Immediate neck hypoalgesic effects of craniocervical flexion exercises and cervical retraction exercises among individuals with non-acute neck pain and a directional preference for retraction or extension: preliminary pretest-posttest randomized experimental design.

Background: Selective deep neck flexor muscle activation through craniocervical flexion exercises has been considered to be different from cervical retraction exercises.
Objective: To compare the immediate analgesic effect of craniocervical flexion versus cervical retraction exercises in individuals with nonacute, directional preference (DP) for cervical retraction or extension.
Methods: A two-arm, assessor-blinded, pretest-posttest randomized experiment was conducted. Participants were randomly assigned to either craniocervical flexion or cervical retraction exercises and those who were confirmed at the post-intervention examination to have a DP for cervical retraction or extension were analyzed. The primary outcome measure was pressure pain thresholds at the C2 and C5-C6 levels.
Results: A total of 10 (mean age = 20.6 years) and nine participants (mean age = 19.4 years) undertook craniocervical flexion and retraction exercises, respectively. One-way analysis of variance demonstrated no statistically significant ( p  > 0.05) interaction effect regardless of the neck level. In the pre-post change percentages, retraction exercises provided greater analgesic effects compared to craniocervical flexion exercises at the C2 (Hedges' g = 0.679) and C5-C6 levels (g = 0.637).
Conclusion: This study showed a comparable or greater immediate neck analgesic effect from cervical retraction exercises compared to craniocervical flexion exercises in individuals with a DP for cervical retraction or extension.