Significant group effects indicate that SM not only increases cervical active ROM but also facilitates the performance of a cervical spine Fitts' task requiring rotation. This task may be used to quantify motor performance in clinically symptomatic populations with reduced ROM who are appropriate candidates for SM.