M.Tech. / Purpose: In soccer the re-injury rate of Hamstring muscle strains is between 12 and 14 percent. A previous or recent Hamstring injury is the most recognised risk factor for future injury. On recurrence of the injury, it tends to be more severe and disabling than the initial injury. Given the high recurrence rates, Hamstring injuries provide a significant challenge to the treating clinician. Knowledge surrounding optimal treatment and preventative measures is therefore critical (Hoskins and Pollard 2005). The aim of this study is to assess the effectiveness of lower lumbar spine segment adjustment, namely the L4/5 spinal level, in the contractile strength of the Hamstring muscle group in professional soccer players that have a history of a Hamstring strain. Design: Forty professional soccer players between the ages of 15 and 34 years with a history of a grade one or grade two Hamstring strain were considered for this study. Participants in this research were obtained from the University of Johannesburg inter-residence players and from the University of Johannesburg first soccer team. Two groups of twenty players were randomly assigned to one of two groups. Group A received spinal adjustive therapy (SAT) to the L4/5 spinal segment with an ultrasound treatment to their Hamstring muscle group and Group B will receive only the ultrasound treatment to the hamstring muscle group. Each participant was treated five times over a period of three weeks. Measurements: Before any intervention was given to either of the groups, Hamstring muscle contractile strength was first recorded using a Cybex system 2000. Hamstring contractile muscle strength measurements were taken again after the fifth treatment for both groups and compared to ascertain if there had been any change in the contractile strength of the Hamstring muscles. Results and Conclusion: Even though the two groups did not start at the same contractile strength for the Hamstring muscle in knee flexion, as measured a CCybex system 2000 possibly due to the selection criteria used in the study in terms of age and body weight of the participants, results showed that spinal adjustive therapy was more effective in improving the muscle contractile strength of the Hamstring muscle in knee flexion since there was a favourable difference in both Group A and Group B following intervention, but more so in Group A (in the once injured leg) which received spinal adjustive therapy due to a greater increase in the overall muscle contraction in the Hamstring muscle group. For the Chiropractic profession this opens huge potential with regards to the Chiropractic benefits and improving the functioning of professional soccer players.

Although traditional prevention and management strategies for hamstring injuries have focussed on optimising muscle strength, flexibility and endurance, incidence and/or recurrence rates of these injuries remains high. A theoretical framework was developed considering additional factors that increase the stabilising demand of the hamstrings. These factors included loss of related stability at the knee and lumbopelvic regions and extrinsic factors during functional and sporting activities. The aims of this research were to determine whether electromyographic (EMG) derived hamstrings, quadriceps and gluteal muscle activation patterns as well as isokinetic torque generation patterns could differentiate athletes who had incurred a hamstring injury from uninjured control athletes. It was hypothesised that the EMG activity of the injured participants would be decreased compared to uninjured control participants during maximal activities, but increased during weight bearing activities. The research included the identification of laboratory-based tasks relevant to the function of the hamstring muscles; test-retest reliability of EMG variables recorded during these tasks; and a comparative cross-sectional study of hamstring-injured (hamstring group, HG) and control athletes (control group, CG). Electromyographic activation patterns were determined during assessment of concentric and eccentric isokinetic strength of the thigh muscles, during transition from double- to single-leg stance, and forward lunging. Isokinetic and EMG onset and amplitude variables were compared both within- and between-groups. Despite no significant differences for peak torque, the HG injured limb generated lower average eccentric flexor torque towards the outer range of motion in comparison to the HG uninjured limb (P = 0.034) and the CG bilateral average (P = 0.025). Furthermore, the EMG root mean square (RMS) decrease from the start to the end range of the eccentric flexor contraction was greater for the HG injured limb hamstrings than the CG bilateral average. During the transition from double- to single-leg stance, the EMG onsets of the HG injured limb (biceps femoris [BF] P < 0.001, medial hamstrings [MH] P = 0.001), and the HG uninjured limb (BF P = 0.023, MH P = 0.011) were earlier in comparison to the CG bilateral average. The transition normalised EMG RMS was significantly higher for the HG injured side BF (P = 0.032), MH (P = 0.039) and vastus lateralis (VL, P = 0.037) in comparison to the CG bilateral average. During the forward lunge, no significant differences were observed within- and between-groups for the normalised EMG amplitude prior to and following initial foot contact. These results suggest that during maximal isokinetic eccentric flexor contractions, the average torque and EMG activity is decreased towards the lengthened position of the hamstring-injured limb. This may be due to structural changes or neurophysiological inhibitory mechanisms. During the static weight bearing task an earlier onset of the HG hamstring muscles was evident in comparison to controls. The hamstrings and the VL of the injured limbs were activated at greater normalised amplitude. The increased muscle activation in the hamstring-injured limbs during the support phase may indicate a greater demand towards stability of the kinetic chain or changes in proprioceptive function. Future research should consider the mechanisms and clinical implications underlying a loss of eccentric flexor torque towards the outer range of contraction, and investigate why increased activation of thigh muscles occurs during the static weight bearing task in hamstring-injured athletes.

Thesis (M.S.)--University of Texas at El Paso, 2008. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (M. Ed.)--Bowling Green State University, 2005. / Includes bibliographical references (leaves 38-44). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M. Ed.)--Bowling Green State University, 2005. / Includes bibliographical references (leaves 38-44).

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.

Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2012. / Background: Hamstring muscle strains are a common musculoskeletal injury amongst athletes, with a high rate of recurrence that suggests room for improvement in the treatment and management of these injuries. Cibulka et al. (1986) suggest a possible link between injuries of the hamstring muscles and dysfunction of the sacroiliac joint. A study by Fyfer (2005) found that sacroiliac manipulation alone had a positive effect in the treatment of recurrent hamstring strains, but this was not combined with or compared to conventional treatment for muscle strain. Fox (2006) found that sacroiliac manipulation added to hamstring stretching increased the resultant flexibility of uninjured hamstring muscles. Objective: The purpose of this study was to determine the relative effectiveness that manipulation may have when combined with and compared to a regime of hamstring stretching and strengthening in the treatment of chronic hamstring strains. Method: Thirty two participants suffering from chronic hamstring injuries and concomitant dysfunction of the sacroiliac joint were randomly allocated into two treatment groups. Both groups attended six consultations over a period of three weeks. Group one received treatment in the form of proprioceptive neuromuscular feedback (PNF) stretching and resisted isometric exercises of the hamstring, and were taught a home routine consisting of static stretching of the hamstring and Theraband® exercises directed at the hamstring. Group two received the same treatment and home routine as those in Group one, with the addition of Chiropractic manipulation of the dysfunctional sacroiliac joint. Outcomes were obtained by using the Numerical Pain Rating Scale (NRS-101), inclinometer testing of passive straight leg raiser test, and algometer assessment of pain threshold in the injured hamstring muscle and ipsilateral sacroiliac joint. Results: Data was analysed using the SPSS version 18.0 (SPSS Inc. Chicago, Ill, USA). Subjective and objectives outcomes were measured quantitatively. The effect of the intervention was measured using repeated measures ANOVA testing. The time versus treatment group interaction effect assessed whether the effect of the different treatment over time is the same, with a p value of <0.05 being v considered significant. Both treatment groups showed improvement of outcomes, and manipulation showed a marginally non-significant trend of greater improvement with regards to sacroiliac joint algometry. Conclusion: This study did not provide conclusive evidence of either a benefit or no benefit of manipulation, but where non-significant trends were shown, it is likely that this was due to lack of statistical power and that with an appropriate a priori analysis being done a greater sample size may have shown the same effect to be statistically significant.

A dissertation submitted in partial compliance with the requirements for a Master's Degree in Technology: Chiropractic, Durban Institute of Technology, 2005. / Low back pain has been shown to be associated with inhibition of the lower limb musculature. This inhibition is called arthrogenic muscle inhibition (AMI). Sacroiliac joint dysfunction has been linked with AMI of the ipsilateral and contralateral quadriceps and hamstring muscles. Sacroiliac manipulation has been shown to significantly reduce ipsilateral AMI, however no studies have been conducted to illustrate the effect of sacroiliac manipulation on contralateral AMI. Neither have their been studies to show the presence or extent of spinal dysfunction between the levels of L2-L5 and its significance on muscle inhibition in the quadriceps and hamstring muscles, nor the effect of manipulation of these levels on AMI of the quadriceps and hamstring muscles. The purpose of this study was therefore to determine whether spinal manipulation has an effect on AMI of the contralateral limb as well as that of the ipsilateral limb. / M

The purpose of the study was to quantify the relative contribution of low back flexibility and hamstring flexibility in the sit and reach test item of the AAHPERD Health Related Fitness Test in order to examine the validity of the sit and reach test. Subjects were 100 female students, 13 to 15 years of age in physical education classes. Hamstring flexibility was measured using the Leighton flexometer. Spinal mobility was measured using a tape measure. The sit and reach test was performed according to instructions given in the AAHPERD Test Manual. Data were analyzed using correlation, linear regression, and multiple regression. Conclusions of the investigation were (1) hamstring flexibility is moderately related to the sit and reach test, (2) low back flexibility has a very small relationship to the sit and reach test, and (3) the sit and reach test is an inadequate measure of low back and hamstring flexibility.

The purpose of this study was to examine the criterion-related validity of the sit and reach test as a measure of hamstring and low back flexibility in adult males and females. Subjects were 52 males and 52 females, 20 to 45 years of age. Hamstring flexibility was measured using a goniometer. Spinal flexibility was measured using a tape measure and an inclinometer. The sit and reach test was performed according to the AAHPERD Health Related Fitness Test Manual. Data were analyzed using correlations and appropriate descriptive statistics. Conclusions of the investigation were: 1) in adult males 20 to 45, the sit and reach test is a valid measure of hamstring flexibility but has questionable validity as a measure of low back flexibility, 2) in adult females 20 to 45, the sit and reach test is a moderately valid measure of hamstring flexibility and is not a valid measure of low back flexibility.