Submitted in partial compliance with the requirements for the Masters’ Degree in Technology: Chiropractic, Department of Chiropractic, Durban University of Technology, Durban, South Africa, 2014. / Background Spinal manipulative therapy (SMT) is a commonly used therapeutic modality. It has been shown that neuromuscular reflexes are elicited during spinal manipulation resulting in changes in the surrounding muscle tonicity and seen as changes in surface electromyography. Despite this little is known about the effect that SMT may have on muscle function. Increased maximum voluntary contraction (MVC) of the paraspinal muscles has been observed following lumbar SMT compared to a control and sham treatment; however its effect on muscle endurance has not been investigated. The aim of this study was to determine the effect of lumbar SMT compared to a placebo treatment on lumbar extensor muscle endurance in asymptomatic individuals. Method This study was a quantitative double blinded, pre-test and post-test placebo controlled experimental trial. Forty asymptomatic participants were randomly allocated to one of two treatment groups. One group received a single SMT applied to the L3 vertebrae and the other received the pre-load force of the SMT but no thrust. Subjective (a self-report of pain/discomfort while performing the Biering-Sorensen test) and objective [surface electromyography (sEMG), paraspinal muscle endurance time and lumbar spine range of motion] measurements were taken pre- and post-intervention. The latest version of SPSS version (IBM SPSS Inc.) was used to analyse the data. A p-value < 0.05 was considered statistically significant. Independent t-tests were used to compare means and two-way factor ANOVA (for repeated measures) was used to compare the change in the two time points between the two treatment groups (intervention and control). RESULTS There were no statistically significant differences between the intervention and placebo groups in terms of subjective reports of pain/discomfort and objective evidence of surface EMG readings, paraspinal muscle endurance time and lumbar spine range of motion.

Submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Department of Chiropractic, Durban University of Technology, Durban, South Africa, 2015. / Background: Spinal manipulative therapy (SMT) is a commonly used treatment for many musculoskeletal conditions although the exact mechanism explaining its effectiveness is not well understood. Several studies have investigated the effect of SMT on the paraspinal muscles where neuromuscular effects have been observed, however few studies have assessed whether these changes result in a change in the functioning of the paraspinal muscles. This study aimed to determine the effect of lower thoracic spinal manipulation compared to a placebo intervention on lumbar extensor muscle endurance in asymptomatic participants. Methodology: This was a quantitative, pre-test post-test, placebo controlled trial involving 40 male participants between the ages of 20 and 40 years. The participants were randomly allocated to either the lower thoracic spinal manipulation group or a placebo group. Manipulation was delivered using the Impulse Adjusting Instrument®. Objective measures included lumbar spinal range of motion, a paraspinal muscle endurance test, and surface electromyography readings. Subjective measures were the verbalisation of pain and/or discomfort during the paraspinal muscle endurance test. IBM® SPSS® statistics version 21 and STATA 11 were used to analyse the data. A p-value of <0.05 was considered statistically significant. Results: There were no statistically significant differences between the groups in terms of subjective and objective measurements. A trend of treatment effect was observed for paraspinal muscle endurance where the intervention group showed noticeable improvements in endurance scores. Conclusion: Further studies need to be conducted to determine if the trends observed would occur in a larger study population.