Thesis (Ph. D.)--University of Sydney, 2002. / Title from title screen (viewed Apr. 23, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Exercise and Sport Science, Faculty of Health Sciences. Degree awarded 2002; thesis submitted 2001. Includes bibliography. Also available in print form.

Thesis--Auburn University, 2009. / Abstract. Vita. Includes bibliographical references (p. 116-119).

Thesis (Ph. D.)--Duke University, 2007. / Includes bibliographical references.

Condensation of Thesis (Ph. D.)--University of Michigan, 1941. / Caption title. "Reprinted from the Anatomical record, vol. 86, no. 2, June, 1943." "Literature cited": p. 136-137.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1976. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Introduction: Lumbar spine stability programs have been advocated to prevent and rehabilitate low back injury. Specifically, abdominal ‘drawing in’ has been used to train motor control deficits in individuals with low back pain. This technique requires differential activity within deep and superficial lumbar multifidus fibres, yet the ability of these fibres to act differentially has not been extensively examined. Deep fibres are hypothesized to act as spinal stabilizers while superficial fibres are hypothesized to act as global movers of the trunk. Objective: To investigate differential excitation of deep and superficial lumbar multifidus fibres during segmental indentation loads to the lumbar spine. Methods: Posterior-anterior indentation loads were applied to individual lumbar spinous processes of prone participants at three different velocities and three different indentation displacements. Indentations consisted of an initial downward displacement that was subsequently held for 500 milliseconds. Intramuscular electromyography (EMG) of deep and superficial lumbar multifidus fibres at L3, L4 and L5 was recorded. EMG was quantified by “average” root mean square (RMS), peak RMS of a sliding RMS window and time-to-peak RMS over the indentation phase and 500 millisecond hold phase. Results: Increased indentation displacement at the slowest velocity resulted in increased “average” RMS of only the L5 superficial multifidus fibres. Increased indentation velocity produced differential effects in deep and superficial multifidus fibres. “Average” RMS and peak RIVIS significantly increased with increasing indentation velocity in most deep fibre recording sites, yet superficial fibre excitation did not significantly increase. In most EMG recording sites, the time-to-peak RMS increased with increasing indentation displacement and decreased with increasing indentation velocity. Conclusion: Differential excitation of superficial and deep multifidus fibres was found with increasing indentation velocity; however, the result was opposite to that hypothesized. This result is clinically relevant because it suggests deep multifidus fibre excitation may increase in response to increased perturbation magnitude, possibly to restore vertebral body position. Differential excitation effects may also be related to different mechanical stimuli experienced by deep and superficial fibres due to vertebral body movement during indentation loads. 11 / Education, Faculty of / Kinesiology, School of / Graduate

No description available.

No description available.

Low back disorders and their prevention is of great importance for companies and their employees. Whole-body vibration is a risk factor for low back disorders, but the neuromuscular, biomechanical, and/or physiological mechanisms responsible for this increased risk are unclear. These studies investigated changes in the biomechanics and control of the trunk in order to further the understanding of the mechanisms responsible for this increased risk. The purpose of the first study was to measure the acute effect of seated whole-body vibration on the postural control of the trunk during unstable seated balance. The findings show that whole-body vibration impaired the postural control of the trunk as evidenced by increased kinematic variance and non-linear stability control measures during unstable sitting. These findings imply an impairment in spinal stability control. The purpose of the second study was to measure the effect of seated whole-body vibration on the parameters of spinal stability control: passive stiffness, active stiffness, and neuromuscular reflexes. The findings show that whole-body vibration altered trunk stiffness (passive stiffness and equivalent reflex stiffness) as well as reflex dynamics. There was no evidence of compensation by active muscle co-contraction recruitment for the decreased trunk stiffness and reflex gain. The purpose of the third study was to measure the changes in the natural frequency characteristics of the trunk (which can be related to trunk stiffness and damping) during exposure to seated whole-body vibration. The findings show that whole-body vibration caused a decrease in natural frequency suggesting a decrease in the trunk stiffness, and also an increase in the peak amplitude of the frequency response functions suggesting a decrease in overall trunk damping. The rate of change of the natural frequency characteristics suggest that the majority of effects happen within the first 10 minutes of vibration exposure. These findings reveal changes in the biomechanical properties of the trunk with exposure to seated whole body vibration, and a mechanism by which vibration may increase the risk of low back injury. / Ph. D.

Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2011. / BACKGROUND: Plain film radiography is the most common imaging technique requested by chiropractors to assist in the management of patients with musculoskeletal complaints. There is a paucity literature indicating that chiropractors’ interpretive radiographic skills are consistently able to achieve the same outcome given a particular set of radiographs. An important indication for the use of radiography in chiropractic is to exclude any possible contraindications to spinal manipulative therapy (SMT) that could cause serious injury to a patient if it is left unmodified or excluded as a treatment option. OBJECTIVES: The study aimed to investigate the inter- and intra-examiner reliability of chiropractor’s diagnosis on cervical spine radiographs. Additionally, the effect of clinical history added to the radiographs was assessed. METHODS: Inter- and intra-examiner evaluations occurred on two consecutive readings of 30 radiographs by six qualified chiropractors. No clinical history was given during Round One, but was available during Round Two. RESULTS: The inter-observer agreement for categorisation and management went from “poor agreement” in Round One (Κ=0.1962 and Κ=0.1996 respectively) to “fair agreement” (Κ= 0.2041 and Κ=0.2036 respectively) beyond that expected by chance in Round Two. Identification remained “fair agreement” beyond that expected by chance over both rounds (Κ=0.3113 and Κ=0.2159). Sensitivity at Round One was 94.4% and the specificity was 61.1%. At Round Two the sensitivity had decreased to 93.8% and the specificity had decreased to 50%. There was no significant difference between the accuracy of the Round One and Round Two results for categorisation (p=0.243) and management (p=0.220), but there was a clinical difference for identification (p=0.014). iii CONCLUSION: Differences in the result were small indicating clinical relevance with regards to inter-examiner reliability was fair in most instances. Although clinical history did not influence categorisation or management, it did improve accuracy of identification of pathology. Chiropractors successfully identified between 93.8% and 94.4% of abnormal radiographic findings demonstrating that chiropractors use of radiographs as a diagnostic tool when looking for contraindications to spinal manipulative therapy was sensitive. This demonstrates that its use as a diagnostic tool for contraindications to spinal manipulative therapy (SMT) is sensitive.