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1.
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   

2.
Abstract

In this holistic review of cycling science, the objectives are: (1) to identify the various human and environmental factors that influence cycling power output and velocity; (2) to discuss, with the aid of a schematic model, the often complex interrelationships between these factors; and (3) to suggest future directions for research to help clarify how cycling performance can be optimized, given different race disciplines, environments and riders. Most successful cyclists, irrespective of the race discipline, have a high maximal aerobic power output measured from an incremental test, and an ability to work at relatively high power outputs for long periods. The relationship between these characteristics and inherent physiological factors such as muscle capilliarization and muscle fibre type is complicated by inter-individual differences in selecting cadence for different race conditions. More research is needed on high-class professional riders, since they probably represent the pinnacle of natural selection for, and physiological adaptation to, endurance exercise. Recent advances in mathematical modelling and bicycle-mounted strain gauges, which can measure power directly in races, are starting to help unravel the interrelationships between the various resistive forces on the bicycle (e.g. air and rolling resistance, gravity). Interventions on rider position to optimize aerodynamics should also consider the impact on power output of the rider. All-terrain bicycle (ATB) racing is a neglected discipline in terms of the characterization of power outputs in race conditions and the modelling of the effects of the different design of bicycle frame and components on the magnitude of resistive forces. A direct application of mathematical models of cycling velocity has been in identifying optimal pacing strategies for different race conditions. Such data should, nevertheless, be considered alongside physiological optimization of power output in a race. An even distribution of power output is both physiologically and biophysically optimal for longer ( >4km) time-trials held in conditions of unvarying wind and gradient. For shorter races (e.g. a 1km time-trial), an‘all out’ effort from the start is advised to‘save’ time during the initial phase that contributes most to total race time and to optimize the contribution of kinetic energy to race velocity. From a biophysical standpoint, the optimum pacing strategy for road time-trials may involve increasing power in headwinds and uphill sections and decreasing power in tailwinds and when travelling downhill. More research, using models and direct power measurement, is needed to elucidate fully how much such a pacing strategy might save time in a real race and how much a variable power output can be tolerated by a rider. The cyclist's diet is a multifactorial issue in itself and many researchers have tried to examine aspects of cycling nutrition (e.g. timing, amount, composition) in isolation. Only recently have researchers attempted to analyse interrelationships between dietary factors (e.g. the link between pre-race and in-race dietary effects on performance). The thermal environment is a mediating factor in choice of diet, since there may be competing interests of replacing lost fluid and depleted glycogen during and after a race. Given the prevalence of stage racing in professional cycling, more research into the influence of nutrition on repeated bouts of exercise performance and training is required.  相似文献   

3.
In this holistic review of cycling science, the objectives are: (1) to identify the various human and environmental factors that influence cycling power output and velocity; (2) to discuss, with the aid of a schematic model, the often complex interrelationships between these factors; and (3) to suggest future directions for research to help clarify how cycling performance can be optimized, given different race disciplines, environments and riders. Most successful cyclists, irrespective of the race discipline, have a high maximal aerobic power output measured from an incremental test, and an ability to work at relatively high power outputs for long periods. The relationship between these characteristics and inherent physiological factors such as muscle capilliarization and muscle fibre type is complicated by inter-individual differences in selecting cadence for different race conditions. More research is needed on high-class professional riders, since they probably represent the pinnacle of natural selection for, and physiological adaptation to, endurance exercise. Recent advances in mathematical modelling and bicycle-mounted strain gauges, which can measure power directly in races, are starting to help unravel the interrelationships between the various resistive forces on the bicycle (e.g. air and rolling resistance, gravity). Interventions on rider position to optimize aerodynamics should also consider the impact on power output of the rider. All-terrain bicycle (ATB) racing is a neglected discipline in terms of the characterization of power outputs in race conditions and the modelling of the effects of the different design of bicycle frame and components on the magnitude of resistive forces. A direct application of mathematical models of cycling velocity has been in identifying optimal pacing strategies for different race conditions. Such data should, nevertheless, be considered alongside physiological optimization of power output in a race. An even distribution of power output is both physiologically and biophysically optimal for longer ( > 4 km) time-trials held in conditions of unvarying wind and gradient. For shorter races (e.g. a 1 km time-trial), an 'all out' effort from the start is advised to 'save' time during the initial phase that contributes most to total race time and to optimize the contribution of kinetic energy to race velocity. From a biophysical standpoint, the optimum pacing strategy for road time-trials may involve increasing power in headwinds and uphill sections and decreasing power in tailwinds and when travelling downhill. More research, using models and direct power measurement, is needed to elucidate fully how much such a pacing strategy might save time in a real race and how much a variable power output can be tolerated by a rider. The cyclist's diet is a multifactorial issue in itself and many researchers have tried to examine aspects of cycling nutrition (e.g. timing, amount, composition) in isolation. Only recently have researchers attempted to analyse interrelationships between dietary factors (e.g. the link between pre-race and in-race dietary effects on performance). The thermal environment is a mediating factor in choice of diet, since there may be competing interests of replacing lost fluid and depleted glycogen during and after a race. Given the prevalence of stage racing in professional cycling, more research into the influence of nutrition on repeated bouts of exercise performance and training is required.  相似文献   

4.
Vertigo has been described after the practice of mountain bike. This study aimed to investigate the prevalence of vertigo following competitions or training sessions of downhill mountain biking (DMB) or road cycling (RC). One hundred and two DMB riders, 79 road cyclists and 73 control participants filled in a survey intended to evaluate the prevalence of vertigo in daily living activities and following competitions or training sessions. Vertigo causal factors (crashes, head trauma, fatigue, characteristics of the path/road ridden) were recorded. DMB riders and road cyclists did not report more vertigo during daily living activities than controls. But DMB riders older than 30 had more risk to report vertigo than age-matched road cyclists (OR: 5.06, 95% CI: 1.23–20.62). Road cyclists aged between 20 and 29 were 2.59-fold (95% CI: 1.06–6.27) more likely to report vertigo than controls. After competitions and training sessions, DMB riders were 2.33-fold (95% CI: 1.22–4.41) more likely to report vertigo than road cyclists. Vertigo causal factors were crash with head trauma in DMB riders and fatigue in road cyclists. Vertigo during daily living activities may be of concern for cyclists, particularly older DMB riders. The accumulation of impacts (crashes, vibrations) during the career of a DMB rider may generate micro-traumatisms of the central nervous system and/or peripheral vestibular structures, particularly the otolith organs. In RC, the pathophysiological mechanisms generating vertigo might be effort-related disturbance of homeostasis. To avoid injuries, DMB riders should be aware that vertigo may occur at the end of training sessions or competitions.  相似文献   

5.
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   

6.
通过实验测试方法,对优秀中长距离自行车运动员进行功率车测试及肌电研究,了解运动员在原地起动阶段的踏频及功率变化情况,以及在原地起动阶段和固定功率车进行踏蹬时．下肢各主要肌肉的激活时间与用力情况,以便掌握运动员骑行过程中主要的用力肌肉,加强训练的针对性和有效性。研究发现,股内侧肌和股外侧肌肌电信号表现明显,提示这两块肌肉可能为踏蹬主要发力肌肉。在踏蹬过程中,运动员的肌肉用力情况存在一定的差异,全能运动员与公路运动员相比,肌肉用力比较平均,肌力也相对要大  相似文献   

7.
The aim of this study was to assess the relationship between several commonly used aerobic and anaerobic cycle ergometer tests and performance during a treadmill cycling hill climb. Eight competitive cyclists (age 27+/-7 years; body mass 73.2+/-5.2 kg; height 177+/-6 cm; mean +/- s) completed six tests in random order: a lactate minimum test; a Wingate anaerobic power test; and two 6-km climbs at 6% and two 1-km climbs at 12% gradient performed on a motorized treadmill. The mean times and power outputs for the 6-km and 1-km climbs were 16:30+/-1:08 min: s and 330+/-17.8 W, and 4:19+/-0:27 min: s and 411+/-24.4 W, respectively. The best individual predictor of 6-km and 1-km performance times was the time for the corresponding climb at the other distance (r = 0.97). The next strongest predictor of both hill climb performances was the average power produced during the Wingate test divided by body mass. Stepwise regression analysis showed that the two variables contributing most to the prediction equation for both climbs were the Wingate average power per unit of body mass and maximal aerobic power divided by total mass (rider + bike), which together accounted for 92 and 96% of the variability in the 6-km and 1-km climbs. In conclusion, among competitive cyclists, the Wingate average power per unit of body mass was the best single predictor of simulated cycling hill climb performance at the distance and gradient used.  相似文献   

8.
We compared selected kinematic variables for four different ski turn techniques performed by five experienced and five intermediate male skiers. The four ski turn techniques were the upstem turn, the downstem turn, the parallel turn and the parallel step turn. Each turn was divided into the initiation phase and the first and second steering phases. Most of the statistically significant differences (P < 0.05) between the two groups were found for the initiation phases of the four turns. Both the hip axis-hand axis angle and the edging angle of the uphill ski were significantly different between the two groups for the upstem turn at the beginning of the initiation phase. For the downstem turn, significant differences between the groups were found at the start of the initiation phase for the hip axis-hand axis angle, the shoulder axis-fall line angle, and the edging angle of the uphill ski. The standard deviation of the distance between the tips of the two skis over the second steering phase also differed significantly between the two groups. For the parallel step turn, significant differences were found at the start of the initiation phase for the edging angle of the downhill ski and the downhill ski to movement direction angle. Significant differences were also found for the edging angle of the downhill ski in the middle of the second steering phase and the shoulder axis to movement direction angle at the end of this phase. For the initiation phase of the parallel turn, significant differences were found for the timing of setting the ski pole, the uphill knee angle at the start of this phase and the range of the knee angle of the uphill leg from the start to the end of this phase. For this turn, significant differences between the two groups were also found for the edging angle of the downhill ski in the middle of the second steering phase and the shoulder axis to movement direction angle at the end of this phase. One of the reasons it was possible to identify a few significant differences only for the turns analysed, was the variability within the intermediate group: for most of the variables analysed, the standard deviation was much higher for the intermediate than for the experienced group.  相似文献   

9.
Abstract

This study explored how differences in orienteering experience are related to differences in how visual attention is allocated to the map, the environment and to travel. Twenty more experienced and 20 less experienced individuals orienteered while wearing a head-mounted video camera with microphone. The participants verbalized what they were attending to (map, environment or travel) at any given time. Each recorded film was coded at each point in time in terms of what the participant was attending to and whether the participant was moving or stationary. More experienced orienteers attended to the map markedly more while moving and spent less time stationary than less experienced orienteers. The participants' performance was significantly related to the ability to attend to the map while moving. The strategic control of attention is proposed to explain this ability. It is proposed that attentional training might enhance performance in sports characterized by multiple and dynamically varying elements.  相似文献   

10.
Abstract

Previous investigators have yielded conflicting results in testing the hypothesis that the use of toe clips during bicycle ergometry produces a higher maximal oxygen uptake ([Vdot]O 2 max) than testing without toe clips. Eight men, four competitive cyclists and four competitive distance runners volunteered to participate in three randomized [Vdot]O 2 max tests: 1) a treadmill running lest, 2) a bicycle ergometer test using standard toe clips, and 3) a test on the same ergometer without toe clips. The highest mean [Vdot]O 2 max was observed in the treadmill condition as expected. However, no statistically significant difference in mean [Vdot]O 2 max or performance time was observed between the toe-clip and no toe-clip conditions. Based on these results, the research hypothesis was rejected and no favorable physiological effect may be attributed to the use of toe clips.  相似文献   

11.
Abstract

The purpose of this study was to determine if there were differences in learning to perform a novel motor task between two equated groups: one group was subjected to learning the task immediately following a heavy physical work bout on a bicycle ergometer; the other group was subjected to learning the task with no imposed physical exercise. It was found that the subjects who practiced the stabilometer exercise in a fatigued state performed significantly better than subjects in the control group except for test 4. The experimental group also performed significantly better than the control group during the 5th test which was performed without any fatiguing task. It appears from this study that the fatigue state of the learner had a favorable influence on both performance and learning of certain novel motor skills.  相似文献   

12.
Abstract

Bicycles are now gradually losing their attraction for utilitarian use, but in recent years, cycling for tourism and recreation has gained in popularity. However, the experiences and well-being involved in cycling tourism from a theoretical perspective have received little attention. This article intends to explore the relationships between cycling tourism and well-being by studying cyclists on Hainan Island in China. Interviews and participation observations were used to collect data. The types of cycling tourists were firstly identified and classified, followed by analysis of how the tourists obtained well-being through physical and social activities and their contexts. The study finds that human–bicycle relationships and China’s collectivistic culture play important roles in how cycling tourists obtain well-being. This study provides a mobility perspective on cycling tourism and well-being.  相似文献   

13.
Eight cyclists were photographed with a digital camera for three trials while positioned on their own bicycle wearing their helmet. The positions were different from each other and described as hands on the brake hoods, hands below the curve of the brake hoods on the handlebars, and using aerobars. Twenty-four trials were digitized by two different individuals three times to estimate the inter- and intra-rater reliability of the method. The intraclass correlation coefficient (p < .05) value for the intra-rater (test–retest) reliability was .993, and for inter-rater consistency, it was .976. There were significant differences (p < .05) between digitizers and between trials, apparently due to a learning effect that disappeared by the third trial. Due to small differences between digitizers and trials, caution is recommended when considering the use of this method.  相似文献   

14.
Abstract

This aim of this study was to analyse the nature of movement variability and to assess whether entropy measures may represent a valuable synthetic index of neuromuscular organization. The regularity of kinematic/kinetic time series during race walking, the changes in the structure of intra-individual variability over the test session, and the influence of athletic skill in (inter)national rank athletes were investigated. Motion analysis techniques were used. Sample entropy (SampEn) was adopted to examine fluctuations in lower limb angles and ground reaction forces. The regularity of both original and surrogate time series was assessed and compared, by estimating SampEn, to verify the presence of non-linear features in movement variability. SampEn was statistically lower in the original data than in surrogates. In contrast, the regularity of time series did not change significantly throughout the subsequent intra-individual repetitions. Hip and ankle joint angles and vertical ground reaction force manifested increased entropy for skilled athletes. Results suggest that race walking variability was not only the product of random noise but also contained information about the inherent propriety of the neuro-musculo-skeletal system. Furthermore, they provide some indications about neuromuscular control of the lower limb joints during race walking gait, and about the differences between more and less skilled individuals.  相似文献   

15.
The stiffness measuring method for bicycle frames is not standardized, leading to a wide variety of test setups; they differ in many aspects such as applied load, support constraints and frame deflection measurement. The aim of this paper is to draw attention to this problem and to quantify the perturbing, unwanted side effects that influence the stiffness measurement of the bicycle frame. This is illustrated by developing a multi-purpose rating test method for bicycle frame stiffness. The proposed test rig design considers different aspects which should be taken into account when measuring the bicycle frame stiffness. In the experimental setup, it is observed that the contribution of the test bench compliance led to 21% difference in the frame stiffness results; the influence due to the head, the tube-bearing type the corresponding preload resulted in up to 19% difference in the stiffness results between the lowest and highest stiffness values measured; hysteresis effects caused by pulleys are estimated to introduce errors up to 11%; and the influence due to the operator variability and sensor accuracy is estimated to be less than 3%.  相似文献   

16.
Eight trained male cyclists who competed regularly in track races, were studied under control, alkalotic (NaHCO3) and placebo (CaCO3) conditions in a laboratory setting to study the effect of orally induced metabolic alkalosis on 60 s anaerobic work and power output on a bicycle ergometer. Basal, pre- and post-exercise blood samples in the three conditions were analysed for pH, pCO2, pO2, bicarbonate, base excess and lactate. All blood gas measurements were within normal limits at basal levels. There were significant differences in the amount of work produced, and in the maximal power output produced by the cyclists in the experimental condition when compared to the control and placebo conditions (P less than 0.01). The post-exercise pH decreased in all three conditions (P less than 0.05) and post-exercise pCO2 increased significantly in the alkalosis trial (P less than 0.01). In the alkalotic condition, the pre-exercise base excess and HCO3- levels were both higher (P less than 0.05) than the basal levels, suggesting that the bicarbonate ingestion had a significant increase in the buffering ability of the blood. Post-exercise lactate levels were significantly higher (P less than 0.05) after the alkalotic trial when compared to the other two conditions, immediately post-exercise and for the next 3 min. Post-exercise lactate levels were higher than basal or pre-exercise levels (P less than 0.001). This was true immediately post-exercise and for the next 5 min. The results of this study suggest that NaHCO3 is an effective ergogenic aid when used for typically anaerobic exercise as used in this experiment. We feel that this ergogenic property is probably due to the accelerated efflux of H+ ions from the muscle tissue due to increased extracellular bicarbonate buffering.  相似文献   

17.
Abstract

The reliability of individual differences in relative endurance performance and physiological response was studied in prepubescent boys (N = 21) and adult men (N = 21). Subjects were tested twice (test and retest) on a relative endurance test consisting of pedalling a bicycle ergometer for 8 minutes duration at a high initial work-rate. The work-rate averaged 103% ± 1.0% VO2 max (mean ± S.E.) for the children and 105% ± 1.1% VO2 max for the adults, p > .05. Except for minute 3, children and adults had similar patterns for consistency of relative endurance performance (RPM). However, in comparison to adults, children had smaller individual difference variation for both VO2 and HR (p > .05). On the average, children had a greater proportion of total variability in VO2 (34% vs. 17%) and HR (49% vs. 13%) due to intra-individual variability in comparison to true individual differences. Children-adult differences were attributed to maturity differences.  相似文献   

18.
Abstract

Three groups of 11 subjects enrolled in required physical education were equated on the basis of bicycling for two minutes at 14 kg. resistance. Group I did weight training, Group II used the Commander Set series of isometric contractions, and Group III participated in normal activities. At the conclusion of the 8-week experimental period all subjects were retested on the bicycle ergometer under the original conditions. Both experimental groups showed statistically significant improvements in the bicycle ergometer test and there were no statistically significant differences between the means of the differences between the initial and final scores of the two experimental groups. It is hypothesized that increases in muscular endurance may be effected by certain programs of isometric contractions as well as by isotonic exercises.  相似文献   

19.
An anthropometric analysis of elite Australian track cyclists   总被引：3，自引：0，他引：3  
An anthropometric analysis was conducted on 35 elite male Australian track cyclists having a mean age of 22.6 years and who had been competing on average for 9 years. The relationship of anthropometric parameters to both bicycle saddle height and cycling performance was also investigated. Subjects were allocated, for purposes of comparison, to an endurance or sprint group on the basis of their competitive event. The group members in total were ectomorphic mesomorphs of height 178 +/- 4.8 cm and weight 72.5 +/- 6.6 kg on average. Percentage of saddle height to lower limb length averaged 99 +/- 1.6%, and significant correlations existed between strength and both body mass (r = 0.57) and thigh girth (r = 0.55). No significant correlation was seen between any anthropometric parameter and performance in an individual event. Cyclists in the spint group were heavier (76.2 +/- 7.4 vs. 70.0 +/- 4.7 kg, P less than 0.01) and stronger (258 +/- 44.4 vs. 216 +/- 30.5 Nm, P less than 0.01), and had larger chest (98.2 +/- 6.2 vs. 92.4 +/- 2.9 cm, P less than 0.01), arm (33.0 +/- 2.2 vs. 30.7 +/- 1.6 cm, P less than 0.01), thigh (57.5 +/- 3.4 vs. 54.3 +/- 2.5 cm, P less than 0.01) and calf girths (37.8 +/- 1.7 vs. 36.2 +/- 1.9 cm, P less than 0.05) than cyclists in the endurance group. They were also more mesomorphic (5.3 +/- 0.7 vs. 4.7 +/- 0.8, P less than 0.05) and less ectomorphic (2.3 +/- 0.9 vs. 2.9 +/- 0.6, P less than 0.05) than the endurance cyclists.  相似文献   

20.
This study investigated the performance-related feasibility and physiological benefits of purposefully eliminating propulsive work while descending in mountain biking and compared values to those measured during road descending. Participants cycled uphill on a road at race pace before descending over three conditions (off-road pedalling; off-road coasting; road coasting). Relatively low power output during off-road pedalling was associated with a greater oxygen uptake (p?<?.01) when compared with off-road coasting despite no difference in vibration exposure (p?>?.05). Importantly, pedalling did not invoke a performance benefit (p?>?.05) on the descent used in this study. Significantly greater heart rate and oxygen uptake (both p?<?.01) were observed between road and off-road descending, likely caused by the increase in terrain-induced vibrations (p?<?.01) experienced between the bicycle and rider. Results indicate that reducing propulsive work during descending can improve recovery without being disadvantageous to performance. Similarly, the vibrations experienced during road descending are relatively low, and further reduce oxygen cost. In an effort to increase efficiency, it is recommended that mountain bike athletes focus on skills to increase descending speed without the addition of pedalling, and that equipment be used to decrease vibrations nearer to those seen on the road.  相似文献   

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