658
Abstracts
TORQUE-ROTATION RESPONSE OF LUMBAR MOTION SEGMENTS IN FLEXION John J. Triano, M.A., D.C. and Ram Gudavalli, PhD National College of Chiropractic, Lombard, Illinois 60148, USA Manipulation treatment of lumbar complaints produces torsional loads where intersegmental flexion is an initial condition. A number of studies have examined tzhe mechanics of rotation in motion segments for neutral and extension postures. Three reports have suggested that degeneration and flexion conditions put the posterolateral motion segment components at risk. Occasional disc injury from manipulaiion has been reported clinically. This study examined the effect of rotation loads like those in a manipulation on a kinero-elasto-staticcomputer model of the lumbar spine. Healthy and degenerative discs under flexion initial conditions were included. Motion limits from stop-action of the facets were exceeded by a factor of 3. The resulting axial rotatton was nearly identical to grade 4 disc response to axial load reported by Adams and Hutton (1981).
RELATIONSHIP BETWEEN FWNCI’IONAL LIlTING MECHANICS AND LUMBAR EXTENSION STRENGTH Wheeler, DL’; Miller, GJ‘, O’Connor, Pt; Hubbard, Rt ’ Department of Orthopaedics, University of Florida i Department of Physical Therapy, Shands Hospital Box 5246, JHMHC, Gainesville, FL 32610 Workers engaged in lifting tasks often injure or strain their lower back musculature either acutely by attempting to lift too much or chronically due to muscle fatigue. These injuries lead to loss of productive work days to the employer as well as pain and inconvenience to the worker. In order to circumvent these injuries, preliminary research has been conducted to determine the relationship between an individual’s maximum lumbar extension strength and the torque at the lumbosacral joint (L5Sl torque) predicted through kinetic analysis during lifting. The strength and lifting mechanics of 6 healthy individuals were evaluated. This assessment provided the basis for prediction and subsequent verification of the maximum weight the subjects could lift for a simple task. A very high correlation (r = 0.995) was found between maximum lumbar extension strength and predicted maximum I_SSl torque during Iifting for this preIiminary study. This correlation provides a means to quantiQ limitations in lifting capacity for normal or injured workers.
SESSION J-PATHOLOGICAL GAIT Chairperson: Mary Rodgers
STATIC AND DYNAMIC MECHANICAL FACTORS BETWEEN THE RELATI ONSHI P STUDY OF PRIMARY A CASE AND T I SSUE DEGENERAT I ON PATTERNS : OSTEOARTHRI TI S OF THE KNEE JOINT Kamlbayashi ,L., Wyss, U.P., Cooke.T.D.V., Cost igan, P. Department of Anatomy/Clinical Mechanics Group Queen’s University, Kingston, Ontario, Canada, Ki’L 3N6. a progressive disease of unknown (OA) is Primary osteoarthritis artlcular hyallne degeneration of the etiology which leads to cartilage and changes to the underlying subchondral bone within a interplay of of an Whfle OA may ultimately be the result jofnt. understanding the stresses within a .lolnt many different factors, explain the cond 1 t 1 ons loading d ynaml c during static and may joint. We within a degenerat 1 on tissue distribution of hypothesize that articular surfaces dlstribut stress degeneration.
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