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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

The experience of female cyclists participating in a cycling club at a South African university

Van der Berg, Louis Jan. January 2007 (has links)
Thesis (M A(Counselling Psychology))--University of Pretoria, 2007. / Includes bibliographical references. Available on the Internet via the World Wide Web.
42

The effect of intermittent simulated altitude exposure via re-breathing on cycling performance

Babcock, Carmen J. January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 113-118).
43

Quantification of pre-competitive sleep/wake behaviour in a sample of South African cyclists

Steenekamp, Travis January 2018 (has links)
The quantification of athlete pre-competitive sleep behaviour is of interest owing to the possibility that sleep loss may have a negative effect on health and performance. The purpose of this study was to monitor and quantify the sleep/wake patterns of South African cyclists prior to competitive races. A total of 336 cyclists, male and female and of differing competition levels, cycling in either the 2015 Tsogo Sun Amashova or the 2016 Telkom 94.7 Cycle Challenge completed an altered version of the Competitive Sports and Sleep Questionnaire. The questionnaire asked cyclists to report on precompetitive sleep over the past year. A subset of 92 cyclists also recorded a Core Consensus Sleep Diary for the three nights leading up to the races. The questionnaire showed that 67% of the cyclists reported worsened sleep at least once prior to competition within the past 12 months. The sleep diary found that the cyclists’ average sleep duration the night before the races was 6h19min (±1h38min), which was significantly less than two and three nights prior to the races. Sleep quality was also shown to deteriorate significantly the night before the races. The contributing factors leading to worsened pre-competitive sleep were the time the cyclists had to wake-up as well as perceived increases in sleep latency and awakenings after sleep onset. Anxiety was found to be the major cause of sleep disturbances. While females were found to be significantly more likely to report having experienced poorer sleep before competition in the past year, the sleep diary showed no difference in sleep the night before the races between the sexes. Females were significantly more likely to report instances of unpleasant dreams and waking up during the night. Again, the sleep diary data did not corroborate these findings. Females were also found to report significantly more accounts of nervousness or thoughts about competition as being the cause of sleep problems. There was no difference in sleep loss the night before competition when comparing competition-level groups. The only significant difference was that recreational cyclists were more likely to report sleeping in foreign environments as a cause of sleep disturbances. Despite a large percentage of cyclists experiencing pre-competitive sleep loss, over half (55%) perceived sleep loss to have no impact on their performance. Analysis of pre-sleep behaviour also revealed that the cyclists engaged in several practices that may have a negative effect on subsequent sleep. The vast majority of the cyclists (61%) indicated having no specific strategy to help them sleep the night before competition. Fifteen percent of cyclists reporting using media devices to help them fall asleep, a practice that has been shown to disrupt sleep. In conclusion, most cyclists, regardless of sex and level of competition experience precompetitive sleep loss attributed largely to anxiety but with the perception that this loss in sleep does not negatively impact their performance.
44

"Are We Building Biking Solidarity": Gendered, Racial, and Spatial Barriers to Bicycling in Portland, Oregon

Tompkins, Kyla Jean 17 August 2017 (has links)
Although Portland, Oregon is widely regarded as a "bike friendly" city, its bike equity remains in question. This thesis explores the barriers to biking that women and people of color face in Portland. This research uses feminist geography scholarship to understand how cycling spaces are unequal for marginalized cyclists. Using data from 28 in-depth, semi-structured interviews with infrequent and marginalized cyclists, I found that gender and race inequalities shape their barriers to biking. A hegemonic white, elite, and masculine bike culture controls the domination of cycling spaces. Women's gendered spatial inequalities are shaped by their childrearing demands, geography of fear, and street harassment. Cyclists of color experience a fear of public space due to racial profiling and police violence, and racial spatial inequalities are shaped by Portland's historic and racist city planning that gentrifies and displaces residents of color. Furthermore, intersectional inequalities of gender, race, and class, emerge and illustrate how cycling spaces are built to be unequal. These findings suggest that spatial inequalities in the urban landscape are pervasive in multiple spaces such as bike lanes, and that more research and policy is needed to increase ridership among women and people of color.
45

Negative attitudes towards cyclists influence the acceptance of an in-vehicle cyclist detection system

De Angelis, Marco, Puchades, Víctor Marín, Fraboni, Federico, Pietrantoni, Luca, Prati, Gabriele 21 December 2020 (has links)
The shift towards automation and safer vehicles will increasingly involve use of technological advancements such as Advanced Driver Assistance Systems (ADAS). Nevertheless, these technologies need to meet users’ perceived needs to be effectively implemented and purchased. Based on an updated version of the Technology Acceptance Model (TAM), this study analyses the main determinants of drivers’ intention to use an ADAS aimed at detecting cyclist and preventing potential collision with them through an auto-braking system. Even if the relevance of perceived usefulness, perceived ease of use and trust on the acceptance of a new system has been already discussed in literature, we considered the role of an external variable such as attitudes towards cyclists in the prediction of an ADAS aimed to improve the safety of cyclists. We administered a questionnaire measuring negative attitudes towards cyclists, trust, perceived usefulness, perceived ease of use and the behavioural intention to use the system to 480 Italian drivers. Path analysis using Bayesian estimation showed that perceived usefulness, trust in the system, and negative attitudes towards cyclists have a direct effect on the intention to use the ADAS. Considering the role of attitudes towards other road users in the intention to use new ADAS aimed to improve their safety could foster the user’s acceptance, especially for those people who express a negative representation of cyclists and are even more unlikely to accept the technology.
46

The effects of water immersion on the recovery and performance of competitive cyclists

Koekemoer, Christa Magrieta 03 1900 (has links)
Thesis (M Sport Sc (Sport Science))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Post-exercise recovery has become an important area in research due to the high demands placed on competitive athletes. Different recovery strategies are used by athletes during competition and training. For the competitive athlete it is important to maintain performances during competition and also to enhance performances during training. However, if the athlete fails to recovery from daily exhaustive training and competition, inadequate recovery may lead to poor performances, burn-out, sickness and even injuries. There is very little evidence available on the possible performance recovery effects of the use of water immersion during multi days of intensive endurance training. Theoretically, water immersion should aid the overall recovery process without any additional energy cost involved as with active recovery. The objective of this investigation was to determine whether water immersion (cold water vs. neutral) has any effects on the post-exercise recovery rate of competitive cyclists during 3 days of intensive endurance training and whether recovery with water immersion is more effective than active recovery. Seventeen competitive cyclists (mean ± SD age: 27.6 ± 5.94 years, weight: 78.8 ± 6.67 kg, height: 180.5 ± 4.42 cm VO2max: 49.8 ± 4.13 L.min-1.kg-1, and PPO: 352.6 ± 35.94 Watts) completed 3 days of intensive endurance cycling sessions. Cyclists were randomly assigned to either a 20 minute ice bath (IB) (n = 6, 11 ± 0.9oC), neutral bath (NB) (n = 6, 30 ± 0.6oC), or active recovery (AR) (n = 5; 81 ± 1.74% of HRLT ) which were performed directly after the training sessions on Day 1 and 2. Dependent variables such as anaerobic performance, creatine kinase concentrations (CK), c-reactive protein concentrations (CRP), blood lactate concentrations, muscle soreness (VAS) and perceived fatigue (POMS), and limb circumferences were measured prior to the training sessions at Day 1, 2 and 3. In addition, changes in exercise performances over the last 2 days were also assessed. There were significant increases over the three days in plasma [CK] (P < 0.05) and [CRP] (P < 0.001) demonstrating that muscle damage and inflammation occurred during and after the training sessions. However, there were no treatment or interaction effects observed for any of the dependent variables for any of the recovery interventions (P > 0.05). Blood [La] was significantly reduced on Day 2 for the IB group in comparison to the NB group (P < 0.05). A strong tendency was observed for [CK] when the IB and NB groups were combined (WG), indicating that AR had a strong tendency to enhance the recovery of [CK] in comparison to the WG (P = 0.05). Also, there were no significant time or interaction effects observed in % changes in performances for the last two 100km TTs between Day 2 and 3 for any of the recovery interventions (P > 0.05). These findings suggest that neither cold water, nor neutral water therapy, have more beneficial effects on post-exercise recovery rates compared to active recovery. Importantly, however, is that the cyclists’ were able to maintain their performances over the three consecutive days, indicating that water therapy per se is not detrimental to endurance performance. / AFRIKAANSE OPSOMMING: Na-oefening herstel het ‘n belangrike area van navorsing geword, aangesien die eise wat aan elite atlete gestel word buitengewoon hoog is. Vir die kompeterende fietsryer is dit baie belangrik om prestasie tydens kompetitisie asook tydens inoefening te handhaaf. Inteendeel, as die atleet nie daarin slaag om effektief te herstel na daaglikse oefening en kompetisie nie, mag dit lei tot swak prestasie, uitbranding, siekte en beserings. Tot hede is daar geen baie min bewyse beskikbaar oor die potensiële voordele van waterterapie vir die herstel van atlete, veral tydens meervoudige dae van intensiewe uithouvermoë inoefening. Teoreties behoort waterterapie die algehele herstelproses bevorder sonder dat enige addisionele energiekostes betrokke is, soos in die geval van aktiewe herstel. Die doel van die ondersoek was om vas te stel of waterterapie (koud teenoor neutraal) enige effekte het op die na-oefening hersteltempo van kompeterende fietsryers tydens 3 dae van intensiewe uithouvermo oefening en om te bepaal of waterterapie meer effektief is as aktiewe herstel. Sewentien kompeterende fietsryers (gemiddeld ± SD; ouderdom: 27.6 ± 5.94 jaar, gewig: 78.8 ± 6.67 kg, lengte: 180.5 ± 4.42 cm, VO2maks: 49.8 ± 4.13 L.min-1.kg-1, en Piek krag uitset: 352.6 ± 35.94 Watts) het 3 dae van intensiewe uithouvermoë inoefeing voltooi. Die fietryers was lukraak ingedeel in ‘n 20 minute Ysbadgroep (IB) (n = 6, 11 ± 0.9oC), neutrale bad groep (NB) (n = 6, 30 ± 0.6oC) en ‘n aktiewe herstelgroep (AR) (n = 5; 81 ± 1.74% van HRLT), Herstelsessies het op Dag 1 en 2 direk na die inoefeningsessies plaasgevind. Afhanklike veranderlikes soos funksionele kapasiteit, kreatienkinase konsentrasies (CK), c-reaktiewe proteïen konsentrasies (CRP), bloedlaktaat konsentrasie ([La]), spierseerheid en persepsie van vermoeienis (STEMS), en beenomtrekke was gemeet voor die inoefeningsessies op Dag 1, 2 en 3. Veranderinge in oefeningprestasie oor die laaste 2 dae was ook geassesseer. Daar was ‘n statistiese betekenisvolle toename in plasma [CK] (P < 0.05) en [CRP] (P < 0.001) oor die drie dae, wat daarop wys dat spierskade en inflammasie wel plaasgevind het. Daar was geen behandeling of interaksie effekte waarneembaar vir enige van die intervensies nie (P > 0.05). Bloed [La] was beduidend verlaag op Dag 2 vir die IB groep in vergelyking met die NB groep (P = 0.05). Die verlaging in plasma [CK] na AR het gegrens aan statisties betekenisvolle resultate (P = 0.05) in vergelyking met die waterterapie (IB en NB gekombineer). Daar was geen statisites beduidende tyd of interaksie effekte waargeneem in die % veranderinge in oefeningprestasie vir die laaste twee 100km tydtoetse tussen Dag 2 en 3 vir enige van die herstelstrategieë nie (P < 0.05) Die resultate wys dat waterterapie nie enige voordelige effekte op die na-inoefening herstel tempo het in vergelyking met aktiewe herstel nie. Dit is egter belangrik om daarop te let dat die fietsryers in staat was om hul oefeningprestasies te handhaaf oor die drie opeenvolgende dae, wat aandui dat waterterapie nie nadelig inwerk op uithouvermoë prestasie nie.
47

Gender disparities in competitive cycling : an analysis of the structural, socio-cultural, and individual factors affecting female participation in Texas

Forrest, Katherine Elizabeth 02 November 2010 (has links)
Of the 2,858 licensed competitive road cyclists in Texas, female cyclists only account for 12%. The gender disparity in participation numbers suggests possible underlying barriers to entry, recruitment, and retention of female athletes compared to that of male cyclists. The current study sought to understand such issues by exploring the entirety of the competitive road cycling experience of female cyclists in Texas. To accomplish such a task, the current study utilized a mixed methods design consisting of content analysis, interviews, and an online survey. Integrating methods allowed for a more comprehensive understanding of the individual as impacted by structural, socio- cultural, and individual factors and further reveals how such factors are interrelated and mutually reinforcing. Results revealed how socio-culturally informed gendered attitudes and norms heavily impact structural policies, rules, and regulations within competitive cycling. Subsequently, structural factors influenced individual choices, attitudes, and behaviors. Further, results emphasized that individuals are complex beings, and although shaped by their environment, embody personal agency, resistance, and coping. Individual decisions, attitudes, and desires subsequently shaped socio-cultural norms and structural processes. Finally, structural reform strategies are suggested to help increase female participation and retention rates within competitive road cycling in Texas. / text
48

Efeito da cadência de pedalada sobre a arquitetura do músculo vasto lateral e o comprimento da unidade músculo-tendínea / Cycling cadence effect on muscle architecture of the vastus lateralis and muscle-tendon unit length

Silva, Júlio Cezar Lima da January 2016 (has links)
A cadência de pedalada é um importante componente na produção de potência, sendo responsável pelas mudanças na velocidade de encurtamento muscular, a qual influencia diretamente o desempenho no ciclismo. Ainda não está claro se a redução na ativação muscular e o menor torque no pedivela estão associados com a redução na contribuição dos tecidos ativos e/ou passivos em diferentes velocidades de pedalada. O objetivo da presente dissertação foi investigar o efeito de diferentes cadências de pedalada (70 e 90 rpm) sobre a arquitetura muscular do vasto lateral (VL) e comprimento da unidade músculo-tendão (UMT). Além de dados adicionais, da unidade músculo-tendão, força e a atividade elétrica dos músculos vasto medial, reto femoral e bíceps femoral, do torque muscular, força, ângulo do joelho, assim como a força resultante no pedal durante a pedalada. A amostra foi composta por 19 atletas (11 ciclistas e 8 triatletas) experientes em ciclismo. As características dos atletas avaliados foram (média±DP): 29 ± 7,4 anos de idade, 72 ± 8,3 kg de massa corporal, 178 ± 8,9 cm de altura, 382 ± 62 km por semana de treinamento de ciclismo, POMAX = 381 ± 37 W da potência máxima aeróbica e 62 ± 6 ml/kg/min de consumo máximo de oxigênio. Os atletas realizaram um teste preliminar para determinação da potência máxima aeróbica durante carga máxima de trabalho, enquanto no segundo teste eles pedalaram na potência referente ao segundo limiar ventilatório (POLV2 = 324±37 W) a 90 e 70 rpm em ordem randomizada por sorteio. A força aplicada no pedal direito, a ativação muscular do membro inferior, a cinemática da articulação do joelho e a arquitetura muscular foram coletadas durante os últimos 20 segundos de cada teste. Esses dados foram utilizados em um modelo biomecânico para verificação da variação do comprimento da unidade músculo-tendão nas respectivas cadências. Comparações estatísticas foram realizadas utilizando testes t de Student entre as duas cadências (70 e 90 rpm) para todas as variáveis do estudo, assumindo uma diferença significativa quando p≤0,05. Para o teste utilizamos o software SPSS 17.0 para Windows. Foi observada uma diminuição significativa no torque extensor do joelho (70 rpm = 108±13% vs. 90 rpm = 97±13%; p<0,01), na força resultante no pedal (70 rpm = 107±11% vs. 90 rpm = 94±7%; p<0,01) e na força do quadríceps (70 rpm = 107±17% vs. 90 rpm = 98±13%; p<0,01) na cadência de 90 rpm comparado a cadência de 70 rpm. Foram observadas ainda similaridade para o ângulo do joelho entre as cadências (100±20% em 70 rpm vs. 99±6% em 90 rpm; p=0,92), e similaridade na espessura do músculo vasto lateral (70 rpm = 101±5%, 90 rpm = 99±6%; p=0,14), enquanto o comprimento do fascículo (70 rpm = 74±33%, 90 rpm = 86±35%; p=0,01) aumentou e o ângulo de penação diminuiu da cadência de 70 para a de 90 rpm (70 rpm = 115±45%, 90 rpm = 96±34%; p<0,01). O comprimento da UMT do quadríceps (70 rpm = 99±2%, 90 rpm = 100±2%; p≤0,05) e o comprimento da UMT do vasto lateral (70 rpm = 98±4%, 90 rpm = 100±4%; p=0,02) apresentaram um aumento na cadência de 70 para a cadência de 90 rpm. Para os músculos reto femoral (70 rpm = 100±1%, 90 rpm = 100±1%; p=0,08) e bíceps femoral (70 rpm = 100±1%, 90 rpm = 100±1%; p=0,16) não houveram diferenças significativas para o comprimento da UMT. A ativação muscular do vasto medial em 90 rpm apresentou um diminuição comparada à cadência de 70 rpm (70 rpm = 114±34% vs. 90 rpm = 83±19%; p≤0,05), enquanto a ativação dos músculos bíceps femoral e reto femoral não apresentaram diferença significativa entre as cadências. Em conclusão, a mudança na cadência de pedalada de 70 para 90 rpm em carga constante de trabalho reduz a produção de força dos extensores do joelho à 90 rpm, provavelmente decorrente de uma menor ativação do vasto medial e de um trabalho do fascículo em um maior comprimento e em um menor ângulo de penação do vasto lateral nessa cadência mais elevada. / Cycling cadence is an important component in power production, where changes muscle shortening velocity can affect cycling performance. It is not yet clear if the reduction in muscle activation and the lower crank torque are associated with decreases in contribution from active and/or passive tissues in different cycling cadences. The propose of this master thesis was to investigated the influence of two cycling cadences (70 and 90 rpm) on muscle architecture of the vastus lateralis and muscle-tendon unit length. As well, addictional data was analyzed as muscle-tendon unit, force, and the muscle activation of vastus medialis, rectus femoris and biceps femoris, muscular torque, force, knee angle and resultant force during pedaling. Nineteen athletes (11 cyclists and 8 triathletes) experienced in cycling have taken part in this study. The characteristics of cyclists/triathletes were(mean ±SD): 29 ±7.4 years of age, 72 ±8.3 kg of body mass, 178 ±8.9 cm of height, 382 ±62 km per week of cycling training, 381 ±37 W of maximal aerobic power output, and 62 ±6 ml/kg/min of maximal oxygen uptake. The athletes performed an incremental cycling test to determinate their maximal workload. In a second they pedalled in their maximal workload and at the workload of their second ventilatory threshold (POVT2 = 324±37 W) at 90 and 70 rpm in random order. The force applied to the right pedal, lower limb muscles’ activation, lower limb kinematics and the ultrasound images from vastus lateralis were collected during the last 20 seconds of each test. This data was used in a biomechanical model to assess the influence of muscle-tendon unit in the two cadences. Student t tests were used to compare effects from pedalling cadences (70 and 90 rpm) in this study, assuming a significant difference when p≤0.05 using a statistical package (SPSS 17.0 for windows). A significant decrease in knee extensor torque (70 rpm = 108±13% vs. 90 rpm = 97±13%; p<0.01), in crank torque (70 rpm = 107±11% vs. 90 rpm = 94±7%; p<0.01) and in quadriceps force (70 rpm = 107±17% vs. 90 rpm = 98±13%; p<0.01) were found at 90 rpm compared to 70 rpm. No differences were found for the knee angle between cadences (100±20% at 70 rpm vs. 99±6% at 90 rpm; p=0.92). Muscle thickness was not significantly different between cadences (70 rpm = 101±5%, 90 rpm = 99±6%; p=0.14), however the fascicle length significantly increased (70 rpm = 74±33%, 90 rpm = 86±35%; p=0.01) and pennation angle decreased (70 rpm = 115±45%, 90 rpm = 96±34%; p<0.01) from 70 rpm to 90 rpm. Muscle-tendon unit length of quadriceps showed a significant increase (70 rpm = 99±2%, 90 rpm = 100±2%; p≤0.05) followed by a significant increase in muscle-tendon unit length of vastus lateralis (70 rpm = 98±4%, 90 rpm = 100±4%; p=0.02) from 70 rpm to 90 rpm. Rectus femoris (70 rpm = 100±1%, 90 rpm = 100±1%; p=0.08) and biceps femoris (70 rpm = 100±1%, 90 rpm = 100±1%; p=0.16) did not differ between the two cadences. Muscle activation of vastus medialis at 90 rpm showed a decrease compare to70 rpm (70 rpm = 114±34% vs. 90 rpm = 83±19%; p≤0.05), whistle biceps femoris and rectus femoris muscle did not differ between the two cadences. In conclusion, changes in cycling cadence from 70 rpm to 90 rpm at constant workload reduced force production at 90 rpm, resulting in a lower activation of the vastus medialis while fascicles worked at longer lengths and at smaller pennation angles.
49

Exploring the Determinants of Vulnerable Road Users' Crash Severity in State Roads

Caviedes Cómbita, Àlvaro Alfonso 08 December 2017 (has links)
Pedestrians and bicyclists are the most vulnerable road users and suffer the most severe consequences when crashes take place. An extensive literature is available for crash severity in terms of driver safety, but fewer studies have explored non-motorized users' crash severity. Furthermore, most research efforts have examined pedestrian and bicyclist crash severity in urban areas. This study focuses on state roads (mostly outside major urban areas) and aims to identify contributing risk factors of fatal and severe crashes involving pedestrians and bicyclists in state roads. Two ordinal regression models were developed (one for pedestrian and the other for bicyclist crashes) to examine crash severity risk factors. Additional models were developed to investigate road and traffic characteristics that could increase the likelihood of fatal crashes. In the model for pedestrian crash severity risk factors such as age, vehicle type and movement, light conditions, road classification, traffic control device, posted speed limit, location of the pedestrian and wet road surface during clear weather conditions are statistically significant. The bicyclist crash severity model indicates that age, crash location, vehicle movement and alcohol intoxication during dark conditions are statistically significant. In terms of road characteristics and traffic conditions, the models suggested risk factors such as arterials, light conditions, posted speed limit, roadways, and high heavy vehicle volume, increased the odds of a crash being fatal. The results seem to suggest that besides improvements in roadway characteristics, additional countermeasures to reduce crash severity for vulnerable users should include separation of vulnerable users from traffic, educational campaigns, more strict control of alcohol intoxicated drivers, and protection strategies of senior pedestrians.
50

Biketivists, hipsters, and spandex queens : bicycle politics and cultural critique in Austin

Ronald, Kirsten Marie 17 June 2011 (has links)
This paper uses an interdisciplinary, multiperspectival approach to analyze biketivism and various anticapitalist biketivist projects in Austin, Texas, in the hopes that a “glocalized” exploration of past and current biketivist struggles can help locate potential sites for political agency in ways that more placeless rhetorical studies cannot. Because the form and content of present-day bike politics in Austin are heavily dependent on biketivism’s historically tense articulations with capitalism, a historical analysis of biketivism as an outgrowth of Progressive Era and Appropriate Technology narratives reveals its crystallization around issues of technological, spatial, and social politics. Three case studies then apply this framework to different sites within the Austin bike community: the sales rhetoric of pro-custom bike shops, the debates over installing a Bike Boulevard in downtown Austin, and the missions and forms of several bike-related cultural organizations. Together, these perspectives on Austin’s bike community indicate that the incorporation (and sometimes outright co-optation) of biketivists’ technological and spatial demands and practices into mainstream culture may fragment the movement into physical and social agendas, but this fragmentation does not necessarily silence biketivism’s more radical social politics. At least in Austin, co-optation of biketivism may paradoxically be helping biketivists meet their goal of bringing (pedal) power to the people. / text

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