Head Repositioning Errors in
Normal Student Volunteers:
A Possible Tool to Assess the
Neck’s Neuromuscular System
AUTHORS: Edward Owens, Jr., D.C., M.S.; Charles Henderson, D.C.;
Ram Gudavalli, Ph.D.; Joel Pickar, D.C.
Joint pain can interfere with the ability to position body parts
accurately. We tested whether repositioning errors could be
induced in a normal population by contraction of the neck
muscles. In the study, volunteers free of neck problems found
a comfortable neutral head posture with eyes closed. They
deconditioned their cervical muscles by moving their heads in
either flexion/extension or lateral flexion and then attempted
to return to the same starting position. Two conditioning
sequences were interspersed within the task: hold the head in
an extended or laterally flexed position for 10 seconds; or
hold a 70 percent maximum voluntary contraction for 10
seconds. The difference between the initial and final head
orientation was calculated in three planes. Forty-eight chiropractic
students participated. During the neck extension test,
actively contracting the posterior neck muscles evoked an
undershoot of the target position by 2.1° (P<0.001). No
differences in repositioning were found during the lateral
flexion test. The results suggest that the recent cervical
paraspinal muscle contraction can influence head repositioning
in flexion/extension. This is the first time that muscle
history has been shown to influence proprioceptive accuracy
in the human neck. This finding may be used to elucidate
the mechanism behind repositioning errors seen in people
with neck pain.
A Randomized Clinical Trial
and Subgroup Analysis to
with Active Exercise for Chronic
Low Back Pain.
AUTHORS: Ram Gudavalli, Ph.D.; Jerrilyn Cambron, D.C., M.P.H.,
Ph.D.; Marion McGregor, D.C., Ph.D.; James Jedlicka, D.C., et al.
Flexion distraction (FD) is a commonly used form of
chiropractic care. No previous clinical trial has assessed its
effectiveness. This study compared two treatment protocols.
The objective was to compare the outcome of chiropractic
FD procedures to an active trunk exercise protocol (ATEP)
performed by physical therapists. A randomized clinical
trial study design was used. A 100-mm visual analogue
scale (VAS) for perceived pain, the Roland Morris (RM)
Questionnaire for low back function, and the SF-36 for
overall health status served as primary outcome measures.
The FD intervention consisted of the application of flexion
and traction applied to the low back, using a speciallydesigned
table. The ATEP intervention included exercises,
modalities and cardiovascular training. Study patients perceived
significantly less pain and better function after intervention,
regardless of which group they were in (P<0.01).
Subjects in the FD group had greater relief from pain than
those in the exercise program (P=0.01). Subjects categorized
as chronic improved most with the FD protocol. Subjects with
recurrent pain and moderate to severe symptoms improved
most with exercise. Patients with radiculopathy did better
with FD. There were no significant differences between groups
on the RM and SF-36 outcome measures. Overall, FD provided
more pain relief than active exercise; however, these results
varied based on stratification of patients with and without
radiculopathy and recurrent symptoms.
The Palmer Center for Chiropractic Research is
located on Palmer’s Davenport Campus in the
William and Jo Harris Building.