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1
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.
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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.
2
Troumbley, Patrick. "Static Versus Dynamic Stretching Effect on Agility Performance." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/695.
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The purpose of this study was to compare effects of static and dynamic stretching on explosive agility movements, and to examine the effect of the interaction of dynamic and static stretching prior to explosive agility movements. Fourteen men and 10 women performed the different warm-up protocols, including no warm-up (NWU), static stretching (SS), dynamic stretching (DS), and dynamic stretching with static stretching (DS+SS). The T-Drill was used to assess agility. The results indicated no difference between the NWU and SS conditions (effect size = 0.40, p = 0.06), as well as no significant difference between the NWU and DS+SS conditions (effect size = 0.01, p = 0.48), and the SS and DS+SS conditions (effect size = 0.40, p = 0.06). Statistically significant differences were found between the NWU and DS conditions (effect size = 0.45, p = 0.03), the SS and DS conditions (effect size = 0.85, p < 0.001), and the DS and DS+SS conditions (effect size = 0.40, p = 0.03). Agility test times, in order from fastest to slowest, were (a) dynamic stretching (10.87 ± 1.07 s), (b) dynamic stretching + static stretching (11.41 ± 1.26 s), (c) no warm-up (11.42 ± 1.21 s), (d) static stretching (11.90 ±1.35 s). Dynamic stretching resulted in the fastest agility test time. Static stretching resulted in the slowest agility times. The benefits of dynamic stretching may have been diluted when followed by Static Stretching, and the agility test time was the same as if no form of stretching was completed. Static stretching prior to agility is not recommended as it has a negative effect on the stretch shortening cycle, and agility. The results support the use of dynamic stretching prior to agility performance.
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Harper, Erin N. "THE EFFECTS OF STATIC AND DYNAMIC STRETCHING ON COMPETITIVE GYMNASTS’ SPLIT JUMP PERFORMANCE." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1312391877.
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Kruse, Nicholas T. "The Acute Effects of Various Stretching Modalities on Performance across a Time Spectrum in NCAA Division I Volleyball Players." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1289846773.
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Herman, Sonja L. "The influence of dynamic-stretching warm up on performance measures in collegiate wrestlers." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1317343961&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.
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Narducci, Elizabeth A. "The Effects of Static Versus Dynamic Stretching on Fall Risk, Balance and Muscle Function in Older Adults: Is Stretching a Beneficial Intervention?" Kent State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=kent1508428967846228.
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Rucker, Timothy A. "Dynamic Warm-Up Improves Mean Power Output Compared to a Warm-Up With Static Stretching." Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1320856261.
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Pamboris, George Michael. "An investigation into the mechanisms of acute effects of dynamic stretching on ankle joint mechanics and running economy." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/16256.
Full textAbstract:
Warm-up routines commonly include stretching to increase flexibility (joint range of motion - ROM), optimise performance, and reduce the risk of injury. Literature suggests that static stretching as part of the warm-up routines decreases force and power production compared to an active warm-up or a warm-up including dynamic stretching, and therefore could be detrimental to performance. This has led to an increased interest in the use of dynamic stretching by many athletes while the benefits of such interventions and their potential mechanisms of action are not well understood. Studies presented in this thesis were conducted to examine the effects of acute dynamic stretching on aspects of performance (e.g. torque production capacity of the plantarflexors and running economy) and to identify possible neuromechanical mechanisms underpinning any potential changes. Furthermore, we attempted to examine whether altered pain tolerance/perception to stretch may be a contributing factor to the increased ROM using adaptations in the neural substrates involved by using functional magnetic resonance imaging (fMRI) technique. In the first study, both slow dynamic stretching and fast dynamic stretching increased ROM, and this was due to an increased tendon elongation. Importantly, dynamic stretching was not detrimental to the torque producing capacity of the ankle plantarflexors. Effects of dynamic stretching on the sensorimotor performance remained mainly unclear. Employment of shear wave elastography technique in the second study suggested an increase in muscle stiffness, a decrease in fascicle strain, and showed an increase in muscle thickness after dynamic stretching, supporting an increase in tendon compliance as a contributing factor to increased flexibility after dynamic stretching. In the third study, the improved running economy by dynamic stretching may be attributable to the decreased dynamic joint ankle and vertical stiffness. The fMRI study was not conclusive due to methodological issues. Present findings have practical implications for the use of dynamic stretching in sporting contexts.
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Poulos, Nicholas. "The influence of complex training design on post-activation performance enhancement of explosive performance in team sport athletes." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2022. https://ro.ecu.edu.au/theses/2531.
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Post-activation performance enhancement (PAPE) is a phenomenon characterised by the acute enhancement of muscular performance consequent to prior voluntary, dynamic contractile activity, and is the premise underpinning complex training (CT). CT involves alternating a conditioning stimulus (CS) with a lighter load biomechanically similar ballistic exercise (complex-pair), separated by a defined intra-complex recovery interval. One of the key benefits of CT is the ability to train both extremes of the forcevelocity curve within a single training session, offering a potentially efficient and effective means of augmenting both acute explosive muscular performance and chronic training adaptations in maximal strength and power. The challenge for sports practitioners is to design CT protocols that facilitate PAPE of muscular power characteristics of the individual athlete within the constraints of a team sport environment. Consideration of the factors that modulate the expression of PAPE in the design of CT protocols is essential. Specifically, consideration of the mode, volume, and intensity of the CS, the intra-complex and inter-set recovery, and the influence of athlete strength characteristics is required. More importantly, the influence of performing multiple complex-sets, the effect of sequencing lower and upper body complex-sets, and the impact of performing ancillary exercise within the intra-complex recovery on the expression of PAPE warrants attention.
Purpose: The primary purpose of this series of studies was to investigate the influence of CT protocol design and the factors that modulate the expression of PAPE of acute explosive performance in developing and trained team sport athletes. Outcomes arising from this work are aimed at providing a practical framework for sports practitioners to better inform the design and implementation of CT protocols in high-performance strength and conditioning programs.
Methodology: The first study examined the effect of CS intensity on the magnitude of PAPE of countermovement jump (CMJ) performance over multiple complex-sets and further investigated if athlete relative strength level is a criterion for identifying responders to PAPE. The second experimental study addressed the parameters of CS mode and intensity in CT session design, examining the efficacy of varying load jump squats (JS) on acute drop jump (DJ) performance. Lastly, the third experimental study investigated the effect of CT session design on PAPE of loaded JS and ballistic bench throws (BBT)—more specifically, if manipulating the sequence of upper and lower body complex-sets and interspersing ancillary exercise within the intra-complex recovery period modified the expression of any PAPE.
Results: CMJ peak jump height was enhanced in response to both moderate intensity (65% 1-RM) and high intensity (87% 1-RM) conditioning stimuli. PAPE of several DJ kinetic and kinematic variables following JS performed at both 30% and 50% 1-RM back squat loads was observed, however, the frequency and magnitude of PAPE was greatest in athletes following the 30% 1-RM CS load. Small magnitudes of PAPE were observed in various JS and BBT kinetic and kinematic variables in each of the three CT protocols examined, yet no clear or consistent performance benefit was present across sets. Associations between relative strength and PAPE are dependent on CS intensity and CT protocol design.
Conclusions: The most important finding of this thesis is that the sequencing of multiple lower and upper body complex-sets and the performance of ancillary exercise within the intra-complex recovery are not detrimental to subsequent explosive performance. Furthermore, PAPE of JS and DJ performance is achievable with a range of CS intensities and appears to be dominant in variables with a prevalent eccentric component. Finally, the influence of relative strength on the expression of PAPE is dependent on CT session design. The application of CT has merit in training team sport athletes and affords practitioners the ability to provide both heavy-resistance and ballistic training stimuli in a time efficient manner.
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Senn, Daniel LeRoy. "Short-term Training Effects of Dynamic Warm Up Volume on Speed, Power, and Agility." Thesis, North Dakota State University, 2011. https://hdl.handle.net/10365/29320.
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This study examined the short-term training effects of two volumes of a dynamic warm up
performed 4 days per week over a 3 1/2-week period. A total of 25 Division III wrestlers
volunteered for the study. Three participants either dropped out or were unable to attend
post-testing, resulting in 22 total participants completing the study. Groups were divided
into control, low volume, and high volume groups. All participants completed pre and poststudy
performance tests including the standing long jump, proagility, start-stop-cut, and 30-
meter sprint. The low and high volume training groups each performed the same dynamic
warm up prior to each pre-season captain's practice. The control group did not participate
in an organized warm up. The low volume group performed one set of each warm up
exercise, and the high volume group performing two sets of each warm up exercise. Data
analysis indicated significant increases in performance for the standing long jump (p =
.011) and start-stop-cut (p = .000) measures among the entire sample population. However,
there was no significant difference between the groups in these measures. No significant
results were found either for the sample as a whole or between groups for the proagility and
30-meter measures. The increased performance of all groups, including the control group,
fails to provide evidence for the effectiveness of training with either warm up volume.
Further research is needed to address limitations of this study to determine effectiveness of
various warm up volumes.
11
Napoli, Ryan David. "The Effects of Two Types of Different Dynamic Warm-Ups and Static Stretching on Total Body Power and Speed." Thesis, North Dakota State University, 2016. https://hdl.handle.net/10365/28039.
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Static stretching has often been found to decrease performance in power and speed activities, but dynamic warm-ups usually increase performance. We examined the effects of a mini-band warm-up, a medicine ball warm-up, and static stretching on 10m and 20m sprint times, as well as overhead medicine ball throw performance. A convenience sample of 24 Division I women?s soccer players participated, however 5 subjects dropped out due to sustaining injuries from a weekend soccer tournament. The subjects completed the three warm-ups and a control 5 minute jog condition on separate days and were tested on the 10m and 20m sprint times and overhead medicine ball throw. ANOVA?s and follow-up paired t-tests (p<0.05) were used to determine differences between the warm-ups. Significant differences were found between groups for the 10m sprint times but not for the 20m sprint times or the overhead medicine ball throw.
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Langerak, Jefta, and Morgan Poopuu. "Effekter av statisk och dynamisk stretching på sprintlöpning: : En experimentell studie av prestationen på 200 meter efter två olika uppvärmningsprotokoll." Thesis, Umeå universitet, Avdelningen för fysioterapi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-178431.
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Stretching som uppvärmningsrutin inför idrottsaktiviteter anses ha både skadeförebyggande och prestationshöjande effekter. Studier antyder att statisk stretching kan ha negativ inverkan på prestationen, särskilt explosiva aktiviteter som hopp och sprintlöpning. Syftet med studien var att undersöka effekten av statisk stretching (SS) respektive dynamisk (DR) rörlighets-uppvärmningsprotokoll på prestationen vid sprintlöpning över 200 meter samt inverkan av muskellängd/rörelseomfång på eventuella effekter. Elva träningsvana löpare, 20-35 år, sju män och fyra kvinnor genomförde vid två tillfällen maximal 200-meterslöpning. Löpningarna föregicks vid ena tillfället av SS och det andra av DR i en randomiserad ordning. Tiden mättes med ett portabelt fotocellsystem. Deltagarna utgjorde sina egna kontroller och skillnaden i löptid mellan SS och DR analyserades parvis (Wilcoxon signed rank test). Korrelation mellan löptid och deltagarnas ROM i nedre extremiteten, mätt med goniometer analyserades (Kendall’s Tau B). Tendens till snabbare löptider visades efter DR (1,01%, p=0,077) jämfört med SS. Skillnader, dock ej signifikanta var störst första 100 meter (2,78%) och omvänt avslutande 100 meter(-0,40%). Ett samband antyddes mellan hur snabba löparna var och effekten av SS-DR (Tau B=0,382), där resultaten för männen, som generellt var snabbare visade signifikant samband (Tau B=0,905, p=0,003). Inga samband återfanns mellan ROM/muskellängd och prestation. Signifikant samband sågs dock mellan duration vid stretching och löptid (Tau B=0,48-0,56, p=0,021-0,042). Studien fann i linje med tidigare forskning tendenser till snabbare löptider vid DR jämfört med SS. Eventuella effekter av stretching kan vara små men av betydelse för snabba löpare på distanser upp till 200 meter. Fortsatt forskning på området bör inkludera homogena grupper där slumpmässiga effekter på prestationen minimeras. Utifrån resultaten föreslås att DR inkluderas i uppvärmningen framför SS.
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Rebelo, Vera Sofia Félix. "Efeito imediato do alongamento estático vs alongamento dinâmico na flexibilidade dos músculos isquiotibiais no sexo feminino." Bachelor's thesis, [s.n.], 2019. http://hdl.handle.net/10284/7661.
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Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciada em FisioterapiaIntrodução: A flexibilidade de um músculo consiste na capacidade que este tem de se alongar, permitindo que uma ou mais articulações se movimentem na sua amplitude de movimento. Objetivo: Analisar o efeito de duas técnicas de alongamento distintas (alongamento estático e alongamento dinâmico) na flexibilidade imediata dos isquiotibiais no sexo feminino. Metodologia: Participaram no estudo 63 alunas de Fisioterapia da Universidade Fernando Pessoa, distribuídas de forma aleatória por três grupos: controlo, alongamento estático e alongamento dinâmico. A amplitude de movimento foi avaliada antes e depois da aplicação da técnica através de um goniómetro e do banco de Wells. Foi apenas realizada uma única sessão, sendo o alongamento estático realizado passivamente apenas durante 30 segundos em cada perna e o alongamento dinâmico, 1 série de 3 repetições. Resultados: Verificou-se que apenas houve diferenças significativas entre os momentos iniciais e finais nos dois grupos de alongamento e no momento final entre o grupo de controlo e os dois grupos de alongamento. No entanto, em nenhum momento se verificou diferença significativa entre o alongamento estático e o dinâmico. Conclusão: Concluímos que apesar de não haver diferenças significativas entre os dois tipos de alongamento, ambos foram eficazes no alongamento imediato dos isquiotibiais, no sexo feminino.
Introduction: The flexibility of a muscle consists of its ability to stretch, allowing one or more joints to move in their range of motion. Objective: To analyze the effect of two distinct stretching techniques (static stretching and dynamic stretching) on the immediate flexibility of the hamstrings in women. Methodology: Sixty-three students from Physiotherapy of Fernando Pessoa University, were randomly assigned into three groups: control, static stretching and dynamic stretching. They were evaluated before and after the application of the technique through a goniometer and the Wells bank. Only one session was held, where the static stretching was passively held through 30s in each leg and the dynamic, 1 serie of 3 repetitions. Results: It was found that there were only significant differences between the initial and final moments in both stretching groups and in the final moment, between the control group and both stretching groups. However, there was no significant difference between static and dynamic stretching in any moment. Conclusion: We conclude that although there were no significant differences between the two types of stretching, both were effective in the immediate stretching of the hamstrings in women.
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Opplert, Jules-Antoine. "Effets aigus des étirements statiques et dynamiques sur le système neuromusculaire." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCK036/document.
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Dans un contexte de performance sportive, de réhabilitation ou de santé, les étirements sont couramment utilisés dans le but de préparer le système neuromusculaire à l’exercice subséquent. Si la littérature montre majoritairement que les étirements altèrent de façon aigue la performance musculaire et/ou fonctionnelle, il existe toutefois des études dont les résultats diffèrent, suggérant l’influence d’un certain nombre de facteurs sur la variabilité des réponses du système neuromusculaire. Pour une meilleure compréhension de cette variabilité et des mécanismes impliqués, cette thèse avait pour objectif d’examiner l’influence de différents paramètres sur le système neuromusculaire : la durée d’étirement, le groupe musculaire et la modalité d’étirement. Au travers de quatre études, il a été montré que les étirements statiques pouvaient altérer la production de force maximale et les propriétés neuromusculaires indépendamment de la durée d’étirement. Cependant, il est apparu que ces modulations étaient spécifiques au muscle, et plus précisément à la raideur relative du système musculo-tendineux. Indépendamment de la durée d’étirement, les étirements statiques ne seraient pas efficaces pour préparer le système neuromusculaire à une activité musculaire subséquente, et notamment pour des muscles raides. Plus particulièrement, les étirements dynamiques ne paraissent pas plus efficaces. Même si les effets néfastes ont été diminués comparativement aux étirements statiques, ils ne favoriseraient pas davantage la production de force ni la commande nerveuse. Toutefois, il est intéressant de noter qu’une durée courte d’étirements dynamiques peut réduire la résistance passive à l’étirement, et donc augmenter potentiellement l’amplitude articulaire maximale, sans affecter les capacités de production de force. Finalement, les étirements dynamiques pourraient être envisagés comme une activité musculaire dynamique, qui compense partiellement les effets néfastes de l’étirement sur la performance musculaire. D’un point de vue pratique, ceci suggère que ce type d’étirements peut être réalisé avant une performance, mais néanmoins accompagnés d’une activité musculaire de plus haute intensité, afin d’optimiser les effets de l’échauffement musculaire sur le système neuromusculaire. En définitive, la variabilité des réponses du système neuromusculaire serait dépendante de facteurs spécifiques, tels que la modalité d’étirement et la raideur relative du système musculo-tendineux, soulignant l’importance de les prendre en considération dans la pratiqueStretching is traditionally incorporated into pre-exercise routines in health, rehabilitation and sporting environments to condition the neuromuscular system for exercise. While a large body of evidence reported that stretching may acutely impair the subsequent muscular performance, some conflicting results highlight possible mitigating factors of neuromuscular responses variability. Because the limited data available do not present a clear consensus, the aim of this thesis was to investigate the effects of different factors on neuromuscular responses to stretch: the muscle group, the stretch duration and modality. By means of four studies, it has been shown that static stretching may alter maximal voluntary torque and neuromuscular properties, irrespective of the stretch duration. However, these modulations were dependent on the muscle group, and more specifically on the intrinsic stiffness of the muscle-tendon system. Regardless of the stretch duration, static stretching appears to be not effective, or even detrimental, to prepare the musculotendinous system for subsequent exercises, and especially for stiff muscles. It is also relevant that dynamic stretching was not better than static stretching. Even if stretch-induced impairments were mitigated compared to static stretching, dynamic stretching would not optimize muscle strength capacities and central nervous system. However, a short duration of dynamic stretching may be sufficient to reduce passive resistive torque, and therefore potentially increase maximal range of motion, without affecting muscle strength capacities. Finally, dynamic stretching could be considered as dynamic muscle activity, which would partly counteract deleterious muscle-tendon stretching effects. From a practical point of view, dynamic stretching could be a part of warm-up procedure, but should be associated to stronger contractions to optimize the improvement in muscle strength capacities. In summary, the variability of neuromuscular responses to stretch would be dependent on specific factors, such as stretching modality and relative stiffness of the musculotendinous system, emphasizing the importance of taking it into consideration in practice
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Alitta, Robin. "Efeitos imediatos da vacuoterapia dinâmica na flexibilidade dos isquiotibiais." Bachelor's thesis, [s.n.], 2018. http://hdl.handle.net/10284/6743.
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Projeto de Graduação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciado em FisioterapiaObjetivo: verificar os efeitos imediatos da vacuoterapia dinamica na flexibilidade dos isquiotibiais em indivíduos saudáveis, associados a um protocolo de alongamento. Métodos: a investigação começou com a avaliação inicial (A0), onde foi aplicado o teste Senta e Alcança aos dois grupos: grupo com vacuoterapia (GCV) (n=27) e grupo sem vacuoterapia (GSV) (n=25). De seguida, ambos os grupos receberam o mesmo protocolo de alongamento dos isquiotibiais, sendo que, posteriormente, no GCV foi aplicada a vacuoterapia dinâmica e no GSV os participantes descansaram durante 6 minutos. Os dois grupos realizaram de novo a mesma avaliação 5 minutos depois (A1). A análise estatística foi realizada recorrendo ao software SPSS v.24 para efetuar os testes Shapiro-Wilk, χ2 (Quiquadrado) e teste t Student emparelhado ou independente. Resultados: o alongamento estático Strait Leg Raise (SLR) produziu aumento significativo e imediato na flexibilidade dos isquiotibiais, que é potenciado e significativamente superior (p<0,0001), após a aplicação de vacuoterapia dinâmica, como se verificou na diferença entre grupos. Conclusão: Os resultados deste estudo sugerem que a vacuoterapia dinâmica, juntamente com alongamento estático SLR, apresenta um aumento significativo da flexibilidade dos isquiotibiais comparando com o alongamento estático SLR.
Objective: to verify the immediate effects of dynamic cupping therapy on hamstring flexibility in healthy individuals, associated to a stretching protocol. Methods: The investigation started with the initial evaluation (A0), where the Sit and Reach test was applied to the two groups: group with cupping therapy (GCV) (n = 27) and group without cupping therapy (GSV) (n = 25). Then, both groups received the same hamstring stretching protocol, after which in the GCV the dynamic cupping therapy was applied and in the GSV the participants rested for 6 minutes. The two groups again performed the same evaluation 5 minutes later (A1). Statistical analysis was performed using the SPSS v.24 software to perform the Shapiro-Wilk test, χ2 (Chi-square) test and paired or independent Student t tests. Results: Static Strait Leg Raise (SLR) stretching produced a significant and immediate increase in the flexibility of the hamstrings, which is boosted and significantly higher (p<0,0001) after the application of dynamic vacuotherapy, as verified in the difference between groups. Conclusion: The results of this study suggest that dynamic vacuotherapy, coupled with static stretching SLR, presents a significant increase in hamstring flexibility compared to static SLR stretching.
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Neves, Guilherme João Albernaz. "Efeitos agudos do alongamento no músculo e na performance muscular: revisão bibliográfica." Bachelor's thesis, [s.n.], 2012. http://hdl.handle.net/10284/3477.
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Trabalho apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Licenciado em FisioterapiaObjectivo: O objectivo deste projecto foi o de reunir artigos que estudassem os efeitos agudos do alongamento na performance e força máxima, permitindo assim, uma revisão bibliográfica. Metodologia: Foi feita uma pesquisa em bases de dados com a MEDLINE/Pubmed research, b-on, e PEDro, para artigos do ano de 2000 até à actualidade, na língua inglesa. Os artigos tinham que ser todos experimentais, e tinham que respeitar os termos usados na pesquisa. Foram excluídos os artigos que fugissem minimamente ao tema. Também o uso dos nomes de autores foi usado, como forma de pesquisa, para poder ter mais estudos sobre este tema. Resultados: Todos os artigos selecionados tiveram resultados idênticos, com provas de que um alongamento estático e por técnica de facilitação neuromuscular proprioceptiva (PNF) diminuíam a performance muscular e também a força máxima. Já um alongamento dinâmico tinha como efeito um aumento da força e da performance muscular. Conclusões: Idealmente, deverão ser usados como forma de aquecimento para actividade fisica, os alongamentos dinâmicos, e evitar usar alongamentos estáticos(protocolos prolongados) ou por PNF. Objective: The objective of this study was to gather articles that would study the effects of stretching in muscle performance and in maximal voluntary force. Methods: A search in databases like MEDLINE/Pubmed research, b-on, and PEDro were made, for articles from the year 2000 to the present day, in the English language. The articles had to be experimental and all had to respect the terms used in the research. All who did not respect the study’s topic were excluded. Further on the research, names of authers were used, in order to bet access to more articles of the same subject. Results: All articles had identical results, proving that static ou PNF stretching could diminish performance and maximal voluntary force. As for dynamic stretch, improvements in performance and force are achieved. Conclution: Idealy, dynamic stretchs should be used as a warm up for physical activities, avoiding the use of static or PNF stretching.
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Smart, Thomas James. "A study of dynamics in microscopic systems using optical tweezers : dynamical stabilisation, cell stretching and thermal fluctuations." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10048277/.
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This thesis presents an investigation into the dynamics of three distinct microscopic systems: dynamical stabilisation in a finitely-rigid over-damped microscopic pendulum; deformability in red blood cells; and thermodynamic fluctuations in a system of hydrodynamically coupled colloidal particles. Each system is studied using optical tweezers. Part I provides an introduction to the development and operation of optical tweezers and gives an overview of the particle dynamics concepts that are built upon later in the thesis. Part II contains the work on dynamical stabilisation. The starting point for this work is the well-known Kapitza pendulum: a rigid pendulum whose suspension point is oscillated in such a way that the pendulum becomes stable in the upright position. Here I consider a pendulum that is finitely rigidity (i.e. a pendulum that is not mathematically infinitely rigid) and subjected to heavy damping. I present a model based on a scanning time-averaged ring-shaped optical trap in which a colloidal particle is trapped. The pendulum is localised by viscous fluid flow and oscillated by modulation of the ring-centre. A mathematical treatment of the model reveals a regime in which the pendulum explores different stability positions based on the modulation amplitude and frequency. These predictions are tested in simulations and experiments. In part III optical tweezers are used to stretch red blood cells (RBCs) in order to measure their deformability. The measured deformability of RBCs from patients suffering from diabetic retinopathy is measured and compared to the deformability of RBCs from healthy patients to investigate a link between DR and reduced RBC deformability. Finally, in part IV an investigation into the fluctuations of work applied to a hydrodynamically coupled system is presented. In a thermodynamically noisy system, the heat and work do not have exact values. Rather, they are represented by a probability distribution. Here, I present simulations and experiments that aim to measure the work distribution in a system consisting of two colloidal particles that are coupled by their aqueous environment.
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Khaksar, Maryam [Verfasser]. "DNA under Hydrodynamic and Mechanical Stretching : Structure and Dynamics / Maryam Khaksar." Konstanz : Bibliothek der Universität Konstanz, 2011. http://d-nb.info/1017360510/34.
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Allirol-Molin, Céline. "Vilken av stretchingmetoderna statisk stretching, dynamisk stretching och proprioceptiv neuromuskulär facilitering är mest effektiv för att öka rörligheten i hamstrings?- en litteraturstudie." Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-23440.
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Sammanfattning Bakgrund: Stretching har använts i många år inom sport och rehabilitering med målet att minska risken för muskelskador, bland annat skador i kombination med kort hamstrings. Flera olika stretchingmetoder används för att uppnå ökad rörlighet. Tre av dessa är; 1) Statisk stretching, 2) Dynamisk stretching, 3) Proprioceptiv neuromuskulär facilitering (PNF). Syfte: Syftet med den här litteraturstudien var att jämföra och undersöka tre olika stretchingmetoder (statisk, dynamisk och PNF stretching) för att se vilken som är mest effektiv för att öka rörligheten i hamstringsmuskulaturen. Metod: Sökning av artiklar gjordes i databaserna Pubmed, Sport Discus, samt Science Direct. Sökorden som användes var static stretching, dynamic stretching, pnf, flexibility samt range of motion. Totalt inkluderades till slut 26 artiklar i den här litteraturöversikten som dels överensstämde med inklusionskriterierna och som dessutom var tillgängliga gratis och i fulltext. Resultat: De flesta studierna var gjorda på unga vuxna mellan 16 och 35 år. Alla studier utom två visade på en statistisk signifikant ökning av rörligheten i hamstrings. Ferber et al. som studerade olika PNF-tekniker, uppvisade bäst resultat med en ökad hamstring rörlighet på 15,66 ± 0,95°. Den PNF-teknik som gav detta resultat var PNF- Agonist Contract-Relax. Slutsats: Baserat på de resultat som gavs i studierna verkar statisk stretching och PNF fungera lika bra, men, studierna som gjorts på PNF är för få för att verkligen kunna fastställa att denna teknik är lika bra som statisk stretching. Mycket få studier har gjorts på dynamisk stretching (färre än PNF) vilket innebär att det är svårt att bedöma exakt vilken effekt dynamisk stretching har på hamstrings rörlighet.
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Richards, C. J. "Probing micro-dynamics with optical tweezers : pendula, cell-stretching, and thermodynamic fluctuations." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10043665/.
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Optical tweezers are a powerful experimental tool, commonly utilised in microscopic experiments in a diverse cross-section of scientific fields, from biophysics to hydrodynamics of small systems, by enabling the exertion and measurement of forces that act in microscopic soft-matter systems. This thesis documents three experiments that probe the micro-dynamics of such systems. First the theory of the mechanical phenomenon of the Kapitza pendulum is described: the unusual behaviour of the equilibrium of a pendulum whose point of suspension undergoes high frequency vertical oscillations. To go beyond this case, a Kapitza pendulum in the presence of significant damping is considered. Theoretical calculations are presented, revealing new regimes and positions of dynamic equilibrium. These are supported by Brownian motion simulations. A microscopic optical analogue of the damped Kapitza pendulum is realised using optical tweezers and the results of the theory and simulations are confirmed experimentally. Next, the condition of diabetic retinopathy within sufferers of diabetes mellitus is discussed with reference to the deformability of red blood cells. A pilot study is conducted to assess the viability of investigating this correlation using optical tweezers with a healthy control group, a diabetic group, and a diabetic group with retinopathy. A dual optical tweezers set-up is utilised to stretch the cells and calculate the extent of their deformability. The deformability of red blood cells from the diabetic groups is found to be significantly lower than that of the healthy control group. Finally fluctuation theorems are considered: the asymmetry of the distributions of probabilities of observing forward and backward trajectories of micro-particles, and how this changes with the duration of the trajectories. Theoretical calculations are presented to find the fluctuation theorems for two methods of performing work on two hydrodynamically coupled particles. Simulations and trial experimental studies are performed to attempt to verify these calculations.
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Heine, Thomas, Daniel Hutzler, Christian Brunner, Petko St Petkov, Sighart F. Fischer, Eberhard Riedle, Reinhard Kienberger, and Hristo Iglev. "Dynamics of the OH stretching mode in crystalline Ba(ClO 4)2 ·3H2O." AIP Publishing, 2018. https://ul.qucosa.de/id/qucosa%3A21498.
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The vibrational dynamics of theOH stretching mode in Ba(ClO4)2 trihydrate are investigated by means of femtosecond infrared spectroscopy. The sample offers plane cyclic water trimers in the solid phase that feature virtually no hydrogen bond interaction between thewater molecules. Selective excitation of the symmetric and asymmetric stretching leads to fast population redistribution, while simultaneous excitation yields quantum beats, which are monitored via a combination tone that dominates the overtone spectrum. The combination of steady-state and time-resolved spectroscopy with quantum chemical simulations and general theoretical considerations gives indication of various aspects of symmetry breakage. The system shows a joint population lifetime of 8 ps and a long-lived coherence between symmetric and asymmetric stretching, which decays with a time constant of 0.6 ps.
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Kruse, Nicholas T. "Blood Flow and Oxygenation Dynamics as a Result of Human Skeletal Muscle Stretching." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1430471839.
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Vuk, Stevanović. "Акутни ефекти различитих садржаја уводно-припремног дела тренинга на моторичке способности и неуромишићну адаптацију кошаркаша." Phd thesis, Univerzitet u Novom Sadu, Fakultet sporta i fizičkog vaspitanja u Novom Sadu, 2016. https://www.cris.uns.ac.rs/record.jsf?recordId=101038&source=NDLTD&language=en.
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Циљ рада: Циљ истраживања је да се утврди разлика у акутним ефектима статичког (СИ) и динамичког истезања (ДИ), у комбинацији са специфичним кошаркашким загревањем (СКЗ), на флексибилност, експлозивну снагу ногу, брзину, агилност и неуромишићну адаптацију кошаркаша јуниорског узраста.Методе: Истраживање у оквиру ове докторске тезе су чинила два одвојена експеримента, један спроведен у теренским условима, и други спроведен у лабораторијским. Оба су била „cross-over“ дизајна. У теренском експерименту је учествовало 46 кошаркаша (узраста 17±0,83 година), док је у лабораторијском учествовало 12 (узраста 17,7±0,49 година). У теренском експерименту су тестиране четири моторичке способности. За процену флексибилности коришћен је тест досезања у седећем претклону, експлозивна снага ногу је процењивана уз помоћ вертикалног скока са контактне плоче, брзина трчањем на 20 метара, док је Т тест коришћен за процену агилности. У лабораторијском експерименту је као мера неурофизиолошке адаптације коришћена промена ексцитабилности α-мотонеурона, која је представљена као однос Хофмановог (Х) рефлекса и М таласа (Х/М). За њихово одређивање се користио Medelec ST-10 стимулатор (Medelec, Old Woking, UK). Површинске електромиографске електроде су биле постављене на унутрашњој глави m.gastrocnemius-a одскочне ноге, применом тзв. „belly-tendon“ монтаже. Као третмани, у оба експеримента су коришћени протокол статичког и протокол динамичког истезања, уз комбинацију са специфичним кошаркашким загревањем. Мерења су се у оба експеримента изводила у 3 временске тачке и то пре протокола истезања, одмах након протокола истезања (а пре специфичног кошаркашког загревања) и одмах након специфичног кошаркашког загревања.Резултати: Резултати истраживања показују да постоје одређене разлике акутних ефеката комбинација протокола СИ+СКЗ и ДИ+СКЗ. Комбинација протокола СИ+СКЗ је повољније утицала на експлозивну снагу ногу и на агилност кошаркаша јуниорског узраста. Ефекти обе комбинације протокола су били готово идентични на флексибилност, а разлика је изостала и у ефектима на брзину, иако је пре СКЗ био уочљив негативан ефекат СИ. Однос Х/М се значајно разликовао одмах након истезања, када је СИ значајно оборило однос, али су се те разлике изгубиле након примене СКЗ.Закључак: Посматрајући ефекте комбинације протокола СИ+СКЗ и ДИ+СКЗ на моторичке способности и неуромишићну адаптацију кошаркаша јуниорског узраста, може се закључити да је примена СИ+СКЗ препоручљивија у свакодневном тренингу и такмичењу.Cilj rada: Cilj istraživanja je da se utvrdi razlika u akutnim efektima statičkog (SI) i dinamičkog istezanja (DI), u kombinaciji sa specifičnim košarkaškim zagrevanjem (SKZ), na fleksibilnost, eksplozivnu snagu nogu, brzinu, agilnost i neuromišićnu adaptaciju košarkaša juniorskog uzrasta.Metode: Istraživanje u okviru ove doktorske teze su činila dva odvojena eksperimenta, jedan sproveden u terenskim uslovima, i drugi sproveden u laboratorijskim. Oba su bila „cross-over“ dizajna. U terenskom eksperimentu je učestvovalo 46 košarkaša (uzrasta 17±0,83 godina), dok je u laboratorijskom učestvovalo 12 (uzrasta 17,7±0,49 godina). U terenskom eksperimentu su testirane četiri motoričke sposobnosti. Za procenu fleksibilnosti korišćen je test dosezanja u sedećem pretklonu, eksplozivna snaga nogu je procenjivana uz pomoć vertikalnog skoka sa kontaktne ploče, brzina trčanjem na 20 metara, dok je T test korišćen za procenu agilnosti. U laboratorijskom eksperimentu je kao mera neurofiziološke adaptacije korišćena promena ekscitabilnosti α-motoneurona, koja je predstavljena kao odnos Hofmanovog (H) refleksa i M talasa (H/M). Za njihovo određivanje se koristio Medelec ST-10 stimulator (Medelec, Old Woking, UK). Površinske elektromiografske elektrode su bile postavljene na unutrašnjoj glavi m.gastrocnemius-a odskočne noge, primenom tzv. „belly-tendon“ montaže. Kao tretmani, u oba eksperimenta su korišćeni protokol statičkog i protokol dinamičkog istezanja, uz kombinaciju sa specifičnim košarkaškim zagrevanjem. Merenja su se u oba eksperimenta izvodila u 3 vremenske tačke i to pre protokola istezanja, odmah nakon protokola istezanja (a pre specifičnog košarkaškog zagrevanja) i odmah nakon specifičnog košarkaškog zagrevanja.Rezultati: Rezultati istraživanja pokazuju da postoje određene razlike akutnih efekata kombinacija protokola SI+SKZ i DI+SKZ. Kombinacija protokola SI+SKZ je povoljnije uticala na eksplozivnu snagu nogu i na agilnost košarkaša juniorskog uzrasta. Efekti obe kombinacije protokola su bili gotovo identični na fleksibilnost, a razlika je izostala i u efektima na brzinu, iako je pre SKZ bio uočljiv negativan efekat SI. Odnos H/M se značajno razlikovao odmah nakon istezanja, kada je SI značajno oborilo odnos, ali su se te razlike izgubile nakon primene SKZ.Zaključak: Posmatrajući efekte kombinacije protokola SI+SKZ i DI+SKZ na motoričke sposobnosti i neuromišićnu adaptaciju košarkaša juniorskog uzrasta, može se zaključiti da je primena SI+SKZ preporučljivija u svakodnevnom treningu i takmičenju.
Objective: The aim of this study was to determine the difference of acute effects of static stretching (SS) and dynamic stretching (DS), in combination with specific basketball warm-up (SBWU), on flexibility, explosive leg strength, speed, agility and neuromuscular adaptation of basketball players U18.Methods: This study consisted of two separated experiments, first in field conditions, and second conducted in laboratory. Both had „cross-over“ design. Forty-six basketball players (age: 17±0,83 years) participated in field experiment, while twelve participated in laboratory experiment (age 17,7±0,49 years). In field experiment, four motor abilities were tested. Seat and rech test was used for the evaluation of flexibility, explosive leg strength was evaluated by vertical jump from contact plate, speed by 20m run, and T test was used for agility testing. In laboratory experiment, the excitability of α-motoneuron was taken for the evaluation of neuromuscular adaptation. It is presented as a ratio of the maximal amplitudes of Hoffman (H) reflex and M wave (H/M). For their determining we used Medelec ST-10 stimulator (Medelec, Old Woking, UK). Surface electromyographic (EMG) electrodes were placed over the m.gastrocnemius medialis, and Achilles tendon, in a „belly-tendon“ montage. In both experiments, SS protocol and DS protocol, in the combination with SBWU, were used as a treatment. Measures were taken in 3 time points: before the stretching, immediately after stretching (and before SBWU) and immediately after the SBWU.Results: Results of this study showed that there are certain differences in acute effects of combination of protocols SS+SBWU and DS+SBWU. Combination of protocols SS+SBWU had more positive influence on explosive leg strength and agility of U18 basketball players. The effects of both protocols were almost the same on flexibility, and there was no noticeable difference in effects on speed, although before SBWU there was significant negative of SS. Immediately after the stretching there was significant difference in H/M ratio, it was significantly lower after the SS, but after the application of SBWU, differences disappeared. Conlcusion: Regarding the effects of SS+SBWU and DS+SBWU protocols on motor abilities and neuromuscular adaptation of U18 basketball players, it could be concluded that the use of SS+SBWU is more preferrable in everyday practice and competition.
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Widlansky, Matthew J. "Climate dynamics of the South Pacific Convergence Zone and similarities with other subtropical convergence zones in the Southern Hemisphere." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37095.
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Three semi-permanent cloud bands exist in the Southern Hemisphere extending southeastward from the equator, through the tropics, and into the subtropics. The most prominent of these features occurs in the South Pacific and is referred to as the South Pacific Convergence Zone (SPCZ). Similar convergence zones, with less intensity, exist in the South Atlantic (SACZ) and Indian (SICZ) oceans. We attempt to explain the physical mechanisms that promote the diagonal orientation of the SPCZ and the processes that determine the timescales of its variability. It is argued that the slowly varying sea surface temperature patterns produce upper tropospheric wind fields that vary substantially in longitude. Regions where 200 hPa zonal winds decrease with longitude (i.e., negative zonal stretching deformation, or dU/dx<0) reduce the group speed of the eastward propagating synoptic (3-6 day period) Rossby waves and locally increase the wave energy density. Such a region of wave accumulation occurs in the vicinity of the SPCZ, thus providing a physical basis for the diagonal orientation and earlier observations that the zone acts as a "graveyard" of propagating synoptic disturbances. In essence, dU/dx=0 demarks the boundary of the graveyard while regions where dU/dx<0 denote the graveyard itself. Composites of the life cycles of synoptic waves confirm this hypothesis. From the graveyard hypothesis comes a more general theory accounting for the SPCZ's spatial orientation and its longer term variability influenced by the El Niño-Southern Oscillation (ENSO), or alternatively, the changing background SST associated with different phases of ENSO.
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Roché, Matthieu. "Rupture d'interfaces en présence d'agents de surface." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2008. http://tel.archives-ouvertes.fr/tel-00407180.
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Le détachement d'une goutte est un phénomène que nous observons quotidiennement. Il résulte de la rupture de l'interface entre le fluide dispersé en goutte et le fluide environnant. Cette rupture a fait l'objet de nombreuses études. Il est bien établi que sa dynamique est régie par une compétition entre la capillarité, l'inertie, et la viscosité du fluide. Ce manuscrit décrit l'influence sur la dynamique de rupture d'une modification des propriétés de l'interface entre deux fluides à l'aide d'agents de surface. Lorsque l'agent de surface est un surfactant (SDS), la dynamique d'amincissement peut se faire selon deux modes. Deux régimes linéaires en temps constituent le premier mode. Le second mode comporte trois régimes linéaires. Dans les deux cas, l'amincissement commence par un premier régime, suivi d'un deuxième régime de pente plus forte. Lorsque le troisième régime existe, sa pente est inférieure à celle du second régime. La variation des pentes des régimes linéaires témoigne du comportement dynamique du surfactant à l'interface. La valeur de la tension interfaciale extraite du premier régime linéaire correspond à la valeur à l'équilibre de la tension interfaciale du système, gamma_eq. La vitesse d'amincissement plus élevée au cours du second régime est reliée à une dépletion partielle en surfactant de la zone d'amincissement maximal. Le ralentissement constaté pendant le troisième régime est lié au déplacement de cette zone vers une région plus riche en surfactant, où la tension est plus faible. La dynamique d'amincissement du cou est très différente lorsque des polymères de poids moléculaire intermédiaire (env. 100 kDa) sont présents simultanément avec du SDS dans la phase continue. Lorsque [SDS] est supérieure à 0,15 fois la concentration micellaire critique (CMC), le comportement est identique à celui observé en présence de surfactant seul. En dessous de 0,15 CMC, l'amincissement ralentit exponentiellement à l'approche de la rupture, et un phénomène de beads-on-a-string apparaît. Ces constatations sont analogues à celles faites lorsqu'une solution de polymères est menée à la rupture. Dans notre cas, les polymères sont uniquement à la surface du jet et non dans son volume ! Une analyse des profils du cou au cours du temps démontre l'existence d'une auto-similarité à l'approche de la rupture. Bien que les systèmes étudiés soient plus complexes, ils présentent des caractéristiques qualitativement analogues à celles observées dans des systèmes de fluides simples. Toutefois, il existe une grande différence quantitative.
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Plan, Emmanuel Lance Christopher VI Medillo. "Retournement, flexion, étirement : particules dans les écoulements laminaires et chaotiques." Thesis, Université Côte d'Azur (ComUE), 2017. http://www.theses.fr/2017AZUR4032/document.
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Les particules soumises à un écoulement peuvent manifester des orientations préférées et une variété de déformations en fonction de leur géométrie et élasticité et du champ de vitesse de l'écoulement. A l’inverse, les flux peuvent être modifiés lorsque les contraintes des particules sont non négligeables. Cette thèse présente des résultats théoriques et numériques sur cette relation bilatérale en deux parties. La Ière partie commence par une analyse de stabilité et des simulations numériques qui montrent une particule brownienne semi-flexible dans un écoulement élongationnel effectuant un retournement, un phénomène associé aux flux de cisaillement. Le Chap. 2 étend les outils analytiques dédiés aux modèles simples ou aux flux indépendante du temps pour les modèles perle-barre-bond généraux dans les flux aléatoires. En partant des résultats des chapitres précédents, Le Chap. 3 aboutit à l'étude d'un degré de liberté lagrangien inexploré dans un écoulement turbulent : la flexion. Une particule semi-flexible courbe différemment dans les flux aléatoires bidimensionnels et tridimensionnels. La IIème partie concerne la turbulence élastique, un régime chaotique créé dans un écoulement de faibles forces inertielles par l'ajout de polymères élastiques. Le Chap. 4 estime le nombre de degrés de liberté d'une solution de ce régime via la dimension Lyapunov de l'attracteur du modèle Oldroyd-B bidimensionnel, un modèle connu de reproduire la turbulence élastique dans les simulations numériques. Le Chap. 5 pose des questions sur la nécessité d'élasticité pour produire un régime chaotique et conclut qu'une solution de polymère de barres peut créer un régime comparable à la turbulence élastiqueParticles, when subjected into a flow, may display preferred orientations and a variety of deformations depending on their geometry and elasticity and the flow velocity field. Flows can conversely be modified when the particle stresses are sufficiently large. This thesis presents theoretical and numerical results on this two-way relationship between particles and flows in two parts. Part I starts with a stability analysis and numerical simulations that show a simple semiflexible Brownian particle in an extensional flow undergo tumbling, a phenomenon normally associated to shear flows. Chapter 2 extends analytical tools available only for elementary polymer models or for steady flows to general bead-rod-spring models in random flows. By building on the results from the previous chapters, Chap. 3 culminates with the study of an unexplored Lagrangian degree of freedom in a turbulent flow: bending. A semiflexible particle is shown to display different bending behaviours in two- and three-dimensional random flows. This prediction is confirmed via direct numerical simulations of the particle in a turbulent flow. Part II concerns “elastic turbulence", a chaotic regime created in a flow with low inertial forces by the addition of elastic polymers. Chapter 4 provides an estimate for the number of degrees of freedom of a solution of this chaotic system via the Lyapunov dimension of the attractor of the two-dimensional Oldroyd-B model, a model known to reproduce elastic turbulence in numerical simulations. Chapter 5 questions the necessity of elasticity in producing a chaotic regime and concludes that a rodlike polymer solution can create a regime similar to elastic turbulence
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Chan, Chao-Chin, and 詹朝欽. "The investigation of dynamic spectrometry of polypropylene film by uniaxial stretching." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/76761849522554939652.
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碩士國立宜蘭大學
化學工程與材料工程學系碩士班
100
This study investigated the change in light transmittance of the polypropylene films during stretching by an optical fiber type spectrometer. The Semi-crystalline film of polypropylene might be generating microcrazes, voids, and whitening of orientated crystallites during stretching. The phenomena can be confirmed by the observation of the morphology through polarized optical microscopy (POM) and X-ray diffractometer (XRD). The thermal properties was determined by differential scanning calorimetry (DSC). The strain of the first appearance of whitening decreased as the stretching rate increased. In the stretching of PP film, microvoids were formed and this caused whitening. The results of POM and XRD could confirm the structure of microcrazes and voids were formed while films were stretched. The above results indicated that the on-line monitoring by the optical fiber type spectrometer can be used to observe the formation of microcrazes, voids, or whitening behavior during stretching.
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Šádek, Petr. "Vliv stretchingu na maximální svalový výkon." Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-339677.
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Title: The effect of stretching on maximal muscle performance Objectives: Due to the number of studies, concerning the effect of the muscle stretch on sport performance and their heterogeneity in the term of used parameters, tests and even performing the stretch exercises themselves, it would be desirable, thanks to the importance of this subject, to consolide and evaluate up-to-date knowledge. The goal of this diploma thesis is to compare and assess available literature concerning the effect of muscle stretch during warmup on the sport performance and, ideally, to define the best type of the stretching itself. Method: The diploma thesis is composed as a literature review - an integrative review with exactly defined criteria for the use of available studies. Result : Even with the nonuniformity of parameters used in available studies there is a consensus in most of the used sources, which met the criteria of inclusion in this research, which (the consensus) determinates the dynamic stretching as the form most appropriate for enhancing the following sport performance. Although studies, proving this result, are in their findings quite unanimous, a precise definition of prefered exercises for peforming the dynamic stretching and of its parameters is still missing. Key words: stretching, dynamic,...
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Dostálová, Anna. "Akutní vliv statického a dynamického strečinku na výskok." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-353298.
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Title Acute effect of static and dynamic stretching on vertical jump. Objectives The aim of this thesis is to assess whether it is better to warm up by static or dynamic stretching in order to improve performance in the vertical jump. Methods The first part of this thesis is theoretical and is the basis for measurement, which is described in the second part. The tested set consists of ten women volleyball players. Each player underwent three vertical jump measurements on power plates Kistler, which recorded flight time of the player over the plates. All measurements were evaluated afterwards. Five attempts were recorded in each measurement. Measurements were carried out without stretching, after dynamic stretching and after static stretching. The thesis includes a survey that monitors the perception of the players` performance. Results Results of the total tested set measurement show that inclusion of dynamic stretching during the warm up leads to a slight decline in the physical performance. This decrease presents about 0.92%. Another conclusion of this research is that the inclusion of static stretching to the warm up also results in a slight decrease in the athletic performance. In this case the decrease is about 1.72%. In a direct comparison of these two types of stretching, the inclusion of...
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Huang, Zih-Jian, and 黃子健. "Effects of different dynamic stretching exercises in flexibility test and muscle strength of hamstring." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/00034078516488497417.
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碩士臺北市立大學
運動健康科學系碩士班
103
Background: It is well known that stretching exercises could enhance body flexibility. Some researches indicate that stretching and strength training could improve joint mobility, flexibility, and muscle strength. Objective: To investigate two ways of dynamic stretching, active straight leg raise (ASLR) and modified toe-touch (MTT), and to compare how they influence the results of flexibility test, muscle function, and muscle strength differently. Methods: A group of 16 healthy male college students, pre-test and post-test their muscle stiffness, pain measurement, flexibility measurements of passive straight leg raise (PSLR) and active straight leg raise (ASLR ), and muscle strength (concentric and eccentric strength) with one dynamic stretching in between. Seven days later, another pre-test and post-test with the other dynamic stretching in between. Results: The result of ASLR group is significant in muscle stiffness, flexibility, and concentric strength (p < .05). The result of MTT group is significant in pain threshold, muscle stiffness, flexibility, and concentric and eccentric muscle strength (p < .05) Conclusion: The results showed that MTT stretching exercises could increase flexibility and decrease muscle stiffness. However, the performance on muscle strength declined and decrease the threshold of muscle soreness. The reason might be excessive stretching that reduces the bonding range of muscle cross bridge and decreases power performance. Adjustments on the intensity and the duration on stretching are recommended.
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Turbák, Filip. "Vliv různých druhů rozcvičení na rychlostní schopnosti u hráčů fotbalu z pohledu ontogeneze." Master's thesis, 2020. http://www.nusl.cz/ntk/nusl-412469.
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Title: The influence of different kinds of warm-up on the speed skills of football players from the ontogenetic point of view. Aims: The main objective of this diploma thesis is to compare the results of the times achieved by football players in the U18 youth team with their previous times measured two years ago, and in this way to evaluate their development of speed capabilities. Another aim of the research is to evaluate the progress of these players' flexibility at a chosen time interval (two years) and to inquire into other possible connections of these outcomes. Methods: For the assessment of speed power performance, each player goes through two runs at a distance of 30 meters, with measurements in this section also at distances of 5, 10 and 15 meters. Before the measurement itself, all participants are being prepared by a selected type of stretching. Two standardized tests are used for secondary research dealing with potential connection between the attained speed and the degree of flexibility of lower limbs. Outcomes: Testing revealed that subjects had a deterioration in the average running time with a two-year interval at distances of up to 15 meters (5,10,15 meters). On the contrary, when analyzing the results of measuring the distance of 30 meters, a significant improvement in average...
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Garin, Theresa May, and 泰瑞莎‧葛琳. "Effects of Dynamic and Static Stretching on the Subsequent Pitching Performance in Collegiate Baseball Players." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/92y9x2.
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碩士中國文化大學
體育學系運動教練碩博士班
102
Stretching is an important component of all athletic warm-up routines. These activities are done before exercises as they are believed to prepare the body for vigorous physical activities and athletic events. The study poses that there is no significant difference between the effects of dynamic and static stretching to the pitching velocity of the players. This research aims to determine the effect of dynamic versus static stretching of throwing shoulder on throwing velocity of baseball players. The subjects of the study were 15 collegiate baseball players of Chinese Culture University. A repeated measure One-Way ANOVA was used to determine if there is any significant differences in velocity performance existed in baseball players. The statistic significance was set at p < .05. The result showed that stretching protocols has no significant effect on the pitching performance of the baseball players. It is concluded that no matter what type of stretching was performed there is no significant effect, either negative or positive, on the performance of throwing velocity among baseball players
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Tzu-HanLiang and 梁紫涵. "Integration of DNA Stretching and AC Electro-kinetics for Preparing a Robust Dynamic FRET Sensor." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/s359dp.
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Lee, Shang-Ju, and 李尚儒. "Effects of dynamic and static stretching on drop jump and electromyographic activity of stretch-shortening cycle." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/38277429567226919075.
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碩士國立體育大學
運動保健學系碩士班
99
Purpose: This study was to investigate the effects of dynamic and stretching on vertical jump SSC electromyographic(EMG) activity of the quadriceps. Methods: Sixteen healthy men(age22.37±2.12) took part in 3 conditions(static stretching[SS], dynamic stretching[DS], and no stretching[NS]) on separate days. During each condition, EMG of m. vastus medialis(VM) and lateralis(VL), rectus femoris(RF) were measured with ZEBRIS EMG system(1000Hz). The angle of knee joint using ZEBRIS ultrasound based three-dimensional motion analysis(100Hz) were recorded with three separated phase including eccentric, coupling, and concentric phase. The EMG values were averaged for three trials and analyzed with paired t-tests for pre- and poststretching(α= .05). Results: The EMG activity of RF, and VL were decreased 6.5%, 8.9% respectively in the eccentric phase. The EMG activity of VM, RF, VL were increased 14%, 16%, 26% respectively in the concentric phase of SS group. The EMG activity of VM was increased 12% in the eccentric phase and the EMG activity of RF, VL were increased 21%, 24% respectively in the concentric phase of DS group. The EMG activity of VM was decreased 8% in the eccentric phase of NS group. Conclusion: The results reveals that after static stretching have lower EMG activity in the eccentric phase, but after dynamic stretching, the EMG activity was increased. This imply that dynamic stretching may raise muscle spindle sensitivity and stretch reflex response to recruit more motor unit to promote vertical jump performance. Therefore, the results suggests that the warm-up by dynamic stretching will facilitate sports performance.
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Řehulka, Filip. "Komparace efektivity rozcvičení florbalistů." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-367828.
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Názevpráce Komparace efektivity rozcvičení florbalistů Cíle práce Zjistit, které z vybraných druhů rozcvičení má největší vliv na rychlostní výkon florbalisty. Metoda Data pro komparaci efektivity rozcvičení budou dosažena pomocí srovnávací studie, kdy probandi podstoupí různé druhy rozcvičení. Probandi budou testováni testovou baterií, která je součástí kondičních testů české reprezentace. Využity budou fotobuňky zapůjčené od České florbalové unie. Výsledky Zobrazují efektivitu jednotlivých druhů rozcvičení florbalistů. Klíčová slova Rozcvičení, dynamický strečink, florbal, experiment, komparace
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Knobová, Kateřina. "Využití statického a dynamického strečinku v tréninku dívek kadetské kategorie ve sportovním aerobiku." Master's thesis, 2020. http://www.nusl.cz/ntk/nusl-412212.
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6 ABSTRACT Tittle: Effect of Static and Dynamic Stretching on the Performance of Cadet Category in Competitive Aerobics Objectives: The aim of the work is to find out the type, method and use of static and dynamic stretching in the training of cadet girls in the training of sports aerobics through the opinions of competitive aerobics coaches. The theoretical part consists of research on the issue. In the practical part, a questionnaire survey and an interview are used, conducted in person by the author of the diploma thesis or sent by e-mail, or conducted by telephone or otherwise online. The outputs from this questionnaire + interview are analyzed, compared and evaluated with specific clear outputs. Methods: The work consists of a theoretical and a practical part, while the theoretical part is conceived descriptively. The research part uses the method of qualitative research - a questionnaire. Competitive aerobics coaches are interviewed through a questionnaire and in the form of a guided interview. The interview is conducted in person, according to the prepared questions, and the answers are then logically sorted, evaluated and commented. Descriptive statistics are used for the actual classification and analysis of the obtained data. Results: The results of the work showed the type, method and use of...
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Plachá, Tereza. "Vliv statického a dynamického strečinku na koordinaci a flexibilitu u dětí 1. stupně ZŠ." Master's thesis, 2019. http://www.nusl.cz/ntk/nusl-397209.
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TITLE: The impact of static and dynamic stretching on coordination and flexibility in children in primary school AUTHOR: Tereza Plachá DEPARTMENT: Katedra tělesné výchovy SUPERVISOR: Mgr. Lucie Kainová ABSTRACT: In my final thesis I want to deal with two types of warm-up - static stretching and dynamic stretching. Warming up is an important part not only of the sport performance, but also at the beginning of the physical education lesson. In schools, this phase is often neglected. With the help of selected tests, I will observe primary school pupils at primary school to get better results after static or dynamic stretching. I will watch them in coordination and flexibility. I compiled two types of stretching, which I will try in grades 1, 3 and 5. In the first lesson, I will do static stretching with the pupils after the proper warm-up. In the second lesson, I will include dynamic stretching along the busy part. In the main part of the lesson, the pupils then pass three tests for coordination - flamingo, crossing the bench and running with the roll; and three for flexibility - standing forward bend, shoulder joint range, and hip joint range. After dynamic stretching, the children are warmed up, reaching the necessary temperature for further activities. They have a greater range of motion and therefore...
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Lin, Jia-Huei, and 林家輝. "Effects of Acute Dynamic Stretching with Weights on Hip Range of Motion in Middle – aged and Older Adults." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/80050087183002950903.
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碩士國立體育大學
運動科學研究所
103
Purpose: The purpose of this study was to investigate effects of static stretching and dynamic stretching with different weights on hip range of motion on immediate and sustained responds in middle – aged and older adults. Methods: Sixteen middle-aged and older adults were recruited as participants in this study (63.2 ± 7.13 yr). All participants were randomly assigned to complete static stretching (SS), dynamic stretching without weighting (DSW0) and dynamic stretching with 0.25 (DSW025) and 0.5 kg (DSW05). We measured and recorded range of motion in right-side hip flexion and extension before, stretching exercise completed immediately (post 0), and post 10, 45 and 60 min. Results: The range of motion in hip flexion, DSW0 was higher than DSW025 and DSW at post 0, 10, 45 and 60 min (p = .014, p = .002; p = .004, p = .004; p = .017, p = .011; p = .017, p = .011). The performance of DSWO was better than that of SS at post 60 minutes (p = .049). The effectiveness of stretching sustained 60 minutes in DSW0 (p = .013). The range of motion in hip extension, DSW025 was higher than SS (p = .039), DSWO (p = .003) and DSW05 (p = .018) at post 10 minutes. The performance of all modes of dynamic stretching was better than that of SS at post 60 min (DWS0, p = .036; DSW025, p = .019; DSW05, p = .012). The effectiveness of dynamic stretching can sustained longer than 45 minutes (DWS0, 60 min, p = .044; DSW025, 45min，p = .035; DSW05, 60 min, p = .028). Conclusion: Dynamic stretching without weighting and static stretching enhanced the range of motion in hip flexion. Dynamic stretching with 0.25 kg or 0.5 kg enhanced range of motion in hip extension.
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Hons, Ondřej. "Vliv dynamického strečinku na výslednou dynamiku dolních končetin u volejbalistů." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-368367.
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Title: Influence of dynamic stretching on the resulting dynamics of lower extremities in volleyball Objectives: The aim of this work was to find out if there is a correlation between long term dynamic stretching and muscle dynamics of lower limbs of volleyball players. Methods: Theoretical part is based on foreign literature and researches. To gain the necessary data, experimental study was created. It contained 10 male probands in the age of 16-19. In the beginning of the experiment, all the participants attended the Bosco test at the biomedical lab at UK FTVS. The main parameter was the total flight time of the entire 60 seconds. After that participants attended 8 weeks of 2 times a week of dynamic stretching before the training instead of their usual stretching stereotype. Immediately after those 8 weeks, second Bosco testing took place and the comparison of the data of the whole group and individuals was made from the view of their volleyball posts. Results: There was a slight improvement in all the data at the whole group and significant improvement in anaerobic endurance. After comparing of the results of all the probands no significant differences between the probands from the perspective of player's volleyball posts. Keywords: volleyball, stretching, static stretching, dynamic stretching,...
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Koskuba, Jakub. "Dynamické rozcvičení u závodních hráčů tenisu." Master's thesis, 2012. http://www.nusl.cz/ntk/nusl-308015.
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Title: Dynamic warm-up race for tennis players Subject: Male and female tennis players from tennis club Tj Lokomotiva Plzen Objective: Compare immediate influence of static and dynamic stretching on performance level during particular movement tests using device Myotest PRO Methods: To meet the objective quantitative comparison was used by performance parameters using load accelerometer. Quantitative stress parameters were evaluated for individual tests as the mean value from a large amount of repetition in individually evaluation. Results: Tests proved it is not possible to confirm acute positive influence of dynamic stretching on all assesed parameters in different tests. In terms of average values of different tests a noticeable lower limbs improvement has been emerged at two out of three tests. Keywords: dynamic stretching, warm up, sport, injuries, regeneration, tennis
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Zhao, Huai-Jia, and 趙懷嘉. "The Acute Effects of Static or Dynamic Stretching Together with Kinesio Taping on Athletic Performance and Muscle Condition in Baseball Athletes." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/cdhq73.
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碩士高雄醫學大學
運動醫學系碩士在職專班
104
Abstract Background: Stretching exercise as a warm-up is an important component of exercise procedures. Stretching exercise includes dynamic stretch（DS）and static stretch（SS）. Currently, the researchers remain addressing that which type of stretching exercise provides more benefits on athletic performance. In particular, kinesio taping（KT） has been widely used to assist and facilitate athletic performance. However, the benefits of KT on sports enhancement remains unclear. Literature searches revealed that the immediate effect of after either DS or SS in combination with KT on performance as well as muscle status in baseball players has not been studied. Purpose: The aim of this study was to examine the immediate effects of distinct types of stretching exercise together with KT taping on athletic performance（flexibility, power, agility, and balance）and muscle status. Methods: Thirty healthy male amateur baseball players（age = 25.26 ± 4.57 years） voluntarily participated in the study. Before the investigation, the participants were randomly allocated to either the KT group or the Control taping（CT）group. The participants were required to complete SS and following DS two days afterwards. The following tests were measured after each types of stretching exercise: sit and reach test, counter movement jump （CMJ）, 20-m sprint, 5-10-5 shuttle agility test, and Y-balance test（YBT）. In addition, the Myoton equipment was adopted to measure the changes of muscle status（muscle tension, muscle elasticity, and muscle stiffness） on quadriceps and gastrocnemius. Results:（1） Athletic performance: A significant difference （p = .034） on CMJ test was found between DS （135.00 ± 11.95 cm） and SS （133.40 ± 11.94 cm） in the CT group, which suggested better performance after DS. Apart from increase of CMJ. No significant difference was shown in other tests in both the KT and the CT groups. Nonetheless, the DS with KT group showed a positive tendency of improvements. Regarding the YBT, the participants had better performance after performing DS in KT and CT groups. （2） Muscle status: Neither DS nor SS with KT /CT had a significant change on muscle status. Conclusion: In the study, DS provides benefits for CMJ and balance ability. However, the KT group with either DS or SS shows no synergistic sports enhancement, albeit with a tendency of improvement. Therefore, we suggest that KT is not first option to enhance athletic performance. Conversely, executing a correct and an appropriate DS for a warm-up is decisive. Key words: athletic performance, static stretching, dynamic stretching, Kinesio taping, muscle tension.
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Kuo, Hsiao yun, and 郭曉韻. "Differential Effect of 30 V.S 60-second Dynamic Muscle Stretching combined Warm-up on Explosiveness of Lower Limbs and Agility Performance in Adults." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ats992.
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碩士高雄醫學大學
運動醫學系碩士在職專班
106
Objective : It has been proposed that pre-exercise dynamic stretching could prevent sports injuries and improve athletic performance. However, as of now, there are still no official lasting durations or operation methods set for the dynamic stretching. The purpose of this study was to compare the effect of 30 seconds versus 60 seconds of pre-exercise dynamic stretching combined with warm-up exercises on the power and the agility of the lower limbs. Methods: The subjects consisted of 30 healthy adults between the ages of 20-40 years old, who were randomly divided into two groups: a 30-second group and a 60-second group. The evaluation test included the standing broad jump to assess the power of lower limbs and the agility T test to assess the agility of lower limbs. They practiced these two items at least one time or up to three times for familiarization before they began to participate the experiment. All participants completed three exercise test sessions within the same day, and they took a 3 minute rest between each session. Every exercise test session included the pre-test, warm-up, dynamic stretching exercise, and the post-test. At first, all participants received the evaluation ( pre-test ), and went jogging for 10 minutes as a warm-up exercise after completing the pre-test. Then subjects in both groups performed 30-second or 60-second dynamic stretching exercises in their Quadriceps, Hamstring, hip flexors, Gluteals and calf muscles. After completing the dynamic stretching exercise, they received the evaluation again ( post-test ) immediately. Results: Except for second agility T test, both groups showed statistically significant differences ( p < 0.05 ) for all the scores ( included average value and maximum value )of the agility T test and the standing broad jump between the pre-test and post-test of 3 test sessions. When comparing the 30-second group with the 60-second group, there were no statistically significant differences for the scores of the standing broad jump. The only significant difference ( p < 0.05 ) observed between the two groups was that the 30-second group increased in the score of the agility T test more than the 60-second group in third test session. Conclusions: The results of this study suggest that both 30 seconds and 60 seconds of pre-exercise dynamic stretching combined with warm-up exercises are positive in improving the power and the agility of the lower limbs. When comparing the 30 seconds with the 60 seconds of pre-exercise dynamic stretching combined with warm-up exercises, the effect of 30 seconds of pre-exercise dynamic stretching combined with warm-up exercises is more effective in improving the agility of lower limbs.
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Maier, Ludvík. "Vliv komplexního strečinku dolní končetiny na posturální stabilitu." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-342026.
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Title: Influence of a complex stretching exercise of lower limb on postural stability Objectives:: The main objective of this diploma these is to find out, using dynamic computerized posturography, whether the increased mobility of the lower limbs has a positive influence on postural stability. Another partial objective is to determine efficiency of the practised stretching exercises. Methods: This is a pilot study where in research participated five probands whose measurement results were evaluated qualitatively. The aged of probands at the time of the first measurement was from 13 to 18 years. All probands are male volleyball league players and during the last two years occurred to a marked grow by all of them. Given their tall stature, it was expected a decrease in the mobility of the lower limbs and muscle shortening. To the data acquisition was used clinical examination of active range of motion and shortened muscle testing according to Janda. Postural stability was measured using computerized dynamic posturography SMART EquiTest System from Neurocom. Measured data were processed using the program NeuroCom Balance Manager software. In the Framework of study were conducted two intrumental measurements in the range of two months. After the first measurement all probands were instructed how to...
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Rudolf, Jan. "Vliv rozcvičení na sílu úderu." Master's thesis, 2020. http://www.nusl.cz/ntk/nusl-434268.
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Title: Acute effect of a warm-up on the force of a punch Objectives: The aim of this diploma thesis is to test whether a warm-up before a performance affects the force of a punch at a sample participants practicing full-contact combat sports. Further goal is to analyze a change in the force of a punch depending on elapsed time after warming up. Methods: Each participant in this experimental study with intra-subject design went through all phases of the measurement, where the force of a punch was tested in four specified times (before a warm-up and then 4, 10 and 25 minutes after the warm-up). Results: No statistically significant effect of a warm-up on the force of a punch was observed, nor was there a statistically significant change in the force of a punch during the time following a warm-up. However, a warm-up did have a significant effect on change in heart rate and body temperature. Keywords: Combat sports, performance, fight, dynamic stretching, explosive power, punch sensor
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Čaklošová, Karolína. "Optimalizace rozcvičení před rychlostně-silovým tréninkem." Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-367731.
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Title: Optimization of warm-up before speed-strenght loading Objectives: The aim of this work is to compare three variants of warming up and to determine the most appropriate one before speed-strenght loading. Methods: The test group consisted of 15 male students of the Faculty of Physical Education and Sport at The Charles University at the age of 22 -26 years. The tested subjects underwent 4 tests within 4 weeks. The first test was used to determine the 1 RM bench press and leg-press, the results of which we needed for the proper determination of the weights for the following protocols. The other three measurement protocols include three warm-up (base, a speed-strenght and toning), followed by a test of explosive strength in arms and legs. Countermovement vertical jump height with arm swing was used for legs testing and medicine ball shoot-up in supine position was used for arms testing. Results: This research shows that best results in the countermovement vertical jump height with arm swing were achieved after the speed-power warm-up. The best results in medicine ball shoot-up in supine position were achieved after the basic warm up, but results are not statistically significant for these testing. Keywords: Warm-up, dynamic stretching, speed-force loading, toning, explosive force, testing
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Formánková, Dita. "Vliv dynamického a statického rozcvičení na svalovou sílu u lezců." Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-335390.
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Title Influence of dynamic and static warm-up on muscle strength in climbers. Objective The aim of the thesis is to assess the influence of dynamic warm-up with Thera-Band and static stretching on maximal muscle strength and its time parameters of finger flexors in dominant upper extremity in climbers. Methods Eight active climbers participated in this testing (age 32.4 ± 5.5, body weight 69.4 ± 6.5, height 176 ± 6.4). Actual performance RP was according to the French scale ranging 6b to 8a. Probands' measurements proceeded in three different days. After a specific warm-up on "boulder wall" and static stretching and dynamic warm-up with Thera-Band without stretching, there was maximal muscle strength of fingers flexors on dominant (preferred) upper limb measured by using a specific climbing test on hangboard. The second measurement assessed maximal strength of finger flexors muscle and its time parameters while proceeding of the maximum hand-grip using a hand dynamometer. Results In the experiment, none of the hypotheses came to be confirmed. There was no significant influence of static stretching and dynamic warm-up with Thera-Band on maximal muscle strength of finger flexors and the time parameters in climbers. Conclusion Despite the failure to prove the influence of the static stretching and...
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Lizana, Paul Antonio Cardenas, and 保羅. "Stretching a Single Condensed DNA Molecule Studied by Molecular Dynamics Simulation." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/47765512014631743572.
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碩士國立清華大學
工程與系統科學系
95
Experiments have shown that a semiflexible polyelectrolyte, such as a DNA, can be condensed by multivalent counterions and the preferred form is toroid. By using molecular dynamics simulations, a single DNA molecule is condensed into a compact toroid-like structure. DNA is treated as a bead-spring chain, using parameters of dsDNA. The influence of the counterion size and DNA monomer size on the DNA structure is studied. We found that for a DNA monomer size of ¾ and counterion size of 0.5¾, the complex (DNA plus condensed counterions) forms a well-defined toroidal structure. The dependence of the structure of the condensed DNA on the initial configuration is investigated. We observed that the final conformation does not depend on the initial state. The condensed DNA toroid is then stretched by pulling one end of the chain at various constant velocities to investigate the effects of the pulling velocity on the force-extension curve (FEC). We found that the pulling velocity influences the force profile and the internal structure of the condensed DNA molecule. Moreover, the responses at both DNA ends are different if the pulling velocity is larger than the reference Rouse velocity, Vo. For velocities larger than Vo, the FEC’s dependence over the pulling velocity is linear at the DNA end which is moving at constant velocity; nevertheless, these FECs oscillate around a constant force (¼ 2.5KBT/¾) at the other end. We found that a pulling velocity equals to 5×10−4¾/¿ does not perturb the complex. Moreover, the influence of the pulling velocity on the bond length is linear. We observed that the entropic behavior of the DNA molecule is strongly affected by the condensed counterions. The FEC shows a series of “stick-release patterns”. It gradually increases with increasing extension and then abruptly decreases; this behavior appears repeatedly and becomes stronger and stronger as the condensed DNA molecule is losing its turns. We showed that these ”stick-release patterns” are a consequence of turn-by-turn unfolding of the condensed DNA toroid. The extensible worm-like chain (EWLC) model is found able to describe qualitatively the behavior of the DNA molecule when its extention is close to the overall contour length. We presented a clear evidence and described the mechanism of why the condensed DNA molecule forms a “stick-release patterns”. Our results provide new microscopic information about the internal structure of a single condensed DNA toroid being stretched and are in qualitative agreement with experiments.
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Lin, Tsung-Hsien, and 林宗賢. "Design and Optimization of a DNA Electrophoretic Stretching Device Using Brownian Dynamics Simulations." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/84954853898528129000.
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碩士國立臺灣大學
化學工程學研究所
99
We use Brownian dynamics-finite element method (BD-FEM) to design microfluidic devices that are capable to efficiently and uniformly stretch DNA for the application of gene mapping. Our design is based on the devices proposed by Kim and Doyle[1] that stretches DNA electrophoretically with the electric field gradient generated in a hyperbolic contraction. To enhance DNA stretching, we propose two strategies that pre-condition DNA before they enter the contraction. For the first approach, we pre-stretch DNA in the direction perpendicular to the funnel axis with a expansion geometry. The partially stretched chains are then turned to align with the axial of the funnel, and experience the second stretching. As a result, DNA chains adapt more extended configurations before going into the funnel, and therefore achieve a higher degree of extension. For the second approach, we pre-condition DNA conformation using an oscillating extensional electric field that has been shown to effectively reducing the population of folded DNA at an ideal condition. However, this approach shows negligible effect in our design, and we find that the original prediction was actually wrong due to the erroneous choice of flow filed. We further examine the efficiency of our design for stretching longer DNA. It is found the performance of the pre-conditioning strategy deteriorates with increasing DNA molecular weight. By analyzing the probability distribution of DNA extension in the device, we propose a new design that utilizes the excluded volume effect of the device boundary to prevent the formation of folded DNA. Our simulation results indeed show that the design with both tricks can provide very uniform, highly stretched DNA even under relatively low field gradient.
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Bartlett, Casey Thomas. "Bouncing, bursting, and stretching: the effects of geometry on the dynamics of drops and bubbles." Thesis, 2015. https://hdl.handle.net/2144/13677.
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In this thesis, we develop a physical understanding of the effects of viscosity and geometry on the dynamics of interfacial flows in drops and bubbles.
We first consider the coalescence of pairs of conical water droplets surrounded by air.
Droplet pairs can form cones under the influence of an electric field and have been observed to coalesce or recoil depending on the angle of this cone.
With high resolution numerical simulations we show the coalescence and non-coalescence of these drop pairs is negligibly affected by the electric field and can be understood through a purely hydrodynamic process.
The coalescence and recoil dynamics are shown to be self similar, demonstrating that for these conical droplet pairs viscosity has a negligible effect on the observed behavior.
We generalize this result to the coalescence and recoil of droplets with different cone angles, and focus on droplets coalescing with a liquid bath and flat substrate.
From the simulations of these droplets with different cone angles, an equivalent angle is found that describes the coalescence and recoil behavior for all water cones of any cone angle.
While viscosity is found to negligibly affect the coalescence of conical water drops, it plays a key role in regulating the coalescence process of bursting gas bubbles.
When these gas bubbles burst, a narrow liquid jet is formed that can break up into tiny liquid jet drops.
Through consideration of the effects of viscosity, we show that these jet drops can be over an order of magnitude smaller than previously thought.
Here, viscosity plays a key role in balancing surface tension and inertial forces and determining the size of the jet drops.
Finally, we investigate the drainage of surfactant free, ultra-viscous bubbles where surface tension serves only to set the initial shape of the bubble.
We use interferometry to find the thickness profiles of draining bubble films up to the point the of rupture.
A theoretical film drainage model considering the balance of viscous and gravitational stresses is developed and numerically computed.
The numerical results are found to be consistent with the experimentally obtained thickness profiles.
In this work we provide insight into the role of viscosity in the outlined interfacial flows.
The results of this thesis will advance the understanding of drop production in clouds, the marine climate, and the degassing of glass melts.
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Tarr, Allan W. "Developments in the local mode theory of XH-stretching overtone spectroscopy : symmetry effects, intensities and vibrational dynamics." 1985. http://hdl.handle.net/1993/24186.
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