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Robinson, Elizabeth M. "Unilateral PNF Hamstring Stretching on Contralateral Hamstring Flexibility." Ohio Dominican University Honors Theses / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=oduhonors1399312746.
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Walker, John W. "Use of Nordic Hamstring Exercise to Improve Hamstrings Function in Patients after ACL Reconstruction." University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1556811041471286.
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Askling, Carl. "Hamstring muscle strain." Doctoral thesis, Swedish School of Sport and Health Sciences, GIH, Laboratory for Biomechanics and Motor Control, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:gih:diva-425.
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<p>Background: Acute hamstring strains are common injuries in different sports. They are often serious, causing long rehabilitation times and a proneness for re-injury. Preliminary observations indicate that the injuries can be of at least two types, one occurring during high-speed running and the other during motions where the hamstring muscles reach extreme lengths.</p><p>Aims: To investigate the possible existence of different types of acute hamstring strains in two specific athletic groups, namely sprinters and dancers, as well as the generality of these findings in other sports.</p><p>Methods: In the first project, 18 sprinters and 15 dancers with acute first time hamstring strains were prospectively included. All subjects were examined, clinically and with magnetic resonance imaging (MRI), on 4 occasions after injury: at day 2-4, 10, 21 and 42. The follow-up period was 2 years. In the second project, 30 subjects from 21 different sports were prospectively included. All subjects were examined clinically and with MRI. The follow-up period lasted until the subjects returned to sport or finished their sport activity due to the injury.</p><p>Results: All sprinters sustained their injuries during competitive high-speed running. In contrast, all dancers encountered their injuries during slow-speed stretching type of exercises. The initial loss of strength and flexibility was significantly greater in sprinters than in dancers. At 42 days after injury, both groups could perform more than 90% of the test values of the uninjured leg. All the sprinters’ injuries were primarily located in biceps femoris long head, whereas the dancers’ injuries were mainly (87%) involving the proximal free tendon of semimembranosus. For the sprinters, involvement of the proximal free tendon, as estimated by MRI, and proximity to the ischial tuberosity, as estimated both by palpation and MRI, were associated with significantly longer time to return to pre-injury level. In the dancers, there were no significant correlations between clinical or MRI parameters and time to return to per-injury level. The time to pre-injury level was significantly longer (median 50 weeks, range 30-76) for the dancers compared to the sprinters (16, 6-50). In the second project, all injuries occurred during movements reaching a position with combined extensive hip flexion and knee extension. They were all located close to the ischial tuberosity and 83% involved the proximal free tendon of semimembranosus. Fourteen subjects (47%) decided to end their sport activity and for the remaining 16 subjects the median time back to sport was 31 (range 9-104) weeks. There were no significant correlations between clinical and MRI parameters and time to return to sport.</p><p>Conclusions: There seems to be a link between the injury situation and the two types of acute hamstring strain in sprinters and dancers with respect to clinical findings, injury location, muscles and tissues involved, and time to return to pre-injury level. Proximity of the injury to the ischial tuberosity, as estimated both by palpation and MRI, is associated with longer recovery time. Also in other sports, an injury situation where the hamstrings reach extensive lengths caused a specific injury to the proximal posterior thigh similar to that described in dancers. Due to the prolonged recovery time associated with this type of injury, correct diagnosis based on history, clinical and MRI investigation, and adequate information to the athletes are essential.</p><br>För att beställa tryckta exemplar av avhandlingen kontakta Carl Askling, carl.askling@gih.se
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Edirnelis, Dimos. "Nordic Hamstrings Exercise och Razor Hamstring Curls effekt på muskelstyrka och rörlighet i hamstrings för fotbollsspelande ungdomar." Thesis, Umeå universitet, Avdelningen för idrottsmedicin, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-177010.
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Syftet med denna studie var att undersöka effekten av 6 veckors styrketräning med så kallad Nordic Hamstring Exercise (NHE) i jämförelse med Razor Hamstring Curl (RHC) med avseende på hamstringsmuskulaturens styrka och rörlighet hos unga fotbollsspelare. 43 fotbollsspelande ungdomar från två olika lag rekryterades till studien varav 40 slutförde den. Deltagarna var av manligt kön och hade en medelålder på 17.2 ± 0.6. De randomiserades till två olika interventionsgrupper, NHE och RHC, där de fick utföra tilldelad övning under träningstid under sex veckor. Mätning av hamstrings rörlighet och isometrisk utvärdering av hamstrings muskelstyrka i 90°-, 45°- och 0°- knävinkel utfördes innan och efter intervention. Parade t-test och Wilcoxon signed rank test användes för att testa förändringen inom grupp och ANCOVA användes för att se skillnaderna mellan grupperna. NHE-gruppen hade en signifikant ökning av muskelstyrkan i samtliga testvinklar. RHC gruppen hade signifikant ökning i endast två av tre testvinklar. Mätningen i 0° visade ingen signifikant ökning av muskelstyrkan. Rörligheten hade en signifikant ökning i båda interventionsgrupperna. När interventionsgrupperna testades mot varandra så hade NHE gruppen en signifikant högre ökning av muskelstyrkan i 0° mätningen jämfört med RHC gruppen. Ingen signifikant skillnad uppmärksammades i de andra testvinklarna eller i ökningen av rörligheten. Både NHE- och RHC-träning under 6 veckor resulterade i signifikant ökning av muskelstyrka och rörlighet i hamstringsmuskulaturen hos unga fotbollsspelare. NHE resulterade dock i en signifikant större ökning av muskelstyrkan i ett större rörelseomfång än RHC-övningen. Baserat på resultaten i denna studie är NHE den föredragna metoden att inkludera i framtida träningsprogram.
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張劍強 and Kim-keung Cheung. "The effect of hamstring stretching technique on hamstring flexibility and isokinetic strength." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B3125715X.
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Cheung, Kim-keung. "The effect of hamstring stretching technique on hamstring flexibility and isokinetic strength /." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B23425374.
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Siegel, Lori L. "Hamstring rehabilitation a systematic review /." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5158.
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Thesis (M.S.)--West Virginia University, 2007.<br>Title from document title page. Document formatted into pages; contains vi, 98 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
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Nejo, Yusuke. "The Graston Technique? Increases Hamstring Flexibility." Thesis, North Dakota State University, 2014. https://hdl.handle.net/10365/27374.
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Soft tissue mobilization techniques have been reported to increase hamstring flexibility. However, no one has reported the effects of the Graston Technique? on increasing hamstring flexibility. The purpose of this study was to determine the changes in range of motion after applying the Graston Technique? to tight hamstring muscles.
Forty five college-aged students participated; 3 well-trained athletes, 35 physically trained students, and 7 untrained students (total 30 men and 15 women). Pre- and post-treatment measurements on hamstring flexibility were taken at the 90/90? position using a goniometer.
There was a statistically significant difference between the sham treatment group and the treatment groups (an only Graston Technique? group and a whole Graston Technique? treatment group). However, there was no significant difference between the only Graston Technique? group and the whole Graston Technique? treatment group. Also, range of motion increase was affected by the adipose tissue thickness.
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Rolf, Ola, and Wictoria Zetterberg. "Korrelation i smärta & obehag vid två olika hamstring tester hos fotbollsspelare." Thesis, Mälardalens högskola, Akademin för hälsa, vård och välfärd, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-14372.
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Bakgrund: Det är viktigt att kliniskt kunna avgöra om idrottaren är tillräckligt rehabiliterad för att återgå till full träning och matchspel eftersom otillräcklig rehabilitering är den största riskfaktorn för återskada i hamstrings. Därför skulle ett test med enkel utrustning behöva komplettera den kliniska undersökningen. Syfte: Studiens syfte är att undersöka vilket samband som finns mellan genomförandet av Nordic hamstring strength test och Asklings hamstring test utifrån skattning av smärta och obehag i samband med testen. Huruvida deltagarnas tilltro till att prestera sitt yttersta i en 90 min fotbollsmatch påverkas efter testerna samt att beskriva obehag och smärta efter testerna för spelare som varit skadad eller inte under senaste sex månaderna. Metod: 22 fotbollsspelare fick skatta sin tilltro till sin egen förmåga att prestera sitt yttersta i en 90 min fotbollsmatch samt skatta obehag och smärta med VAS i samband med testerna. Hamstring Outcome Score användes för att få en helhetssyn av deltagarnas funktion och skadehistoria kring hamstring. Spearman’s rho och Wilcoxon’s teckenrang test användes för att analysera resultatet. Resultat: Korrelationen mellan Asklings hamstring test och Nordic hamstring strength test var moderat (0,4-0,6) dock signifikant på <0,05. Majoriteten av spelarna sänkte sin tilltro efter testerna. De yngre spelarna har varit skadade senast men det är de äldsta spelarna som har dragit på sig flest skador. Slutsatser: Vidare forskning på ett större antal deltagare behövs för att avgöra om Nordic hamstring strength test skulle kunna användas som ett kompletterande test till den kliniska undersökningen.<br>Backgroud: It’s important to clinically determine whether the athlete is ready to return to full training and match play as inadequate rehabilitation are the major risk factor for reinjury in the hamstrings. Therefore, a test with simple equipment is needed to complement the clinical examination. Purpose: The study aims to investigate the relationship between the implementation of the Asklings hamstring test and the Nordic hamstring strength test based on the estimation of pain and discomfort during the tests. Whether the participants’ confidences to perform their best in a 90 minutes soccer game is affected by the tests, and describe pain and discomfort after the tests for those who had or had not been injured during the last six months. Methods: 22 football players had to rate their confidence in their own ability to perform their best in a 90 minutes football game, and estimate the discomfort and pain using VAS during the tests. Hamstring Outcome Score was used to obtain a holistic view of the participants’ function and injury history about hamstrings. Spearman’s Rho and Wilcoxon’s Rank Sum test was used to analyze the results. Result: There is a moderate correlation (0,4-0,6) between Askling hamstring test and Nordic hamstring strength test with a significance level of p<0,05. The majority of the players lowered their confidence after the tests. The younger players have been injured most recently but the oldest players have had the most injuries. Conclusion: Further research with a larger number of participants is needed to determine whether Nordic hamstring strength test could be used as a complementary test to the clinical examination.
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Waterworth, Sally. "Hamstring flexibility : measurement, stretching and injury susceptibility." Thesis, University of Pretoria, 2013. http://hdl.handle.net/2263/40275.
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Flexibility has traditionally been considered an important component of human physical fitness but this conjecture lacks supporting empirical evidence. While there is extensive published research examining the relative importance of flexibility and the impact of various methods of stretching on levels of flexibility, performance and injury risk, the quality of studies has varied considerably, reliability and validity of methodology has not always been proven, and rationale has at times been questionable. Additionally, much literature has focused on static flexibility which is not necessarily related to properties of the musculotendinous unit and thus dynamic flexibility. This thesis was designed to fill gaps in the existing literature by using accepted methods to establish relative and absolute reliability of hamstring flexibility tests, consider the comparability of static and dynamic components of the global concept of flexibility and explore how dynamic flexibility and performance are influenced by fatiguing exercise and subsequent static stretching. The first aim was realised by a repeated measures study designed to establish the intraday and interday, intrarater reliability and measurement error of static and dynamic measures of hamstring flexibility. Significant relative reliability for measures of static and dynamic hamstring flexibility was demonstrated via intraclass correlation coefficient (3,1) but limits of agreement analysis indicated there was a degree of absolute measurement error that must be interpreted in relation to analytical goals. The second aim required evaluation of relationships shared by static and dynamic measures of hamstring flexibility. Significant relationships between the different static flexibility tests were established but the extent of unexplained variance indicated that only measurements from the same tests should be directly compared to each other. Relationships between different measures of dynamic flexibility and static flexibility varied from non-significant to moderately strong, suggesting that measures of static and dynamic flexibility are not identical and results should not be interchanged between the two types of tests. Due to a lack of explanatory empirical evidence, the final chapter aimed via a prospective randomised repeated measures study to investigate the impact of fatigue and post-exercise static stretching on measures of dynamic flexibility and performance. Fatigue resulted in no significant changes to passive or active dynamic flexibility measures but a significant worsening of static flexibility levels and perceived stiffness. Post-exercise stretch resulted in significantly increased passive and active energy absorption immediately and 18 hours post-exercise and in significantly reduced joint position sense immediately post-exercise. Effect sizes were small so the clinical meaningfulness of performing post-exercise static stretching is questionable, particularly if performed in place of other, potentially more beneficial practices.<br>Thesis (DPhil)--University of Pretoria, 2013.<br>gm2014<br>Biokinetics, Sport and Leisure Sciences<br>unrestricted
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Muggleton, Shaun T. "Kinematics and kinetics of the Nordic hamstring curl." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/83951/1/Shaun_Muggleton_Thesis.pdf.
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This thesis describes, for the first time, the forces involved in the Nordic hamstring exercise, its reliability and the biomechanical effects of extra loading during the movement. The results provide practitioners with valuable information to enhance hamstring injury prevention and rehabilitation programs.
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Valadao, Jaime Andre. "The effect of neuromuscular electrical stimulation on hamstring prehabilitation." University of the Western Cape, 2018. http://hdl.handle.net/11394/6566.
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Masters of Science<br>BACKGROUND: Hamstring injuries remain a growing concern within a large
variety of sports from the elite athlete to the weekend warrior. A copious
amount of research has been performed in an attempt to reduce these
injuries. The aim of this study was to understand the changes in lengthened
state eccentric strength of the hamstrings following four separate protocols.
METHODS: A quantitative research approach, using a true experimental
design, was adopted for this study. A convenience sample of non-sedentary,
35 male participants, between the ages of 18 and 35 within the City of Cape
Town was used. Participants were randomly allocated to one of four groups
namely; Control group (C), resistance training alone (RT), neuromuscular
electrical stimulation alone (NMES), or NMES superimposed with RT
(NMES&RT). Participant’s eccentric hamstring strength was tested in a
lengthened state, on the Biodex system 4 Pro™ for the pre- and post-test.
The intervention spanned over four weeks. SPSS version 25 was used for
data analysis.
RESULTS: All groups demonstrated a mean increase in relative peak torque.
However, a repeated-measures analysis of variance (ANOVA) showed no
interaction effect (p = 0.411) between the four groups. Further analysis using
Magnitude-based inferences (MBI), to identify the magnitude of changes,
showed a small positive effect for both the NMES and NMES&RT group when
compared to the C and RT groups.
CONCLUSION: Although there are no statistically significant differences
between the four groups employed in this study (C, RT, NMES, NMES&RT),
NMES and NMES&RT did show small positive effects compared to C and RT
with a very low likelihood of negative effects. Thus, using NMES either alone
or superimposed with resistance training will be beneficial for trained athletes
but it is not a necessity and the use of specific resistance training may be just
as effective.<br>2019-04-30
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White, Jessica M. "A Hamstring emphasized strengthening program for female collegiate athletes." Defiance College / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=def1281465088.
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Daly, Colm. "Biomechanical factors associated with previous hamstring injury in high level sprinting athletes." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/24590.
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Hamstring injury is common in sprinting sports and injury recurrence remains a major concern. The aim of this thesis is to explore the biomechanical characteristics of athletes following sprint related hamstring injury. We conducted 1) An examination of already published research on biomechanical deficits following hamstring injury in athletes who had returned to sport by means of a systematic review and meta-analysis; 2) A detailed examination of sprinting following hamstring injury in athletes who had returned to sport muscle activity using 3D motion capture and surface EMG; 3) An examination of high intensity eccentric loading performance in previously injured athletes using low density, high surface area surface EMG and measures of force; 4) An analysis of hamstring muscle recovery until return to sport following hamstring injury using low density, high surface area surface EMG and measures of force via case reports in two elite athletes. Previous research indicates that athletes who had returned to sport following hamstring injury continue to display deficits in force production, especially during slow eccentric contractions. The observational studies indicate that athletes run with significantly asymmetric movements about the pelvis and hip that would place their hamstrings under increased length during the terminal swing phase of sprinting. Furthermore, significant alterations in late swing EMG ratios suggest relatively reduced activity in the previously injured biceps femoris. Spatial activation of the hamstring appears altered in previously injured athletes, with reduced relative activation of the proximal muscle and reduced median frequency values in the medial muscle compared to control limbs. Asymmetries in activation patterns are also noted in the pre-return to sport phase. Previous hamstring injury is associated with significant alterations in force production, movement symmetry and muscle activation patterns following return to sport highlighting the complexity of this injury and the need for advanced rehabilitation screening approaches.
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Sole, Gisela, and n/a. "Neuromuscular control of thigh and gluteal muscles following hamstring injuries." University of Otago. School of Physiotherapy, 2008. http://adt.otago.ac.nz./public/adt-NZDU20081103.100628.
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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.
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Small, Katie Ann. "Effect of fatigue on hamstring strain injury risk in soccer." Thesis, University of Hull, 2008. http://hydra.hull.ac.uk/resources/hull:1742.
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Hamstring strains are one of the primary injuries within modern soccer match-play. The injury is well recognised by medical personnel, coaches and athletes as a major concern causing significant financial costs and lost time from training and matches. The temporal pattern of hamstring injury incidence during matches has shown almost half of all injuries to occur during the latter stages of each half, thus suggesting fatigue as an important contributing factor for injury. This thesis comprises four experimental chapters that examine the effect of multidirectional soccer-specific fatigue on the primary aetiological risk factors and mechanism of injury. This was then used to create and evaluate an injury prevention programme aimed at reducing the risk of hamstring strains in soccer.
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Al-Mousawi, Abdul-Majeed M. "A study of warm-up and injury in hamstring muscles." Thesis, University of Glasgow, 2005. http://theses.gla.ac.uk/6899/.
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This project is the first to investigate blood perfusion in the human hamstrings during isometric exercise with a near infrared spectroscopy (NIRS). A Kin Com dynamometer has been used to fix the knee positions and to measure torques during contractions. Both the NIRS optodes and the electromyography (EMG) electrodes were attached to the skin over the hamstrings. Previous studies used a NIRS to measure muscle blood flow in the forearm, quadriceps and calf muscles. The changes in haemoglobin concentrations were calculated using Spike 2 software. A total of 46 male volunteers participated in the four series of experiments described in this thesis. The following overall conclusions can be drawn: perfusion decreases in the hamstrings during contractions and then returns to normal levels after a period of time, changing the limb position at which the contractions are made does not affect the perfusion, warm-up exercises increase in blood perfusion for 8 minutes at 30 and 40% of MVC. The perfusion did not significantly change during an episode of DOMS or in the injured and non-injured limbs. These conclusions show the importance of warm-up before sports activities but not necessarily avoid injury. It can be concluded that there is no association between such conditions with hamstring injuries. The maintained perfusion at different conditions is a positive finding as the perfusion is not restricted indicating good delivery of oxygen despite muscle injury.
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Gregoire, Meghan. "The Relationship Between Hamstring Strength and Agonist-Antagonist Co-Activation." University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1556791315939376.
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Bourne, Matthew N. "Hamstring strain injury: The role of strength and voluntary activation." Thesis, Queensland University of Technology, 2016. https://eprints.qut.edu.au/98262/4/Matthew_Bourne_Thesis.pdf.
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Hamstring strain injuries are endemic in running-based sports, often resulting in substantial performance decrements and costing professional sporting organisations millions of dollars each year. This program of research has contributed new knowledge relating to factors which may predispose to, and manifest as a result of hamstring injury, while also providing novel data which may be used to inform injury prevention and rehabilitation practices.
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Alsén, Jonna. "Effekten av stretching." Thesis, Halmstad University, School of Business and Engineering (SET), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1107.
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Snyder, Alison Rose. "The acute influence of static and ballistic stretching on the biomechanics and muscle activity associated with the hamstring stretch /." See Full Text at OhioLINK ETD Center (Requires Adobe Acrobat Reader for viewing), 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1102522627.
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Thesis (Ph.D.)--University of Toledo, 2004.<br>Typescript. "A dissertation [submitted] as partial fulfillment of the requirements of the Doctor of Philosophy degree in Exercise Science." Bibliography: leaves 72-77.
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Sonnekalb, Sara. "Impact of different warm-up conditions on hamstring torque and power." Connect to this title online, 2005. http://www.oregonpdf.org.
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Thesis (M. Ed.)--Bowling Green State University, 2005.<br>Includes bibliographical references (leaves 38-44). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.
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Salci, Yasar. "Effects Of Eccentric Hamstring Training On Lower Extremity Strength &." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609693/index.pdf.
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The purpose of this study was to display increase in eccentric hamstring strength after 10-weeks training program. Secondly, if such an increase occurred, would this strength change result in altered landing kinetics and improved jumping performance?
27 recreational female athletes assigned into experimental (n = 14) and control (n = 13) groups. Baseline measures of landing kinetics were collected using a force plate, strength data and proprioceptive measurements were evaluated using an isokinetic dynamometer and vertical jump performance were determined by a jumping mat.
Results indicated that NHST group increased their eccentric hamstring strength after eccentric strength training program (week-1 = 233.6±<br>27.5, week-10 = 253.8±<br>28.4 Nm/kgbw<br>p<<br>.05). The results demonstrated that there were significant differences in landing mechanics for NHST group. PVGRF (week-1 = 6.2±<br>0.9, week-5 = 5.3±<br>0.9<br>p<<br>.05), PAPGRF (week-1 = 1.1±<br>0.2 &<br>week-10 = 0.8±<br>0.3<br>p<<br>.05) and APImp results demonstrated significant differences in trained group (week-1 = 78.1±<br>13.6 &<br>week-10 = 67.8±<br>9.2<br>p<<br>.05). NHST group exhibited significant increase in vertical jumping ability (week-1 = 0.25±<br>0.0 &<br>week-10 = 0.27±<br>0.0 cm<br>p<<br>.01).
This study supported the following points: 1) increases in the eccentric hamstring strength were evident after NHST program, 2) the increases in isokinetic strength were sufficient to cause alterations in landing kinetics to decrease the applied joint forces, so the NHST program would be an influential factor in decreasing the lower extremity injuries, and 3) the increase in the efficiency of force transfer at the final take off phase of jumping contributed to a higher performance in vertical jump.
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Rohrback, Mitchell. "Predicting Diameter of ACL Quadrupled Hamstring Autograft in a Pediatric Population." Thesis, The University of Arizona, 2018. http://hdl.handle.net/10150/626886.
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Beard, David John. "Hamstring contraction latency following anterior cruciate ligament rupture, reconstruction and rehabilitation." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308448.
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Whyte, Enda. "The influence of reduced hamstring muscle length on patellofemoral joint kinematics." Thesis, University of Strathclyde, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502313.
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Lombard, Rene Naylor. "Preseason risk factors associated with hamstring injuries in club rugby players." Master's thesis, University of Cape Town, 2004. http://hdl.handle.net/11427/3018.
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Epperson, Travis Arthur. "The effect of whole body vibration platform training on hamstring flexibility /." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd3122.pdf.
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Epperson, Travis A. "The Effects of Whole Body Vibration Platform Training on Hamstring Flexibility." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/1881.
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Introduction: Very few studies have looked at the effect of vibration on flexibility, and no studies exist that have looked at stretching concurrently with whole body vibration (WBV) training. Therefore, the purpose of this study was to determine if whole-body-vibration training (WBV) done concurrently with static stretch (SV) is more effective than static stretching alone (SS), and to see if WBV training independently (SQ) improves hamstring flexibility without stretching. A secondary purpose of this study is to determine if retention of flexibility gains are maintained. Methods: Forty-four subjects (31 men, 13 women) completed this study (age 22.5 ± 1.8 years; body mass 75.54 ± 13.18 kg; height 176.7 ± 8.06 kg). All subjects were randomly assigned to 1 of 5 groups: SV group (8 males, 3 females), SQ group (8 m, 4 f), SS group (8 m, 3 f), and the C group (7 m, 3 f). All subjects were measured bilaterally for hamstring flexibility using the lying passive knee extension test (LPKE) prior to group assignment. Subjects from each treatment group reported to lab 5 times per week for treatment. Subjects stood on the WBV platform for 5 repetitions of 30-seconds at with 30-seconds in between bouts. The SV group stretched hamstrings while standing on the WBV during the vibration bouts (at 26 Hz and 4 mm amplitude). The SS group did the same thing except the unit was not turned on. The SQ group stood on the WBV platform in a semi-squat position similar to most WBV training studies, without stretching, but with vibration. The C group stood on the WBV platform in a semi-squat without vibration. Analysis and Results: A mixed models analysis of covariance (ANCOVA) was used while blocking on subjects to analyze data using the statistical program SAS (version 9.1). A Bonferroni correction was used for significance on all post hoc tests (p<.0001). At baseline there were no significant differences between groups for flexibility (see Table 1), showing that each group was similar in flexibility to start. Throughout the treatment period (3 weeks of stretching) both the SS and SV groups had significant increases in flexibility compared to SQ and C. Analysis of the slopes (rate of change) for the treatment period was significantly different between the SV group and all other groups (p<.0001 for all comparisons), showing that the SV group had a greater rate of change than all other groups. For the retention period there was no significant difference between the SV and SS group (p=0.0455), but there was a significant difference between both the SV and SS groups and all other groups (p<.0001 for all comparisons). Conclusion: Stretching during WBV improves flexibility more than static stretching alone and at a faster rate. WBV on its own without stretching does not significantly improve hamstring flexibility.
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Opar, David A. "Neuromuscular hamstring function in response to intermittent running and previous injury." Thesis, Queensland University of Technology, 2013. https://eprints.qut.edu.au/64107/4/David_Opar_Thesis.pdf.
Full textAbstract:
This thesis examined the impact of previous hamstring injury and fatigue on the function of the hamstring muscles and their neural control. The work established the role of neuromuscular inhibition after hamstring injury and involved the development of a new field testing device for eccentric hamstring strength, which is now in high demand in elite sport worldwide. David has four peer-reviewed publications from this doctoral work.
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Sims, Casey K. E. "Impact of prior hamstring strain injury & biofeedback on eccentric & isometric knee flexor strength." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/127300/1/Casey_Sims_Thesis.pdf.
Full textAbstract:
Hamstring strain injury is a prevalent non-contact injury in running based sports. Little is known about the effects of lower grade injury on the capacity to perform common rehabilitation exercises protocols as well as hamstring strength tests. Novel data from these studies has contributed to the evolving hamstring injury literature, showing relatively mild hamstring injury has no significant effects on the strength performance in varying hamstring tests of different contraction modes. However, muscle architectural deficits were apparent despite athletes meeting return to play criteria, further solidifying the need to enhance rehabilitation protocols to restore structure and function for individuals.
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Rebello, Gayle, and n/a. "Measuring dynamic hamstring flexibility: Dynamic versus static stretching in the warm-up." University of Canberra. School of Health Sciences, 2006. http://erl.canberra.edu.au./public/adt-AUC20070618.095511.
Full textAbstract:
The main purpose of this study was to compare the acute effects of static and dynamic stretching
in the warm-up, on hamstring flexibility using a reliable set-up for measurement.
Static and dynamic flexibility was measured using five modifications of the Straight Leg Raise
(SLR) test to measure hip flexion range of motion (ROM). In the first part of the study (n = 33)
hamstring flexibility was measured using a Static-passive, Static-active, Dynamic-supine and
Dynamic-standing tests. The results of this study were used to calculate reliability statistics and
to compare the various static and dynamic flexibility tests. There was a significant difference
between Static-passive (SPH) and the Dynamic-supine (DSUH) tests (p less than .05).
This was followed by an intervention study (n = 12) where participants were randomly assigned
to three intervention treatments of 225 seconds on separate days: No stretching (Treatment I),
Static stretching (Treatment 2) and Dynamic stretching (Treatment 3) in a cross-over study
design. Static stretching had no impact on dynamic hamstring flexibility; however, dynamic
stretching improved dynamic flexibility while simultaneously increasing static flexibility. This
has implications for the specificity of stretching in sport.
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Coombs, Rosalind Claire. "Relationship between hamstring and quadriceps strength : evaluation of the functional moment ratio." Thesis, University of East London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403780.
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Areia, Carlos Morgado. "Neuromuscular adaptations in football athletes with prior history of hamstring strain injury." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15791.
Full textAbstract:
Mestrado em Fisioterapia<br>Background: Hamstring strain injuries (HSI) are one of the most common injuries in a wide variety of running-sports, resulting in a considerable loss of competition and training time. One of the most problematic consequences regarding HSI is the recurrence rate and its non-decrease over the past decades, despite increasing evidence. Recent studies also found several maladaptations post-HSI probably due to neuromuscular inhibition and it has been proposed that these adaptations post-injury may contribute as risk factors for the injury-reinjury cycle and high recurrence rates. Furthermore it has been recently proposed not to disregard the inter-relationship between these adaptations and risk-factors post-injury in order to better understand the mechanisms of this complex injury.
Objective: To determine, analyze and correlate neuromuscular adaptations in amateur football players with prior history of HSI per comparison to uninjured athletes in similar conditions.
Methodology: Every participant was subjected to isokinetic concentric (60 and 240deg.sec) and eccentric (30 and 120deg.sec¯¹) testing, and peak torque, angle of peak torque and hamstrings to quadriceps (H:Q) conventional ratios were measured, myoelectrical activity of Bicep Femoris (BF) and Medial Hamstrings (MH) were also measured during isokinetic eccentric testing at both velocities and muscle activation percentages were calculated at 30, 50 and 100ms after onset of contraction. Furthermore active and passive knee extension, knee joint position sense (JPS) test, triple-hop distance (THD) test and core stability (flexors and extensors endurance, right and left side bridge test) were used and correlated.
Results: Seventeen players have participated in this study: 10 athletes with prior history of HSI, composing the Hamstring injury group (HG) and 7 athletes without prior severe injuries as control group (CG). We found statistical significant differences between HG injured and uninjured sides in the BF myoelectrical activity at almost all times in both velocities and between HG injured and CG non-dominant sides at 100ms in eccentric 120deg.sec¯¹ velocity (p<.05). We found no differences in MH activity. Regarding proprioception we found differences between the HG injured and uninjured sides (p=.027). We found no differences in the rest of used tests. However, significant correlation between myoelectrical activation at 100ms in 120deg.sec¯¹ testing and JPS with initial position at 90º (r-.372; p=0.031) was found, as well as between isokinetic H:Q ratio at 240deg.sec and THD score (r=-.345; p=.045).
Conclusion: We found significant differences that support previous research regarding neuromuscular adaptations and BF inhibition post-HSI. Moreover, to our knowledge, this was the first study that found correlation between these adaptations, and may open a door to new perspectives and future studies.<br>Enquadramento: As lesões dos isquiotibiais são bastante comuns numa grande variedade de desportos que envolvem corrida, resultando num grande período de abstinência desportiva e competitiva. Uma das consequências mais problemáticas desta lesão é a sua alta taxa de recorrência que, embora tenha sido alvo de bastantes estudos, não tem diminuído nas últimas décadas. Estudos recentes encontraram também várias maladaptações em atletas com história desta lesão, provavelmente devido a inibição neuromuscular, sendo proposto que estas adaptações pós-lesão possam contribuir como factores de risco no ciclo de lesão-recorrência, e para a elevada taxa desta. Pelo que recentemente estudos sugerem considerar a interacção destas adaptações e factores de risco, de modo a aprofundar o nosso conhecimento dos mecanismos desta complexa lesão.
Objectivo: Determinar, analisar e correlacionar adaptações neuromusculares em futebolistas amadores com história de lesão dos isquiotibiais em comparação com atletas sem história de lesões, em condições semelhantes.
Metodologia: Todos os participantes foram sujeitos a testes isocinéticos em modo concêntrico (60 e 240º.sec) e excêntricos (30 e 120º.seg¯¹) em ambos os membros, com análise do pico de torque, ângulo de pico de torque e rácio convencional isquiotibial:quadriceps (H:Q), também foi medida a actividade mioeléctrica do Bicípite Femoral (BF) e dos isquiotibiais mediais (MH) durante a avaliação isocinética excêntrica em ambas as velocidades e a percentagem de activação muscular foi calculada a 30, 50 e 100ms após início da contracção. Além destes, foram medidos e correlacionados os testes de extensão do joelho activa e passiva, teste de sensação de posição do joelho (JPS), triple-hop distance (THD) e testes de estabilidade do core (endurance dos flexores e extensores, side bridge para o lado direito e esquerdo).
Resultados: Dezassete jogadores participaram neste estudo: 10 atletas com história de lesão dos isquiotibiais (HG) e 7 atletas sem história de lesões graves (CG). Foram encontradas diferenças significativas entre o lado lesado e não lesado do HG na actividade mioeléctrica do BF em quase todos os tempos em ambas as velocidades, e entre o lado lesado do HG e lado não dominante do CG aos 100ms durante o teste excêntrico á velocidade de 120º.seg¯¹ (p<.05). Não foram encontradas diferenças significativas na actividade dos MH. Quanto ao teste proprioceptivo foram encontradas diferenças no HG entre o membro lesado e não lesado no JPS quando a posição inicial era a extensão completa do joelho (p=.027). Não foram encontradas alterações nos outros testes. No entanto houve correlação significativa entre a actividade mioeléctrica do BF aos 100ms a 120º.seg¯¹ e os resultados do JPS com a 90º de flexão do joelho (r-.372; p=0.031) como posição inicial, assim como entre o rácio H:Q no teste isocinético concêntrico a 240graus.sec e o score to THD (r=-345.; p=.045).
Conclusão: Neste estudo foram encontradas diferenças significativas que suporta literatura anterior no que toda a existência de adaptações neuromusculares e inibição do BF após lesão dos isquiotibiais. Além disso, no nosso conhecimento, este foi o primeiro estudo a encontrar correlação significativa entre estas adaptações, pelo que pode abrir uma porta a novas perspectivas e estudos futuros.
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Elnagar, Youssif Omran. "Sex differences in the functional hamstring to quadriceps ratio and neuromuscular performance." Thesis, University of Gloucestershire, 2012. http://eprints.glos.ac.uk/1952/.
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Increased relative risk of non-contact anterior cruciate ligament (ACL) injury has been attributed to numerous biomechanical, anatomical and neuromuscular factors. Females are at greater relative risk of non-contact ACL injury compared with males. Dynamic knee stability is an important component required to reduce relative risk of injury, especially to the knee joint. It is difficult to directly measure knee stability; however the eccentric ability of the hamstrings to co-contract to counter the torque produced by concentric quadriceps actions during knee extension is important in stabilising the knee (determined as the functional H/Q ratio [FH/Q]). One of the proposed reasons for a greater incidence of non-contact ACL injury in females is a reduced capacity for neuromuscular functioning to stabilise the knee joint effectively. Most injuries occur in the second half of an athletic event when fatigue is commonly present, therefore identifying fatigue as a potential risk factor for ACL injury and this may allow for the development of improved prevention strategies. The three experimental studies included within this thesis (chapter 4-6) have generated novel data on sex differences in the FH/Q ratio and neuromuscular performance prior to and following a downhill running fatigue task. One hundred and ten healthy males (n=55; mean ± SD 29 ± 5 yrs) and females (n=55; mean ± SD 27 ± 6 yrs) were recruited from the university population. Isokinetic torque of the hamstrings and quadriceps was determined at 60, 120 and 240˚·s–1with the hip flexed at 0°. Range of movement of the knee joint was 90° with 0° determined as full volitional extension. Concentric (CON) torque was determined first followed by eccentric (ECC) torque, with the slowest velocity tested first. Torque was gravity corrected and filtered to only include constant velocity periods. For functional relevance FH/Q ratio was determined at 15, 30, 45º (as these are the joint angles where injury is most likely to occur) and where peak torque (PT) was achieved (to compare with the extant literature) for each movement velocity. Surface electromyography was recorded from the semitendinosus (ST), semimembranosus (SM) and biceps femoris (BF) of the dominant limb using an 8-channel DelSys EMG telemetry system. The biodex square wave synchronization pulse was configured with the EMG software via a trigger system so that EMG and torque data were completely time aligned. Raw EMG data were collected at a sampling frequency of 1024 Hz and included a common mode rejection ratio of <80 dB and an amplifier gain of 1000. Raw EMG data was band pass filtered at 20 – 450 Hz. The electromechanical delay (EMD) was determined as the time delay between the onset of muscle activation (change in activation of +15 μV) and onset of torque production (9.6 N·m) according to the procedures described by Zhou et al (1995). The aim of the first study (chapter 4) was to explore sex differences in the FH/Q ratio whilst taking into account joint angle and movement velocity. A 2 (sex) x 3 (movement velocity) x 4 (joint angle) ANOVA was performed to determine interactions and main effects. FH/Q ratio ranged from 59 to 98% in females and 66 to 109% in males across joint angles and movement velocities. No significant differences between males and females in age but males were significantly taller and had greater body mass. Irrespective of sex the FH/Q ratio increased with joint angle and movement velocity to improve knee stability during high velocity movement and near full extension. However, the FH/Q ratio is significantly lower in females compared with males and importantly this sex difference increases as movement velocity increases. Females have a lower FH/Q ratio than males close to full knee extension and during high velocity movements, both of which are predisposing factors for increased injury risk. This reduced FH/Q ratio may impair dynamic knee stability in females during fast velocity movements and may predispose them to a greater relative risk of knee injury. The aim of the second study (chapter 5) was to examine sex differences in the EMD of the hamstring muscles during eccentric muscle actions at 60, 120 and 240˚·s–1. A 2 (sex) x 3 (muscle group) x 3 (movement velocity) ANOVA was performed to determine interactions and main effects. During eccentric hamstring muscle actions there were no differences in the EMD of the 3 muscles examined. Irrespective of sex, significant main effects for angular velocity was demonstrated, indicating an increase in the delay time with increasing angular velocity. This increased delay during fast velocity movements may account for the increased risk of injury during fast movements. No significant sex differences in EMD was found irrespective of movement velocity of muscle examined, suggesting that females do not have impaired neuromuscular performance of the hamstring compared with males during eccentric hamstring muscle actions in the rested state. The aim of the third study (chapter 6) was to examine the effects of a fatigue task on sex differences of the FH/Q ratio and EMD. The procedures used in study 1 and 2 were repeated pre and post a downhill running fatigue task to explore fatigue related effects on neuromuscular functioning. Each participant performed a 40 min intermittent downhill running protocol consisting of 5 × 8 min bouts on a -10% decline, with 2 min standing rest between each bout. Irrespective of sex, joint angle or angular velocity, the FH/Q ratio was lower and EMD of hamstrings muscle was longer post-fatigue compared to pre-fatigue. Significant interactions between sex and time (pre-post) for the FH/Q ratio and EMD of hamstring muscles were found. The interactions showed a significantly lower FH/Q ratio and significantly longer EMD post fatigue in females compared to males. These data suggest that functional stability of the knee is reduced when fatigue is present and the impact of fatigue is greater in females. The findings of this thesis indicate the importance of determining the FH/Q ratio using angle specific torque as well as taking into account movement velocity, rather than simply using PT values to monitor muscle function of the knee. The findings of the present thesis support the notion that fatigue compromises the stability of the knee by reducing the FH/Q ratio and lengthening EMD. These effects are greater in females compared to males and may predispose them to greater relative risk of injury. Therefore, movement velocity, joint angle and fatigue resistance all need to be considered when designing training programmes to reduce the relative risk of injury. The focus of such training should be aimed at eccentric conditioning of the hamstring muscles to improve both muscular and neuromuscular functioning to limit the fatigue related effects, especially in females.
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Nugent, Ryan P. "Therapeutic efficacy of platelet-rich plasma injections in treating high hamstring tendinopathy." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12175.
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Thesis (M.A.)--Boston University<br>Hamstring muscle and tendon injuries are commonly seen in sports medicine clinics, especially in track and field athletes. However, a less common subset of these injuries has recently begun to gain more attention among researchers and clinicians and is referred to as high hamstring tendinopathy. Patients suffering from this condition typically report deep buttock pain brought on by running, or in severe cases even by prolonged sitting, such as in driving a car for long periods of time. Diagnosis of this condition requires a specific patient history, positive signs on physical exams, as well as positive findings on imaging studies, primarily MRI and ultrasound. Treatment for high hamstring tendinopathy typically starts with conservative measures for pain management including ice, electrical stimulation, and pulsed ultrasound. As soon as patients are able, a physical therapy protocol is prescribed involving stretching, along with
strengthening, progressing to eccentric exercises. In cases where symptoms are persistent, more aggressive treatments can be followed, such as corticosteroid injections, extracorporeal shockwave therapy, and surgery in more severe cases. However, because these therapies are often ineffective, expensive, and potentially carry high risks, physicians have begun to turn to alternative forms of therapy. One such treatment gaining recent popularity is the use of platelet-rich plasma injections (PRP).
The widely held belief is that PRP provides a higher than average concentration of growth factors than is normally contained in platelets and that these stimulate the wound healing cascade and help in tissue repair and regeneration. PRP is prepared using autologous whole blood from patients by two rounds of centrifugation, separating and concentrating the platelets from other components such as red blood cells and leukocytes. [TRUNCATED]
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Schippers, Raven Chriscendo. "Relationship between selected physical characteristics and hamstring injuries in male soccer players." University of the Western Cape, 2018. http://hdl.handle.net/11394/6851.
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Magister Artium (Sport, Recreation and Exercise Science) - MA(SRES)<br>Hamstrings muscle injury is the most frequent soccer-related injury in amateur and professional soccer players. Despite various interventions, the risk of hamstrings re-injury remains high. Several scientific studies examined the potential risk factors and their contribution to the occurrence of hamstrings injuries in male soccer players. The aim of the study was to investigate the relationship between selected physical characteristics, such as time-to-peak torque, hip abduction peak torque, hamstrings-to-quadriceps strength ratio, and hamstrings flexibility and the occurrence of hamstrings injuries in amateur male soccer players. A prospective, quantitative cross-sectional study design was utilized in this study. A total of 89 amateur male soccer players aged 18-35 years were recruited from the Cape Town Football District to perform functional assessments before injury occurred, which included anthropometric measurements, an evaluation of lower extremity isokinetic muscle strength (both knee and hip) and hamstrings flexibility tests. Instruments used to measure the anthropometric data were a calibrated Seca balance beam scale and stadiometer, a skinfold caliper, a sliding caliper, an anthropometer (All Harpenden, UK) and a metal tape measure. The Biodex Pro System 4 isokinetic dynamometer was used to measure lower extremity isokinetic muscle strength and a goniometer to measure hamstrings flexibility. Descriptive statistics included means and standard deviations, and inferential statistics included Pearson product-moment correlation to determine the relationship between selected physical characteristics and the occurrence of hamstrings injuries. Multivariate logistic regression via the forward stepwise method was utilised to predict potential physical characteristics (risk factors) for hamstrings injury in amateur male soccer players. Statistical significance was a p value of below 0.05. The prevalence of hamstrings injury was 4.3 %, with the multivariate logistic regression analysis indicating that time-to-peak torque was a significant predictor of the occurrence of hamstrings injury (OR = 1; p = 0.027). In conclusion, time-to-peak torque was a significant predictor of the occurrence of hamstrings injury. The players with hamstrings injuries produced a significantly slower time-to-peak torque, which has relevance for soccer players and coaches in addressing this common injury at all levels of competition.
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Fernandes, Santos Amanda Aparecida. "The effect of joint angle on surface electromyography amplitude of hamstring muscles." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/231385/1/Amanda%20Aparecida_Fernandes%20Santos_Thesis.pdf.
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This thesis investigated the effect of knee angle position on the electrical signal of two hamstring muscles using a traditional technique (bipolar electromyography) and a modern technique (high-density electromyography). The results suggest that changes in knee position affect the electrical activity on bipolar electromyography and these changes are associated with the rotation of muscle fibers under the pair of electrodes. However, using high-density electromyography, there was no difference between different knee positions. These findings suggest that high-density electromyography has different responses compared to bipolar electromyography. Hence, studies using bipolar montages need to be interpreted with caution to avoid wrong conclusions.
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Muller, Brusco Clarissa. "Hamstring muscle architecture parameters in static and dynamic conditions using ultrasound imaging." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2022. https://ro.ecu.edu.au/theses/2571.
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Biceps femoris long head (BFlh) fascicle length (Lf), fascicle angle (FA), and muscle thickness (MT) were assessed at rest and during dynamic contractions using B-mode ultrasound imaging. The assessments were performed in men and women with no previous hamstring strain injury. Volunteers visited the laboratory for two separate data collection sessions (Day 1 and Day 2) relating to two independent projects, seven days apart at the same time of day for test-retest measurements of the static assessments. For the dynamic assessments, familiarization with the isokinetic concentric and eccentric knee flexion exercises were performed on Day 1. On Day 2, BFlh Lf, FA and MT were assessed in real time using two serially aligned ultrasound devices whilst performing consecutive concentric and eccentric knee flexions at 30°/s and 180°/s.
To acquire images at rest, ultrasound imaging was performed using extended field-of-view (EFOV) and static image acquisition sequences of four single images acquired in-series along the muscle. From these images, Lf was assessed using seven methods: EFOV, Collage, manual linear extrapolation, and using four different trigonometric equations, and then FA and MT were measured in EFOV, Collage, and Single images. Lf, FA and MT measured on Days 1 and 2 were not different (p > 0.05) for any method, reliabilities were very high (ICC: 0.91-0.98), and correlations were strong ( ≥ 0.84). Significant correlations (p < 0.05; r=0.67-0.98) were found between EFOV and the other measurement techniques for Lf, FA and MT. The Collage method had the highest reliability for Lf, and highest rank order and correlation with EFOV. The Collage method can therefore be recommended for use if the methodology presented herein is followed.
For assessments during dynamic contractions, participants performed consecutive concentric and eccentric contractions at 30°/s and 180°/s whilst in vivo muscle function was recorded using two in-series transducers. At 30°/s both submaximal (55% maximum) and maximal contractions were performed whilst at 180°/s only maximal contractions were performed both before and after fatiguing exercise. Ultrasound videos were exported and edited to create a single, synchronized video and three fascicles were analyzed through the range of motion. Changes during concentric and eccentric contractions (Δ) in Lf, FA and MT at short (60-90° knee angle; 0° full knee extension) and long (0-30°) muscle lengths and across the full knee flexion range were measured and compared. Comparisons were made within exercises performed with the same contraction velocity. When fascicle behaviors were compared during submaximal and maximal concentric and eccentric contractions at 30°/s, greater ΔLf was observed at longer muscle length during both eccentric and concentric contractions (p=0.01), and this alteration was greater during eccentric contractions (p=0.02) at longer muscle lengths (p < 0.001). Greater ΔFA was observed at long length during eccentric contractions (p=0.02). When whole range of motion was analyzed, greater ΔMT was observed (p=0.03) in concentric contractions. When fascicle behavior was compared in the maximal contractions at 180°/s before and after fatiguing exercise, greater ΔLf was observed in the eccentric contraction at the long muscle length (p = 0.01), ΔFA was greater at short muscle lengths in the concentric contractions (p=0.02) and at long muscle lengths (p=0.006) and at full range of motion (p=0.006) during eccentric contractions. Less ΔFA was detected across all contractions (p < 0.05) after the fatiguing exercise when measured through the full range of motion. Greater dynamic torque was observed at long muscle lengths, during eccentric contraction, and before the fatiguing exercise (p < 0.05).
Although the six different techniques used to estimate Lf during rest provided values similar to EFOV, the Collage sonographic method provided the most accurate and reliable results and is therefore recommended for BFlh architectural analysis when EFOV is not available. Greater ΔLf and ΔFA were observed for a given joint rotation increment during submaximal and maximal eccentric contractions at long muscle lengths. The increased fascicle strain at long muscle length might contribute to both increased metabolic stress, and therefore longer-term muscle hypertrophy, and to muscle strain injuries.
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Clayton, Zane. "Hamstring activation in variants of the Romanian Deadlift: A functional Mri and surface EMG study." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/208155/1/Zane_Clayton_Thesis.pdf.
Full textAbstract:
Hamstring strain injuries continue to be expensive and time consuming for running based sports. Of the hamstring group, the biceps femoris long head is the most often injured. To date, hamstring injury rehabilitation and prevention methods have focussed predominantly on knee flexion exercises, despite the fact that hip extension exercises better activate this muscle. The aim of this thesis was to compare hamstring activation during variants of the hip extension based Romanian deadlift, to explore the patterns of hamstring and other hip extensor muscle activation. Data from this thesis can be used as a basis for future training studies.
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Tafazzoli, Faryaneh. "Mechanical behaviour of hamstring muscles in low-back pain patients and control subjects." Thesis, University of Ottawa (Canada), 1994. http://hdl.handle.net/10393/9583.
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Willhoit, Kristin Florence. "Effect of ankle position on hamstring strength during maximum and submaximum leg curls." [Pensacola, Fla.] : University of West Florida, 2007. http://purl.fcla.edu/fcla/etd/WFE0000048.
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Trahan, Brittany A. "Evaluation of the Effects of an Elastic Hamstring Assistance Device During Downhill Running." Thesis, University of Louisiana at Lafayette, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1594368.
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<p>Trahan, Brittany A. Bachelor of Science, University of Louisiana at Lafayette, Spring 2011; Master of Science, University of Louisiana at Lafayette, Spring 2015
Major: Kinesiology
Title of Thesis: Evaluation of the Effects of an Elastic Hamstring Assistance Device During Downhill Running
Thesis Director: Dr. Randy Aldret
Pages in Thesis: 72; Words in Abstract: 207
ABSTRACT
This investigation determined the benefits of the Hamstrong device after downhill running. Sixteen healthy college-aged males volunteered to participate in the repeated measures experimental study. They were assigned to either run with or without the device. They ran for forty minutes at 75% of their calculated VO2 Max speed. The effects of the device or absence of the device were examined as well as the PROM and isometric hamstring strength. The subjects had to repeat the protocol (minus the running) at three different time periods following the exercise. Repeated measures ANOVA did not reveal a significant (F=0.119, p=0.705) effect for the left leg PROM, nor a significant (F=0.016, p=0.977) effect for the right leg PROM. Repeated measures ANOVA did not reveal a significant effect (F=0.578, p=0.128) for the right leg at 90 degrees of extension during isometric strength testing, but there was a significant effect (F=1.027, p=0.032) for the left leg at the same angle. Repeated measures ANOVA did not reveal a significant effect (F=0.797, p=0.063) for the right leg at 135 degrees of extension during isometric strength testing, nor a significant effect (F=0.227, p=0.467) for the left leg at the same angle. There were no other changes regarding the effects of the device regarding myoglobin concentration.
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Patton, Renita L. "Isokinetic strength status post anterior cruciate ligament reconstruction hamstring vs. patellar tendon autograft." Online version, 2000. http://www.uwstout.edu/lib/thesis/2002/2002pattonr.pdf.
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Smink, Kyle Andrew. "The effects of hamstring delayed onset muscle soreness on functional knee joint stability." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001500.
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Buhmann, Robert Lee. "Potential mechanisms contributing to deficiencies in voluntary activation associated with hamstring strain injury." Thesis, Queensland University of Technology, 2020. https://eprints.qut.edu.au/180911/2/Robert_Buhmann_Thesis.pdf.
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Recent evidence suggests an inability of those with a prior hamstring strain injury to fully voluntarily activate the previously injured muscle. This may limit gains in strength and muscle fibre length during rehabilitation, both of which are linked to increased risk of injury. Understanding the mechanisms contributing to voluntary activation deficits may assist in developing effective rehabilitation strategies and consequently limiting re-injury risk. The aim of this body of work was to determine the site(s) of failure within the nervous system underpinning lower levels of voluntary activation in participants with prior hamstring injury.
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Baker, Alice Ann. "The Relative Contribution of Flexibility of the Back and Hamstring Muscles in the Performance of the Sit and Reach Component of the AAHPERD Health Related Fitness Test in Girls Thirteen to Fifteen Years of Age." Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc500769/.
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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.
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Langford, Nancy Jane. "The Relationship of the Sit and Reach Test to Criterion Measures of Hamstring and Back Flexibility in Adult Males and Females." Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc501137/.
Full textAbstract:
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.
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Timmins, Ryan Gregory. "Biceps femoris long head architecture: The association with hamstring injury and response to training." Thesis, Australian Catholic University, 2015. https://acuresearchbank.acu.edu.au/download/0354c5ac484886ca04a2c10c72ff04ff65995e14d4598cb8d8c0eb7360de939b/2922267/201509_Ryan_Timmins.pdf.
Full textAbstract:
Hamstring strain injuries (HSIs) are the most common injury in many running based sports, and following the initial insult the risk of recurrence remains high. In order to reduce the risk of a hamstring strain re-injury, developing a greater understanding of the maladaptations associated with a previous insult is important. Despite continual research over the past decade, recurrence rates have not declined suggesting the aetiology of re-injury is still not well understood. Whilst non-modifiable risk factors (e.g. increasing age and previous injury history) have been implicated in the incidence of first time and recurrent injuries, there are still a number of modifiable risk factors that are yet to be examined in detail in the scientific literature. One such factor hypothesized to influence the risk of HSI is the architectural characteristics of the biceps femoris long head (BFlh). The primary aim of this thesis was to explore the association between BFlh architecture and the aetiology of HSI and re-injury. If BFlh architecture was found to be associated with the occurrence and recurrence of HSI, the secondary aim of this thesis was to then determine the malleability of these architectural characteristics in response to a resistance training intervention.
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Spengler, Christoph. "Intraoperative RHCL (Reflex Hamstring Contraction Latency) Bestimmung unter direkter mechanischer Reizung des vorderen Kreuzbandes." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-60862.
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