The frequency of hamstrings injuries in football has increased in recent years. Hamstring injuries have been studied extensively. There is, of course, not just one reason for the occurrence of hamstring injuries, as several risk factors should be examined. The aim of the study was to investigate the frequency and risk factors related to hamstring injuries among academy football players aged 15-21. The survey was sent out to 15 football clubs and 32 high schools with nationally approved sports programs (NIU) in southern Sweden (Götaland). The response rate was equal to 67 survey responses, of which 17 had experienced a hamstring injury at some point, and eight had suffered a hamstring injury in the past 12 months. The injury frequency was calculated to be 0,05 injuries per 1000 training hours. The number of participants was too small to draw any definitive conclusions. However, different tendencies were observed, such as the majority of injuries being so-called “non-contact” injuries, as well as the indication that preventive training can be a crucial factor in avoiding injuries. / Frekvensen av hamstringsskador i fotboll har ökat under de senaste åren. Hamstringsskador har studerats i en stor omfattning. Det finns flera anledningar till förekomsten av hamstringsskador, därför bör ett flertal riskfaktorer examineras. Syftet med detta arbete var att undersöka skadefrekvensen och riskfaktorerna kring hamstringsskador hos akademifotbollsspelare mellan 15-21 år. Enkäten skickades ut till 15 fotbollsföreningar och 32 gymnasieskolor med nationellt godkända idrottsutbildningar (NIU), i södra Sverige (Götaland). Svarsfrekvensen blev 67 enkätsvar varav 17 hade någon gång haft en hamstringsskada och åtta hade haft en hamstringsskada de senaste 12 månaderna. Skadefrekvensen beräknades vara 0,05 skador per 1000 tränade timmar. Deltagarantalet var för litet för att kunna fastställa några slutsatser. Däremot observerades olika tendenser, till exempel att största delen av skadorna var så kallade“non-contact” skador och att förebyggande träning kan vara en avgörande faktor för att inte bli skadad.

Thesis (M.Tech.:Chiropractic)-Dept. of Chiropractic, Durban Institute of Technology, 2005 120 leaves / 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.

PURPOSE The purpose of this study was to determine if performing static active knee extension hamstring stretching using the Pneumex Pro-Vibe vibrating platform increased acute hamstring range of motion (ROM) greater than traditional static active knee extension hamstring stretching. METHODS: A within subject design was utilized with subjects undergoing static stretching with vibration and without vibration (conditions counterbalanced). Pre- and post-test active and passive ROM was measured for the right leg, with subjects first undergoing a 5-minute warm-up on a stationary bicycle. Supine active knee extension was performed on the Pro-Vibe platform with and without vibration. The stretch was held 3 times each for 30 seconds, with a 20-second rest period between each stretch. Vibration was set at 30 Hz at the “high” amplitude setting. Active hamstring ROM was measured via active knee extension using a goniometer with the leg in 90° of hip flexion. Passive ROM was measured via clinician-assisted knee extension with the leg in 90° of hip flexion. RESULTS: A 2-way repeated measures ANOVA was performed for passive ROM, and revealed a significant main effect for condition, F (1, 23) = 0.5875, p < 0.05, and time, F (1, 23) = 5.029, p < 0.05. Another repeated measures ANOVA was performed for active ROM with the same factors, and revealed a significant time by condition interaction, F (1, 23) = 4.730, p < 0.05, and a significant main effect for time, F (1, 23) = 18.612, p < 0.001. Post-hoc paired samples t-tests determined the difference between the pre-test and post-test measurements for each condition. Active ROM showed a significant difference pre-test to post-test for the vibration condition, t (23) = -5.41, p < 0.001. The vibration condition also resulted in significantly different pre-test vs. post-test measurements on passive ROM, t (23) = -2.55, p < 0.05. In both cases the average ROM was higher for the post-test. DISCUSSION: Three 30-second active knee extension hamstring stretches using a vibrating platform are sufficient to cause significant acute increases in hamstring ROM. These findings suggest this device may be useful when desiring increased hamstring ROM.

Background: The incidence of anterior cruciate ligament (ACL) –injury is 3-5 times greater in female athletes compared to male athletes. This may be partially attributed to lower levels of hamstring-quadriceps co-contraction in females with subsequent knee kinematics that increases risk of ACL-injury. Finding training methods that improves co-contraction and increases knee stability is important. Objectives: To evaluate the effects of a new device on hamstring-quadriceps co-contraction and to investigate if training with the device can alter knee kinematics in female athletes. Study design: Controlled experimental study design with repeated measures. Method: Twenty soccer and floor ball athletes were measured with electromyography (EMG) for hamstring-quadriceps co-contraction while performing squats with and without the device. Thirteen athletes also underwent three-dimensional kinematic analyses, measuring knee abduction angles (at initial ground contact and peak angle) during a drop jump, before and after a six week intervention period with the device. Friedman’s test and Wilcoxon signed rank test was used to assess differences and effect sizes (ES) were calculated. Results: Co-contraction was consistently larger on the device (medial side: p&lt;0.001, ES=0.88; lateral side: p&lt;0.001, ES=0.80) and the ratio of medial-to-lateral co-contraction increased (p=0.001, ES=0.79). In the kinematic analysis low adherence rates amongst our subjects meant that the effects of the device on kinematics could not be measured. Conclusion: Performing squats with the new training device stimulates increased hamstring-quadriceps co-contraction and increases the ratio of medial-to-lateral co-contraction. The effects of the device on knee kinematics have yet to be determined.

The purpose of this study was to investigate the effects of Nordic hamstring strength training (NHST) program on (1) leg power, (2) vertical jump, (3) and knee proprioception measurements of 10-12 years old male basketball players. Nordic Hamstring Strength Training (NHST) group (N=16), participated in basketball training plus in Nordic hamstring strength training, while the control group (N=11) participated in basketball training only. Subjects were tested before and after 5-week training program for, vertical jump, isokinetic leg strength and knee proprioception. Each subject who agreed to participate in this investigation signed a consent form along their parent. Pre and post test differences between experimental and control group was investigated by MANOVA and paired sample t-test was used to evaluate the differences between pre and post tests of both groups. There was no significant difference in pre and post test results of NHST and control group. There were statistically significant increase in concentric quadriceps and hamstring strength, eccentric quadriceps strength, conventional H:Q strength ratio, and vertical jumping measurements in experimental group between the pre and post tests. It can be concluded that NHST program combine with basketball training has beneficial effects on the leg strength and H:Q strength ratio. These findings also suggest that hamstring exercise may be beneficial or helpful for preventing the hamstring injury occurrence and improving the physical performances such as jumping ability.

No description available.

Mini-dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2012. / Purpose: Patellofemoral Pain Syndrome is a common condition in all age groups, with a multifactorial etiology. This study aimed to investigate the association between the Quadriceps femoris muscle group, Hamstring muscle group and Adductor muscle group, and to establish the relationship between myofascial trigger points (MFTP’s) in these muscle groups and patellofemoral pain syndrome (PFPS). Methods: A cross-sectional, observational, quantitative non-intervention clinical assessment study was conducted at the Chiropractic Day Clinic at Durban University of Technology (DUT), to determine the extent of the PFPS, the MFTPs and thus the relationship between the two. The study included eighty patients with PFPS, who were recruited by convenience sampling. The results were captured using Microsoft excel and SPSS version 15.0 was used to analyze the data. Results: Quadriceps femoris muscle group MFTPs were noted in 92.5% of the patients (most prevalent being Vastus medialis TP1 (63.8%), Vastus lateralis TP1 (33.8%) and Vastus intermedius at 27,5%). Least common was Vastus lateralis TP2 only presenting in 2,5% of the patients. Hamstring muscle group MFTPs were found overall in 86.3% of patients (most prevalent being in Biceps femoris muscle (66%), and least prevalent being in Semitendinosus muscle (11,3%)). MFTPs were present in 64% overall of the Adductor muscle group (Adductor magnus muscle being the most common). Significant associations were made between the presence of MFTPs in the Vastus lateralis TP2 (p=0.00), Vastus medialis TP1 (p=0.046; 0.005; 0.004), the NRS and the PPSS. Also significant was the relationship between the NRS, PPSS and the Semimembranosus and Adductor magnus muscles indicated that these muscles were the most likely causes of pain even though they had fewer MFTPs than other comparable muscles. Conclusion: The outcomes of this study supports previous research indicating that an extensor dysfunction of the Quadriceps femoris muscle group may be of MFTP origin and indicates that other muscles in the thigh require further research indicating their role in the development of PFPS.

Title: Physical therapy procedures in patients following the operation of the anterior cruciate ligament Objectives: The main objective of this work is to determine the influence of the chosen method of reconstruction and subsequent physiotherapy on the final status of the patient. And also if the group physiotherapy is the ideal therapeutic approach. Methods: In quantitative research the numerical analysis of the data was performed. Comparison of individual groups was performed simply through finding the frequency distribution of individual characters. Evaluated were the basic sets A (patients operated on by Bone - Tendon - Bone method, BTB) and B (patients operated on by hamstring graft method, STG). Both sets were assessed using the input and the output kinesiological analysis. The resulting values of the variables in each category (individual examinations in the input and output kinesiological analysis) were compared with each other.The statistical significance of observed differences was tested using the x2 (chi square) test at the significance level of p < 0.05. Results: It was determined that the selected surgical method (BTB and STG) has an effect on certain parameters evaluated in the input rated kinesiological analysis. These parameters in the majority of examinations performed at the...

Einleitung: Die Verwendung der Hamstringsehnen als Transplantate in der rekonstruktiven Chirurgie des vorderen Kreuzbandes stellt eine wenig invasive Alternative zur herkömmlichen Verwendung des mittleren Patellarsehnendrittels dar. Hier ist jedoch die Transplantatverankerung, die bisher meist extrakortikal, also weit entfernt der nativen Kreuzbandinsertion angelegt wurde problematisch. Hierdurch zeigt das Transplantat-Verankerungs-Konstrukt ein unbefriedigendes elastisches und plastisches Dehnungsverhalten, welches u.A. für eine geringere Kniestabilität und eine gestörte ossäre Transplantatintegration verantwortlich gemacht wird. Eine anatomiegerechte Transplantatverankerung auf Gelenkniveau könnte die mechanischen und biologischen Rahmenbedingungen verbessern, um so die Hamstringsehnen als Alternativtransplantat mit verbesserter klinischer Prognose einsetzten zu können. Eine direkte Verankerung mit Interferenzschrauben erlaubt eine solche anatomische Transplantatverankerung, so dass wir dieses neue Operationsverfahren biomechanisch und tierexperimentell untersucht haben. Methoden: In sechs biomechanischen Teilprojekten und in zwei tierexperimentellen Untersuchungen wurde die Eignung der direkten Verankerung mit biodegradierbaren Interferenzschrauben der Hamstringsehnen im Vergleich zu konventionellen Patellar- und Hamstringsehnen-Techniken untersucht. Ergebnisse: Wir konnten demonstrieren, dass die initiale femorale Verankerungsfestigkeit, auch in Sinne der sog. Hybridfixation ausreichend ist. Die tibiale Verankerung unterliegt jedoch verschiedenen Variablen und bedarf einer differenzierten klinischen Anwendung. Im Vergleich zu konventionellen Techniken der Hamstringsehnen-Verankerung kann das plastische und elastische Dehnungsverhalten durch die Verankerung mit Interferenzschrauben deutlich verbessert werden, wobei jedoch das mechanische Verhalten des Patellarsehnen-Transplantates nicht erreicht wurde. Die tierexperimentelle Analyse zeigt auf, dass die ossäre Integration durch die Kompression des Transplantates auf Gelenkniveau soweit verbessert werden kann, dass sog. Tunnelaufweitungen, als Zeichen einer gestörten Einheilung vermieden werden und, dass das Transplantat mit einer direkten Bandinsertion, entsprechend des nativen vorderen Kreuzbandes, auf Gelenkniveau einheilt. Schlussfolgerung: Die hier vorgelegten Untersuchungen haben erstmals umfassend die Rahmenbedingungen der Interferenzschrauben-Verankerung der Hamstringsehnen beschrieben; einer Technik die inzwischen weltweit verbreitete Anwendung findet. Durch eine anatomische Transplantatverankerung auf Gelenkniveau besteht nun die Möglichkeit, mit optimierten mechanischen und biologischen Rahmenbedingungen eine adäquate Alternativtechnik zur konventionellen Verwendung der Patellarsehnen anzubieten. / Introduction: The use of hamstring tendon grafts as a substitute for anterior cruciate ligament reconstruction presents a less invasive procedure compared to the conventional bone-patellar tendon- bone graft. Current techniques of hamstring tendon anterior cruciate ligament reconstruction utilise an extra-cortical fixation. An extra-cortical fixation, however, shows inferior structural parameters with respect to construct slippage or stiffness. These factors may contribute to less stable knees after reconstruction and a delayed osseous integration of the grafted tissue. An anatomic hamstring tendon graft fixation close to the joint line may overcome these problems and may present an alternative to the conventional bone-patellar tendon-bone graft by means of optimised mechanical and biological boundary conditions. We therefore studied anatomic interference fit fixation of hamstring tendon grafts in different mechanical and animal experimental setups. Methods: In six different biomechanical projects and two animal studies, we studied the capability of hamstring tendon interference fit fixation to be used as a secure and reproducible technique of anterior cruciate ligament reconstruction and compared these data to the bone-patellar tendon-bone graft and other conventional hamstring tendon graft fixation techniques. Results: We could demonstrate that the initial femoral fixation strength, as well as a hybrid fixation is sufficient. However, the tibial fixation presents the weak link and underlies different variables, such as bone density and screw geometry. Compared to conventional extra-cortical fixation techniques, the viscoelastic and viscoplastic deformation behaviour could be optimized, but did not reach comparable data to the bone-patellar tendon-bone graft. Animal experiments could clearly demonstrate that interference fit fixation promotes osseous tendon incorporation and minimises the likely hood of a tunnel enlargement. We further found that in contrast to conventional fixation techniques the use of interference screws resulted in the development of a direct ligament insertion anatomy, directly at the joint line, like it is found with the native anterior cruciate ligament. Conclusion: With the present studies we could first describe the mechanical and biological boundary conditions of hamstring tendon interference fit fixation, a technique which gains increased world wide attention as a standard procedure in cruciate ligament surgery. By using an anatomic joint line fixation of hamstring tendon grafts, there are optimised boundary conditions, which therefore presents an adequate alternative to the conventional bone-patellar tendon-bone graft in cruciate ligament reconstruction.

Hamstring injuries have a high prevalence in rugby union players. Delayed transverse abdominus activation as well as lordosis is associated with hamstring injuries. No literature regarding this relationship in rugby players could have been found. The main purpose of this study was therefore to determine the relationship between pelvic biomechanics (transverse abdominus activation and pelvis tilt) and gluteus maximus, hamstring and erector spinae activation patterns in semi–professional rugby union players as well as the relationship of the above mentioned variables and hamstring injuries. A total of 65 players voluntarily participated in this study. Pelvis tilt (left and right) was assessed by Dartfish version 4.06.0 (Dartfish, Switzerland). Transverse abdominus activation (TrA) was assessed by pressure biofeedback and the mean onset times of the left and right gluteus maximus (GM), biceps femoris (BF), semitendinosus (ST) and lumbar erector spinae (LES) was measured with electromyography (EMG). In order to determine the role of the pelvic biomechanics and activation patterns on hamstring injuries, players were retrospectively grouped in injured and uninjured groups. Differences between the groups were determined with regards to the variables determined. Activation patterns were determined by means of descriptive statistics. The between–group pelvic biomechanic (pelvic tilt and TrA) differences in the muscle (GM, LES and hamstrings) onset times were analysed by determining practical significance by means of effect sizes. An anterior pelvic tilt on the left side was observed in 64.6% of the participants and on the right side in 83.1% of the participants. TrA testing indicated that 68.4% of participants were classified with bad activation and 31.6% with good activation. No practical significant difference was found in the mean onset times of each muscle relative to the other in the normal and anterior tilted pelvis groups as well as in the bad and good TrA groups. A total of 24.6% of the rugby players previously suffered from hamstring injuries, 37.5% of those injured participants were suffering from re–injury. No practical significant between group differences were found when the injured and uninjured groups were compared with regards to anterior pelvis tilt values (d=0.061) and TrA values (d=0.189). EMG results on the right and left side of the injured and uninjured participants present a pattern of the following activation order: LES, GM, BF and lastly ST. No practical significant between groups differences were found in the onset times of the muscles relative to each other in the injured compared to uninjured groups. The conclusions that can be drawn from this study is that semi–professional rugby union players (injured and uninjured) are prone to postural defects such as anterior tilt of the pelvis and bad TrA. Anterior pelvic tilt and bad TrA may be the reason for the earlier activation of the LES and hamstrings muscles relative to the GM in the prone hip extension to stabilize the lumbar spine. These activation patterns were however not influenced by previous hamstring injuries. / Thesis (M.A. (Biokinetics))--North-West University, Potchefstroom Campus, 2011.