Changes in pressure pain thresholds over C5-C6 zygapophyseal joint after a cervicothoracic junction manipulation in healthy subjects.
OBJECTIVE
This study examines if C7-T1 manipulation results in changes in pressure pain thresholds (PPT) over bilateral C5-C6 zygapophyseal joints in asymptomatic subjects.


METHODS
Thirty subjects, 13 men and 17 women, without a current history of neck, shoulder, or upper extremity pain participated. Participants were randomly divided into 3 groups: experimental dominant group, subjects who received the manipulative thrust directed at the right side of the C7-T1 joint; experimental nondominant group, those who received the thrust on the left side of the C7-T1 joint; and a placebo group, those who received a sham-manual procedure. The outcome measure was the PPT on both right and left C5-C5 zygapophyseal joints, which was assessed at preintervention and 5 minutes postintervention by an assessor blinded to the treatment allocation of the subject. A 3-way repeated measures analysis of covariance was used to evaluate changes in PPT.


RESULTS
The analysis of covariance revealed time x group (F = 32.3; P < .001), time x side (F = 4.9; P < .05), time x sex (F = 7.93; P < .01), and time x group x sex (F = 7.606; P < .001) interactions. Post hoc analyses found that (a) both experimental groups showed greater improvements in PPT than the placebo group (P < .05), without significant differences between them (P > .6); (b) the right side had greater increases in PPT in both experimental groups (P < .05), but not within the placebo group (P > .8); (c) men experienced greater increases in PPT levels than women, particularly in the experimental nondominant group (P < .01). Within-group effect sizes were large for both experimental groups (d > 1), but small for the placebo condition (d < 0.2).


CONCLUSIONS
These results suggest that a C7-T1 manipulation induced changes in PPT in both right and left C5-C6 zygapophyseal joints in healthy subjects.
Professor, Department of Physical Therapy, Occupational Therapy, Physical Medicine and Rehabilitation, Universidad Rey Juan Carlos, Alcorcón, Spain. cesar.fernandez@urjc.es
César
C
Fernández-de-Las-Peñas
Cristina
C
Alonso-Blanco
Joshua A
JA
Cleland
Cleofás
C
Rodríguez-Blanco
Francisco
F
Alburquerque-Sendín
D000328:Adult; D002574:Cervical Vertebrae / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D020393:Manipulation, Spinal / Q000379:methods*; D017288:Pain Threshold / Q000502:physiology*; D011312:Pressure; D011336:Probability; D016059:Range of Motion, Articular / Q000502:physiology*; D012016:Reference Values; D012680:Sensitivity and Specificity; D013904:Thoracic Vertebrae / Q000502:physiology*; D021801:Zygapophyseal Joint / Q000502:physiology*