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1.
In time trial cycling stage, aerodynamic properties of cyclists are one of the main factors that determine performances. Such aerodynamic properties are strongly dependent on the cyclist ability to get into the most suitable posture to have minimal projected frontal area facing the air. The accurate knowledge of the projected frontal area (A) is thus of interest to understand the performance better. This study aims for the first time at a model estimating accurately A as a function of anthropometric properties, postural variations of the cyclist and the helmet characteristics. From experiments carried out in a wind tunnel test-section, drag force measurements, 3D motion analysis and frontal view of the cyclists are performed. Computerized planimetry measurements of A are then matched with factors related to the cyclist posture and the helmet inclination and length. Data show that A can be fully represented by a rate of the cyclist body height, his body mass, inclination and length of his helmet. All the above-mentioned factors are thus taken into account in the present modelling and the prediction accuracy is then determined by comparisons between planimetry measurements and A values estimated using the model.  相似文献   

2.
Kinsey F 《国际体育史杂志》2011,28(8-9):1121-1137
During the 1890s, in Australia and around the world, there was a convergence of the cycle, the camera and women. With the advent of the revolutionary safety bicycle, cycling had become a craze. At the same time, photographic technology had undergone changes that meant photographs were cheaper and more accessible. Women became avid consumers of both these new technologies; they became cyclists in unprecedented numbers for the first time, and they also became the popular subjects, and proud owners, of photographic portraits. These two trends converged, resulting in a proliferation of photographic portraits of women cyclists, many of which were published in newspapers and magazines. These bicycle portraits have now become a rich source for historians. More than just visually interesting artefacts, these photographic depictions of the Australian woman cyclist are important windows into the history of Australian women's cycling in the last decade of the nineteenth century. Bicycle portraits provide significant insights into the study of Australian women cyclists, from historical detail ranging from costume, bicycle and cycling activity choices to more complex understandings of the expression of feminine identity among Australian women cyclists in the 1890s.  相似文献   

3.
Aerodynamic drag in cycling: methods of assessment   总被引：1，自引：0，他引：1  
When cycling on level ground at a speed greater than 14 m/s, aerodynamic drag is the most important resistive force. About 90% of the total mechanical power output is necessary to overcome it. Aerodynamic drag is mainly affected by the effective frontal area which is the product of the projected frontal area and the coefficient of drag. The effective frontal area represents the position of the cyclist on the bicycle and the aerodynamics of the cyclist-bicycle system in this position. In order to optimise performance, estimation of these parameters is necessary. The aim of this study is to describe and comment on the methods used during the last 30 years for the evaluation of the effective frontal area and the projected frontal area in cycling, in both laboratory and actual conditions. Most of the field methods are not expensive and can be realised with few materials, providing valid results in comparison with the reference method in aerodynamics, the wind tunnel. Finally, knowledge of these parameters can be useful in practice or to create theoretical models of cycling performance.  相似文献   

4.
When cycling on level ground at a speed greater than 14 m/s, aerodynamic drag is the most important resistive force. About 90% of the total mechanical power output is necessary to overcome it. Aerodynamic drag is mainly affected by the effective frontal area which is the product of the projected frontal area and the coefficient of drag. The effective frontal area represents the position of the cyclist on the bicycle and the aerodynamics of the cyclist-bicycle system in this position. In order to optimise performance, estimation of these parameters is necessary. The aim of this study is to describe and comment on the methods used during the last 30 years for the evaluation of the effective frontal area and the projected frontal area in cycling, in both laboratory and actual conditions. Most of the field methods are not expensive and can be realised with few materials, providing valid results in comparison with the reference method in aerodynamics, the wind tunnel. Finally, knowledge of these parameters can be useful in practice or to create theoretical models of cycling performance.  相似文献   

5.
ABSTRACT

Guidance to maintain an optimal aerodynamic position is currently unavailable during cycling. This study used real-time vibrotactile feedback to guide cyclists to a reference position with minimal projected frontal area as an indicator of aerodynamic drag, by optimizing torso, shoulder, head and elbow position without compromising comfort when sitting still on the bike. The difference in recapturing the aerodynamic reference position during cycling after predefined deviations from the reference position at different intensities was analysed for 14 participants between three interventions, consisting of 1) vibrotactile feedback with a margin of error of 1.5% above the calibrated reference projected frontal area, 2) vibrotactile feedback with a margin of 3%, and 3) no feedback. The reference position is significantly more accurately achieved using vibrotactile feedback compared to no feedback (p < 0.001), but there is no significant difference between the 1.5% and 3% margin (p = 0.11) in terms of relative projected frontal area during cycling compared to the calibrated reference position (1.5% margin ?0.46 ± 1.76%, 3% margin ?0.01 ± 2.01%, no feedback 2.59 ± 3.29%). The results demonstrate that vibrotactile feedback can have an added value in assisting and correcting cyclists in recapturing their aerodynamic reference position.  相似文献   

6.
This study investigates the rolling and drag resistance parameters and bicycle and cargo masses of typical urban cyclists. These factors are important for modelling of cyclist speed, power and energy expenditure, with applications including exercise performance, health and safety assessments and transportation network analysis. However, representative values for diverse urban travellers have not been established. Resistance parameters were measured utilizing a field coast-down test for 557 intercepted cyclists in Vancouver, Canada. Masses were also measured, along with other bicycle attributes such as tire pressure and size. The average (standard deviation) of coefficient of rolling resistance, effective frontal area, bicycle plus cargo mass, and bicycle-only mass were 0.0077 (0.0036), 0.559 (0.170) m2, 18.3 (4.1) kg, and 13.7 (3.3) kg, respectively. The range of measured values is wider and higher than suggested in existing literature, which focusses on sport cyclists. Significant correlations are identified between resistance parameters and rider and bicycle attributes, indicating higher resistance parameters for less sport-oriented cyclists. The findings of this study are important for appropriately characterising the full range of urban cyclists, including commuters and casual riders.  相似文献   

7.
The speed attained by a track cyclist is strongly influenced by aerodynamic drag, being the major retarding force in track events of more than 200 m. The aims of this study were to determine the effect of changes in shoulder and torso angles on the aerodynamic drag and power output of a track cyclist. The drag of three competitive track cyclists was measured in a wind tunnel at 40 kph. Changes in shoulder and torso angles were made using a custom adjustable handlebar setup. The power output was measured for each position using an SRM Power Meter. The power required by each athlete to maintain a specific speed in each position was calculated, which enabled the surplus power in each position to be determined. The results showed that torso angle influenced the drag area and shoulder angle influenced the power output, and that a low torso angle and middle shoulder angle optimised the surplus power. However, the lowest possible torso angle was not always the best position. Although differences between individual riders was seen, there was a strong correlation between torso angle and drag area.  相似文献   

8.
优秀短距离自行车运动员无氧代谢能力特征研究   总被引：13，自引：2，他引：11  
目的:比较不同性别和训练水平运动员无氧能力的差异,探讨短距离自行车运动员高能磷酸原供能、糖酵解供能和混合无氧供能能力的特征。方法:对16名优秀短距离自行车运动员进行10s(女)、15s(男)、30s和60s的无氧功测定,测定运动后即刻、运动后3min恢复心率和血乳酸。结果:1)磷酸原代谢能力表现出明显的性别差异,男运动员最大功率、相对最大功率、平均功率、相对平均功率、最大圈数都明显高于女运动员;2)30s和60s两种测试中,运动员爆发力表现出相同水平,但糖酵解代谢持续供能能力随运动时间的延长而明显下降;3)男子优秀运动员组15s无氧功最大功率、平均功率明显高于普通组。男、女最大圈数大于普通组,达到最大圈数时间小于或等于普通组;4)男子优秀组运动员30s、60s平均功率高于普通运动员组。女子优秀运动员组30s、60s平均功率、最大圈数明显高于普通运动员组,60s最大功率明显高于普通运动员组(P<0.05)。结论:1)优秀短距离自行车运动员具有较强的磷酸原代谢能力,男运动员明显强于女运动员;2)较强的糖酵解代谢能力是短距离自行车运动员无氧代谢能力的特征;3)评定磷酸原系统能力时,男、女运动员都使用10s无氧功测试为好;4)不同水平运动员的无氧代谢能力表现出明显差异,优秀运动员组强于普通运动员组。  相似文献   

9.
Abstract

Aerodynamic and rolling resistances are the two major resistances that affect road cyclists on level ground. Because of reduced speeds and markedly different tyre-ground interactions, rolling resistance could be more influential in mountain biking than road cycling. The aims of this study were to quantify 1) aerodynamic resistance of mountain-bike cyclists in the seated position and 2) rolling resistances of two types of mountain-bike tyre (smooth and knobby) in three field surfaces (road, sand and grass) with two pressure inflations (200 and 400 kPa). Mountain-bike cyclists have an effective frontal area (product of projected frontal area and drag coefficient) of 0.357 ± 0.023 m2, with the mean aerodynamic resistance representing 8–35% of the total resistance to cyclists' motion depending on the magnitude of the rolling resistance. The smooth tyre had 21 ± 15% less rolling resistance than the knobby tyre. Field surface and inflation pressure also affected rolling resistance. These results indicate that aerodynamic resistance influences mountain-biking performance, even with lower speeds than road cycling. Rolling resistance is increased in mountain biking by factors such as tyre type, surface condition and inflation pressure that may also alter performance.  相似文献   

10.
ABSTRACT

Mobile power meters provide a valid means of measuring cyclists’ power output in the field. These field measurements can be performed with very good accuracy and reliability making the power meter a useful tool for monitoring and evaluating training and race demands. This review presents power meter data from a Grand Tour cyclist’s training and racing and explores the inherent complications created by its stochastic nature. Simple summary methods cannot reflect a session’s variable distribution of power output or indicate its likely metabolic stress. Binning power output data, into training zones for example, provides information on the detail but not the length of efforts within a session. An alternative approach is to track changes in cyclists’ modelled training and racing performances. Both critical power and record power profiles have been used for monitoring training-induced changes in this manner. Due to the inadequacy of current methods, the review highlights the need for new methods to be established which quantify the effects of training loads and models their implications for performance.  相似文献   

11.
不同专项训练对男子短距离自行车运动员无氧能力的影响   总被引：2，自引：2，他引：0  
分析两个阶段不同侧重的专项训练前后男子短距离自行车运动员无氧功和专项成绩的变化,探讨不同专项训练对无氧能力的影响,为合理安排训练计划、评价训练效果提供依据。在冬训期间,对运动员的15s、30s无氧功和场地专项成绩测试结果显示,专项力量训练提高了运动员的磷酸原供能能力,但8周训练时间过长,造成了专项频率水平的降低,影响了成绩。专项频率训练虽然使无氧能力小幅下降,但对运动员骑行频率的改善从整体上提高了短距离运动员的专项成绩。在训练计划的制定中,应合理安排各种专项训练手段的比例。  相似文献   

12.
在对第2届环青海湖国际公路自行车赛全体中、外参赛运动员比赛成绩进行统计处理和全面分析基础上,着重对成绩较好的中、外运动员进行相对成绩、平均排名、速度方差和相对速度方差各项指标的对比分析。结果显示:我国优秀运动员有与国外优秀运动员抗争的实力,而团队整体实力与国外强队仍有一定差距,处于中等水平;在全程速度分配上较为合理,但相对速度能力较差,关键性赛段波动较大,参与激烈竞争的能力远不如国外优秀运动员。  相似文献   

13.
《Sport in History》2013,33(3):497-514
Since the Tour de France doping scandal of 1998 there has been a concerted effort to ‘clean up’ cycling. But has this meant a change in attitude regarding the use of doping within the professional cycling community? In order to compare norms and values of today's elite cyclist with those of earlier periods, three historical phases in modern cycling are identified, and an account of professional cyclists’ preparations is given for each phase. Because of the different attitudes to doping found between riders of different categories, the article considers it necessary to reject the commonly held view that elite cyclists all take part in the same deviant subculture.  相似文献   

14.
To reduce aerodynamic resistance cyclists lower their torso angle, concurrently reducing Peak Power Output (PPO). However, realistic torso angle changes in the range used by time trial cyclists have not yet been examined. Therefore the aim of this study was to investigate the effect of torso angle on physiological parameters and frontal area in different commonly used time trial positions. Nineteen well-trained male cyclists performed incremental tests on a cycle ergometer at five different torso angles: their preferred torso angle and at 0, 8, 16 and 24°. Oxygen uptake, carbon dioxide expiration, minute ventilation, gross efficiency, PPO, heart rate, cadence and frontal area were recorded. The frontal area provides an estimate of the aerodynamic drag. Overall, results showed that lower torso angles attenuated performance. Maximal values of all variables, attained in the incremental test, decreased with lower torso angles (P < 0.001). The 0° torso angle position significantly affected the metabolic and physiological variables compared to all other investigated positions. At constant submaximal intensities of 60, 70 and 80% PPO, all variables significantly increased with increasing intensity (P < 0.0001) and decreasing torso angle (P < 0.005). This study shows that for trained cyclists there should be a trade-off between the aerodynamic drag and physiological functioning.  相似文献   

15.
β-alanine is a common ingredient in supplements consumed by athletes. Indeed, athletes may believe that the β-alanine induced paresthesia, experienced shortly after ingestion, is associated with its ergogenic effect despite no scientific mechanism supporting this notion. The present study examined changes in cycling performance under conditions of β-alanine induced paresthesia. Eight competitive cyclists (VO2max = 61.8 ± 4.2 mL·kg·min?1) performed three practices, one baseline and four experimental trials. The experimental trials comprised a 1-km cycling time trial under four conditions with varying information (i.e., athlete informed β-alanine or placebo) and supplement content (athlete received β-alanine or placebo) delivered to the cyclist: informed β-alanine/received β-alanine, informed placebo/received β-alanine, informed β-alanine/received placebo and informed placebo/received placebo. Questionnaires were undertaken exploring the cyclists’ experience of the effects of the experimental conditions. A possibly likely increase in mean power was associated with conditions in which β-alanine was administered (±95% CL: 2.2% ± 4.0%), but these results were inconclusive for performance enhancement (p = 0.32, effect size = 0.18, smallest worthwhile change = 56% beneficial). A possibly harmful effect was observed when cyclists were correctly informed that they had ingested a placebo (–1.0% ± 1.9%). Questionnaire data suggested that β-alanine ingestion resulted in evident sensory side effects and six cyclists reported placebo effects. Acute ingestion of β-alanine is not associated with improved 1-km TT performance in competitive cyclists. These findings are in contrast to the athlete’s “belief” as cyclists reported improved energy and the ability to sustain a higher power output under conditions of β-alanine induced paresthesia.  相似文献   

16.
The aims of this study were to measure the aerodynamic drag in professional cyclists, to obtain aerodynamic drag reference values in static and effort positions, to improve the cyclists' aerodynamic drag by modifying their position and cycle equipment, and to evaluate the advantages and disadvantages of these modifications. The study was performed in a wind tunnel with five professional cyclists. Four positions were assessed with a time-trial bike and one position with a standard racing bike. In all positions, aerodynamic drag and kinematic variables were recorded. The drag area for the time-trial bike was 31% higher in the effort than static position, and lower than for the standard racing bike. Changes in the cyclists' position decreased the aerodynamic drag by 14%. The aero-helmet was not favourable for all cyclists. The reliability of aerodynamic drag measures in the wind tunnel was high (r > 0.96, coefficient of variation < 2%). In conclusion, we measured and improved the aerodynamic drag in professional cyclists. Our results were better than those of other researchers who did not assess aerodynamic drag during effort at race pace and who employed different wheels. The efficiency of the aero-helmet, and the validity, reliability, and sensitivity of the wind tunnel and aerodynamic field testing were addressed.  相似文献   

17.
Bioelectrical impedance vector-analysis (BIVA) describes cell-mass, cell function and hydration status of an individual or a group. The goal of the present investigation was to provide bioelectrical impedance data for 525 male road cyclists (155 professionals, 79 elite, 59 elite-youth, and 232 amateurs) at the time of their optimal performance level. Data were plotted on the resistance-reactance (R-Xc) graph to characterize cyclists group vectors using BIVA. Compared to the general male population, the mean vector position of the road cyclists indicates a higher body cell mass (BCM) and phase angle (p<0.001). The vector position of the high-performance, compared to the amateur cyclists showed similar patterns with higher BCM and phase angles and higher reactance values for the high-performance athletes (p<0.001). The bio-impedance data were used to calculate the 50%, 75%, and 95% tolerance ellipses of each group of cyclists. The characteristic vector positions of the road cyclists indicate normal hydration and greater muscle mass and function of the high-performance cyclists compared to amateur cyclists and the normal population. The cyclists specific tolerance ellipses, particularly the high-performance cyclists might be used for classifying a cyclist according to the individual vector position and to define target vector regions for lower level cyclists.  相似文献   

18.
目的:通过40名自行车专业运动员在功率自行车上进行3种递增负荷运动实验比较有氧耐力.方法:40名自行车运动员(男21,女19)在功率自行车上进行有氧力竭运动,分别采用3 min递增法、1 min递增法和线性递增法进行运动负荷递增,用Oxyam Pro运动心肺功能仪观察最大耗氧量(VO2max)、心率(HRmax)、呼吸商(RQ)等指标,运动前、后采集血乳酸(Lac).结果:3种递增负荷运动实验的VO2max、HRmax指标无显著性差异(P>0.05),3种实验的RQ、Lac指标差异无显著规律性.结论:自行车运动员进行功率自行车3种递增负荷运动实验比较有氧耐力没有统计学差异,3种递增负荷运动实验均可作为功率自行车进行有氧耐力测试的方法.  相似文献   

19.
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20.
Abstract

Knee functional disorders are one of the most common lower extremity non-traumatic injuries reported by cyclists. Incorrect bicycle configuration may predispose cyclist to injury but the evidence of an effect of saddle setback on knee pain remains inconclusive. The aim of this study was to determine the effect of saddle setback on knee joint forces during pedalling using a musculoskeletal modelling approach. Ten cyclists were assessed under three saddle setback conditions (range of changes in saddle position ~6 cm) while pedalling at a steady power output of 200 W and cadence of 90 rpm. A cycling musculoskeletal model was developed and knee joint forces were estimated using an inverse dynamics method associated with a static optimisation procedure. Our results indicate that moving the saddle forwards was not associated with an increase of patellofemoral joint forces. On the contrary, the tibiofemoral mean and peak compression force were 14 and 15% higher in the Backward than in the Forward condition, respectively. The peak compression force was related to neither pedal force nor quadriceps muscle force but coincided with the eccentric contraction of knee flexor muscles. These findings should benefit bike fitting practitioners and coaches in the design of specific training/rehabilitation protocols.  相似文献   

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