Study Design. This study investigated the effects of a lumbar support belt on lumbar disc deformation and joint angles. Trunk strength and endurance were also compared to disc deformation and joint angles to determine if any meaningful relationships existed. Objective. The purpose of this study was to determine if back support belts relieve stresses encountered by the lumbar spine during lifting activities and thus reduce the risk of injury. Additionally, trunk strength and endurance measures were collected in order to determine if strong, well conditioned trunk musculature aids in the support of the lumbar spine. Summary of Background Data. Low-back pain and injury are responsible for a major portion of lost work days and injury compensation claims. Back support belts have been proposed as a counter measure towards reducing low-back injuries in the industrial setting. Methods. Twelve male subjects (average age, 49.7 years) performed two sessions of stoop type lifting with a loaded milk crate (11.5 kg), at a rate of 4 repetitions per minute, for a total 15 minutes per session in accordance with the NIOSH 1993 lifting equation. The order of testing with and without a belt was randomized for the two sessions. Fluoroscopic images were collected prior to and following both lifting sessions. Fluoroscopic images were collected with the subjects positioned at the initiation (flexed trunk), mid-range, and completion of the lift (erect standing). Images were imported into Auto Cad where lumbar disc deformation and joint angles were measured by calculating changes in position of adjacent vertebra (L3-4 and L4-5). A reduction of deformation was deemed indicative of reduced stress. Trunk extension and flexion strength were measured with a Kin Com isokinetic dynamometer. Trunk flexion endurance was measured via a 60 second curl-up test. Results. Analysis of variance revealed that compressive and shear disc deformation were reduced while in the erect trunk posture for the support belt condition (p<.05). No significant reduction in disc deformation was detected while in flexed trunk postures for the support belt condition (p>.05). A significant inverse relationship was detected (p<05) between: abdominal strength and shear stress (flexed trunk positions), abdominal endurance and shear stress (erect trunk), and spinal erector strength and L4-L5 joint angle (erect trunk). Conclusions. During stoop type lifting, support belts provide a measurable amount of stress reduction of the lumbar spine when the trunk is in the erect posture, with little effect during flexed trunk positions. Strong, well conditioned trunk musculature is associated with reduced stress on the lumbar spine. / Graduation date: 1998

The purpose of this study was to investigate the differences in muscle activity of the lumbar and pelvic extensor muscles during the hyperextension and reverse hyperextension exercises. Fifteen healthy and weight-trained volunteers (8 women, 7 men) were recruited from a university setting. Electromyographic (EMG) activity of selected hip and trunk extensor muscles was recorded during the execution of a hyperextension and a reverse hyperextension. Three muscles were analyzed: lumbar erector spinae (ES), biceps femoris (BF) and gluteus maximus (GM). The amount of external load used by each individual was determined by equating the amount of torque produced at the hip joint for both exercises. Participants performed two trials of each exercise, and completed at least three repetitions within the eight-second data collection period. Peak integrated EMG (iEMG) activity was expressed as a percentage of maximal voluntary isometric contraction (%MVC). A two-way repeated measures analysis of variance (ANOVA) failed to demonstrate significant differences in %MVC activity between the two exercises, (p>0.05). A comparison of the hyperextension and reverse hyperextension exercises revealed that under similar loading conditions, there is no significant difference in muscle activity of the lumbar and hip extensor muscles. / School of Physical Education

Thesis (PhD)--University of South Australia, 2002.

Thesis (M.Tech.: Chiropractic)-Durban University of Technology, 2008 / To evaluate the lumbar lordosis, lumbosacral angle, lumbosacral disc angle, lumbosacral lordosis angle, intervertebral disc angles and heights, interpedicular distances, sagittal canal diameters and the lumbar gravity line (selected radiographic parameters) in young to middle aged Indian females in Durban. To determine any association between the selected radiographic parameters and the age of the subjects, weight, height and body mass index of the subjects, occupation, smoking, previous pregnancy and leg length inequality (selected anthropometric and demographic factors). Methods: Sixty healthy, asymptomatic, young to middle aged, Indian females were recruited for this study. All subjects underwent a case history, a physical examination and radiographic evaluation (AP and lateral views) of the lumbar spine. SPSS version 15.0 (SPSS Inc., Chicago, Ill, USA) was used to analyze the data. Results: The mean (± SD) of the lumbar lordosis, lumbosacral angle, lumbosacral disc angle and lumbosacral lordosis angle was 49º (± 6º), 39º (± 8º), 12º (± 5º) and 143.2º (± 5º) respectively. For the lumbar intervertebral disc angles at L1-L2, L2-L3, L3-L4, L4-L5 and L5- S1 levels, the mean (± SD) was 6º (± 2º), 8º (± 2º), 10º (± 3º), 12º (± 4º) and 12º (± 5º) respectively. The anterior and posterior intervertebral disc heights at the respective vertebral levels were: L1-L2: anterior: 8 mm (± 2), posterior 5 mm (± 2); L2-L3: anterior: 10 mm (± 2), posterior 5 mm (± 2); L3-L4: anterior: 12 mm (± 2), posterior 5 mm (± 2); L4-L5: anterior: 14 mm (± 3), posterior 5 mm (± 2) and L5-S1: anterior: 13 mm (± 4), posterior 6 mm (± 2). The mean (± SD) of the interpedicular distance at the L1, L2, L3, L4 and L5 vertebral levels was 23 mm (± 2), 24 mm (± 2), 25 mm (± 2), 27 mm (± 2) and 31 mm (± 3) respectively. For the sagittal canal diameter at the L1, L2, L3, L4 and L5 vertebral levels, the mean (± SD) was 20 mm (± 5), 21 mm (± 3), 21 mm (± 3), 21 mm (± 3) and 19 mm (± 3) respectively. The lumbar gravity line intersected the sacrum in 67.3% of the subjects. In 29.1% of the subjects, the lumbar gravity line passed anterior to the sacrum while in 3.6% of the subjects, it passed posterior to the sacrum. iv A significant association was found between lumbar lordosis and the height of the subjects in this study (p = 0.004). A decrease in the intervertebral disc height at L5-S1 was associated with smoking (p = 0.005). A decrease in the intervertebral disc height at L4-L5 was associated with previous pregnancy (p = 0.016). Body mass index of 26–30 kg.m-2 was significantly associated with an increase in the intervertebral disc angles at L3-L4 (p = 0.028) and L4-L5 (p = 0.031). A decrease in the L5-S1 intervertebral disc angle was also significantly associated with smoking (p = 0.023). There was a significant association between previous pregnancy and an increase in the intervertebral disc angle at L3-L4 (p = 0.016). A significant association was found between the age of the subjects and the L5-S1 intervertebral disc angle (p = 0.007). Specifically it was the 23–27 year group and 33–37 year group who were significantly different from each other (p = 0.033). Conclusion: Similarities and differences were found in the mean values of the radiographic parameters measured in this study and those reported in the literature. A number of the selected anthropometric and demographic factors were associated with some of the lumbar radiographic parameters. Further studies are required to establish the clinical significance of these findings.

Thesis (M.Tech.: Chiropractic)-Durban University of Technology, 2008 / To evaluate the lumbar lordosis, lumbosacral angle, lumbosacral disc angle, lumbosacral lordosis angle, intervertebral disc angles and heights, interpedicular distances, sagittal canal diameters and the lumbar gravity line (selected radiographic parameters) in young to middle aged Indian females in Durban. To determine any association between the selected radiographic parameters and the age of the subjects, weight, height and body mass index of the subjects, occupation, smoking, previous pregnancy and leg length inequality (selected anthropometric and demographic factors). Methods: Sixty healthy, asymptomatic, young to middle aged, Indian females were recruited for this study. All subjects underwent a case history, a physical examination and radiographic evaluation (AP and lateral views) of the lumbar spine. SPSS version 15.0 (SPSS Inc., Chicago, Ill, USA) was used to analyze the data. Results: The mean (± SD) of the lumbar lordosis, lumbosacral angle, lumbosacral disc angle and lumbosacral lordosis angle was 49º (± 6º), 39º (± 8º), 12º (± 5º) and 143.2º (± 5º) respectively. For the lumbar intervertebral disc angles at L1-L2, L2-L3, L3-L4, L4-L5 and L5- S1 levels, the mean (± SD) was 6º (± 2º), 8º (± 2º), 10º (± 3º), 12º (± 4º) and 12º (± 5º) respectively. The anterior and posterior intervertebral disc heights at the respective vertebral levels were: L1-L2: anterior: 8 mm (± 2), posterior 5 mm (± 2); L2-L3: anterior: 10 mm (± 2), posterior 5 mm (± 2); L3-L4: anterior: 12 mm (± 2), posterior 5 mm (± 2); L4-L5: anterior: 14 mm (± 3), posterior 5 mm (± 2) and L5-S1: anterior: 13 mm (± 4), posterior 6 mm (± 2). The mean (± SD) of the interpedicular distance at the L1, L2, L3, L4 and L5 vertebral levels was 23 mm (± 2), 24 mm (± 2), 25 mm (± 2), 27 mm (± 2) and 31 mm (± 3) respectively. For the sagittal canal diameter at the L1, L2, L3, L4 and L5 vertebral levels, the mean (± SD) was 20 mm (± 5), 21 mm (± 3), 21 mm (± 3), 21 mm (± 3) and 19 mm (± 3) respectively. The lumbar gravity line intersected the sacrum in 67.3% of the subjects. In 29.1% of the subjects, the lumbar gravity line passed anterior to the sacrum while in 3.6% of the subjects, it passed posterior to the sacrum. iv A significant association was found between lumbar lordosis and the height of the subjects in this study (p = 0.004). A decrease in the intervertebral disc height at L5-S1 was associated with smoking (p = 0.005). A decrease in the intervertebral disc height at L4-L5 was associated with previous pregnancy (p = 0.016). Body mass index of 26–30 kg.m-2 was significantly associated with an increase in the intervertebral disc angles at L3-L4 (p = 0.028) and L4-L5 (p = 0.031). A decrease in the L5-S1 intervertebral disc angle was also significantly associated with smoking (p = 0.023). There was a significant association between previous pregnancy and an increase in the intervertebral disc angle at L3-L4 (p = 0.016). A significant association was found between the age of the subjects and the L5-S1 intervertebral disc angle (p = 0.007). Specifically it was the 23–27 year group and 33–37 year group who were significantly different from each other (p = 0.033). Conclusion: Similarities and differences were found in the mean values of the radiographic parameters measured in this study and those reported in the literature. A number of the selected anthropometric and demographic factors were associated with some of the lumbar radiographic parameters. Further studies are required to establish the clinical significance of these findings.

Thesis (Doctor of Physic) -- Colombia College, 1804. / Film 633 reel 5 is part of Research Publications Early American Medical Imprints collection (RP reel 5, no. 129). DNLM Includes bibliographical references.

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Thesis (M.S.)--Springfield College, 2004. / Includes bibliographical references. Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.S.)--University of British Columbia, 2003. / Includes bibliographical references (leaves 76-81).

Thesis (M.S.)--Springfield College, 2004. / Includes bibliographical references.