DOWLING, GR 1993, 'DEVELOPING YOUR COMPANY IMAGE INTO A CORPORATE ASSET', LONG RANGE PLANNING, vol. 26, no. 2, pp. 101-109.
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Lee, M & Svensson, NL 1993, 'Effect of loading frequency on response of the spine to lumbar posteroanterior forces.', J Manipulative Physiol Ther, vol. 16, no. 7, pp. 439-446.
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OBJECTIVE: The purpose of this investigation was to study the spinal deformations produced by applying a force to a lumbar vertebra and to compare the deformation responses at three different loading rates. SETTING: The study was conducted in a laboratory setting using a mechanical device to simulate the manipulative procedure being studied. SUBJECTS: Twelve volunteers (mean age 28.1 yr) formed a convenience sample for testing. All subjects had no significant history of low back pain. INTERVENTIONS: During loading the displacements of the skin were measured at the point of loading, as well as over the spinous processes of L1, T11, T8, and S1 and 30 mm caudad to S1. The loading rates were 1.0 Hz, 0.5 Hz and a very slow 'quasistatic' rate. The order of presentation of the loading rates was systematically varied between subjects to minimize the effect of order on the responses. Between 20 and 100 N, the force-displacement relations were highly linear and were characterized by the coefficients of the equation of the line of best fit. MAIN RESULTS: At all three loading rates there were displacements throughout the entire region studied. Changing from quasistatic loading to cyclical loading produced a significant reduction in displacements. CONCLUSIONS: This study found that when a force was applied over L3 there was generalized movement of the whole lumbar and lower thoracic spine. Therefore, a diversity of tissues would be expected to contribute to the resistance to lumbar posteroanterior movements.
Lee, M, Esler, M-A, Mildren, J & Herbert, R 1993, 'Effect of extensor muscle activation on the response to lumbar posteroanterior forces', Clinical Biomechanics, vol. 8, no. 3, pp. 115-119.
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The purpose of this study was to examine the responses of normal subjects to the application of cyclical lumbar posteroanterior forces which simulated a manipulative therapy technique known as mobilization. The specific aim was to determine whether increases in spinal extensor muscle activity could modify the stiffness of lumbar posteroanterior movements. The lumbar posteroanterior stiffness was measured in eleven asymptomatic subjects in the prone position, both in the relaxed condition and during maximal voluntary isometric muscle contractions. The electromyographic activity of lumbar extensor muscles was measured in the relaxed and maximal contraction conditions during the application of mobilization. The posteroanterior stiffness was found to be significantly greater during maximum activation of the extensor muscles. The results indicate that muscle activity can significantly alter lumbar posteroanterior stiffness. Clinicians often apply posteroanterior forces over a spinous process of a vertebra to assess the resistance to movement. Information about the degree and nature of perceived resistance to posteroanterior movement is used to help make a diagnosis and select treatment techniques. This study has shown that increased activity of the spinal extensor muscles can increase the stiffness of lumbar posteroanterior movements, compared with the case where the subject is relaxed. When interpreting the posteroanterior responses of patients, clinicians should be aware that spinal extensor mucle activity can influence resistance to posteroanterior movement. © 1993.
Lee, M, Latimer, J & Maher, C 1993, 'Manipulation: investigation of a proposed mechanism', Clinical Biomechanics, vol. 8, no. 6, pp. 302-306.
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The purpose of this study was to investigate whether spinal manipulation alters the posteroanterior stiffness of the manipulated region. Thirty subjects with no history of thoracic pain or contraindication to manipulation participated. The manipulation studied was a posteroanterior thrust applied to the T4-5 spinal level. The effect of the manipulation was compared to a control intervention of supine lying. The posteroanterior stiffness of all subjects was measured at the T4 and T5 levels initially, and remeasured after both the manipulation and control interventions. Change scores relating to the change in posteroanterior stiffness due to manipulation and due to the control intervention were computed. A t-test comparing the change scores between interventions revealed no significant difference. However, the posteroanterior stiffness at T5 was found to be significantly greater than at T4. It was concluded that in the case of asymptomatic subjects these results did not provide support for the hypothesis that posteroanterior stiffness is altered by manipulation. © 1993.
MIDGLEY, DF & DOWLING, GR 1993, 'A LONGITUDINAL-STUDY OF PRODUCT FORM INNOVATION - THE INTERACTION BETWEEN PREDISPOSITIONS AND SOCIAL MESSAGES', JOURNAL OF CONSUMER RESEARCH, vol. 19, no. 4, pp. 611-625.
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Shirley, D & Lee, M 1993, 'A Preliminary Investigation of the Relationship Between Lumbar Postero-anterior Mobility and Low Back Pain', Journal of Manual & Manipulative Therapy, vol. 1, no. 1, pp. 22-25.
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It is widely assumed that there is a relationship between pain, stiffness and muscle activity in patients with low back pain. This preliminary study was designed to begin an investigation of the existence of this relationship. Two subjects with low back pain and six normal subjects participated. The postero- anterior mobility of L3 and L4 was measured together with lumbar extensor muscle EMG. All normal subjects showed negligible muscle activity whereas both low back pain subjects demonstrated elevated EMG levels. In addition, both low back pain subjects were found to have relatively low mobility of L3 and L4 as compared to the normal subjects. Further research to investigate the relationship between these variables is indicated. © 1993 Maney Publishing.
