On the exposure of hands to vibration in road cycling: an assessment of the effect of gloves and handlebar tape

The objective of this work was to assess the effectiveness of cycling gloves and handlebar tape in reducing the vibration transmitted to the cyclist’s hands in the classic “hoods” position for shock-type excitation at the front wheel on a bicycle treadmill. Three pairs of conditions were tested on a single participant: (1) With gloves vs. no gloves, no bar tape; (2) With bar tape vs. no bar tape, no gloves; (3) With gloves and bar tape vs. no gloves and no bar tape. We have shown that a rider can expect a small but significant drop in the level of transmitted power and energy through the handlebars when wearing a standard pair of road cycling gloves. If bar tape is used however (both with and without gloves), there is a significantly larger drop in the level of transmitted power and energy through the handlebars

Vibration Cycling Did Not Affect Energy Demands Compared to Normal Cycling During Maximal Graded Test

The aim of this study was to compare the physiological responses between a vibration induced cycling step protocol (Vib) and normal cycling (without vibration, no-Vib). Eighteen moderate trained males (age 24.1 ± 4.3 years; weight 76.5 ± 10.5 kg; height 178.0 ± 6.4 cm) have participated in this study. They randomly performed two gradual maximal exercise tests on two separate days using a new bike that automatically induces vibration cycling and the Corival cycle ergometer. The choice of two different bikes was made because of the impossibility to recreate the same power output without altering the cycling cadence on the vibration Bike. Both protocols were matched for power output and cycling cadence incrementations. Oxygen uptake (VO2), carbon dioxide production (VCO2), ventilation (VE), heart rate (HR), blood lactate and rating of perceived exertion (RPE) during each stage were continuously recorded. No statistical differences were founded for all variables when comparing the Vib to no-Vib trials, except a higher ventilation during the vibration trial at submaximal levels. The results of this study do not confirm those of previous studies stated that Vib increased metabolic demands during cycling exercise. Added vibration stimulus to an incremental cycling protocol does not affect physiological parameters.We would like to thank all the participants who took part in this investigation. A particular thank to Mr. Emanuele Gariffo who has substantially helped in the data collection. Also, our thank goes to the Sport Science Department at Greenwich University, London, United Kingdom, that logistically supported the study together with K. C. Wong Magna Fund at Ningbo University for their continuing encouragement

Effect of cyclist’s posture on performance and interaction with the bicycle

Los ciclistas usualmente definen su postura considerando requerimientos de desempeño y confort. Sin embargo, al modificar la postura, los ciclistas deben balancear estos requerimientos ya que son competitivos entre sí. En esta investigación, se desarrolló una metodología de optimización para seleccionar la postura óptima de ciclistas considerando el mejor compromiso entre desempeño e interacción con la bicicleta. El desempeño se definió por medio del tiempo de carrera, el cual se estimó considerando la capacidad de entrega de potencia y fuerzas resistivas como la resistencia aerodinámica. La interacción con la bicicleta se caracterizó utilizando índices de presión y vibración. La metodología de optimización se implementó para seleccionar la altura de las aerobarras de cinco ciclistas en carreras de contrarreloj individuales de 20 km con diferentes inclinaciones de vía y velocidades de viento. Los resultados mostraron que la reducción de la altura de aerobarras mejoró el arrastre aerodinámico y empeoró la capacidad de entrega de potencia, y la presión y vibración en el sillín para los ciclistas medidos. Se observó que las vibraciones en el sillín constituyen la restricción más estricta para el ciclista limitando los tiempos viables de exposición, y en algunos casos, modificando los resultados de selección de postura. Se concluyó que la selección de la postura óptima debe realizarse para cada ciclista con su bicicleta y para cada condición de carrera ya que el resultado depende de estos factores.Cyclists usually define their posture according to performance and comfort requirements. However, when modifying their posture, cyclists experience a trade-off between these requirements. In this research, an optimization methodology was developed to select the optimal posture of cyclists considering the best compromise between performance and interaction with the bicycle. Performance was defined as the race time estimated from the power delivery capacity and resistive forces (e.g., aerodynamic drag). The interaction with the bicycle was characterized using pressure and vibration indices. The optimization methodology was implemented to select the aerobars’ height for five cyclists riding on 20-km individual time-trial races with various wind speed and road grade conditions. The results showed that the reduction of the aerobars’ height improved the drag area and deteriorated the power delivery capacity, pressure on the saddle, and vibrations on the saddle for all the tested cyclists. It was observed that the vibrations on the saddle imposed the greatest constraint for the cyclists, limiting the feasible exposure time and, in some cases, modifying the result obtained if the posture was selected considering only performance. It was concluded that optimal posture selection should be performed specifically for each cyclist and race condition due to the dependence of the results on these factors.Doctor en IngenieríaDoctorad

Comparison of in-sight and handheld navigation devices toward supporting industry 4.0 supply chains: First and last mile deliveries at the human level

Last (and First) mile deliveries are an increasingly important and costly component of supply chains especially those that require transport within city centres. With reduction in anticipated manufacturing and delivery timescales, logistics personnel are expected to identify the correct location (accurately) and supply the goods in appropriate condition (safe delivery). Moving towards more environmentally sustainable supply chains, the last/first mile of deliveries may be completed by a cyclist courier which could result in significant reductions in congestion and emissions in cities. In addition, the last metres of an increasing number of deliveries are completed on foot i.e. as a pedestrian. Although research into new technologies to support enhanced navigation capabilities is ongoing, the focus to date has been on technical implementations with limited studies addressing how information is perceived and actioned by a human courier. In the research reported in this paper a comparison study has been conducted with 24 participants evaluating two examples of state-of-the-art navigation aids to support accurate (right time and place) and safe (right condition) navigation. Participants completed 4 navigation tasks, 2 whilst cycling and 2 whilst walking. The navigation devices under investigation were a handheld display presenting a map and instructions and an in-sight monocular display presenting text and arrow instructions. Navigation was conducted in a real-world environment in which eye movements and device interaction were recorded using Tobii-Pro 2 eye tracking glasses. The results indicate that the handheld device provided better support for accurate navigation (right time and place), with longer but less frequent gaze interactions and higher perceived usability. The in-sight display supported improved situation awareness with a greater number of hazards acknowledged. The benefits and drawbacks of each device and use of visual navigation support tools are discussed

No-Reference Video Quality Assessment Model for Distortion Caused by Packet Loss in the Real-Time Mobile Video Services

Packet loss will make severe errors due to the corruption of related video data. For most video streams, because the predictive coding structures are employed, the transmission errors in one frame will not only cause decoding failure of itself at the receiver side, but also propagate to its subsequent frames along the motion prediction path, which will bring a significant degradation of end-to-end video quality. To quantify the effects of packet loss on video quality, a no-reference objective quality assessment model is presented in this paper. Considering the fact that the degradation of video quality significantly relies on the video content, the temporal complexity is estimated to reflect the varying characteristic of video content, using the macroblocks with different motion activities in each frame. Then, the quality of the frame affected by the reference frame loss, by error propagation, or by both of them is evaluated, respectively. Utilizing a two-level temporal pooling scheme, the video quality is finally obtained. Extensive experimental results show that the video quality estimated by the proposed method matches well with the subjective quality

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 197, September 1979

This bibliography lists 193 reports, articles, and other documents introduced into the NASA scientific and technical information system in August 1979

A general approach for analysis and enhancement performance in mountain biking modality

Mountain biking (MTB) is an off-road cycling modality which is performed on a variety of unpaved terrains that normally include natural and/or artificial obstacles, such as trails in forests, rock garden and mud, involving successive uphill and downhill sections. Cross-country (XC) is the most popular competition format in MTB, which is composed by eight events, being Olympic cross-country (XCO) the best known among them. In addition to XCO, other XC events have gained popularity, but there are few studies on the topic. The cross-country mountain biking (XC-MTB) regulations and bicycles have been changed along the years, generating debates and uncertainties among cyclists. In this sense, the general aim of this thesis was to provide an up-todate overview of the topic, and to contribute to the advancement of knowledge on the XC-MTB events. For this, four studies were developed. Study one is a literature review that presents and discusses the most relevant scientific evidence on the XC-MTB, focusing on the characteristics of the main XC events and cyclists, as well as the development of bicycles, accidents and injuries in this sport. Evidence suggests that the physiological responses and mechanical demands change according to XC event. Moreover, we identified that the characteristics of cyclists differ according to the level of performance, and we highlighted the importance of pacing and the ability to perform technical sections of the circuit to be competitive in XC-MTB. Regarding bicycles, it is possibly to suggest that the bicycle equipped with 29” wheel and full suspension (frame with front and rear suspension) has the potential to achieve superior performance on XC-MTB circuits. The purpose of the study two was to investigate the pacing profile and performance level of XC cyclists on different technical and non-technical sections during a cross-country short track (XCC) event. Twenty professional cyclists (under23 and elite) performed six laps on a XCC circuit during the International MTB Cup. In general, the cyclists adopted a positive pacing profile, the same profile adopted by the elite and under-23. Faster cyclists adopted a more even pacing profile, while slower cyclists adopted a reverse J-shaped pacing profile. In addition, faster cyclists spent less time than slower cyclists during a non-technical sustained uphill section. Therefore, we conclude that superior XCC performance was associated with a more even pacing profile and a higher performance on a non-technical sustained climb section. The purpose of the study three was to evaluate mechanical parameters and pacing profile adopted by twelve professional male elite XC cyclists during XCC and XCO events in MTB World Cup. During both competitions, total time, speed, power output (PO) and cadence (CA) were recorded. While total race time was higher in XCO, speed, PO and CA were significantly higher in XCC. The pacing profile adopted by the cyclists in XCC was variable, while in XCO was positive. In addition, cyclists adopted a more conservative starting pace in XCC (below average race speed) but a more aggressive start in XCO (above average race speed). Therefore, since the parameters evaluated are different between XCC and XCO, the strategies and training methods developed to achieve superior performance must be specific to each competition format. Finally, the purpose of the study four was to assess whether body mass and body composition may be related to performance measures in XC-MTB, such as PO and time to exhaustion. Forty amateur XC cyclists were recruited to participate in this study. Anthropometric measurements were take and an incremental test on a cycle ergometer was performed. Our findings show that body mass and fat mass are associated with XC-MTB performance measures, but fat-free mass did not.O ciclismo de montanha (do termo em inglês mountain biking – MTB) é uma modalidade do ciclismo fora de estrada (do termo em inglês off-road) o qual é praticado sob uma variedade de terrenos não pavimentados que normalmente incluem obstáculos naturais ou artificiais, como trilhas em florestas, cascalho e lama, envolvendo várias seções de subidas e descidas. O cross-country (XC) é o formato de competição mais popular no MTB, envolvendo 8 eventos ao todo, sendo crosscountry Olímpico (XCO) o mais conhecido entre eles. Além do XCO, outros eventos do XC têm ganhado popularidade, mas existem poucos estudos sobre o tema. O regulamento do cross-country mountain biking (XC-MTB) e as bicicletas sofreram várias modificações ao longo dos anos, gerando discussões e incertezas entre os praticantes. Portanto, o principal objetivo desta tese foi fornecer um panorama atualizado sobre o tópico, e contribuir com o avanço do conhecimento sobre os eventos do XC-MTB. Para isso, foram desenvolvidos quatro estudos. O estudo um é uma revisão de literatura que apresenta e discute as evidências científicas mais relevantes sobre o XC-MTB, com foco nas características dos principais eventos do XC e dos ciclistas, bem como no desenvolvimento das bicicletas, acidentes e lesões neste esporte. As evidências sugerem que as respostas fisiológicas e as demandas mecânicas mudam de acordo com o evento do XC. Além disso, nós identificamos que as características dos ciclistas diferem de acordo com o nível de desempenho, além de destacar a importância do pacing e da capacidade de desempenhar seções técnicas do circuito para ser competitivo no XC-MTB. Sobre as bicicletas, é possível sugerir que a bicicleta equipada com aro de 29” e com um sistema de amortecimento full suspension (quadro com suspensão frontal e traseira) tem potencial para alcançar um desempenho superior nos circuitos de XC-MTB. Por fim, parece que adotar estratégias como equipamentos de proteção, bike fit, treinamento resistido e medidas de prevenção de acidentes podem reduzir a gravidade e o número de lesões. A proposta do estudo dois foi investigar o perfil de pacing e o nível de desempenho de ciclistas do XC sob diferentes seções técnicas e não técnicas do circuito durante um evento de cross-country short track (XCC). Vinte ciclistas profissionais (sub-23 e elite) realizaram seis voltas no circuito de XCC durante a Copa Internacional de MTB. Em geral, os ciclistas adotaram um perfil de pacing positivo, o mesmo perfil adotado pela categoria elite e sub-23. Os ciclistas mais rápidos adotaram um perfil de pacing mais uniforme, enquanto os ciclistas mais lentos adotaram um perfil de pacing em “J” inverso. Inclusive, os ciclistas mais rápidos gastaram menos tempo que os ciclistas mais lentos durante a seção de subida sustentada não técnica. Portanto, nós concluímos que o melhor desempenho no XCC foi associado com um perfil de pacing mais uniforme e com um desempenho mais alto na seção de subida sustentada não técnica. A proposta do estudo três foi avaliar parâmetros mecânicos e o perfil de pacing adotado por doze ciclistas profissionais do XC da categoria elite durante o XCC e XCO da Copa do Mundo de MTB. Durante ambas as competições, o tempo total, velocidade, potência (PO) e cadência (CA) foram gravadas. Enquanto o tempo total de prova foi maior no XCO, a velocidade, PO e CA foram significativamente maiores no XCC. No XCC o perfil de pacing adotado pelos ciclistas foi variável e no XCO foi um perfil de pacing positivo. Além disso, os atletas adotaram um ritmo mais conservador no início do XCC (abaixo da velocidade média da corrida), mas um início mais agressivo durante o XCO (acima da velocidade média da corrida). Portanto, uma vez que os parâmetros avaliados são diferentes entre XCC e XCO, as estratégias e os métodos de treinamento desenvolvidos para alcançar um desempenho superior devem ser específicos para cada formato de competição. Por fim, a proposta do estudo quatro foi avaliar se a massa corporal e a composição corporal podem ter alguma relação com medidas de desempenho no XC-MTB, tal como PO e tempo até exaustão. Quarenta ciclistas amadores do XC foram submetidos a realização de medidas antropométricas e de um teste incremental em cicloergômetro. Nossos achados mostram que a massa corporal e a massa de gordura estão associadas com as medidas de desempenho do XC-MTB, mas a massa livre de gordura, não.FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerai

Gravel cycling craft and the senses: scenes, sounds, vibrations, fatigue and typifications on off-road tracks

Although cycling has been researched at the interactional level, there is scant literature regarding embodiment, and the somatic experiences from rider-bike-ground interactions. Via an ethnographic approach using video obtained from participant observation as a “graveller” sensory practices are examined. Firstly, the research is positioned with the literature on craft studies. Secondly the domains of action namely space, place and the body are theorized and conceptualized. Thirdly, the sensory perceptions generated by gravel riders are depicted. Fourthly, these combined perceptions in turn foster the establishment of subcultural typifications of gravel tracks which are portrayed and form part of the craft knowledge of the above group. The paper concludes by pointing out the link between the sensory and the development of a particular consciousness, and also sport as a fertile ground for investigating craft practices