The efficacy of manual and manipulative
therapy for low back pain
in military active duty personnel:
A feasibility study.
The Palmer Center for Chiropractic Research
conducts research at the William and Jo Harris
Building on the Davenport Campus, left, as well
as on the West Campus and the Florida Campus.
CO-PRINCIPAL INVESTIGATORS: Christine Goertz-Choate,
D.C., Ph.D.; and Keith P. Myers, M.D., D.C.
CO-INVESTIGATORS: Maria Hondras, D.C., M.P.H.; and
Cynthia R. Long, Ph.D.
The Palmer Center for Chiropractic Research is collaborating
with the William Beaumont Army Medical Center at Fort
Bliss in El Paso, Texas, to collect data on 100 active-duty
military personnel with acute low back pain. The specific
aims of this project are to 1) determine the feasibility of, and
the comparative treatment effect size for, conducting a larger
clinical trial of chiropractic treatment in restoring peak performance
in military personnel in operational environments;
and 2) evaluate the ability of the addition of chiropractic care
to standard care to decrease pain and increase function for
patients with low back pain. This project will provide information
about the challenges and opportunities involved in
conducting clinical research of chiropractic in a military setting.
Its long-term goal is to use this information to conduct
additional studies on chiropractic at a wider number of bases
throughout the U.S. This study was funded by the Samueli
Institute for Information Biology in Alexandria, Va.
Time course for the development
of muscle history in lumbar
paraspinal muscle spindles arising
from changes in vertebral position.
AUTHORS: Weiqing Ge, Ph.D.; and Joel Pickar, D.C.
Proprioceptive feedback from muscle spindles is considered
important for muscle control. Because muscle spindles are
thixotropic, their length history changes their responsiveness. We
explored a mechanism that could affect paraspinal muscle spindle
responsiveness in the lumbar spine. METHODS: Neural recordings
from lumbar paraspinal muscle spindle afferents were
obtained during changes in position of the L6 vertebra. Position
was controlled using a displacement-controlled feedback motor.
L6 was held in each of 3 different conditioning positions for durations
of 0, 0.5, 1, 1.5, 2, 4, 6 and 8 seconds. Two conditioning
positions stretched (hold-long) or shortened (hold-short) the spindles
and one position conditioned the spindle in an intermediate
position (hold-intermediate). Hold-long and hold-short ranged
between 0.9-2.0 mm of vertebral movement relative to the intermediate
position. Following conditioning, the vertebra was
returned to the intermediate position and muscle spindle discharge
determined at rest and during vertebral movement that
stretched the spindle. Conditioning was thought to simulate a
motion segment’s position that might be passively maintained due
to fixation, external load, a prolonged posture, or structural
change. RESULTS: Both resting discharge and discharge during
movement were affected differently by the specific type of conditioning.
Hold-long decreased spindle discharge and hold-short
increased spindle discharge compared to hold-intermediate. The
effects developed with a time course following a first order exponential
reaching a maximal value after approximately 4 seconds of
history. The time constant for hold-short history was 2.6 seconds
and for hold-long history was approximately half of that at 1.1
seconds. DISCUSSION: These findings are consistent with a
mechanism that involves the rapid, spontaneous formation of stable
crossbridges between the intrafusal muscle fibers of the spindle.
These history-dependent effects on spindle responsiveness
would evoke proprioceptive input not necessarily representative of
the current state of intersegmental positioning. This could constitute
a source of inaccurate proprioceptive feedback.
The full abstract of this study was published in The Spine
Journal, Volume 8, Issue 2, March-April 2008, pages 320-328.