Relationship Between Proprioception and Endurance Functionality of the Cervical Flexor Muscles in Chronic Neck Pain and Asymptomatic Participants.

OBJECTIVE: The purpose of this study was to compare the relationship between flexion endurance capacity and joint position error in participants with or without chronic neck pain (CNP). METHODS: Sixty-one CNP and 60 asymptomatic volunteers participated in this cross-sectional, case-control, and correlational analysis study. The measured variables included absolute and constant joint repositioning errors in the sagittal and horizontal directions, clinical flexor endurance test score, pain intensity, and neck disability index. RESULTS: The groups did not statistically differ in flexion endurance (P > .05). The CNP group had a smaller absolute error on the right (P < .01) and left (P = .01) rotation and an overshooting error pattern in the flexion direction (P < .05). But the asymptomatic group did not exhibit any over-/undershooting pattern tendency (P > .05). Although flexion endurance was not correlated with any of the joint repositioning error components in either group, pain and disability scores were significantly correlated with left rotation absolute error (r = -0.34 and ρ = -0.37, respectively). CONCLUSION: The clinical cervical flexor endurance test, ignoring the relative contribution of the deep and superficial groups of muscles, may not efficiently characterize CNP patients.

Effect of the Abdominal Hollowing and Bracing Maneuvers on Activity Pattern of the Lumbopelvic Muscles During Prone Hip Extension in Subjects With or Without Chronic Low Back Pain: A Preliminary Study.

OBJECTIVE: The purpose of this study was to compare the effect of abdominal hollowing (AH) and abdominal bracing (AB) maneuvers on the activity pattern of lumbopelvic muscles during prone hip extension (PHE) in participants with or without nonspecific chronic low back pain (CLBP). METHODS: Twenty women with or without CLBP participated in this cross-sectional observational study. The electromyographic activity (amplitude and onset time) of the contralateral erector spinae (CES), ipsilateral erector spinae (IES), gluteus maximus, and biceps femoris muscles was measured during PHE with and without abdominal maneuvers. A 3-way mixed model analysis of variance and post hoc tests were used for statistical analysis. RESULTS: Between-group comparisons showed that the CES onset delay during PHE alone was greater (P = .03) and the activity level of IES, CES, and biceps femoris in all maneuvers (P < .05) was higher in patients with CLBP than in asymptomatic participants. In asymptomatic participants, PHE + AH significantly decreased the signal amplitude (AMP) of IES (P = .01) and CES (P = .02) muscles. In participants with CLBP, IES muscle AMP was lower during PHE + AH compared with PHE + AB and PHE alone. With regard to onset delay, the results also showed no significant difference between maneuvers within either of the 2 groups (P > .05). CONCLUSIONS: Performance of the AH maneuver decreased the erector spinae muscle AMP in both groups, and neither maneuver altered the onset delay of any of the muscles in either group. The low back pain group showed higher levels of activity in all muscles (not statistically significant in gluteus maximus during all maneuvers). The groups were similar according to the onset delay of any of the muscles during either maneuver.