共查询到20条相似文献，搜索用时 31 毫秒
1.
Giuseppe Gibertini Donato Grassi Carlo Macchi Giuseppe De Bortoli 《Sports Engineering》2010,12(3):155-161
The present paper describes the activity carried out to investigate the aerodynamic effects of cycling shoes for time trial
competitions. This subject has not been widely studied but can be important for an accurate aerodynamic optimisation of a
time trial cyclist. The study was carried out by means of wind tunnel testing: an appropriate test setup and an appropriate
test procedure (based on “effective angle of attack approach”) were developed in order to produce realistic test conditions.
The developed testing procedure was applied to two different shoe models, differently fastened. Furthermore, an important
point was the investigation of the overshoe effect. The results showed that the power required to overcome the shoe’s drag
is almost a tenth of the total power and that differences between the shoes can affect the cyclist’s performance. 相似文献
2.
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
3.
4.
Aerodynamic drag in cycling: methods of assessment 总被引：1，自引：0，他引：1
Debraux P Grappe F Manolova AV Bertucci W 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(3):197-218
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.
6.
Pierre Debraux Frederic Grappe Aneliya V. Manolova William Bertucci 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):197-218
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
7.
Aerodynamics has such a profound impact on cycling performance at the elite level that it has infiltrated almost every aspect of the sport from riding position and styles, equipment design and selection, race tactics and training regimes, governing rules and regulations to even the design of new velodromes. This paper presents a review of the aspects of aerodynamics that are critical to understanding flows around cyclists under racing conditions, and the methods used to evaluate and improve aerodynamic performance at the elite level. The fundamental flow physics of bluff body aerodynamics and the mechanisms by which the aerodynamic forces are imparted on cyclists are described. Both experimental and numerical techniques used to investigate cycling aerodynamic performance and the constraints on implementing aerodynamic saving measures at the elite level are also discussed. The review reveals that the nature of cycling flow fields are complex and multi-faceted as a result of the highly three-dimensional and variable geometry of the human form, the unsteady racing environment flow field, and the non-linear interactions that are inherent to all cycling flows. Current findings in this field have and will continue to evolve the sport of elite cycling while also posing a multitude of potentially fruitful areas of research for further gains in cycling performance. 相似文献
8.
In a number of sport disciplines characterized by high velocities, aerodynamic performance of sports apparel is a concern. The goal is often to reduce the aerodynamic drag force and thereby increase speed. In the design of optimized competition apparel the fabric properties will be very important. One fabric property which has traditionally been considered an influencing parameter on aerodynamic performance is the air permeability. In this paper the effect of air-permeability, treated as an independent variable, upon aerodynamic drag on a bluff body is investigated. Similar multilayer textiles with internal membranes regulating air permeability were tested on cylindrical models in wind tunnel experiments in order to identify a possible relation between air-permeability and drag force. A weak dependence of flow transition on air-permeability could be found, but this could be considered to have a limited effect on the aerodynamic performance of sports garments. 相似文献
9.
第18届国际运动生物力学讨论会录用论文述评 总被引：1，自引：1，他引：0
从基础理论研究、应用研究和方法学研究三个层面 ,对第 18届国际运动生物力学讨论会录用的论文进行了述评。认为 2 1世纪我国运动生物力学研究 ,应围绕生物材料的力学特性、人体基本动作与运动、大众体育和解决本学科的方法学问题进行 ,注重加强同相关学科学者和本学科学者间的国际、国内交流。 相似文献
10.
The aim of this study was to describe and validate a new cycling ergometer with original characteristics that allow the measurement
of biomechanical variables with position and crank inertial load used by the cyclist in field condition. The braking pedalling
force, that permitted the simulation of the resistance to the cyclist in the field, is performed with a brushless electric
motor. The validity and the reproducibility of the power output measurements were compared with the widely accepted SRM powermeter.
The results indicate that taking into account a systematic error, the measurements are valid compared with the SRM, and the
reproducibility of the power output measurements is similar to the SRM. In conclusion, this ergometer is the only one that
allows at the same time for (1) valid and reproducible power output measurements at submaximal intensity, (2) utilisation
of the personal bicycle of the cyclist, and (3) simulation of the inertial characteristics of the road cycling. 相似文献
11.
《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
12.
Michael J. Falvo Brian K. Schilling Lawrence W. Weiss 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):293-311
Power is an integral aspect of many sports. Although power output of the lower body is often measured during jumping and cycling movements, much less is known about power as pertains to the upper body musculature. Recently, isoinertial methods ‐ with constant gravitational load ‐ of power testing have become common, but little is known of the reliability and criterion validity of these tests as they pertain to sport performance. In addition, the varied methodology makes a lucid model more evasive. The aims of this review are to examine the various methods of assessing upper body power, to establish its role in predicting athletic performance, and to assess the body of literature that has assessed power output of the upper extremities by isoinertial methods. To our knowledge, only two studies on isoinertial upper‐body power have shown a direct correlation to sporting ability (Baker, 2001; Baker et al., 2001); therefore, many unanswered questions exist as to the efficacy of these tests as predictors of athletic ability or as a method to track athletes’ training over time. From this review we hope to allow the sport coach to assess the overall utility of these tests in terms of availability, safety and external validity. 相似文献
13.
Falvo MJ Schilling BK Weiss LW 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(2):293-311
Power is an integral aspect of many sports. Although power output of the lower body is often measured during jumping and cycling movements, much less is known about power as pertains to the upper body musculature. Recently, isoinertial methods--with constant gravitational load--of power testing have become common, but little is known of the reliability and criterion validity of these tests as they pertain to sport performance. In addition, the varied methodology makes a lucid model more evasive. The aims of this review are to examine the various methods of assessing upper body power, to establish its role in predicting athletic performance, and to assess the body of literature that has assessed power output of the upper extremities by isoinertial methods. To our knowledge, only two studies on isoinertial upper-body power have shown a direct correlation to sporting ability (Baker, 2001; Baker et al., 2001); therefore, many unanswered questions exist as to the efficacy of these tests as predictors of athletic ability or as a method to track athletes' training over time. From this review we hope to allow the sport coach to assess the overall utility of these tests in terms of availability, safety and external validity. 相似文献
14.
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
15.
发展短中距离自行车运动员专项力量素质的探讨 总被引：7，自引：0，他引：7
夏春晓 《哈尔滨体育学院学报》2004,22(3)
结合自行车运动训练实践 ,阐述自行车中短距离运动员力量训练的方法与途径和自行车专项力量训练的解剖学与动力学特点 ,并针对运动员的专项训练特点和与肌肉快速收缩规律 ,提出自行车专项力量训练原则性构思及应采取的有效训练手段 相似文献
16.
目的:研究以浙江省场地自行车短距离项目男子运动员为研究对象,通过六年的训练负荷反馈指标和机能反馈指标的采集、测试和分析,探讨上述指标对我省场地自行车短距离项目男子运动员成长存在的影响,为我省场地自行车男子短距离项目的持续高效的发展提供一定的理论依据。方法:在六年的训练周期中,对我省自行车运动员的血红蛋白、血清睾酮、血清肌酸激酶和血尿素氮进行定期测试,并形成比较完整的数据库进行对比分析。结果:①优秀组和普通组的血清睾酮、血清肌酸激酶和血尿素氮6年间变化趋势基本一致,而血红蛋白存在不同的变化趋势;②在机能反馈变化方面,与优秀组相比较,普通组的血红蛋白平均值在2012年、2016年和2017年有非常显著性差异(P<0.01),而血清睾酮则在2012年、2013年和2016年存在非常显著性差异(P<0.01);③在训练负荷反馈方面,仅在2017年,优秀组的血清肌酸激酶平均值与普通组相比较,出现非常显著性差异(P<0.01)。结论:①对场地自行车短距离男子运动员来说,血红蛋白在训练初期可能不是最主要的机能指标,但是到训练中后期可能会成为评价运动员恢复能力的一项主要指标;②血清睾酮水平的高低对场地自行车短距离男子运动员的成才至关重要,是训练初期就需要重点关注的一个指标;③血清肌酸激酶和血尿素氮分别是训练强度和训练量的机体反馈指标,优秀运动员在训练内容转换的过程中,适应能力要好于普通运动员。 相似文献
17.
为探究体育旅游体验的构成及内部要素之间的关系,研究从"动态依附"视角观察骑行旅游实践,选取12位沿川藏线(G318)骑行旅游者,采用深度访谈法分析其体验内容及规律。研究发现:骑行旅游体验由场域体验、身体体验、心理体验及体验转向构成,以身体、心理为基础的场域变化为旅游者创造了体验转向的环境,其过程可简要概括为"身心依附",此种结构的生成依赖于"骑行动觉"经验,置身于广泛的生理、心理和文化情境中。研究揭示了体育旅游体验的内部规律,丰富了体育旅游体验领域的理论成果,旨在促进体育旅游产业的高质量发展。 相似文献
18.
Matthew C. Miller Philip W. Fink Paul William Macdermid Blake G. Perry Stephen R. Stannard 《Sports biomechanics / International Society of Biomechanics in Sports》2018,17(3):303-313
Real-world cycling performance depends not only on exercise capacities, but also on efficiently traversing the bicycle through the terrain. The aim of this study was to determine if it was possible to quantify the braking done by a cyclist in the field. One cyclist performed 408 braking trials (348 on a flat road; 60 on a flat dirt path) over 5 days on a bicycle fitted with brake torque and angular velocity sensors to measure brake power. Based on Newtonian physics, the sum of brake work, aerodynamic drag and rolling resistance was compared with the change in kinetic energy in each braking event. Strong linear relationships between the total energy removed from the bicycle-rider system through braking and the change in kinetic energy were observed on the tar-sealed road (r2 = 0.989; p < 0.0001) and the dirt path (r2 = 0.952; p < 0.0001). T-tests revealed no difference between the total energy removed and the change in kinetic energy on the road (p = 0.715) or dirt (p = 0.128). This study highlights that brake torque and angular velocity sensors are valid for calculating brake power on the disc brakes of a bicycle in field conditions. Such a device may be useful for investigating cyclists’ ability to traverse through various terrains. 相似文献
19.
Luca Oggiano Olga Troynikov Inna Konopov Aleksandar Subic Firoz Alam 《Sports Engineering》2009,12(1):1-12
Wind tunnel testing has been carried out on nine-knitted single jersey fabrics (100% polyester) using cylinder and leg models
to determine its aerodynamic behaviour over a range of speeds (20–80 km/h) representative of sports activities. Strong correlation
between fabric manufacturing (cover factor) and fabric roughness and aerodynamic parameters has been established. Similar
aerodynamic behaviour of fabrics was observed when tested on the cylinder model and on the leg model. 相似文献
20.
This paper investigates the optimisation of the chain drive system on sports motorcycles. Recently there has been the development
of a chain transmission efficiency model that is suitable for motorcycles. The new model is used to predict the efficiency
of 600cc sports motorcycle at different speeds. The transmission efficiency is estimated to be between 96 and 99% for speeds
less than 75 mile/h. Between 75 and 150 mile/h the transmission efficiency can be as low as 85% due to inertial tension. The
transmission efficiency model presented in this paper enables optimisation of sprocket and chain sizes. In general, large
sprockets are better at low speeds and smaller sprockets are better at high speeds. The optimum chain size is the chain with
the smallest pitch that can meet the torque and power requirement. The sprocket centre distance also has a big effect on efficiency
and it is important to use an effective installation procedure. In particular, it is important to set a chain up when the
rear wheel axle, front crank and swing arm bearing are all in-line. 相似文献