Does neck flexion improve performance? Effects on reaction time depend on whether responses are expected.

This research investigates the limitations of the apparent paradox in which neck flexion, which is associated with poor inhibition and neck pain, seems to facilitate performance in some tasks. We compared the effect of a flexed neck on performance in a reaction time and go-nogo task using a novel method of fixing neck posture. We hypothesize that using a flexed neck posture speeds response time for tasks with high prepotency (when participants are biased toward responding), but not for tasks with low prepotency (when participants are more likely to withhold a response). Previous findings demonstrated the effect of neck flexion on reaction time with a harness. In this study, participants complete both simple reaction time and go-nogo tasks with neck angles fixed in neutral or forward positions with tape. We found that simple reaction times were 10 ms faster in the forward neck position than in neutral; this facilitation was not seen in the go-nogo task. We conclude that using tape to induce a flexed neck posture facilitates reaction time during tasks that always require a response and does not affect reaction time on a task which may require withholding a response.