Abstract
M.Tech. (Chiropractic)
Purpose: This study aims to compare the effects of spinal manipulation versus mobilization of the lumbar spine and sacroiliac (SI) joints on the contractile strength of the hamstring muscle group with regards to strength and flexibility.
Method: This study consisted of 2 groups of 15 participants between the ages of 18 and 50 years of age. Males and females were first separated to ensure equal male to female ratios within each group. The potential participants were examined and accepted according to the inclusion and exclusion criteria. The method of treatment administered to each group was determined by group allocation. Group 1 received spinal manipulation directed towards restrictions located within the lumbar spine and/or SI joints. Group 2 received spinal mobilization directed towards restrictions located within the lumbar spine and/or SI joints.
Procedure: Treatment consisted of 4 treatment sessions with an additional follow up visit over a 2 week period. Objective data was recorded on visit 1 before and after treatment, visit 3 before and after treatment and on visit 5 in which there was no treatment administered, its purpose was purely to obtain measurements. The measurements were taken in this way in order to determine immediate as well as medium term changes. Objective data consisted of hamstring muscle strength readings taken using a handheld dynamometer and hamstring muscle flexibility readings taken using a digital inclinometer. Analysis of collected data was performed by a statistician. The manipulation and mobilization techniques used were directed towards dysfunctional joints within the lumbar spine and/or SI regions, which were detected by motion palpation.
Results: Regarding muscle strength, statistically significant results were noted in Group 1 at visits 1 and 3 on both the right and left sides when determining the immediate effects of the treatment. Medium term changes were seen during the time interval between visits 1 and 3, as well as between visits 1 and 5 bilaterally. When determining the immediate effects of the treatment, Group 2 did not demonstrate muscle strength changes at visit 1 on the right, however statistically significant results were found at visit 3 on the right as well as at visits 1 and 3 on the left. Medium term changes were seen during the time interval between visits 1 and 3, as well as between visits 1 and 5 bilaterally. Manipulation and mobilization were shown to have a statistically significant effect on hamstring muscle strength, although manipulation was shown to have a more beneficial effect on muscle strength both immediately and over time, though this was only found on the left. Regarding muscle flexibility, statistically significant results were noted in Group 1 on both right and left sides at visits 1 and 3 when determining the immediate effects of the treatment. Statistically significant changes only occurred on the left between visits 1 and 5 when determining the medium term effects of the treatment. Group 2 showed statistically significant changes at visit 3 on the right as well as at visits 1 and 3 on the left when determining the immediate effects of the treatment. When determining the medium term effects of the treatment no statistically significant changes were found over the duration of the study. There was no difference found between the groups in terms of the effect that the treatment had on hamstring muscle flexibility, although isolated improvements occurred over time in the manipulation group.
Conclusion: The results show that both manipulation and mobilization have a statistically significant effect on hamstring muscle strength. However, manipulation was shown to have a more significant effect. Changes in hamstring muscle flexibility were found to occur immediately and over time in the manipulation group, however only immediate effects were noted in the mobilization group. Therefore, when compared to mobilization, manipulation appears to have a greater effect on hamstring muscle strength and flexibility.