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Theses and dissertations (Health Sciences)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/12

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Subject: search.filters.subject.Biomechanics

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    The association between static biomechanical parameters and musculoskeletal injury in lower extremities in male recreational weight trainers
    (2022) Makada, Fahmeeda; Matkovich, Grant
    Background: Anatomical alignment of the lower extremity has been proposed as a risk factor for acute and chronic lower extremity injuries such as ACL injuries, patellofemoral syndrome, and plantar fasciitis. Lower extremity malalignment influences the load distribution on the joints, mechanical efficiency of the muscles and proprioceptive orientation and feedback from the hip and knee, resulting in altered neuromuscular function and control of the lower extremities. During recreational weight training, the weight trainer performs exercises with gradual load on machines or free weights, aimed to improve their muscular condition, fitness, power, or performance in other sports. The weight trainer uses his own bodyweight or specialised forms of equipment such as barbells, dumbbells and resistance training machines to target specific muscle groups and to perform specific joint actions. Various intrinsic and extrinsic factors contribute to injury. Anatomical alignment – amongst others - is regarded as an intrinsic factor. Studies state that suggested risk factors for injuries include heavy loads in extreme joint positions, training frequency, intensity, volume, muscle strength, stability and foot morphology. Several studies have examined musculoskeletal injuries in specific weight training populations such as powerlifters, weightlifters and bodybuilders. Very few studies have investigated the recreational weight training population. The purpose of this study is to identify whether associations exist between the relevant biomechanical parameters and injury, to prevent or correct these abnormalities. Objectives: This study aimed to establish lower extremity static biomechanical parameters of the hip (flexion, extension and Craig’s test), knee (quadriceps angle and tibial torsion test), ankle (dorsiflexion, Feiss line, hindfoot, and forefoot alignment) and leg length discrepancy, and to establish if an association exists between the above- mentioned parameters and musculoskeletal injuries in the lower extremities in male recreational weight trainers. Method: 30 Male recreational weight trainers were recruited from fitness centres within the greater Durban area to the DUT Chiropractic clinic, where the assessment took place. Each participant was assessed for injury and static biomechanical measurements were taken. The statistical analysis was performed using Stata version 16. For normally distributed continuous variable the mean and 95% CI was done. Shapiro Wilk test was used to test for normality. For not normally distributed variables, median and interquartile range was performed. 15 participants were diagnosed as injured and 15 participants as uninjured. As the sample size of this study is small, Fisher’s exact test was used to evaluate the association between two categorical variables. Results: The statistical analysis was performed using Stata version 16. For normally distributed continuous variables the mean and 95% CI were done and Shapiro Wilk test was used to test for normality. For not normally distributed variables, median and interquartile range were performed. As the sample size of this study is small, Fisher’s exact test was used to test the association between two categorical variables. Prevalence of injury was thus 50%. In the injured population, 46.67% were acute and chronic injuries. 16.67% of injuries were traumatic and 33.3% were non-traumatic. Fisher’s exact test was used to see the association between biomechanical measurement and existence of injury. Accordingly, Fisher’s exact test with p-value 0.036 indicated that there was enough evidence of association between right quadriceps angle and injury. The injured participants were more likely to have a low right quadriceps angle. However, the rest of the biomechanical measurements have no association with injury Conclusion: The injured participants were more likely to have a low right quadriceps angle. The rest of the biomechanical measurements have no association with injury.
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    The effects of an upper cervico-thoracic segment manipulation on posture and muscle activity in participants with forward head and round-shouldered posture
    (2023-05-31) Petzer, Matthew; Abdul-Rasheed, Ashura
    Background: Postural dysfunction in the cervico-thoracic spine often leads to segmental restrictions and hypomobility, and this is often caused by biomechanical alterations due to postural changes and over activity of skeletal muscles in that region. These muscles include the pectoralis and trapezius muscles. Postural dysfunction and joint restrictions are often treated by manual therapies, such as spinal manipulation. Previous studies have established that joint manipulation reduces postural dysfunction and improves joint mobility, which could be explained by a combination of neurophysiological,and biomechanical effects.In literature, the immediate benefitsof acervico-thoracicmanipulation on muscleactivityandposture are not well understood and, therefore, an investigation into the immediate effects of manipulation on muscle activity and posture was implemented in this study. Aim: This study aimed to observe the immediate effect of an uppercervico-thoracic segment manipulation on posture and muscle activity in participants with forward head and round-shouldered posture. Methods: This study was a quantitative, observational study with a pre-test posttest design. Surface electromyography was used to measure the muscle activity of the pectoralis major, upper and middle trapezius muscles prior to and after the cervico-thoracic intervention. A sample size of 40 asymptomatic participants were recruited to participate. The participants were randomly divided into two groups: group A, which was the control group, and group B, which was the intervention group. The intervention group received a cervico-thoracic manipulation, but the control group received no intervention and remained prone for 3 minutes between the pre-test and post-test readings. The within-group comparisons of pre- and postmuscleactivity were achieved usingpairedT-tests. Within groupandbetween group comparisonsof the change between pre- andpost-intervention wereachieved using repeated ANOVA testing. A p-value below 0.05 was statistically significant. IBM Statistical Package for Social Sciences (SPSS) version 26 software was used to process the data. Results: There was no statistically significant treatment effect of cervico-thoracic spinal manipulation in the effects on muscle activity. Although there was not a statistically significant change in muscle activity, there was a positive change in pectoralis major compared to the upper or middle trapezius. The upper and middle trapezius muscles decrease activity followed an evident trend between the participants who received the intervention compared to the control group. Postural results were not statistically significant but positive correlations to treatment were found. The craniovertebral angle was seen to decrease at a higher rate compared to the control group. Additionally, the study provided evidence of a treatment effect on the acromiovertebral angle, decreasing overall in severity. Conclusion: The results of this study do not provide conclusive evidence that the intervention has any immediate statistical effect on the three muscle activity measurements outcomes observed. In terms of the Posture Pro Analysis System measurements, changes (decrease in angles) between the pre- and postintervention were mostly significant in both groups, but statistically there was no difference between the control and intervention groups. Posture Pro ratings did not provide evidence of changes in categories within the groups. Therefore, the null hypothesis was retained.
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    The immediate effect of sham laser and three different spinal manipulative protocols on the throwing speed of baseball players in the KwaZulu-Natal Baseball Union
    (2018) Robson, Michael; Haswell, Garrick David
    Background: ABSTRACT Baseball pitching is a whole body ballistic movement that requires transfer of energy from the lower extremity to the upper extremity via the trunk. Adverse changes can occur within the surrounding ligaments, tendons and muscular tissue of the trunk when immobilization or restricted motion within a joint segment occurs. Improper transfer of energy is thought to cause abnormal stresses on the joints and may lead to injury and/or decreased performance. Spinal manipulation therapy (SMT) was the focus of this study, aimed to improve flexibility and joint mobility (Range of motion), thereby allowing for a more efficient closed kinetic chain movement, which could result in a faster speed of the baseball pitch. Objective: To determine and compare the immediate effect of placebo and SMT of the thoracic and lumbar spines in respects of range of motion (ROM) and the velocity of the pitching participants. Methods: Fourty asymptomatic baseball players were divided randomly into four groups. Group A received thoracic spine manipulation, Group B received lumbar spine manipulation, Group C received combined thoracic and lumbar spine manipulation and Group D received the sham laser intervention as a placebo controlled group. Pre- and post- intervention trunk flexion and lateral flexion ROM and pitching speeds were measured, using a digital inclinometer and a radar gun respectively. A subjective measurement of the participant’s perception of a change in pitching speed post-intervention was also recorded. SPSS version 23 was used to analyse the data. Results: There was a significant increase in pitching speed in the SMT interventions groups (p<0.05). However, between the SMT and placebo groups they were not considered significantly different at 5% (p>0.05). A significant increase in Thoracic RLAT ROM was noticed on the inter-group analysis (p<0.05). There was no correlation seen between subjects’ perception of change in throwing speed post-intervention and the objective results obtained. Conclusion The immediate effect of SMT on baseball pitching speed was inconclusive. The outcome of this study suggests that SMT results in an increase in the average speed of baseball pitching but not at a level of statistical significance.