Effects of Adolescent Sport Practice on Health Outcomes of Adult Amateur Endurance Cyclists: Adulthood Is Not Too Late to Start.

PubMed

Munguia-Izquierdo, Diego; Mayolas-Pi, Carmen; Peñarrubia-Lozano, Carlos; Paris-Garcia, Federico; Bueno-Antequera, Javier; Oviedo-Caro, Miguel Angel; Legaz-Arrese, Alejandro

2017-11-01

We investigated the effects of adolescent sport practice on the training, performance, and health outcomes of adult amateur endurance cyclists and compared health outcomes of 3 adult groups: amateur endurance cyclists who practiced sports during adolescence, amateur endurance cyclists who did not practice sports during adolescence, and inactive individuals. In 859 (751 men and 108 women) adult cyclists and 718 inactive subjects (307 men and 411 women), we examined adolescent sport practice, current training status, quality of life, quality of sleep, anxiety and depression, and cardiometabolic risk: body mass index, physical activity, physical fitness, adherence to Mediterranean diet, and alcohol and tobacco consumption. Independent of gender, no significant differences in training, performance, or health outcomes were observed between amateur endurance cyclists who practiced sports during adolescence and those who did not. Independent of gender, cyclists reported significantly better health outcomes than inactive individuals in all variables, except depression. Training, performance, and health outcomes did not differ between adult amateur endurance cyclists who practiced sports during adolescence and those who did not, but their health outcomes were significantly improved compared with inactive individuals, except for depression.

Reporting on cyclist crashes in Australian newspapers.

PubMed

Boufous, Soufiane; Aboss, Ahmad; Montgomery, Victoria

2016-10-01

To assess information on cyclist crashes reported in Australian newspapers. The Factiva news archive was searched for articles on cyclist crashes published in major Australian newspapers between 2010 and 2013. Information on the circumstances of cyclist crashes were extracted and coded. A total of 160 cyclist crashes were covered by 198 newspaper articles, with 44% of crashes resulting in cyclist fatalities. Crashes reported by more than one newspaper were more likely to involve public figures or protracted court cases. Individual characteristics of cyclists as well as the location of the crash were reported for more than 80% of crashes. The road user at fault was reported for more than half of crashes. In contrast, information on helmet use, alcohol and cycling lanes was mentioned for only about 10% of crashes. Fewer than one in five articles mentioned prevention strategies including education campaigns, legislative and infrastructure changes. Australian newspapers tend to focus on the most dramatic and more 'newsworthy' aspects of cyclist crashes. Cycling advocates need to work with journalists to improve the quality of this coverage. Better communication between cycling advocates and journalists is likely to have a positive impact on the safety and the uptake of cycling in the community. © 2016 Public Health Association of Australia.

Aerodynamic study of time-trial helmets in cycling racing using CFD analysis.

PubMed

Beaumont, F; Taiar, R; Polidori, G; Trenchard, H; Grappe, F

2018-01-23

The aerodynamic drag of three different time-trial cycling helmets was analyzed numerically for two different cyclist head positions. Computational Fluid Dynamics (CFD) methods were used to investigate the detailed airflow patterns around the cyclist for a constant velocity of 15 m/s without wind. The CFD simulations have focused on the aerodynamic drag effects in terms of wall shear stress maps and pressure coefficient distributions on the cyclist/helmet system. For a given head position, the helmet shape, by itself, obtained a weak effect on a cyclist's aerodynamic performance (<1.5%). However, by varying head position, a cyclist significantly influences aerodynamic performance; the maximum difference between both positions being about 6.4%. CFD results have also shown that both helmet shape and head position significantly influence drag forces, pressure and wall shear stress distributions on the whole cyclist's body due to the change in the near-wake behavior and in location of corresponding separation and attachment areas around the cyclist. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cyclists' perceptions of motorist harassment pre- to post-trial of the minimum passing distance road rule amendment in Queensland, Australia.

PubMed

Heesch, Kristiann C; Schramm, Amy; Debnath, Ashim Kumar; Haworth, Narelle

2017-12-01

Issues addressed Cyclists' perceptions of harassment from motorists discourages cycling. This study examined changes in cyclists' reporting of harassment pre- to post-introduction of the Queensland trial of the minimum passing distance road rule amendment (MPD-RRA). Methods Cross-sectional online surveys of cyclists in Queensland, Australia were conducted in 2009 (pre-trial; n=1758) and 2015 (post-trial commencement; n=1997). Cyclists were asked about their experiences of harassment from motorists while cycling. Logistic regression modelling was used to examine differences in the reporting of harassment between these time periods, after adjustments for demographic characteristics and cycling behaviour. Results At both time periods, the most reported types of harassment were deliberately driving too close (causing fear or anxiety), shouting abuse and making obscene gestures or engaging in sexual harassment. The percentage of cyclists who reported tailgating by motorists increased between 2009 and 2015 (15.1% to 19.5%; P<0.001). The percentage of cyclists reporting other types of harassment did not change significantly. Conclusions Cyclists in Queensland continue to perceive harassment while cycling on the road. The amendment to the minimum passing distance rule in Queensland appears to be having a negative effect on one type of harassment but no significant effects on others. So what? Minimum passing distance rules may not be improving cyclists' perceptions of motorists' behaviours. Additional strategies are required to create a supportive environment for cycling.

Evaluating the impact of bike network indicators on cyclist safety using macro-level collision prediction models.

PubMed

Osama, Ahmed; Sayed, Tarek

2016-12-01

Many cities worldwide are recognizing the important role that cycling plays in creating green and livable communities. However, vulnerable road users such as cyclists are usually subjected to an elevated level of injury risk which discourages many road users to cycle. This paper studies cyclist-vehicle collisions at 134 traffic analysis zones in the city of Vancouver to assess the impact of bike network structure on cyclist safety. Several network indicators were developed using Graph theory and their effect on cyclist safety was investigated. The indicators included measures of connectivity, directness, and topography of the bike network. The study developed several macro-level (zonal) collision prediction models that explicitly incorporated bike network indicators as explanatory variables. As well, the models incorporated the actual cyclist exposure (bike kilometers travelled) as opposed to relying on proxies such as population or bike network length. The macro-level collision prediction models were developed using generalized linear regression and full Bayesian techniques, with and without spatial effects. The models showed that cyclist collisions were positively associated with bike and vehicle exposure. The exponents of the exposure variables were less than one which supports the "safety in numbers" hypothesis. Moreover, the models showed positive associations between cyclist collisions and the bike network connectivity and linearity indicators. In contrast, negative associations were found between cyclist collisions and the bike network continuity and topography indicators. The spatial effects were statistically significant in all of the developed models. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exploring factors influencing the strength of the safety-in-numbers effect.

PubMed

Elvik, Rune

2017-03-01

Several studies have found a so-called safety-in-numbers effect for vulnerable road users. This means that when the number of pedestrians or cyclists increases, the number of accidents involving these road users and motor vehicles increases less than in proportion to the number of pedestrians or cyclists. In other words, travel becomes safer for each pedestrian or cyclist the more pedestrians or cyclists there are. This finding is highly consistent, but estimates of the strength of the safety-in-numbers effect vary considerably. This paper shows that the strength of the safety-in-numbers effect is inversely related to the number of pedestrians and cyclists. A stronger safety-in-numbers is found when there are few pedestrians or cyclists than when there are many. This finding is counterintuitive and one would expect the opposite relationship. The relationship between the ratio of the number of motor vehicles to the number of pedestrians or cyclists and the strength of the safety-in-numbers effect is ambiguous. Possible explanations of these tendencies are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of training mode on post-exercise heart rate recovery of trained cyclists.

PubMed

McDonald, Kelia G; Grote, Silvie; Shoepe, Todd C

2014-06-28

The sympathetic nervous system dominates the regulation of body functions during exercise. Therefore after exercise, the sympathetic nervous system withdraws and the parasympathetic nervous system helps the body return to a resting state. In the examination of this relationship, the purpose of this study was to compare recovery heart rates (HR) of anaerobically versus aerobically trained cyclists. With all values given as means ± SD, anaerobically trained track cyclists (n=10, age=25.9 ± 6.0 yrs, body mass=82.7 ± 7.1 kg, body fat=10.0 ± 6.3%) and aerobically trained road cyclists (n=15, age=39.9 ± 8.5 yrs, body mass=75.3 ± 9.9 kg, body fat=13.1 ± 4.5%) underwent a maximal oxygen uptake test. Heart rate recovery was examined on a relative basis using heart rate reserve as well as the absolute difference between maximum HR and each of two recovery HRs. The post-exercise change in HR at minute one for the track cyclists and road cyclists respectively were 22 ± 8 bpm and 25 ± 12 bpm. At minute two, the mean drop for track cyclists was significantly (p<0.05) greater than the road cyclists (52 ± 15 bpm and 64 ± 11 bpm). Training mode showed statistically significant effects on the speed of heart rate recovery in trained cyclists. Greater variability in recovery heart rate at minute two versus minute one suggests that the heart rate should be monitored longer than one minute of recovery for a better analysis of post-exercise autonomic shift.

Evaluation of Noise Exposure Secondary to Wind Noise in Cyclists.

PubMed

Seidman, Michael D; Wertz, Anna G; Smith, Matthew M; Jacob, Steve; Ahsan, Syed F

2017-11-01

Objective Determine if the noise levels of wind exposure experienced by cyclists reach levels that could contribute to noise-induced hearing loss. Study Design Industrial lab research. Setting Industrial wind tunnel. Subjects and Methods A commercial-grade electric wind tunnel was used to simulate different speeds encountered by a cyclist. A single cyclist was used during the simulation for audiometric measurements. Microphones attached near the ears of the cyclist were used to measure the sound (dB sound pressure level) experienced by the cyclist. Loudness levels were measured with the head positioned at 15-degree increments from 0 degrees to 180 degrees relative to the oncoming wind at different speeds (10-60 mph). Results Wind noise ranged from 84.9 dB at 10 mph and increased proportionally with speed to a maximum of 120.3 dB at 60 mph. The maximum of 120.3 dB was measured at the downwind ear when the ear was 90 degrees away from the wind. Conclusions Wind noise experienced by a cyclist is proportional to the speed and the directionality of the wind current. Turbulent air flow patterns are observed that contribute to increased sound exposure in the downwind ear. Consideration of ear deflection equipment without compromising sound awareness for cyclists during prolonged rides is advised to avoid potential noise trauma. Future research is warranted and can include long-term studies including dosimetry measures of the sound and yearly pre- and postexposure audiograms of cyclists to detect if any hearing loss occurs with long-term cycling.

Difference between car-to-cyclist crash and near crash in a perpendicular crash configuration based on driving recorder analysis.

PubMed

Ito, Daisuke; Hayakawa, Kosei; Kondo, Yuma; Mizuno, Koji; Thomson, Robert; Piccinini, Giulio Bianchi; Hosokawa, Naruyuki

2018-08-01

Analyzing a crash using driving recorder data makes it possible to objectively examine factors contributing to the occurrence of the crash. In this study, car-to-cyclist crashes and near crashes recorded on cars equipped with advanced driving recorders were compared with each other in order to examine the factors that differentiate near crashes from crashes, as well as identify the causes of the crashes. Focusing on cases where the car and cyclist approached each other perpendicularly, the differences in the car's and cyclist's parameters such as velocity, distance and avoidance behavior were analyzed. The results show that car-to-cyclist crashes would not be avoidable when the car approaching the cyclist enters an area where the average deceleration required to stop the car is more than 0.45 G (4.4 m/s 2 ). In order for this situation to occur, there are two types of cyclist crash scenarios. In the first scenario, the delay in the drivers' reaction in activating the brakes is the main factor responsible for the crash. In this scenario, time-to-collision when the cyclist first appears in the video is more than 2.0 s. In the second scenario, the sudden appearance of a cyclist from behind an obstacle on the street is the factor responsible for the crash. In this case, the time-to-collision is less than 1.2 s, and the crash cannot be avoided even if the driver exhibited avoidance maneuvers. Copyright © 2018 Elsevier Ltd. All rights reserved.

Investigating traffic light violations by cyclists in Dublin City Centre.

PubMed

Richardson, Matthew; Caulfield, Brian

2015-11-01

This research examines the behaviour of cyclists in Dublin City with specific regard to red light running. A number of specific research questions are raised by this study. These questions address the impact of different infrastructure types on red light running, as well as the behavioural patterns and demographics of offending cyclists. Two data collection methods were used to gather information on cyclists in Dublin City - an observational survey and an online questionnaire. The observational surveys examined cyclist compliance with different traffic signal systems and the impact of on-road and off-road cycle infrastructure. An online questionnaire was used to get direct feedback from cyclists in Dublin City on the reasons (if any) they decide to commit infringement at traffic lights. With the recent growth of cycling in Dublin City (as well as many other international cities) it is vital to accommodate and manage this growing demand by ensuring the safety and road discipline of cyclists. The next few years will be crucial for the continued development of cycling in Dublin, particularly due to the increasing investment by transport planners in cycle infrastructure. It is therefore important to identify now the main factors which influence cyclist's decisions to break red lights in order to guide local traffic authorities in their efforts to reduce such transgressions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Differences in pedalling technique between road cyclists of different competitive levels.

PubMed

García-López, Juan; Díez-Leal, Sergio; Ogueta-Alday, Ana; Larrazabal, Josu; Rodríguez-Marroyo, José A

2016-09-01

The purpose of this study was to compare the pedalling technique in road cyclists of different competitive levels. Eleven professional, thirteen elite and fourteen club cyclists were assessed at the beginning of their competition season. Cyclists' anthropometric characteristics and bike measurements were recorded. Three sets of pedalling (200, 250 and 300 W) on a cycle ergometer that simulated their habitual cycling posture were performed at a constant cadence (~90 rpm), while kinetic and kinematic variables were registered. The results showed no differences on the main anthropometric variables and bike measurements. Professional cyclists obtained higher positive impulse proportion (1.5-3.3% and P < 0.05), mainly due to a lower resistive torque during the upstroke (15.4-28.7% and P < 0.05). They also showed a higher ankle range of movement (ROM, 1.1-4.0° and P < 0.05). Significant correlations (P < 0.05) were found between the cyclists' body mass and the kinetic variables of pedalling: positive impulse proportion (r = -0.59 to -0.61), minimum (r = -0.59 to -0.63) and maximum torques (r = 0.35-0.47). In conclusion, professional cyclists had better pedalling technique than elite and club cyclists, because they opted for enhancing pulling force at the recovery phase to sustain the same power output. This technique depended on cycling experience and level of expertise.

Complete Streets and Adult Bicyclist Fatalities: Applying G-Computation to Evaluate an Intervention That Affects the Size of a Population at Risk.

PubMed

Mooney, Stephen J; Magee, Caroline; Dang, Kolena; Leonard, Julie C; Yang, Jingzhen; Rivara, Frederick P; Ebel, Beth E; Rowhani-Rahbar, Ali; Quistberg, D Alex

2018-05-14

"Complete Streets" policies require transportation engineers to make provisions for pedestrians, cyclists and transit users. These policies may make bicycling safer for individual cyclists while increasing overall bicycle fatalities if more individuals cycle due to improved infrastructure. We merged county-level records of Complete Streets policies with Fatality Analysis Reporting System counts of cyclist fatalities occurring between January 2000 and December 2015. Because comprehensive county cycling estimates were not available, we used bicycle commute estimates from the American Community Survey and US Census as a proxy for the cycling population, and limited analysis to 183 counties (accounting for over half the US population) for which cycle commute estimates were consistently non-zero. We used G-computation to estimate the effect of policies on overall cyclist fatalities while also accounting for potential policy effects on the size of the cycling population. Over 16 years, 5,254 cyclists died in these counties, representing 34 fatalities per 100,000 cyclist-years. We estimated that Complete Streets policies made cycling safer, averting 0.6 fatalities per 100,000 cyclist-years (95% CI: 0.3, 1.0) by encouraging a 2.4% increase in cycling and a 0.7% increase in cyclist fatalities. G-computation is a useful tool for understanding policy impact on risk and exposure.

Effect of physical effort on mental workload of cyclists in real traffic in relation to age and use of pedelecs.

PubMed

Boele-Vos, M J; Commandeur, J J F; Twisk, D A M

2017-08-01

To improve cycling safety, insight is required into the factors that contribute to road safety of older cyclists. From the wide range of possible factors, this paper addresses the role of physical effort on mental workload of cyclists with the aim to investigate whether physical effort affects mental workload of cyclists in real traffic in a field experiment. Two instrumented bicycles, a conventional bicycle and a pedelec, were used. Mental workload of cyclists in two age groups - 30-45 years and 65 years and over - was measured by means of a secondary cognitive task requiring the detection and reaction to visual stimuli on a cycle route that varied in physical effort and task complexity. We expected physical effort to impair performance on the secondary task in complex traffic sections and not in simple sections, and that this impairment would be greater for older cyclists because of age related reduced muscle strength than for younger cyclists. We expected this impairment to be smaller if a pedelec was used. If such would be the case, this would indicate pedelecs to be beneficial for this older age group, because of a lower mental workload. Our study confirmed that increased physical effort in complex traffic sections deteriorated the detection of relevant stimuli in both age groups. Overall, older cyclists had longer reaction times and lower hit rates than younger cyclists. Mental workloads of cyclists are basically the same when cycling on a conventional bicycle or on a pedelec. In theory, pedelecs may be beneficial to reduce physical effort in cycling in order to maintain enough mental capacity to handle complex traffic situations. However, this study did not demonstrate these benefits. As pedelecs are often used for longer trips, by elderly with low muscle strength, future studies should also explore the effect of higher physical effort over longer periods of time, and also specifically in elderly with low muscle strength. Copyright © 2016 Elsevier Ltd. All rights reserved.

Cyclists' Anger As Determinant of Near Misses Involving Different Road Users.

PubMed

Marín Puchades, Víctor; Prati, Gabriele; Rondinella, Gianni; De Angelis, Marco; Fassina, Filippo; Fraboni, Federico; Pietrantoni, Luca

2017-01-01

Road anger constitutes one of the determinant factors related to safety outcomes (e.g., accidents, near misses). Although cyclists are considered vulnerable road users due to their relatively high rate of fatalities in traffic, previous research has solely focused on car drivers, and no study has yet investigated the effect of anger on cyclists' safety outcomes. The present research aims to investigate, for the first time, the effects of cycling anger toward different types of road users on near misses involving such road users and near misses in general. Using a daily diary web-based questionnaire, we collected data about daily trips, bicycle use, near misses experienced, cyclist's anger and demographic information from 254 Spanish cyclists. Poisson regression was used to assess the association of cycling anger with near misses, which is a count variable. No relationship was found between general cycling anger and near misses occurrence. Anger toward specific road users had different effects on the probability of near misses with different road users. Anger toward the interaction with car drivers increased the probability of near misses involving cyclists and pedestrians. Anger toward interaction with pedestrians was associated with higher probability of near misses with pedestrians. Anger toward cyclists exerted no effect on the probability of near misses with any road user (i.e., car drivers, cyclists or pedestrians), whereas anger toward the interactions with the police had a diminishing effect on the occurrence of near misses' involving all types of road users. The present study demonstrated that the effect of road anger on safety outcomes among cyclists is different from that of motorists. Moreover, the target of anger played an important role on safety both for the cyclist and the specific road users. Possible explanations for these differences are based on the difference in status and power with motorists, as well as on the potential displaced aggression produced by the fear of retaliation by motorized vehicle users.

Physical characteristics and resistance parameters of typical urban cyclists.

PubMed

Tengattini, Simone; Bigazzi, Alexander York

2018-03-30

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) m 2 , 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.

Potential factors associated with knee pain in cyclists: a systematic review.

PubMed

Bini, Rodrigo Rico; Flores Bini, Alice

2018-01-01

The potential factors associated with overuse injuries and pain in cyclists that are supported by evidence remain unclear. Our study aimed at assessing, using a systematic search of the most updated evidence, the main factors related to overuse knee-related pain and/or injuries in cyclists. The search assessed any potential mechanism related to knee pain or injury that could be used in the clinical practice. Databases were searched (i.e., PubMed, Scopus, Web of Science, and EBSCO). Studies were included if they presented results from original studies. They had to include, preferably but not limited to, recreational and/or competitive cyclists with or without knee pain. Quality of articles was assessed. Eleven articles were deemed eligible for full text appraisal. Studies involved generally the assessment of biomechanical outcomes associated with knee pain in cyclists. Overall, studies showed that cyclists with knee pain present larger knee adduction and larger ankle dorsiflexion and differences in activation for hamstrings and quadriceps muscles. Unclear results were observed for knee moments and no differences were observed for knee flexion angle, tibiofemoral and patellofemoral forces. It is important to state that varied types of knee pain were mixed in most studies, with 2 focused on anterior-related pain. Cyclists with overuse-related pain or injuries on their knees presented an increased medial projection of their knees and an altered activation of the Vastus Medialis and Vastus Lateralis muscles. However, this limited evidence is based on retrospective studies comparing cyclists with and without pain, which limits the conclusion on how cyclists develop knee pain and what are the main options for treatment of knee pain.

Mathematical model for studying cyclist kinematics in vehicle-bicycle frontal collisions

NASA Astrophysics Data System (ADS)

Condrea, OA; Chiru, A.; Chiriac, RL; Vlase, S.

2017-10-01

For the development of effective vehicle related safety solutions to improve cyclist protection, kinematic predictions are essential. The objective of the paper was the elaboration of a simple mathematical model for predicting cyclist kinematics, with the advantage of yielding simple results for relatively complicated impact situations. Thus, the use of elaborated math software is not required and the calculation time is shortened. The paper presents a modelling framework to determine cyclist kinematic behaviour for the situations in which a M1 category vehicle frontally hits the rear part of a bicycle. After the primary impact between the vehicle front bumper and the bicycle, the cyclist hits the vehicle’s bonnet, the windscreen or both the vehicle’s bonnet and the windscreen in short succession. The head-windshield impact is often the most severe impact, causing serious and potentially lethal injuries. The cyclist is represented by a rigid segment and the equations of motion for the cyclist after the primary impact are obtained by applying Newton’s second law of motion. The impact time for the contact between the vehicle and the cyclist is yielded afterwards by formulating and intersecting the trajectories for two points positioned on the cyclist’s head/body and the vehicle’s windscreen/bonnet while assuming that the cyclist’s equations of motion after the primary impact remain the same. Postimpact kinematics for the secondary impact are yielded by applying linear and angular momentum conservation laws.

[An assessment of the effect of helmet use among cyclists and the risk of head injury and death in Spain, 1990 to 1999].

PubMed

Lardelli Claret, Pablo; Luna del Castillo, Juan de Dios; Jiménez Moleón, José Juan; García Martín, Miguel; Bueno Cavanillas, Aurora; Gálvez Vargas, Ramón

2003-02-01

This study aimed to assess the protective effect of helmet use by cyclists on risk of suffering head injury or dying as a consequence of a traffic crash. 26,832 cyclists involved in traffic crashes with victims registered in the Dirección General de Tráfico database from 1990 to 1999 in Spain were studied. From this database, variables relating to each cyclist (i.e., age, sex, presence of head trauma, severity of lesions) and those related with the crash (i.e., place, date, type of crash), were collected. The odds ratio and the proportion of the population attributable risk for non-use of a helmet by cyclist were estimated. An adjusted odds ratio of 2.45 (2.19-2.73) for the association between non-use of a helmet and the risk of head injury was obtained. As death of the cyclist as the outcome, the corresponding odds ratio was 1.35 (1.09-1.67). The values of proportion of the population attributable risk were 0.51 (0.47-0.55) and 0.22 (0.07-0.36), for head injury and death, respectively. This study confirms that helmet use among cyclists significantly decreased the risk of head injury and, to a lesser extent, death. These results constitute a strong argument for increasing in the frequency of helmet use among cyclists in Spain.

Cycling to work in London and inhaled dose of black carbon.

PubMed

Nwokoro, Chinedu; Ewin, Clare; Harrison, Clare; Ibrahim, Mubin; Dundas, Isobel; Dickson, Iain; Mushtaq, Naseem; Grigg, Jonathan

2012-11-01

Modelling studies suggest that urban cycling is associated with an increased inhaled dose of fossil fuel-derived black carbon (BC). Using the amount of black material in airway macrophages as a marker of long-term inhaled BC, we sought to compare inhaled BC dose in London (UK) cyclists and non-cyclists. Airway macrophage carbon was assessed in 28 (58%) out of 48 healthy adults (14 cyclists and 14 non-cyclists) who attended for induced sputum. Short-term (24 h) exposure to BC was assessed on a representative working day in 27 out of 28 subjects. Serum interleukin (IL)-1β, IL-2, IL-6, IL-8, granulocyte-macrophage colony-stimulating factor and tumour necrosis factor (TNF)-α were assessed in 26 out of the 28 subjects. Cyclists were found to have increased airway macrophage carbon when compared with non-cyclists (mean ± se 1.81 ± 0.21 versus 1.11 ± 0.07 μm(2); p<0.01). Short-term monitoring showed no difference in 24 h BC exposure between the two groups. However, cyclists were exposed to higher concentrations of BC during commuting (p<0.01). Airway macrophage carbon was associated with monitored commute BC (n=28; r=0.47, p<0.05). TNF-α was found to be increased in cyclists (p<0.05), but no other cytokines were increased. Commuting to work by bicycle in London is associated with increased long-term inhaled dose of BC. Whether cycling per se increases inhaled BC dose remains unclear.

Positive Pacing Strategies Are Utilized by Elite Male and Female Para-cyclists in Short Time Trials in the Velodrome.

PubMed

Wright, Rachel L

2015-01-01

In para-cycling, competitors are classed based on functional impairment resulting in cyclists with neurological and locomotor impairments competing against each other. In Paralympic competition, classes are combined by using a factoring adjustment to race times to produce the overall medallists. Pacing in short-duration track cycling events is proposed to utilize an "all-out" strategy in able-bodied competition. However, pacing in para-cycling may vary depending on the level of impairment. Analysis of the pacing strategies employed by different classification groups may offer scope for optimal performance; therefore, this study investigated the pacing strategy adopted during the 1-km time trial (TT) and 500-m TT in elite C1 to C3 para-cyclists and able-bodied cyclists. Total times and intermediate split times (125-m intervals; measured to 0.001 s) were obtained from the C1-C3 men's 1-km TT (n = 28) and women's 500-m TT (n = 9) from the 2012 Paralympic Games and the men's 1-km TT (n = 19) and women's 500-m TT (n = 12) from the 2013 UCI World Track Championships from publically available video. Split times were expressed as actual time, factored time (for the para-cyclists) and as a percentage of total time. A two-way analysis of variance was used to investigate differences in split times between the different classifications and the able-bodied cyclists in the men's 1-km TT and between the para-cyclists and able-bodied cyclists in the women's 500-m TT. The importance of position at the first split was investigated with Kendall's Tau-b correlation. The first 125-m split time was the slowest for all cyclists, representing the acceleration phase from a standing start. C2 cyclists were slowest at this 125-m split, probably due to a combination of remaining seated in this acceleration phase and a high proportion of cyclists in this group being trans-femoral amputees. Not all cyclists used aero-bars, preferring to use drop, flat or bullhorn handlebars. Split times increased in the later stages of the race, demonstrating a positive pacing strategy. In the shorter women's 500-m TT, rank at the first split was more strongly correlated with final position than in the longer men's 1-km TT. In conclusion, a positive pacing strategy was adopted by the different para-cycling classes.

Positive Pacing Strategies Are Utilized by Elite Male and Female Para-cyclists in Short Time Trials in the Velodrome

PubMed Central

Wright, Rachel L.

2016-01-01

In para-cycling, competitors are classed based on functional impairment resulting in cyclists with neurological and locomotor impairments competing against each other. In Paralympic competition, classes are combined by using a factoring adjustment to race times to produce the overall medallists. Pacing in short-duration track cycling events is proposed to utilize an “all-out” strategy in able-bodied competition. However, pacing in para-cycling may vary depending on the level of impairment. Analysis of the pacing strategies employed by different classification groups may offer scope for optimal performance; therefore, this study investigated the pacing strategy adopted during the 1-km time trial (TT) and 500-m TT in elite C1 to C3 para-cyclists and able-bodied cyclists. Total times and intermediate split times (125-m intervals; measured to 0.001 s) were obtained from the C1-C3 men's 1-km TT (n = 28) and women's 500-m TT (n = 9) from the 2012 Paralympic Games and the men's 1-km TT (n = 19) and women's 500-m TT (n = 12) from the 2013 UCI World Track Championships from publically available video. Split times were expressed as actual time, factored time (for the para-cyclists) and as a percentage of total time. A two-way analysis of variance was used to investigate differences in split times between the different classifications and the able-bodied cyclists in the men's 1-km TT and between the para-cyclists and able-bodied cyclists in the women's 500-m TT. The importance of position at the first split was investigated with Kendall's Tau-b correlation. The first 125-m split time was the slowest for all cyclists, representing the acceleration phase from a standing start. C2 cyclists were slowest at this 125-m split, probably due to a combination of remaining seated in this acceleration phase and a high proportion of cyclists in this group being trans-femoral amputees. Not all cyclists used aero-bars, preferring to use drop, flat or bullhorn handlebars. Split times increased in the later stages of the race, demonstrating a positive pacing strategy. In the shorter women's 500-m TT, rank at the first split was more strongly correlated with final position than in the longer men's 1-km TT. In conclusion, a positive pacing strategy was adopted by the different para-cycling classes. PMID:26834643

Transit vehicle-to-infrastructure (V2I) applications : near term research and development. Transit bus-pedestrian/cyclist crossing safety application : operational concept.

DOT National Transportation Integrated Search

2013-11-01

This document serves as an Operational Concept for the Transit Bus-Pedestrian/Cyclist Crossing Safety application. The purpose of this document is to provide an operational description of how the Transit Bus-Pedestrian/Cyclist Crossing Safety W...

A cross-comparison of different techniques for modeling macro-level cyclist crashes.

PubMed

Guo, Yanyong; Osama, Ahmed; Sayed, Tarek

2018-04-01

Despite the recognized benefits of cycling as a sustainable mode of transportation, cyclists are considered vulnerable road users and there are concerns about their safety. Therefore, it is essential to investigate the factors affecting cyclist safety. The goal of this study is to evaluate and compare different approaches of modeling macro-level cyclist safety as well as investigating factors that contribute to cyclist crashes using a comprehensive list of covariates. Data from 134 traffic analysis zones (TAZs) in the City of Vancouver were used to develop macro-level crash models (CM) incorporating variables related to actual traffic exposure, socio-economics, land use, built environment, and bike network. Four types of CMs were developed under a full Bayesian framework: Poisson lognormal model (PLN), random intercepts PLN model (RIPLN), random parameters PLN model (RPPLN), and spatial PLN model (SPLN). The SPLN model had the best goodness of fit, and the results highlighted the significant effects of spatial correlation. The models showed that the cyclist crashes were positively associated with bike and vehicle exposure measures, households, commercial area density, and signal density. On the other hand, negative associations were found between cyclist crashes and some bike network indicators such as average edge length, average zonal slope, and off-street bike links. Copyright © 2018 Elsevier Ltd. All rights reserved.

Exploring the impacts of safety culture on immigrants' vulnerability in non-motorized crashes: a cross-sectional study.

PubMed

Chen, Cynthia; Lin, Haiyun; Loo, Becky P Y

2012-02-01

Pedestrians and cyclists are a vulnerable group of road users. Immigrants are disproportionally represented in pedestrian and cyclist crashes. We postulate that the mismatch in safety culture between countries of their origin and the U.S.A. contribute to their vulnerability in pedestrian and cyclist crashes. Over time, the differences may disappear and immigrants' traffic behavior gravitates toward those of native-borns. We describe this process as safety assimilation. Using the pedestrian and cyclist crash database in New York City between 2001 and 2003, we examined the effects of foreign-born population, their countries of origin, and time of entry into the USA on census tract-level pedestrian and cyclist crashes. We find that neighborhoods with a higher concentration of immigrants, especially those from Latin America, Eastern Europe, and Asia, have more crashes. Our results also exhibit a pattern of the hypothesized safety assimilation process. The study suggests a higher level of vulnerability of immigrants to pedestrian and cyclist crashes. We propose that targeted policies and programs need to be developed for immigrants of different countries of origin.

Features of fatal injuries in older cyclists in vehicle-bicycle accidents in Japan.

PubMed

Matsui, Yasuhiro; Oikawa, Shoko; Hitosugi, Masahito

2018-01-02

The purpose of this study was to identify and better understand the features of fatal injuries in cyclists aged 75 years and over involved in collisions with either hood- or van-type vehicles. This study investigated the fatal injuries of cyclists aged 75 years old and over by analyzing accident data. We focused on the body regions to which the fatal injury occurred using vehicle-bicycle accident data from the Institute for Traffic Accident Research and Data Analysis (ITARDA) in Japan. Using data from 2009 to 2013, we examined the frequency of fatally injured body region by gender, age, and actual vehicle travel speed. We investigated any significant differences in distributions of fatal injuries by body region for cyclists aged 75 years and over using chi-square tests to compare with cyclists in other age groups. We also investigated the cause of fatal head injuries, such as impact with a road surface or vehicle. The results indicated that head injuries were the most common cause of fatalities among the study group. At low vehicle travel speeds for both hood- and van-type vehicles, fatalities were most likely to be the result of head impacts against the road surface. The percentage of fatalities following hip injuries was significantly higher for cyclists aged 75 years and over than for those aged 65-74 or 13-59 in impacts with hood-type vehicles. It was also higher for women than men in the over-75 age group in impacts with these vehicles. For cyclists aged 75 years and over, wearing a helmet may be helpful to prevent head injuries in vehicle-to-cyclist accidents. It may also be helpful to introduce some safety measures to prevent hip injuries, given the higher level of fatalities following hip injury among all cyclists aged 75 and over, particularly women.

The association of bicycle-related genital numbness and Sexual Health Inventory for Men (SHIM) score: results from a large, multinational, cross-sectional study.

PubMed

Baradaran, Nima; Awad, Mohannad; Gaither, Thomas W; Fergus, Kirkpatrick B; Ndoye, Medina; Cedars, Benjamin E; Balakrishnan, Ashwin S; Eisenberg, Michael L; Sanford, Tom; Breyer, Benjamin N

2018-05-23

To assess the association of genital numbness and erectile dysfunction in male cyclists. Cyclists were recruited through Facebook advertisements and outreach to sporting clubs. This is a secondary analysis of a larger epidemiological population-based study that examined sexual and urinary wellness in athletes. We queried cycling habits and erectile function using Sexual Health Inventory for Men (SHIM). A total of 2 774 male cyclists were included in the analysis. Amongst cyclists, there was a statistically significant increase in the trend of genital numbness presence with more years of cycling (P = 0.002), more frequent weekly cycling (P < 0.001), and longer cycling distance at each ride (P < 0.001). Less frequent use of padded shorts (odds ratio [OR] 0.14, P < 0.001) and lower handlebar (OR 0.49, P < 0.001) were associated with numbness, but body mass index (BMI) (OR 1.1, P = 0.33) and age (OR 1.2, P = 0.15) were not. In a multivariate logistic regression model, after adjusting for age, BMI, and lifetime miles (calculated by average daily cycling mileage × cycling days/week × cycling years.), there were no statistically significant differences in mean SHIM score between cyclists with and cyclists without numbness (20.3 vs 20.2, P = 0.83). However, interestingly, the subset of cyclists who reported numbness in the buttock reported statistically significantly worse SHIM scores (20.3 vs 18.4, P < 0.001). This association was not present in cyclists who reported numbness in the scrotum, penis, or perineum and remained significant after adjusting for overall biking intensity. Cyclists report genital numbness in proportion with biking intensity but numbness is not associated with worse sexual function in this cohort. © 2018 The Authors BJU International © 2018 BJU International Published by John Wiley & Sons Ltd.

Built environment effects on cyclist injury severity in automobile-involved bicycle crashes.

PubMed

Chen, Peng; Shen, Qing

2016-01-01

This analysis uses a generalized ordered logit model and a generalized additive model to estimate the effects of built environment factors on cyclist injury severity in automobile-involved bicycle crashes, as well as to accommodate possible spatial dependence among crash locations. The sample is drawn from the Seattle Department of Transportation bicycle collision profiles. This study classifies the cyclist injury types as property damage only, possible injury, evident injury, and severe injury or fatality. Our modeling outcomes show that: (1) injury severity is negatively associated with employment density; (2) severe injury or fatality is negatively associated with land use mixture; (3) lower likelihood of injuries is observed for bicyclists wearing reflective clothing; (4) improving street lighting can decrease the likelihood of cyclist injuries; (5) posted speed limit is positively associated with the probability of evident injury and severe injury or fatality; (6) older cyclists appear to be more vulnerable to severe injury or fatality; and (7) cyclists are more likely to be severely injured when large vehicles are involved in crashes. One implication drawn from this study is that cities should increase land use mixture and development density, optimally lower posted speed limits on streets with both bikes and motor vehicles, and improve street lighting to promote bicycle safety. In addition, cyclists should be encouraged to wear reflective clothing. Copyright © 2015 Elsevier Ltd. All rights reserved.

Risks of Serious Injuries and Fatalities of Cyclists Associated with Impact Velocities of Cars in Car-Cyclist Accidents in Japan.

PubMed

Matsui, Yasuhiro; Oikawa, Shoko

2015-11-01

The main purpose of this study is to define the relationship between the car impact velocity and serious injury risk or fatality risk of cyclists. The authors investigated the risks of serious injuries and fatalities of cyclists using vehicle-cyclist accident data from the database of the Institute for Traffic Accident Research and Data Analysis (ITARDA) in Japan. The vehicle types considered are sedans, mini vans, box vans, light passenger cars and light cargo vans. The results revealed that a 10-km/h decrease in the impact velocity could reduce the severe injury risk and fatality risk for impact velocities of 40 km/h or higher. Specifically, when the impact velocity was less than or equal to 30 km/h, the serious injury risks were less than 21% and the fatality risks were less than or equal to 1% for the above listed vehicle types. Therefore, if the Collision Damage Mitigation Braking System (CDMBS) equipped vehicles can perform its functions effectively so as to reduce the impact velocities, then cyclist injuries will likely be significantly reduced. Another purpose of this study is to assess the effect of wearing a helmet for protection of the cyclist's head. Impact experiment results showed that the measured head injury criterion (HIC) with helmets are lower than that of head-form impactor without a helmet, reducing the HIC by 57%.

Eating and nutrition habits in young competitive athletes: a comparison between soccer players and cyclists.

PubMed

Galanti, Giorgio; Stefani, Laura; Scacciati, Irene; Mascherini, Gabriele; Buti, Gabriella; Maffulli, Nicola

2015-01-01

The study evaluated the dietary habits in two groups of young athletes, practicing two different sports: soccer players and cycling. The dietary habits of 47 athletes were investigated by questionnaire. Body Mass Index, Fat Mass, Free Fat Mass, Total Body, Intracellular, Extracellular Water and Phase Angle were measured by bioimpedance. The t-Student test for unpaired data was used. Significance was set at P < 0.05. Body Mass Index was similar between the groups, while total body water and extracellular water were significantly higher in the soccer player group (soccer players: 63.8±1.96%; cyclists : 59.8 ± 8.7%; and soccer players 43.9±3.1%, cyclists 43.8 ±2.1%, respectively). Fatty mass of the soccer player group (14.5±2.9%) was significantly lower than that of the cyclist group (19.5±3.6%). Daily food intake was similar between the two groups (2844 kCal/die for soccer players /2630 kcal/die for cyclists), and lower than recommended. There was a low intake of Calcium (soccer players 1120±128.9 mg/die, cyclists 718±309 mg/die) for both groups, and a low intake of Potassium for soccer player (2576 mg/die ± 52.4) The caloric intake of adolescent athletes is lower than recommended. Body composition is significantly different between soccer players and cyclists.

Eating and nutrition habits in young competitive athletes: a comparison between soccer players and cyclists.

PubMed Central

Galanti, Giorgio; Stefani, Laura; Scacciati, Irene; Mascherini, Gabriele; Buti, Gabriella; Maffulli, Nicola

2015-01-01

The study evaluated the dietary habits in two groups of young athletes, practicing two different sports: soccer players and cycling. The dietary habits of 47 athletes were investigated by questionnaire. Body Mass Index, Fat Mass, Free Fat Mass, Total Body, Intracellular, Extracellular Water and Phase Angle were measured by bioimpedance. The t-Student test for unpaired data was used. Significance was set at P < 0.05. Body Mass Index was similar between the groups, while total body water and extracellular water were significantly higher in the soccer player group (soccer players: 63.8±1.96%; cyclists : 59.8 ± 8.7%; and soccer players 43.9±3.1%, cyclists 43.8 ±2.1%, respectively). Fatty mass of the soccer player group (14.5±2.9%) was significantly lower than that of the cyclist group (19.5±3.6%). Daily food intake was similar between the two groups (2844 kCal/die for soccer players /2630 kcal/die for cyclists), and lower than recommended. There was a low intake of Calcium (soccer players 1120±128.9 mg/die, cyclists 718±309 mg/die) for both groups, and a low intake of Potassium for soccer player (2576 mg/die ± 52.4) The caloric intake of adolescent athletes is lower than recommended. Body composition is significantly different between soccer players and cyclists. PMID:25674549

Exercise Induced Cardiac Fatigue Following Prolonged Exercise in Road Cyclists

ERIC Educational Resources Information Center

Wyatt, Frank; Pawar, Ganesh; Kilgore, Lon

2011-01-01

The purpose of this study was to examine cardiac function following a 100-mile ride in high ambient temperatures by healthy, competitive cyclists. Methods: Subjects were six (n=6) competitive cyclists racing in a 100-mile road race. Measures (pre/post) included: body mass (kg); E:A ratio (ventricular compliance); stroke volume (ml); ejection…

Performance effects of acute β-alanine induced paresthesia in competitive cyclists.

PubMed

Bellinger, Phillip M; Minahan, Clare L

2016-01-01

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.

More screen operation than calling: the results of observing cyclists' behaviour while using mobile phones.

PubMed

de Waard, Dick; Westerhuis, Frank; Lewis-Evans, Ben

2015-03-01

Operating a mobile telephone while riding a bicycle is fairly common practice in the Netherlands, yet it is unknown if this use is stable or increasing. As such, whether the prevalence of mobile phone use while cycling has changed over the past five years was studied via on-road observation. In addition the impact of mobile phone use on lateral position, i.e. distance from the front wheel to the curb, was also examined to see if it compared to the results seen in previous experimental studies. Bicyclists were observed at six different locations and their behaviour was scored. It was found that compared to five years ago the use of mobile phones while cycling has changed, not in frequency, but in how cyclists were operating their phones. As found in 2008, three percent of the bicyclists were observed to be operating a phone, but a shift from calling (0.7% of cyclists observed) to operating (typing, texting, 2.3% of cyclists) was found. In 2008 nearly the complete opposite usage was observed: 2.2% of the cyclists were calling and 0.6% was texting. Another finding was that effects on lateral position were similar to those seen in experimental studies in that cyclists using a phone maintained a cycling position which was further away from the curb. It was also found that when at an intersection, cyclist's operating their phone made less head movements to the right than cyclists who were just cycling. This shift from calling to screen operation, when combined with the finding related to reduced head movements at intersections, is worrying and potentially dangerous. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparison of body composition, heart rate variability, aerobic and anaerobic performance between competitive cyclists and triathletes

PubMed Central

Arslan, Erşan; Aras, Dicle

2016-01-01

[Purpose] The aim of this study was to compare the body composition, heart rate variability, and aerobic and anaerobic performance between competitive cyclists and triathletes. [Subjects] Six cyclists and eight triathletes with experience in competitions voluntarily participated in this study. [Methods] The subjects’ body composition was measured with an anthropometric tape and skinfold caliper. Maximal oxygen consumption and maximum heart rate were determined using the incremental treadmill test. Heart rate variability was measured by 7 min electrocardiographic recording. The Wingate test was conducted to determine anaerobic physical performance. [Results] There were significant differences in minimum power and relative minimum power between the triathletes and cyclists. Anthropometric characteristics and heart rate variability responses were similar among the triathletes and cyclists. However, triathletes had higher maximal oxygen consumption and lower resting heart rates. This study demonstrated that athletes in both sports have similar body composition and aerobic performance characteristics. PMID:27190476

Dietary status of trained female cyclists.

PubMed

Keith, R E; O'Keeffe, K A; Alt, L A; Young, K L

1989-11-01

Dietary status was evaluated in eight highly trained female cyclists. Each cyclist kept a 3-day weighed food record. Diets were analyzed for nutrient content using a computerized software package. Blood was also obtained and evaluated for hemoglobin, hematocrit, and albumin. For an athletic group, the cyclists' diets were found to be low in energy (85% RDA) and carbohydrate (4.4 gm/kg body weight per day). Mean daily dietary intakes were well below the RDAs for folacin (76% RDA), magnesium (81%), iron (59%), and zinc (48%). In addition, more than one-third of the cyclists failed to consume 67% of the RDA for the following micronutrients: pyridoxine, folacin, cobalamin, vitamin E, magnesium, iron, and zinc. Hemoglobin (135 gm/L), hematocrit (0.39), and albumin (45 gm/L) values were all normal, although most hemoglobin values were in the lower 50% of normal range. Foods such as meats, poultry, fish, beans, peas, and nuts were low or absent from the diets of most athletes. Dietary quality in this group of female cyclists could have been greatly improved with the addition of more of those foods. These athletes could benefit from nutrition education and diet counseling.

Health and doping in elite-level cycling.

PubMed

Lentillon-Kaestner, V; Hagger, M S; Hardcastle, S

2012-10-01

The protection of the health of athletes is one of the three criteria taken into account when registering a substance in the World Anti-Doping Agency prohibited list. Nevertheless, in elite-level cycling, banned substance use is widespread. The present research adopted a psychological approach to examine how or whether perceived health risks influence elite-level cyclists' decisions to use banned substances. Sixteen semi-structured interviews were conducted with cyclists hoping to join a professional team (n=6), neo-professional cyclists (n=2), and former professional cyclists (n=8). Although an evolution was observed in the organization of doping and perceptions of doping over the last decade, the perceived health hazards did not influence, most of the time, decisions to use banned substances among the sample of cyclists. There was a systematization of exogenous substance use in the cycling environment and a trivialization of the side effects of the banned substances. Finally, younger cyclists were not concerned about the long-term health consequences of banned substances; they were more focused on the short-term performance-enhancing benefits. There is a need to implement more effective preventive programs to change athletes' attitudes toward doping and its health risks. © 2011 John Wiley & Sons A/S.

Traveling by Bus Instead of Car on Urban Major Roads: Safety Benefits for Vehicle Occupants, Pedestrians, and Cyclists.

PubMed

Morency, Patrick; Strauss, Jillian; Pépin, Félix; Tessier, François; Grondines, Jocelyn

2018-04-01

Some studies have estimated fatality and injury rates for bus occupants, but data was aggregated at the country level and made no distinction between bus types. Also, injured pedestrians and cyclists, as a result of bus travel, were overlooked. We compared injury rates for car and city bus occupants on specific urban major roads, as well as the cyclist and pedestrian injuries associated with car and bus travel. We selected ten bus routes along major urban arterials (in Montreal, Canada). Passenger-kilometers traveled were estimated from vehicle counts at intersections (2002-2010) and from bus passenger counts (2008). Police accident reports (2001-2010) provided injury data for all modes. Injury rates associated with car and bus travel were calculated for vehicle occupants, pedestrians, and cyclists. Injury rate ratios were also computed. The safety benefits of bus travel, defined as the number of vehicle occupant, cyclist, and pedestrian injuries saved, were estimated for each route. Overall, for all ten routes, the ratio between car and bus occupant injury rates is 3.7 (95% CI [3.4, 4.0]). The rates of pedestrian and cyclist injuries per hundred million passenger-kilometers are also significantly greater for car travel than that for bus travel: 4.1 (95% CI [3.5, 4.9]) times greater for pedestrian injuries; 5.3 (95% CI [3.8, 7.6]) times greater for cyclist injuries. Similar results were observed for fatally and severely injured vehicle occupants, cyclists, and pedestrians. At the route level, the safety benefits of bus travel increase with the difference in injury rate associated with car and bus travel but also with the amount of passenger-kilometers by bus. Results show that city bus is a safer mode than car, for vehicle occupants but also for cyclists and pedestrians traveling along these bus routes. The safety benefits of bus travel greatly vary across urban routes; this spatial variation is most likely linked to environmental factors. Understanding the safety benefits of public transit for specific transport routes is likely to provide valuable information for mobilizing city and transportation planners.

Cycling injuries and alcohol.

PubMed

Airaksinen, Noora K; Nurmi-Lüthje, Ilona S; Kataja, J Matti; Kröger, Heikki P J; Lüthje, Peter M J

2018-05-01

Most of the cycling accidents that occur in Finland do not end up in the official traffic accident statistics. Thus, there is minimal information on these accidents and their consequences, particularly in cases in which alcohol was involved. The focus of the present study is on cycling accidents and injuries involving alcohol in particular. Data on patients visiting the emergency department at North Kymi Hospital because of a cycling accident was prospectively collected for two years, from June 1, 2004 to May 31, 2006. Blood alcohol concentration (BAC) was measured on admission with a breath analyser. The severity of the cycling injuries was classified according to the Abbreviated Injury Scale (AIS). A total of 217 cycling accidents occurred. One third of the injured cyclists were involved with alcohol at the time of visiting the hospital. Of these, 85% were males. A blood alcohol concentration of ≥ 1.2 g/L was measured in nearly 90% of all alcohol-related cases. A positive BAC result was more common among males than females (p < 0.001), and head injuries were more common among cyclists where alcohol was involved (AI) (60%) than among sober cyclists (29%) (p < 0.001). Two thirds (64%) of the cyclists with AI were not wearing a bicycle helmet. The figure for serious injuries (MAIS ≥ 3) was similar in both groups. Intoxication with an alcohol level of more than 1.5 g/L and the age of 15 to 24 years were found to be risk factors for head injuries. The mean cost of treatment was higher among sober cyclists than among cyclists with AI (€2143 vs. €1629), whereas in respect of the cost of work absence, the situation was the opposite (€1348 vs. €1770, respectively). Cyclists involved with alcohol were, in most cases, heavily intoxicated and were not wearing a bicycle helmet. Head injuries were more common among these cyclists than among sober cyclists. As cycling continues to increase, it is important to monitor cycling accidents, improve the accident statistics and heighten awareness of the risks of head injuries when cycling under the influence of alcohol. Copyright © 2018 Elsevier Ltd. All rights reserved.

Are signalized intersections with cycle tracks safer? A case-control study based on automated surrogate safety analysis using video data.

PubMed

Zangenehpour, Sohail; Strauss, Jillian; Miranda-Moreno, Luis F; Saunier, Nicolas

2016-01-01

Cities in North America have been building bicycle infrastructure, in particular cycle tracks, with the intention of promoting urban cycling and improving cyclist safety. These facilities have been built and expanded but very little research has been done to investigate the safety impacts of cycle tracks, in particular at intersections, where cyclists interact with turning motor-vehicles. Some safety research has looked at injury data and most have reached the conclusion that cycle tracks have positive effects of cyclist safety. The objective of this work is to investigate the safety effects of cycle tracks at signalized intersections using a case-control study. For this purpose, a video-based method is proposed for analyzing the post-encroachment time as a surrogate measure of the severity of the interactions between cyclists and turning vehicles travelling in the same direction. Using the city of Montreal as the case study, a sample of intersections with and without cycle tracks on the right and left sides of the road were carefully selected accounting for intersection geometry and traffic volumes. More than 90h of video were collected from 23 intersections and processed to obtain cyclist and motor-vehicle trajectories and interactions. After cyclist and motor-vehicle interactions were defined, ordered logit models with random effects were developed to evaluate the safety effects of cycle tracks at intersections. Based on the extracted data from the recorded videos, it was found that intersection approaches with cycle tracks on the right are safer than intersection approaches with no cycle track. However, intersections with cycle tracks on the left compared to no cycle tracks seem to be significantly safer. Results also identify that the likelihood of a cyclist being involved in a dangerous interaction increases with increasing turning vehicle flow and decreases as the size of the cyclist group arriving at the intersection increases. The results highlight the important role of cycle tracks and the factors that increase or decrease cyclist safety. Results need however to be confirmed using longer periods of video data. Copyright © 2015 Elsevier Ltd. All rights reserved.

Discriminant analysis of cardiovascular and respiratory variables for classification of road cyclists by specialty.

PubMed

Nikolić, Biljana; Martinović, Jelena; Matić, Milan; Stefanović, Đorđe

2018-05-29

Different variables determine the performance of cyclists, which brings up the question how these parameters may help in their classification by specialty. The aim of the study was to determine differences in cardiorespiratory parameters of male cyclists according to their specialty, flat rider (N=21), hill rider (N=35) and sprinter (N=20) and obtain the multivariate model for further cyclists classification by specialties, based on selected variables. Seventeen variables were measured at submaximal and maximum load on the cycle ergometer Cosmed E 400HK (Cosmed, Rome, Italy) (initial 100W with 25W increase, 90-100 rpm). Multivariate discriminant analysis was used to determine which variables group cyclists within their specialty, and to predict which variables can direct cyclists to a particular specialty. Among nine variables that statistically contribute to the discriminant power of the model, achieved power on the anaerobic threshold and the produced CO2 had the biggest impact. The obtained discriminatory model correctly classified 91.43% of flat riders, 85.71% of hill riders, while sprinters were classified completely correct (100%), i.e. 92.10% of examinees were correctly classified, which point out the strength of the discriminatory model. Respiratory indicators mostly contribute to the discriminant power of the model, which may significantly contribute to training practice and laboratory tests in future.

Selective training-induced thigh muscles hypertrophy in professional road cyclists.

PubMed

Hug, François; Marqueste, Tanguy; Le Fur, Yann; Cozzone, Patrick J; Grélot, Laurent; Bendahan, David

2006-07-01

Muscular adaptations linked to a high volume and intensity of training have been scarcely reported. We aimed at documenting, using MRI, the cross-sectional area changes associated with a high volume and intensity of training in 11 thigh muscles of a population of professional road cyclists as compared with sport science students. We were also interested in determining, whether selective muscle hypertrophy in professional road cyclists, if any, was correlated to selective exercise-induced T (2) changes during a pedaling exercise on a cycloergometer. Cross-sectional area of 11 thigh muscles was quantified in sixteen subjects (i.e. eight professional road cyclists and eight sport science students) using MRI. In addition, transverse relaxation times (T (2)) were measured before and just after a maximal standardized constant-load exercise in order to investigate exercise-related T (2) changes in these muscles. Professional road cyclists had a significantly higher relative amount of muscle (including the whole set of thigh muscles, 90.5+/-3.3%) as compared to controls (81.6+/-7.3%). Regarding relative values expressed with respect to the total thigh muscles CSA, Vastus lateralis and Biceps femoris CSA were significantly larger in cyclists whereas CSA of the Vastus intermedius was smaller. However, this selective hypertrophy was not correlated to the exercise-induced T (2)-increase. We have reported, for the first time, a selective hypertrophy of Vastus lateralis and Biceps femoris in professional road cyclists confirming their involvement in pedaling task and suggesting a possible cause-effect relationship between muscle activation and hypertrophy, associated with a specific pedaling skill.

Predicting High-Power Performance in Professional Cyclists.

PubMed

Sanders, Dajo; Heijboer, Mathieu; Akubat, Ibrahim; Meijer, Kenneth; Hesselink, Matthijs K

2017-03-01

To assess if short-duration (5 to ~300 s) high-power performance can accurately be predicted using the anaerobic power reserve (APR) model in professional cyclists. Data from 4 professional cyclists from a World Tour cycling team were used. Using the maximal aerobic power, sprint peak power output, and an exponential constant describing the decrement in power over time, a power-duration relationship was established for each participant. To test the predictive accuracy of the model, several all-out field trials of different durations were performed by each cyclist. The power output achieved during the all-out trials was compared with the predicted power output by the APR model. The power output predicted by the model showed very large to nearly perfect correlations to the actual power output obtained during the all-out trials for each cyclist (r = .88 ± .21, .92 ± .17, .95 ± .13, and .97 ± .09). Power output during the all-out trials remained within an average of 6.6% (53 W) of the predicted power output by the model. This preliminary pilot study presents 4 case studies on the applicability of the APR model in professional cyclists using a field-based approach. The decrement in all-out performance during high-intensity exercise seems to conform to a general relationship with a single exponential-decay model describing the decrement in power vs increasing duration. These results are in line with previous studies using the APR model to predict performance during brief all-out trials. Future research should evaluate the APR model with a larger sample size of elite cyclists.

Vertigo in downhill mountain biking and road cycling.

PubMed

Lion, Alexis; Vibert, Dominique; Bosser, Gilles; Gauchard, Gérome C; Perrin, Philippe P

2016-01-01

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.

Incidents between Straight-ahead Cyclists and Right-turning Motor Vehicles at Signalised Junctions.

PubMed

Buch, Thomas Skallebæk; Jensen, Søren Underlien

2017-08-01

Accidents between right-turning motor vehicles and straight-ahead cyclists are one of the most common accident types leading to cyclist injuries at signalised junctions in Denmark. A before-after safety evaluation of applying staggered stop lines in 189 arms at 123 signalised junctions is presented. The evaluation accounts for long-term accident trends and changes in motor vehicle traffic volumes. Applying staggered stop lines gives no decline in accidents between right-turning motor vehicles and straight-ahead cyclists. However, there is a statistical tendency to a decline of these right-turn accidents involving heavy vehicles. There are several questions about factors leading to right-turn accidents that cannot be answered by recorded accident data. A study of conflicting behaviour focuses on factors leading to conflicts. Video observations have been carried out in 10 arms at signalised junctions. A total of 45 situations with conflicting behaviour between right-turning motor vehicles and straight-ahead cyclists have been investigated and compared to a reference group of simultaneous arrivals. The relative risk is lowest when both parties stop on red before entering the junction. Upon simultaneous arrival of both parties at a green light, the relative risk is highest. Cyclists tend to have a higher relative risk of being involved in conflicts if they; a) ride through on yellow, b) have a time distance of at least 2seconds to other cyclists, c) wear a black jacket, and/or d) arrive at the junction at a speed of at least 25km/h. Much less can be said about the motor vehicles or their drivers on the basis of these video observations, but motor vehicles stopping in the cycle crossing in order to yield to pedestrians or cyclists have a higher relative risk of being involved in conflicts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exercise addiction risk and health in male and female amateur endurance cyclists

PubMed Central

Mayolas-Pi, Carmen; Simón-Grima, Javier; Peñarrubia-Lozano, Carlos; Munguía-Izquierdo, Diego; Moliner-Urdiales, Diego; Legaz-Arrese, Alejandro

2017-01-01

Background and aims To determine the relationship between the risk of exercise addiction (REA) and health status in amateur endurance cyclists. Methods In 859 (751 men and 108 women) cyclists and 718 inactive subjects (307 men and 411 women), we examined the REA (Exercise Addiction Inventory), training status (volume, frequency, experience, and performance), socioeconomic status, quality of life (QoL) (SF-12), quality of sleep (Pittsburgh Sleep Quality Index), anxiety and depression (Hospital Anxiety and Depression Scale), and cardiometabolic risk: body mass index, physical activity (International Physical Activity Questionnaire), physical condition (International Fitness Scale), adherence to the Mediterranean diet (Mediterranean Diet Adherence Screener), alcohol and tobacco consumption. Results In total, 17% of the cyclists showed evidence of REA and 83% showed low REA. REA occurred independent of age, sex, training, and socioeconomic status (all ps > .05). Regardless of REA, the cyclists displayed a better physical QoL and a lower cardiometabolic risk than the inactive subjects (all ps < .05). The cyclists with REA displayed worse values of mental QoL, quality of sleep, and anxiety than cyclists with low REA (all ps < .05). The REA group had better values of mental QoL and anxiety and similar values of quality of sleep than the inactive subjects. The differences in mental QoL between the REA and low REA groups were significantly greater in women (p = .013). There was no Addiction × Sex interaction in the other analyzed variables. Conclusion Our results suggest that an increased prevalence of REA limits the benefits that amateur endurance cycling has on mental health and quality of sleep. PMID:28358644

Exercise addiction risk and health in male and female amateur endurance cyclists.

PubMed

Mayolas-Pi, Carmen; Simón-Grima, Javier; Peñarrubia-Lozano, Carlos; Munguía-Izquierdo, Diego; Moliner-Urdiales, Diego; Legaz-Arrese, Alejandro

2017-03-01

Background and aims To determine the relationship between the risk of exercise addiction (REA) and health status in amateur endurance cyclists. Methods In 859 (751 men and 108 women) cyclists and 718 inactive subjects (307 men and 411 women), we examined the REA (Exercise Addiction Inventory), training status (volume, frequency, experience, and performance), socioeconomic status, quality of life (QoL) (SF-12), quality of sleep (Pittsburgh Sleep Quality Index), anxiety and depression (Hospital Anxiety and Depression Scale), and cardiometabolic risk: body mass index, physical activity (International Physical Activity Questionnaire), physical condition (International Fitness Scale), adherence to the Mediterranean diet (Mediterranean Diet Adherence Screener), alcohol and tobacco consumption. Results In total, 17% of the cyclists showed evidence of REA and 83% showed low REA. REA occurred independent of age, sex, training, and socioeconomic status (all ps > .05). Regardless of REA, the cyclists displayed a better physical QoL and a lower cardiometabolic risk than the inactive subjects (all ps < .05). The cyclists with REA displayed worse values of mental QoL, quality of sleep, and anxiety than cyclists with low REA (all ps < .05). The REA group had better values of mental QoL and anxiety and similar values of quality of sleep than the inactive subjects. The differences in mental QoL between the REA and low REA groups were significantly greater in women (p = .013). There was no Addiction × Sex interaction in the other analyzed variables. Conclusion Our results suggest that an increased prevalence of REA limits the benefits that amateur endurance cycling has on mental health and quality of sleep.

Peak oxygen uptake in a sprint interval testing protocol vs. maximal oxygen uptake in an incremental testing protocol and their relationship with cross-country mountain biking performance.

PubMed

Hebisz, Rafał; Hebisz, Paulina; Zatoń, Marek; Michalik, Kamil

2017-04-01

In the literature, the exercise capacity of cyclists is typically assessed using incremental and endurance exercise tests. The aim of the present study was to confirm whether peak oxygen uptake (V̇O 2peak ) attained in a sprint interval testing protocol correlates with cycling performance, and whether it corresponds to maximal oxygen uptake (V̇O 2max ) determined by an incremental testing protocol. A sample of 28 trained mountain bike cyclists executed 3 performance tests: (i) incremental testing protocol (ITP) in which the participant cycled to volitional exhaustion, (ii) sprint interval testing protocol (SITP) composed of four 30 s maximal intensity cycling bouts interspersed with 90 s recovery periods, (iii) competition in a simulated mountain biking race. Oxygen uptake, pulmonary ventilation, work, and power output were measured during the ITP and SITP with postexercise blood lactate and hydrogen ion concentrations collected. Race times were recorded. No significant inter-individual differences were observed in regards to any of the ITP-associated variables. However, 9 individuals presented significantly increased oxygen uptake, pulmonary ventilation, and work output in the SITP compared with the remaining cyclists. In addition, in this group of 9 cyclists, oxygen uptake in SITP was significantly higher than in ITP. After the simulated race, this group of 9 cyclists achieved significantly better competition times (99.5 ± 5.2 min) than the other cyclists (110.5 ± 6.7 min). We conclude that mountain bike cyclists who demonstrate higher peak oxygen uptake in a sprint interval testing protocol than maximal oxygen uptake attained in an incremental testing protocol demonstrate superior competitive performance.

Pedestrian injuries due to collisions with bicycles in New York and California.

PubMed

Tuckel, Peter; Milczarski, William; Maisel, Richard

2014-12-01

Scant attention has been given to pedestrians injured in accidents resulting from collisions with cyclists. This scholarly neglect is surprising given the growing popularity of cycling. This study examines the incidence of pedestrians injured by cyclists in New York between 2004 to 2011 and in California from 2005 to 2011. The study also profiles the pedestrians injured in these two states during these two time frames. The data for this study are based upon patient-level hospital records from New York and California. The data for New York comes from the Statewide Planning and Research Cooperative System (SPARCS) under the auspices of New York State's Department of Health. The data for California come from two sources: the Healthcare Cost and Utilization Project (HCUP) and the California Office of Statewide Health Planning and Development. The rate of pedestrians injured in collisions with cyclists has decreased over time. This decline has occurred despite the increase in the number of cyclists in these states during this same time period. Two possible explanations for this decline are: (a) less exposure of children to cyclists, and (b) improvements in the cycling infrastructure. Although the rate of injuries to pedestrians from collisions with cyclists has been decreasing, improvements to the cycling infrastructure will need to continue. Bike lanes, particularly protected bike lanes, have been shown to be an effective way of reducing cycling-pedestrian accidents. The results of the current study are consistent with this research. Educational campaigns aimed at cyclists that emphasize the safety of all road users--including pedestrians--will also need to continue to assure that this downward trend in the number of accidents is not reversed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Anger expression among Danish cyclists and drivers: A comparison based on mode specific anger expression inventories.

PubMed

Møller, M; Haustein, S

2017-11-01

Based on the short form of the driving anger expression inventory (DAX-short, 15-item), the present study developed an adapted version of the DAX for cyclists (CAX, 14 items). The data basis was an online survey of 2000 inhabitants of Denmark. A principle component analysis on the translated DAX-short confirmed the 4-factor solution of the original study differentiating between (1) personal physical aggressive expression, (2) use of a vehicle to express anger, (3) verbal aggressive expression and (4) adaptive/constructive expression. In case of cycling, the factor "use of a vehicle to express anger" only included one item and was left out. Based on the results, reliable subscales were developed. Drivers scored higher in verbal aggressive expression than cyclists, while there was no significant difference in constructive expression. The subscales for drivers and cyclists showed significant relations to age, gender, self-reported aggressive behaviours and traffic fines: Women scored for instance lower in physical expression, while older people scored higher in constructive expression. The effect of age and gender on anger expression among drivers and cyclists remained significant when controlling for exposure and other factors in linear regression analyses. These analyses also showed a relationship between a positive attitude towards driving and higher levels of anger expression among drivers, while this was not the case for cyclists. Copyright © 2017 Elsevier Ltd. All rights reserved.

Helmet use among cyclists in New York City.

PubMed

Basch, Corey H; Zagnit, Emily A; Rajan, Sonali; Ethan, Danna; Basch, Charles E

2014-10-01

Lack of helmet use while bicycling can have deleterious effects on health. Despite evidence that helmets can greatly reduce the risk of head injury, the prevalence of helmet use among riders, including those in urban bicycle-share programs, has been shown to be very low. Building upon the authors' previous work, this study's aim was to assess prevalence of helmet use among cyclists riding on widely used New York City (NYC) bike lanes. Across a 2-month period, cyclists were filmed in five NYC locations with bike lanes. Filming took place at two separate time periods (recreation and commute) at each location. Helmet use was coded for each cyclist. A total of 1,921 riders were observed across 10 h. Overall, half (50.0 %) of all riders were observed wearing a helmet. Rates of using a helmet were consistent across all five locations. In addition, only 21.7 % of Citi Bike users and 15.3 % of other bicycle rentals were observed wearing helmets while cycling. The prevalence of helmet use was significantly higher among males than females (z = 4.48, p < .001). Cyclists observed during the recreational time period were also less likely than those observed during the commuting time period to be wearing a helmet (z = 7.17, p < .001). The results of this study contribute to the growing literature about cyclist helmet use in urban areas.

Geriatric Cyclists: Assessing Risks, Safety, and Benefits

PubMed Central

Ikpeze, Tochukwu C.; Glaun, Gabriel; McCalla, Daren

2018-01-01

Nearly 1 in every 3 Americans ride bicycles each year, but only 20% of the reported 100 million cyclists ride on a weekly basis. Bicycling is a common form of transportation and recreation and has gained popularity among the elderly patients. In recent years, the number of elderly cyclists has increased steadily and studies have cited ease of use, need for exercise, and enjoyment as important contributing factors. The benefits of physical activity on health is well-documented, and elderly individuals are encouraged to remain active to reduce the progression of age-related weakness and loss of muscle mass. Safety concerns, however, have been a prevalent public health issue. According to the Center for Disease Control and Prevention, elderly and teenage cyclists account for the highest number of head injuries and fatalities among all cyclists. Safety measures that include wearing protective gear such as helmets and choosing the appropriate bicycle have been recommended to minimize the risk of sustaining injuries while riding. Despite these concerns, bicycling has remained a popular and exciting activity for the elderly patients. PMID:29383267

Aerodynamics of cyclist posture, bicycle and helmet characteristics in time trial stage.

PubMed

Chabroux, Vincent; Barelle, Caroline; Favier, Daniel

2012-07-01

The present work is focused on the aerodynamic study of different parameters, including both the posture of a cyclist's upper limbs and the saddle position, in time trial (TT) stages. The aerodynamic influence of a TT helmet large visor is also quantified as a function of the helmet inclination. Experiments conducted in a wind tunnel on nine professional cyclists provided drag force and frontal area measurements to determine the drag force coefficient. Data statistical analysis clearly shows that the hands positioning on shifters and the elbows joined together are significantly reducing the cyclist drag force. Concerning the saddle position, the drag force is shown to be significantly increased (about 3%) when the saddle is raised. The usual helmet inclination appears to be the inclination value minimizing the drag force. Moreover, the addition of a large visor on the helmet is shown to provide a drag coefficient reduction as a function of the helmet inclination. Present results indicate that variations in the TT cyclist posture, the saddle position and the helmet visor can produce a significant gain in time (up to 2.2%) during stages.

Cyclists Have Greater Chondromalacia Index Than Age-Matched Controls at the Time of Hip Arthroscopy.

PubMed

Stone, Austin V; Howse, Elizabeth A; Mannava, Sandeep; Stubbs, Allston J

2016-10-01

To evaluate the clinical symptoms and intraoperative pathology associated with hip pain in the cyclist compared with a matched hip arthroscopy surgical group. In an institutional review board-approved study, we retrospectively reviewed a prospective database of 1,200 consecutive hip arthroscopy patients from 2008 to 2015. Adult patients were identified who reported cycling as a major component of their activity. Patients were age, gender, and body mass index matched to a control, noncycling group. Pain symptoms, preoperative examinations, radiographic and operative findings were compared. Primary outcome variables included the femoral and acetabular Outerbridge chondromalacia grade. Additional outcome measurements included the involved area and the chondromalacia index (CMI; the product of the Outerbridge chondromalacia grade and surface area [mm 2  × severity]). A total of 167 noncyclists were matched to the cycling group (n = 16). Cyclists had significantly greater femoral head chondromalacia grade (2.0 [95% confidence interval (CI), 1.5-2.5] v 1.4 [95% CI, 1.3-1.6], P = .043), femoral head chondromalacia area (242 mm 2 [95% CI, 191-293 mm 2 ] v 128 mm 2 [95% CI, 113-141 mm 2 ], P < .001), and femoral head CMI (486 [95% CI, 358-615] v 247 [95% CI, 208-286], P = .001) assessed intraoperatively. Hip pain in cyclists positively correlated with an increased acetabular center-edge angle (R = 0.261, P < .001) and an increased Tonnis grade (R = 0.305, P < .001). Cyclists were also more likely to have a coxalgic gait on physical examination (R = 0.250, P = .006). Cyclists had a greater degree of femoral chondromalacia than a matched group of noncyclists. Cycling activity positively correlated with the presence of femoral chondromalacia with clinically significant gait alterations. These data support the hypothesis that cyclists with hip pain have more chondral pathology than a similar group of other patients with hip pain. Ultimately, cyclists with hip pain should be identified as higher risk for more advanced chondral damage. Level III, case-control study, therapeutic. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Effects of a Mindfulness Intervention on Sports-Anxiety, Pessimism, and Flow in Competitive Cyclists.

PubMed

Scott-Hamilton, John; Schutte, Nicola S; Brown, Rhonda F

2016-03-01

This study investigated whether mindfulness training increases athletes' mindfulness and flow experience and decreases sport-specific anxiety and sport-specific pessimism. Cyclists were assigned to an eight-week mindfulness intervention, which incorporated a mindful spin-bike training component, or a wait-list control condition. Participants completed baseline and post-test measures of mindfulness, flow, sport-anxiety, and sport-related pessimistic attributions. Analyses of covariance showed significant positive effects on mindfulness, flow, and pessimism for the 27 cyclists in the mindfulness intervention condition compared with the 20 cyclists in the control condition. Changes in mindfulness experienced by the intervention participants were positively associated with changes in flow. Results suggest that mindfulness-based interventions tailored to specific athletic pursuits can be effective in facilitating flow experiences. © 2016 The International Association of Applied Psychology.

Identification of pre-impact conditions of a cyclist involved in a vehicle-bicycle accident using an optimized MADYMO reconstruction combined with motion capture.

PubMed

Sun, Jie; Li, Zhengdong; Pan, Shaoyou; Feng, Hao; Shao, Yu; Liu, Ningguo; Huang, Ping; Zou, Donghua; Chen, Yijiu

2018-05-01

The aim of the present study was to develop an improved method, using MADYMO multi-body simulation software combined with an optimization method and three-dimensional (3D) motion capture, for identifying the pre-impact conditions of a cyclist (walking or cycling) involved in a vehicle-bicycle accident. First, a 3D motion capture system was used to analyze coupled motions of a volunteer while walking and cycling. The motion capture results were used to define the posture of the human model during walking and cycling simulations. Then, cyclist, bicycle and vehicle models were developed. Pre-impact parameters of the models were treated as unknown design variables. Finally, a multi-objective genetic algorithm, the nondominated sorting genetic algorithm II, was used to find optimal solutions. The objective functions of the walk parameter were significantly lower than cycle parameter; thus, the cyclist was more likely to have been walking with the bicycle than riding the bicycle. In the most closely matched result found, all observed contact points matched and the injury parameters correlated well with the real injuries sustained by the cyclist. Based on the real accident reconstruction, the present study indicates that MADYMO multi-body simulation software, combined with an optimization method and 3D motion capture, can be used to identify the pre-impact conditions of a cyclist involved in a vehicle-bicycle accident. Copyright © 2018. Published by Elsevier Ltd.

The impact of a simulated grand tour on sleep, mood, and well-being of competitive cyclists.

PubMed

Lastella, M; Roach, G D; Halson, S L; Martin, D T; West, N P; Sargent, C

2015-12-01

Professional cycling is considered one of the most demanding of all endurance sports. The three major professional cycling stages races (i.e. Tour de France, Giro d'Italia and Vuelta a España) require cyclists to compete daily covering between ~150-200 km for three consecutive weeks. Anecdotal evidence indicates that such an event has a significant effect on the sleep, mood, and general well-being of cyclists, particularly during the latter stages of the event. The primary aim of this study was to simulate a grand tour and determine the impact a grand tour has on the sleep, mood, and general well-being of competitive cyclists. Twenty-one male cyclists (M±SD, age 22.2±2.7 years) were examined for 39 days across three phases (i.e. baseline, simulated grand tour, and recovery). Sleep was assessed using sleep diaries and wrist activity monitors. Mood and general well-being were assessed using the Brunel Mood Scale (BRUMS) and Visual Analogue Scales (VAS). The amount and quality of sleep as assessed by the wrist activity monitors declined during the simulated grand tour. In contrast, self-reported sleep quality improved throughout the study. Cyclists' mood and general well-being as indicated by vigour, motivation, physical and mental state declined during the simulated tour. Future investigations should examine sleep, mood and well-being during an actual grand tour. Such data could prove instrumental toward understanding the sleep and psychological changes that occur during a grand tour.

Comparison of running and cycling economy in runners, cyclists, and triathletes.

PubMed

Swinnen, Wannes; Kipp, Shalaya; Kram, Rodger

2018-07-01

Exercise economy is one of the main physiological factors determining performance in endurance sports. Running economy (RE) can be improved with running-specific training, while the improvement of cycling economy (CE) with cycling-specific training is controversial. We investigated whether exercise economy reflects sport-specific skills/adaptations or is determined by overall physiological factors. We compared RE and CE in 10 runners, 9 cyclists and 9 triathletes for running at 12 km/h and cycling at 200 W. Gross rates of oxygen consumption and carbon dioxide production were collected and used to calculate gross metabolic rate in watts for both running and cycling. Runners had better RE than cyclists (917 ± 107 W vs. 1111 ± 159 W) (p < 0.01). Triathletes had intermediate RE values (1004 ± 98 W) not different from runners or cyclists. CE was not different (p = 0.20) between the three groups (runners: 945 ± 60 W; cyclists: 982 ± 44 W; triathletes: 979 ± 54 W). RE can be enhanced with running-specific training, but CE is independent of cycling-specific training.

Time-to-collision analysis of pedestrian and pedal-cycle accidents for the development of autonomous emergency braking systems.

PubMed

Lenard, James; Welsh, Ruth; Danton, Russell

2018-06-01

The aim of this study was to describe the position of pedestrians and pedal cyclists relative to the striking vehicle in the 3 s before impact. This information is essential for the development of effective autonomous emergency braking systems and relevant test conditions for consumer ratings. The UK RAIDS-OTS study provided 175 pedestrian and 127 pedal-cycle cases based on in-depth, at-scene investigations of a representative sample of accidents in 2000-2010. Pedal cyclists were scattered laterally more widely than pedestrians (90% of cyclists within around ±80° compared to ±20° for pedestrians), however their distance from the striking vehicle in the seconds before impact was no greater (90% of cyclists within 42 m at 3 s compared to 50 m for pedestrians). This data is consistent with a greater involvement of slow moving vehicles in cycle accidents. The implication of the results is that AEB systems for cyclists require almost complete 180° side-to-side vision but do not need a longer distance range than for pedestrians. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Analysis of road traffic injuries in Mexican cyclists].

PubMed

Muro-Báez, Victoria Alejandra; Mendoza-García, M Eulalia; Vera-López, Juan Daniel; Pérez-Núñez, Ricardo

2017-01-01

With the objective of analyzing fatal and non-fatal road traffic injuries in cyclists and to document helmet use in this road user to inform sustainable mobility policies, a descriptive analysis of four secondary official information sources was conducted at the national level: mortality, Ministry of Health's hospital discharges, Unintentional and Violence Registry System (SIS-SS-17-P) and the 2012 National Health and Nutrition Survey (ENSANUT). Only SIS-SS-17-P and ENSANUT document helmet use. Except for ENSANUT information analyzed is of 2014.A total of 190 cyclists died in Mexico during 2014 and 392 were hospitalized; head was the anatomical region most frequently affected (63% and 32%, respectively). Only 0.75% of the 667 cases registered in SIS-17 reported helmet use and 24% suffered head injuries. Of the 165,348 non-fatally injured cyclists from ENSANUT <10% used helmet, 24% had head injuries and more than 16,000 suffered permanent injuries. Whereas cyclist-friendly infrastructure is an effective intervention to prevent injuries in the long term, helmet use could potentially reduce the frequency and severity of head injuries in the short run while bicycle use widespread as a means of transportation providing "safety in numbers".

Visual map and instruction-based bicycle navigation: a comparison of effects on behaviour.

PubMed

de Waard, Dick; Westerhuis, Frank; Joling, Danielle; Weiland, Stella; Stadtbäumer, Ronja; Kaltofen, Leonie

2017-09-01

Cycling with a classic paper map was compared with navigating with a moving map displayed on a smartphone, and with auditory, and visual turn-by-turn route guidance. Spatial skills were found to be related to navigation performance, however only when navigating from a paper or electronic map, not with turn-by-turn (instruction based) navigation. While navigating, 25% of the time cyclists fixated at the devices that present visual information. Navigating from a paper map required most mental effort and both young and older cyclists preferred electronic over paper map navigation. In particular a turn-by-turn dedicated guidance device was favoured. Visual maps are in particular useful for cyclists with higher spatial skills. Turn-by-turn information is used by all cyclists, and it is useful to make these directions available in all devices. Practitioner Summary: Electronic navigation devices are preferred over a paper map. People with lower spatial skills benefit most from turn-by-turn guidance information, presented either auditory or on a dedicated device. People with higher spatial skills perform well with all devices. It is advised to keep in mind that all users benefit from turn-by-turn information when developing a navigation device for cyclists.

Mobile phone conversations, listening to music and quiet (electric) cars: Are traffic sounds important for safe cycling?

PubMed

Stelling-Konczak, A; van Wee, G P; Commandeur, J J F; Hagenzieker, M

2017-09-01

Listening to music or talking on the phone while cycling as well as the growing number of quiet (electric) cars on the road can make the use of auditory cues challenging for cyclists. The present study examined to what extent and in which traffic situations traffic sounds are important for safe cycling. Furthermore, the study investigated the potential safety implications of limited auditory information caused by quiet (electric) cars and by cyclists listening to music or talking on the phone. An Internet survey among 2249 cyclists in three age groups (16-18, 30-40 and 65-70year old) was carried out to collect information on the following aspects: 1) the auditory perception of traffic sounds, including the sounds of quiet (electric) cars; 2) the possible compensatory behaviours of cyclists who listen to music or talk on their mobile phones; 3) the possible contribution of listening to music and talking on the phone to cycling crashes and incidents. Age differences with respect to those three aspects were analysed. Results show that listening to music and talking on the phone negatively affects perception of sounds crucial for safe cycling. However, taking into account the influence of confounding variables, no relationship was found between the frequency of listening to music or talking on the phone and the frequency of incidents among teenage cyclists. This may be due to cyclists' compensating for the use of portable devices. Listening to music or talking on the phone whilst cycling may still pose a risk in the absence of compensatory behaviour or in a traffic environment with less extensive and less safe cycling infrastructure than the Dutch setting. With the increasing number of quiet (electric) cars on the road, cyclists in the future may also need to compensate for the limited auditory input of these cars. Copyright © 2017 Elsevier Ltd. All rights reserved.

An Analysis of Technology-Related Distracted Biking Behaviors and Helmet Use Among Cyclists in New York City.

PubMed

Ethan, Danna; Basch, Corey H; Johnson, Glen D; Hammond, Rodney; Chow, Ching Man; Varsos, Victoria

2016-02-01

Bicycling is becoming an increasingly utilized mode of transportation in New York City. Technology-related distracted bicycling and helmet use are behaviors that can impact bike safety. The aims of this study were twofold: (1) to determine rates and types of technology-related distracted behaviors among bicyclists in the borough of Manhattan in New York City; and (2) to assess the rate of bicycle helmet use among these cyclists. Bicyclists in five popular riding areas in Manhattan were observed for a total of 50 h using a digital video camera during summer months in 2014. Videos were coded and enumerated for the total number and gender of cyclists, type of bicycle, number wearing headphones/earbuds and/or using a mobile phone, and whether the cyclist was wearing a helmet. Almost 25,000 cyclists were observed across the five selected locations (n = 24,861). Riders were almost four times more likely not to wear a helmet on rental bikes as compared with non-rentals (Citi Bike(®) OR 3.8; 95% CI 2.5, 5.9: other rental OR 3.8; 95% CI 3.0, 4.9). Significantly increased odds of not wearing a helmet were observed for females relative to males (OR 1.4; 95% CI 1.1, 1.8) across varied times and locations. Overall, rates of technology-related distraction were low, with headphone use being most prevalent. Males were more likely to wear headphones/earbuds (OR 2.0; 95% CI 1.4, 2.9), as were cyclists on Citi Bikes relative to other rental bikes (OR 2.2; 95% CI 1.3, 3.6). Findings from this study contribute to the growing literature on distracted biking and helmet use among bike share program riders and other cyclists and can inform policymakers and program planners aiming to improve bicycle safety in urban settings.

Safety in numbers in Australia: more walkers and bicyclists, safer walking and bicycling.

PubMed

Robinson, Dorothy L

2005-04-01

Overseas research shows that fatality and injury risks per cyclist and pedestrian are lower when there are more cyclists and pedestrians. Do Australian data follow the same exponential 'growth rule' where (Injuries)/(Amount of cycling) is proportional to ((Amount of cycling)-0.6)? Fatality and injury risks were compared using three datasets: 1) fatalities and amounts of cycling in Australian States in the 1980s; 2) fatality and injury rates over time in Western Australia as cycling levels increased; and 3) deaths, serious head injuries and other serious injuries to cyclists and pedestrians in Victoria, before and after the fall in cycling with the helmet law. In Australia, the risks of fatality and injury per cyclist are lower when cycling is more prevalent. Cycling was safest and most popular in the Australian Capital Territory (ACT), Queensland and Western Australia (WA). New South Wales residents cycled only 47% as much as residents of Queensland and WA, but had 53% more fatalities per kilometre, consistent with the growth rule prediction of 52% more for half as much cycling. Cycling also became safer in WA as more people cycled. Hospitalisation rates per 10,000 regular cyclists fell from 29 to 15, and reported deaths and serious injuries from 5.6 to 3.8 as numbers of regular cyclists increased. In Victoria, after the introduction of compulsory helmets, there was a 30% reduction in cycling and it was associated with a higher risk of death or serious injury per cyclist, outweighing any benefits of increased helmet wearing. As with overseas data, the exponential growth rule fits Australian data well. If cycling doubles, the risk per kilometre falls by about 34%; conversely, if cycling halves, the risk per kilometre will be about 52% higher. Policies that adversely influence the amount of cycling (for example, compulsory helmet legislation) should be reviewed.

Mapping commuter cycling risk in urban areas.

PubMed

Yiannakoulias, Nikolaos; Bennet, Scott A; Scott, Darren M

2012-03-01

Cycling is becoming an increasingly important transportation option for commuters. Cycling offers exercise opportunities and reduces the burden of motor vehicle travel on society. Mapping the risk of collision between cyclists and motor vehicles in urban areas is important to understanding safe cyclist route opportunities, making informed transportation planning decisions, and exploring patterns of injury epidemiology. To date, many geographic analyses and representations of cyclist risk have not taken the concept of exposure into account. Instead, risk is either expressed as a rate per capita, or as a count of events. Using data associated with the City of Hamilton, Canada, we illustrate a method for mapping commuter cyclist collision risk per distance travelled. This measure can be used to more realistically represent the underlying geography of cycling risk, and provide more geographically and empirically meaningful information to those interested in understanding how cycling safety varies over space. Copyright © 2011 Elsevier Ltd. All rights reserved.

Use of augmented feedback for the modification of the pedaling mechanics of cyclists.

PubMed

Sanderson, D J; Cavanagh, P R

1990-03-01

On-line computer representation of forces applied to the pedals during a 90-degree sector of the pedaling cycle were used to train a group of cyclists to alter their pattern of force application while they cycled on a stationary cycle. The subjects rode for 32 min each day for ten days. During these training rides, three cyclists were given augmented feedback on only their pedaling rate, while three other cyclists were presented with augmented, visual feedback on the magnitude of force application in the sector of interest as well as cadence. At the end of the training period it was noted that the experimental group showed significantly reduced pedal forces in the sector of interest while the control group did not. It was concluded that this technique of modifying a well-practised task was an effective one and that it could be used to explore various training modalities and other pedaling styles.

The injury epidemiology of cyclists based on a road trauma registry.

PubMed

Amoros, Emmanuelle; Chiron, Mireille; Thélot, Bertrand; Laumon, Bernard

2011-08-17

Bicycle use has increased in some of France's major cities, mainly as a means of transport. Bicycle crashes need to be studied, preferably by type of cycling. Here we conduct a descriptive analysis. A road trauma registry has been in use in France since 1996, in a large county around Lyon (the Rhône, population 1.6 million). It covers outpatients, inpatients and fatalities. All injuries are coded using the Abbreviated Injury Scale (AIS). Proxies were used to identify three types of cycling: learning = children (0-10 years old); sports cycling = teenagers and adults injured outside towns; cycling as means of transport = teenagers and adults injured in towns. The study is based on 13,684 cyclist casualties (1996-2008). The percentage of cyclists injured in a collision with a motor vehicle was 8% among children, 17% among teenagers and adults injured outside towns, and 31% among those injured in towns. The percentage of serious casualties (MAIS 3+) was 4.5% among children, 10.9% among adults injured outside towns and 7.2% among those injured in towns. Collisions with motor-vehicles lead to more internal injuries than bicycle-only crashes. The description indicates that cyclist type is associated with different crash and injury patterns. In particular, cyclists injured in towns (where cycling is increasing) are generally less severely injured than those injured outside towns for both types of crash (bicycle-only crashes and collisions with a motor vehicle). This is probably due to lower speeds in towns, for both cyclists and motor vehicles.

Can cyclist safety be improved with intelligent transport systems?

PubMed

Silla, Anne; Leden, Lars; Rämä, Pirkko; Scholliers, Johan; Van Noort, Martijn; Bell, Daniel

2017-08-01

In recent years, Intelligent Transport Systems (ITS) have assisted in the decrease of road traffic fatalities, particularly amongst passenger car occupants. Vulnerable Road Users (VRUs) such as pedestrians, cyclists, moped riders and motorcyclists, however, have not been that much in focus when developing ITS. Therefore, there is a clear need for ITS which specifically address VRUs as an integrated element of the traffic system. This paper presents the results of a quantitative safety impact assessment of five systems that were estimated to have high potential to improve the safety of cyclists, namely: Blind Spot Detection (BSD), Bicycle to Vehicle communication (B2V), Intersection safety (INS), Pedestrian and Cyclist Detection System+Emergency Braking (PCDS+EBR) and VRU Beacon System (VBS). An ex-ante assessment method proposed by Kulmala (2010) targeted to assess the effects of ITS for cars was applied and further developed in this study to assess the safety impacts of ITS specifically designed for VRUs. The main results of the assessment showed that all investigated systems affect cyclist safety in a positive way by preventing fatalities and injuries. The estimates considering 2012 accident data and full penetration showed that the highest effects could be obtained by the implementation of PCDS+EBR and B2V, whereas VBS had the lowest effect. The estimated yearly reduction in cyclist fatalities in the EU-28 varied between 77 and 286 per system. A forecast for 2030, taking into accounts the estimated accident trends and penetration rates, showed the highest effects for PCDS+EBR and BSD. Copyright © 2016 Elsevier Ltd. All rights reserved.

Key influences on motivations for utility cycling (cycling for transport to and from places).

PubMed

Heesch, Kristiann C; Sahlqvist, Shannon

2013-12-01

Although increases in cycling in Brisbane are encouraging, bicycle mode share to work (the proportion of people travelling to work by bicycle) in the state of Queensland remains low. The aim of this qualitative study was to draw upon the lived experiences of Queensland cyclists to understand the main motivators for utility cycling (cycling as a means to get to and from places) and compare motivators between utility cyclists (those who cycle for utility as well as for recreation) and non-utility cyclists (those who cycle only for recreation). For an online survey, members of a bicycle group (831 utility cyclists and 931 non-utility cyclists, aged 18-90 years) were asked to describe, unprompted, what would motivate them to engage in utility cycling (more often). Responses were coded into themes within four levels of an ecological model. Within an ecological model, built environment influences on motivation were grouped according to whether they related to appeal (safety), convenience (accessibility) or attractiveness (more amenities) and included adequate infrastructure for short trips, bikeway connectivity, end-of-trip facilities at public locations and easy and safe bicycle access to destinations outside of cities. A key social-cultural influence related to improved interactions among different road users. The built and social-cultural environments need to be more supportive of utility cycling before even current utility and non-utility cyclists will be motivated to engage (more often) in utility cycling. SO WHAT?: Additional government strategies and more and better infrastructure that support utility cycling beyond commuter cycling may encourage a utility cycling culture.

Training Prescription Guided by Heart Rate Variability in Cycling.

PubMed

Javaloyes, Alejandro; Sarabia, Jose Manuel; Lamberts, Robert Patrick; Moya-Ramon, Manuel

2018-05-29

Road cycling is a sport with extreme physiological demands. Therefore, there is a need to find new strategies to improve performance. Heart rate variability (HRV) has been suggested as an effective alternative for prescribing training load against predefined training programs. The purpose of this study is to examine the effect of training prescription based on HRV in road cycling performance. Seventeen well-trained cyclists participated in this study. After an initial evaluation week (EW), cyclists performed 4 baseline weeks (BW) of standardized training to establish their resting HRV. Then, cyclists were divided into two groups, a HRV-guided group (HRV-G) and a traditional periodization group (TRAD) and they carried out 8 training weeks (TW). Cyclists performed two EW, after and before TW. During the EW, cyclists performed: (1) a graded exercise test to assess VO2max, peak power output (PPO) and ventilatory thresholds with their corresponding power output (VT1, VT2, WVT1, and WVT2, respectively) and (2) a 40-min simulated time-trial. HRV-G improved PPO (5.1 ± 4.5 %; p = 0.024), WVT2 (13.9 ± 8.8 %; p = 0.004) and 40TT (7.3 ± 4.5 %; p = 0.005). VO2max and WVT1 remained similar. TRAD did not improve significantly after TW. There were no differences between groups. However, magnitude-based inference analysis showed likely beneficial and possibly beneficial effects for HRV-G instead of TRAD in 40TT and PPO, respectively. Daily training prescription based on HRV could result in a better performance enhancement than a traditional periodization in well-trained cyclists.

Correlation Between Cycling Power and Muscle Thickness in Cyclists.

PubMed

Lee, Hyung-Jin; Lee, Kang-Woo; Lee, Yong-Woo; Kim, Hee-Jin

2018-05-17

The aim of this study was to determine the correlation between muscle thickness (MT) and cycling power in varsity cyclists using ultrasonography (US) and to identify any differences in MT between short- and long-distance cyclists. Twelve cyclists participated in this study. Real-time two-dimensional B-mode US was used to measure the MT in the anterior thigh, anterior lower leg, and trunk, especially in the abdominal and lumbar regions. A Wattbike cycle ergometer was used to measure cycling power parameters such as maximum anaerobic power (over 5 s), mean anaerobic power (over 30 s), and aerobic power (over 3 min). This study was approved by the Ethics Committee of Korea National Sports University. There was a significant relationship between the MT and cycling power for the rectus femoris (RF) and vastus lateralis (VL) in the thigh, the rectus abdominis (RA) in the abdominal region, and the erector spinae (ES) in the lower back. The MT values of the RF, VL, and ES were strongly associated with the maximum and mean anaerobic power. There were significant differences between short- and long-distance cyclists in the MT of the RF in the thigh, the RA, the external abdominal oblique, the internal abdominal oblique, and the transverse abdominis muscle in the abdomen. We suggest that training programs attempting to improve cycling performance focus on improving the VL and ES via resistance weight or cycle training and also the core muscles for short-distance cyclists. This article is protected by copyright. All rights reserved. © 2018 Wiley Periodicals, Inc.

Aerodynamic study of different cyclist positions: CFD analysis and full-scale wind-tunnel tests.

PubMed

Defraeye, Thijs; Blocken, Bert; Koninckx, Erwin; Hespel, Peter; Carmeliet, Jan

2010-05-07

Three different cyclist positions were evaluated with Computational Fluid Dynamics (CFD) and wind-tunnel experiments were used to provide reliable data to evaluate the accuracy of the CFD simulations. Specific features of this study are: (1) both steady Reynolds-averaged Navier-Stokes (RANS) and unsteady flow modelling, with more advanced turbulence modelling techniques (Large-Eddy Simulation - LES), were evaluated; (2) the boundary layer on the cyclist's surface was resolved entirely with low-Reynolds number modelling, instead of modelling it with wall functions; (3) apart from drag measurements, also surface pressure measurements on the cyclist's body were performed in the wind-tunnel experiment, which provided the basis for a more detailed evaluation of the predicted flow field by CFD. The results show that the simulated and measured drag areas differed about 11% (RANS) and 7% (LES), which is considered to be a close agreement in CFD studies. A fair agreement with wind-tunnel data was obtained for the predicted surface pressures, especially with LES. Despite the higher accuracy of LES, its much higher computational cost could make RANS more attractive for practical use in some situations. CFD is found to be a valuable tool to evaluate the drag of different cyclist positions and to investigate the influence of small adjustments in the cyclist's position. A strong advantage of CFD is that detailed flow field information is obtained, which cannot easily be obtained from wind-tunnel tests. This detailed information allows more insight in the causes of the drag force and provides better guidance for position improvements. Copyright 2010 Elsevier Ltd. All rights reserved.

Effects of shoe cleat position on physiology and performance of competitive cyclists.

PubMed

Paton, Carl D

2009-12-01

Aerobic economy is an important factor that affects the performance of competitive cyclists. It has been suggested that placing the foot more anteriorly on the bicycle pedals may improve economy over the traditional foot position by improving pedaling efficiency. The current study examines the effects of changing the anterior-posterior pedal foot position on the physiology and performance of well-trained cyclists. In a crossover study, 10 competitive cyclists completed two maximal incremental and two submaximal tests in either their preferred (control) or a forward (arch) foot position. Maximum oxygen consumption and peak power output were determined from the incremental tests for both foot positions. On two further occasions, cyclists also completed a two-part 60-min submaximal test that required them to maintain a constant power output (equivalent to 60% of their incremental peak power) for 30 min, during which respiratory and blood lactate samples were taken at predetermined intervals. Thereafter, subjects completed a 30-min self-paced maximal effort time trial. Relative to the control, the mean changes (+/-90% confidence limits) in the arch condition were as follows: maximum oxygen consumption, -0.5% (+/-2.0%); incremental peak power output, -0.8% (+/-1.3%); steady-state oxygen consumption at 60%, -2.4% (+/-1.1%); steady-state heart rate 60%, 0.4% (+/-1.7%); lactate concentration 60%, 8.7% (+/-14.4%); and mean time trial power, -1.5% (+/-2.9%). We conclude that there was no substantial physiological or performance advantage in this group using an arch-cleat shoe position in comparison with a cyclist's normal preferred condition.

Autonomic cardiovascular modulation in masters and young cyclists following high-intensity interval training.

PubMed

Borges, Nattai R; Reaburn, Peter R; Doering, Thomas M; Argus, Christos K; Driller, Matthew W

2017-04-01

This study aimed at examining the autonomic cardiovascular modulation in well-trained masters and young cyclists following high-intensity interval training (HIT). Nine masters (age 55.6 ± 5.0 years) and eight young cyclists (age 25.9 ± 3.0 years) completed a HIT protocol of 6 x 30 sec at 175% of peak power output, with 4.5-min' rest between efforts. Immediately following HIT, heart rate and R-R intervals were monitored for 30-min during passive supine recovery. Autonomic modulation was examined by i) heart rate recovery in the first 60-sec of recovery (HRR 60 ); ii) the time constant of the 30-min heart rate recovery curve (HRRτ); iii) the time course of the root mean square for successive 30-sec R-R interval (RMSSD 30 ); and iv) time and frequency domain analyses of subsequent 5-min R-R interval segments. No significant between-group differences were observed for HRR 60 (P = 0.096) or HRR τ (P = 0.617). However, a significant interaction effect was found for RMSSD 30 (P = 0.021), with the master cyclists showing higher RMSSD 30 values following HIT. Similar results were observed in the time and frequency domain analyses with significant interaction effects found for the natural logarithm of the RMSSD (P = 0.008), normalised low-frequency power (P = 0.016) and natural logarithm of high-frequency power (P = 0.012). Following high-intensity interval training, master cyclists demonstrated greater post-exercise parasympathetic reactivation compared to young cyclists, indicating that physical training at older ages has significant effects on autonomic function.

The injury epidemiology of cyclists based on a road trauma registry

PubMed Central

2011-01-01

Background Bicycle use has increased in some of France's major cities, mainly as a means of transport. Bicycle crashes need to be studied, preferably by type of cycling. Here we conduct a descriptive analysis. Method A road trauma registry has been in use in France since 1996, in a large county around Lyon (the Rhône, population 1.6 million). It covers outpatients, inpatients and fatalities. All injuries are coded using the Abbreviated Injury Scale (AIS). Proxies were used to identify three types of cycling: learning = children (0-10 years old); sports cycling = teenagers and adults injured outside towns; cycling as means of transport = teenagers and adults injured in towns. The study is based on 13,684 cyclist casualties (1996-2008). Results The percentage of cyclists injured in a collision with a motor vehicle was 8% among children, 17% among teenagers and adults injured outside towns, and 31% among those injured in towns. The percentage of serious casualties (MAIS 3+) was 4.5% among children, 10.9% among adults injured outside towns and 7.2% among those injured in towns. Collisions with motor-vehicles lead to more internal injuries than bicycle-only crashes. Conclusion The description indicates that cyclist type is associated with different crash and injury patterns. In particular, cyclists injured in towns (where cycling is increasing) are generally less severely injured than those injured outside towns for both types of crash (bicycle-only crashes and collisions with a motor vehicle). This is probably due to lower speeds in towns, for both cyclists and motor vehicles. PMID:21849071

Promoting bicycle commuter safety.

DOT National Transportation Integrated Search

2012-02-01

A basic premise in this report is that cycling should be encouraged because as the number of cyclists increases, the attention of motorists and safety improves; however, an important caveat is that the number of cyclists has to be commensurate with t...

Cyclist Path Choices Through Shared Space Intersections in England

DOT National Transportation Integrated Search

2016-07-01

In the last several years, there has been growing worldwide interest in making streets safer for all users pedestrians, cyclists, and motorists. One approach, shared space, is a traffic calming technique as well as urban design concept. This techn...

Promoting bicycle commuter safety : [research brief].

DOT National Transportation Integrated Search

2012-02-01

A basic premise in this report is that cycling should be encouraged because as the number of cyclists increases, the attention of motorists and safety improves. However, an important caveat is that the number of cyclists has to be commensurate with t...

Characteristics of utility cyclists in Queensland, Australia: an examination of the associations between individual, social, and environmental factors and utility cycling.

PubMed

Sahlqvist, Shannon L; Heesch, Kristiann C

2012-08-01

Initiatives to promote utility cycling in countries like Australia and the US, which have low rates of utility cycling, may be more effective if they first target recreational cyclists. This study aimed to describe patterns of utility cycling and examine its correlates, among cyclists in Queensland, Australia. An online survey was administered to adult members of a state-based cycling community and advocacy group (n=1813). The survey asked about demographic characteristics and cycling behavior, motivators and constraints. Utility cycling patterns were described, and logistic regression modeling was used to examine associations between utility cycling and other variables. Forty-seven percent of respondents reported utility cycling: most did so to commute (86%). Most journeys (83%) were >5 km. Being male, younger, employed full-time, or university-educated increased the likelihood of utility cycling (P<.05). Perceiving cycling to be a cheap or a convenient form of transport was associated with utility cycling (P<.05). The moderate rate of utility cycling among recreational cyclists highlights a potential to promote utility cycling among this group. To increase utility cycling, strategies should target female and older recreational cyclists and focus on making cycling a cheap and convenient mode of transport.

"Where have all the bicycles gone?" Are bicycle sales in Australia translated into health-enhancing levels of bicycle usage?

PubMed

Bauman, Adrian; Merom, Dafna; Rissel, Chris

2012-02-01

To explore whether the reported increase in bicycle sales in Australia is corroborated by increases in numbers of cyclists. Australian representative data on cycling from annual Exercise, Recreation and Sport Surveys (ERASS) from 2001 to 2008 were used. Based on the weighted proportion of cyclists and 'regular cyclists' each year, the number of 'new' riders each year was calculated. Generous assumptions about the number of new bicycle purchased by new riders plus replacement bicycles by regular riders were compared with industry sales figures. Any cycling increased from 9.5% of all adults in 2001 to 11.6% in 2008, an increase of 2.1% [95% CI: 1.14 to 2.76]. This 2.1% represents an overall increase in cyclists of around 343,552 (95% CI from 186,500 to 441,710 new cyclists). The difference between the estimated number bought and the actual industry total average number of bicycles sold (n=753,843 per annum) numbered at least 395,000 unused adult bicycles sold each year after sensitivity analyses. There appear to be many more bicycles sold in Australia than are used. Further improvements may be needed in the cycling environment before a possible latent desire for cycling translates to participation. Copyright © 2011 Elsevier Inc. All rights reserved.

Accuracy of Cycling Power Meters against a Mathematical Model of Treadmill Cycling.

PubMed

Maier, Thomas; Schmid, Lucas; Müller, Beat; Steiner, Thomas; Wehrlin, Jon Peter

2017-06-01

The aim of this study was to compare the accuracy among a high number of current mobile cycling power meters used by elite and recreational cyclists against a first principle-based mathematical model of treadmill cycling. 54 power meters from 9 manufacturers used by 32 cyclists were calibrated. While the cyclist coasted downhill on a motorised treadmill, a back-pulling system was adjusted to counter the downhill force. The system was then loaded 3 times with 4 different masses while the cyclist pedalled to keep his position. The mean deviation (trueness) to the model and coefficient of variation (precision) were analysed. The mean deviations of the power meters were -0.9±3.2% (mean±SD) with 6 power meters deviating by more than±5%. The coefficients of variation of the power meters were 1.2±0.9% (mean±SD), with Stages varying more than SRM (p<0.001) and PowerTap (p<0.001). In conclusion, current power meters used by elite and recreational cyclists vary considerably in their trueness; precision is generally high but differs between manufacturers. Calibrating and adjusting the trueness of every power meter against a first principle-based reference is advised for accurate measurements. © Georg Thieme Verlag KG Stuttgart · New York.

Cyclists' experiences of harassment from motorists: findings from a survey of cyclists in Queensland, Australia.

PubMed

Heesch, Kristiann C; Sahlqvist, Shannon; Garrard, Jan

2011-12-01

Harassment from motorists is a major constraint on cycling that has been under-researched. We examined incidence and correlates of harassment of cyclists. Cyclists in Queensland, Australia were surveyed in 2009 about their experiences of harassment while cycling, from motor vehicle occupants. Respondents also indicated the forms of harassment they experienced. Logistic regression modeling was used to examine gender and other correlates of harassment. Of 1830 respondents, 76% of men and 72% of women reported harassment in the previous 12 months. The most reported forms of harassment were driving too close (66%), shouting abuse (63%), and making obscene gestures/sexual harassment (45%). Older age, overweight/obesity, less cycling experience (<2 years) and less frequent cycling (<3 days/week) were associated with less likelihood of harassment, while living in highly advantaged areas (SEIFA deciles 8 or 9), cycling for recreation, and cycling for competition were associated with increased likelihood of harassment. Gender was not associated with reports of harassment. Efforts to decrease harassment should include a closer examination of the circumstances that give rise to harassment, as well as fostering road environments and driver attitudes and behaviors that recognize that cyclists are legitimate road users. Copyright © 2011 Elsevier Inc. All rights reserved.

Effects of on-street parking on cyclist route choice and the operational behavior of cyclists and motorists.

DOT National Transportation Integrated Search

2009-04-01

Because of the serious societal, environmental, economic, and public health problems associated with motorized : transportation, there is increased interest in encouraging non-motorized modes of travel. The current study contributes toward this : obj...

Heterogeneity of muscle recruitment pattern during pedaling in professional road cyclists: a magnetic resonance imaging and electromyography study.

PubMed

Hug, François; Bendahan, David; Le Fur, Yann; Cozzone, Patrick J; Grélot, Laurent

2004-07-01

Although a number of studies have been devoted to the analysis of the activity pattern of the muscles involved in pedaling in sedentary subjects and/or amateur cyclists, data on professional cyclists are scarce and the issue of inter-individual differences has never been addressed in detail. In the present series of experiments, we performed a non-invasive investigation using functional magnetic resonance imaging and surface electromyography to determine the pattern of activity of lower limb muscles during two different exhausting pedaling exercises in eight French professional cyclists. Each subject performed an incremental exercise during which electromyographic activity of eight lower limb muscles and respiratory variables were recorded. After a 3-h recovery period, transverse relaxation times (T2) were measured before and just after a standardized constant-load maximal exercise in order to quantify exercise-related T2 changes. The global EMG activity illustrated by the root mean square clearly showed a large inter-individual difference during the incremental exercise regardless of the investigated muscle (variation coefficient up to 81%). In addition, for most of the muscles investigated, the constant-load exercise induced T2 increases, which varied noticeably among the subjects. This high level of variation in the recruitment of lower limb muscles in professional cyclists during both incremental and constant-load exercises is surprising given the homogeneity related to maximal oxygen consumption and training volume. The high degree of expertise of these professional cyclists was not linked to the production of a common pattern of pedaling and our results provide an additional evidence that the nervous system has multiple ways of accomplishing a given motor task, as has been suggested previously by neural control theorists and experimentalists.

Differences in Physiological Responses to Interval Training in Cyclists With and Without Interval Training Experience

PubMed Central

Hebisz, Rafal; Borkowski, Jacek; Zatoń, Marek

2016-01-01

Abstract The aim of this study was to determine differences in glycolytic metabolite concentrations and work output in response to an all-out interval training session in 23 cyclists with at least 2 years of interval training experience (E) and those inexperienced (IE) in this form of training. The intervention involved subsequent sets of maximal intensity exercise on a cycle ergometer. Each set comprised four 30 s repetitions interspersed with 90 s recovery periods; sets were repeated when blood pH returned to 7.3. Measurements of post-exercise hydrogen (H+) and lactate ion (LA-) concentrations and work output were taken. The experienced cyclists performed significantly more sets of maximal efforts than the inexperienced athletes (5.8 ± 1.2 vs. 4.3 ± 0.9 sets, respectively). Work output decreased in each subsequent set in the IE group and only in the last set in the E group. Distribution of power output changed only in the E group; power decreased in the initial repetitions of set only to increase in the final repetitions. H+ concentration decreased in the third, penultimate, and last sets in the E group and in each subsequent set in the IE group. LA- decreased in the last set in both groups. In conclusion, the experienced cyclists were able to repeatedly induce elevated levels of lactic acidosis. Power output distribution changed with decreased acid–base imbalance. In this way, this group could compensate for a decreased anaerobic metabolism. The above factors allowed cyclists experienced in interval training to perform more sets of maximal exercise without a decrease in power output compared with inexperienced cyclists. PMID:28149346

Walking, cycling and transport safety: an analysis of child road deaths.

PubMed

Sonkin, Beth; Edwards, Phil; Roberts, Ian; Green, Judith

2006-08-01

To examine trends in road death rates for child pedestrians, cyclists and car occupants. Analysis of road traffic injury death rates per 100 000 children and death rates per 10 million passenger miles travelled. England and Wales between 1985 and 2003. Children aged 0-14 years. None. Death rates per 100,000 children and per 10 million child passenger miles for pedestrians, cyclists and car occupants. Death rates per head of population have declined for child pedestrians, cyclists and car occupants but pedestrian death rates remain higher (0.55 deaths/100,000 children; 95% confidence interval [CI] 0.42 to 0.72 deaths) than those for car occupants (0.34 deaths; 95% CI 0.23 to 0.48 deaths) and cyclists (0.16 deaths; 95% CI 0.09 to 0.27 deaths). Since 1985, the average distance children travelled as a car occupant has increased by 70%; the average distance walked has declined by 19%; and the average distance cycled has declined by 58%. Taking into account distance travelled, there are about 50 times more child cyclist deaths (0.55 deaths/10 million passenger miles; 0.32 to 0.89) and nearly 30 times more child pedestrian deaths (0.27 deaths; 0.20 to 0.35) than there are deaths to child car occupants (0.01 deaths; 0.007 to 0.014). In 2003, children from families without access to a vehicle walked twice the distance walked by children in families with access to two or more vehicles. More needs to be done to reduce the traffic injury death rates for child pedestrians and cyclists. This might encourage more walking and cycling and also has the potential to reduce social class gradients in injury mortality.

Does hydrotherapy help or hinder adaptation to training in competitive cyclists?

PubMed

Halson, Shona L; Bartram, Jason; West, Nicholas; Stephens, Jessica; Argus, Christos K; Driller, Matthew W; Sargent, Charli; Lastella, Michele; Hopkins, Will G; Martin, David T

2014-08-01

Cold water immersion (CWI) may be beneficial for acute recovery from exercise, but it may impair long-term performance by attenuating the stimuli responsible for adaptation to training. We compared effects of CWI and passive rest on cycling performance during a simulated cycling grand tour. Thirty-four male endurance-trained competitive cyclists were randomized to CWI for four times per week for 15 min at 15°C or control (passive recovery) groups for 7 d of baseline training, 21 d of intensified training, and an 11-d taper. Criteria for completion of training and testing were satisfied by 10 cyclists in the CWI group (maximal aerobic power, 5.13 ± 0.21 W·kg; mean ± SD) and 11 in the control group (5.01 ± 0.41 W·kg). Each week, cyclists completed a high-intensity interval cycling test and two 4-min bouts separated by 30 min. CWI was performed four times per week for 15 min at 15°C. Between baseline and taper, cyclists in the CWI group had an unclear change in overall 4-min power relative to control (2.7% ± 5.7%), although mean power in the second effort relative to the first was likely higher for the CWI group relative to control (3.0% ± 3.8%). The change in 1-s maximum mean sprint power in the CWI group was likely beneficial compared with control (4.4% ± 4.2%). Differences between groups for the 10-min time trial were unclear (-0.4% ± 4.3%). Although some effects of CWI on performance were unclear, data from this study do not support recent speculation that CWI is detrimental to performance after increased training load in competitive cyclists.

A false start in the race against doping in sport: concerns with cycling's biological passport.

PubMed

Hailey, Nicholas

2011-11-01

Professional cycling has suffered from a number of doping scandals. The sport's governing bodies have responded by implementing an aggressive new antidoping program known as the biological passport. Cycling's biological passport marks a departure from traditional antidoping efforts, which have focused on directly detecting prohibited substances in a cyclist's system. Instead, the biological passport tracks biological variables in a cyclist's blood and urine over time, monitoring for fluctuations that are thought to indirectly reveal the effects of doping. Although this method of indirect detection is promising, it also raises serious legal and scientific concerns. Since its introduction, the cycling community has debated the reliability of indirect biological-passport evidence and the clarity, consistency, and transparency of its use in proving doping violations. Such uncertainty undermines the legitimacy of finding cyclists guilty of doping based on this indirect evidence alone. Antidoping authorities should address these important concerns before continuing to pursue doping sanctions against cyclists solely on the basis of their biological passports.

Analysis of factors associated with traffic accidents of cyclists attended in Brazilian state capitals.

PubMed

Sousa, Carlos Augusto Moreira de; Bahia, Camila Alves; Constantino, Patrícia

2016-12-01

Brazil has the sixth largest bicycles fleet in the world and bicycle is the most used individual transport vehicle in the country. Few studies address the issue of cyclists' accidents and factors that contribute to or prevent this event. VIVA is a cross-sectional survey and is part of the Violence and Accidents Surveillance System, Brazilian Ministry of Health. We used complex sampling and subsequent data review through multivariate logistic regression and calculation of the respective odds ratios. Odds ratios showed greater likelihood of cyclists' accidents in males, people with less schooling and living in urban and periurban areas. People who were not using the bike to go to work were more likely to suffer an accident. The profile found in this study corroborates findings of other studies. They claim that the coexistence of cyclists and other means of transportation in the same urban space increases the likelihood of accidents. The construction of bicycle-exclusive spaces and educational campaigns are required.

The co-contraction index of the upper limb for young and old adult cyclists.

PubMed

Kiewiet, H; Bulsink, V E; Beugels, F; Koopman, H F J M

2017-08-01

Bicycling is a popular and convenient means of transportation amongst the elderly in the Netherlands. However, the uptake of the electric bicycle resulted in an increase of single-sided bicycle accidents amongst the elderly (Veiligheid, 2010). Since elderly are prone to severe injuries, bicycle stability is currently a popular research topic. Three main balance strategies have been proposed in former studies: steering as the primary balance strategy and trunk -and lateral knee movement as secondary balance strategies (Moore et al., 2011; Cain, 2013). Since steering is the primary strategy for bicycle stability, the stiffness of the arms plays an important role in active stability during cycling. It has been shown that the arm stiffness of a passive rider is an important factor on the stability of a bicycle (Doria and Tognazzo, 2014). In the study presented here, the co-contraction index (CCI) of the upper limb for young and old adult cyclist is studied. Data is collected during experiments based on the setup described in (Kiewiet et al., 2014), wherein contact forces, muscle activities and motions of the rider and bicycle are measured for 15 young adult (mean±sd: 25.3±2.8 yrs) and 15 old adult (mean±sd: 58.1±2.1 yrs) subjects during unperturbed and perturbed cycling. The arm stiffness is defined as a co-contraction ratio between muscle activity of the m. Biceps Brachii and m. Triceps Lateralis. Results suggest that older adult cyclists use more co-contraction of their arm muscles during cycling, compared to young cyclists. The inter-subject variability of the found CCI was higher for the old adult subject group, compared to the young group. The results support the initial hypothesis that the increase in co-contraction of the upper limb for older cyclists is higher during perturbed cycling compared to unperturbed cycling than for younger cyclists. The findings might give direction towards solutions for increasing the safety and stability for elderly cyclists. Copyright © 2016 Elsevier Ltd. All rights reserved.

Identifying Characteristics of High Risk Intersections for Pedestrians and Cyclists : A Case Study from Salt Lake County

DOT National Transportation Integrated Search

2012-09-01

While the transportation network is meant to accommodate a variety of transportation modes, the experience varies for the users of each mode. For example; an automobile, cyclist, transit rider, and pedestrian will all have a very different experience...

Evaluating the use of crowdsourcing as a data collection method for bicycle performance measures and identification of facility improvement needs.

DOT National Transportation Integrated Search

2015-08-01

This research developed a smartphone application called ORcycle to collect cyclists routes, users, and : comfort levels. ORcycle combines GPS revealed route data collection with new questionnaires that try : to elicit cyclists attitudes as well...

Challenges in Maintaining Emotion Regulation in a Sleep and Energy Deprived State Induced by the 4800Km Ultra-Endurance Bicycle Race; The Race Across AMerica (RAAM).

PubMed

Lahart, Ian M; Lane, Andrew M; Hulton, Andrew; Williams, Karen; Godfrey, Richard; Pedlar, Charles; Wilson, Mathew G; Whyte, Gregory P

2013-01-01

Multiday ultra-endurance races present athletes with a significant number of physiological and psychological challenges. We examined emotions, the perceived functionality (optimal-dysfunctional) of emotions, strategies to regulate emotions, sleep quality, and energy intake-expenditure in a four-man team participating in the Race Across AMerica (RAAM); a 4856km continuous cycle race. Cyclists reported experiencing an optimal emotional state for less than 50% of total competition, with emotional states differing significantly between each cyclist over time. Coupled with this emotional disturbance, each cyclist experienced progressively worsening sleep deprivation and daily negative energy balances throughout the RAAM. Cyclists managed less than one hour of continuous sleep per sleep episode, high sleep latency and high percentage moving time. Of note, actual sleep and sleep efficiency were better maintained during longer rest periods, highlighting the importance of a race strategy that seeks to optimise the balance between average cycling velocity and sleep time. Our data suggests that future RAAM cyclists and crew should: 1) identify beliefs on the perceived functionality of emotions in relation to best (functional-optimal) and worst (dysfunctional) performance as the starting point to intervention work; 2) create a plan for support sufficient sleep and recovery; 3) create nutritional strategies that maintain energy intake and thus reduce energy deficits; and 4) prepare for the deleterious effects of sleep deprivation so that they are able to appropriately respond to unexpected stressors and foster functional working interpersonal relationships. Key PointsCompleting the Race Across AMerica (RAAM); a 4856km continuous cycle race associated with sleep disturbance, an energy-deficient state, and experiencing intense unwanted emotions.Cyclists reported experiencing an optimal emotional state for less than 50% of total competition and actual sleep and sleep efficiency was better maintained during longer rest periods.We suggest that future RAAM cyclists and crew should:Identify individual beliefs on the perceived functionality of emotional states in relation to best (optimal) and worst (dysfunctional) performance as the starting point to identifying if emotion regulation strategies should be initiated.Plan for enhanced sleep and recovery not just plan and train for maintaining a high average velocity;Create nutritional strategies that maintain energy intake and thus reduce energy deficits;Psychologically prepare cyclists and crew for the deleterious effects of sleep deprivation so that they both are able to appropriately respond to unexpected stressors and foster functional interpersonal working relationships.

Monitoring Physical and Cognitive Overload During a Training Camp in Professional Female Cyclists.

PubMed

Decroix, Lieselot; Piacentini, Maria Francesca; Rietjens, Gerard; Meeusen, Romain

2016-10-01

High training loads combined with other stressors can lead to performance decrements. The time needed to recover determines the diagnosis of (non)-functional overreaching or the overtraining syndrome. The aim of this study was to describe the effects of an 8-day (intensified) training camp of professional female cyclists on physical and cognitive performance. Nine subjects performed a 30-min time trial (TT), cognitive test, and Profile of Mood States questionnaire before, during, and after a training camp (49% increased training volume). On data collection, cyclists were classified as "overreached" (OR) or "adapted" (A) based on TT performance. Two-way repeated-measures analysis of variance was used to detect changes in physical and cognitive parameters. Five cyclists were described as OR based on decreased mean power output (MPO) (-7.03%) on day 8. Four cyclists were classified as A (increased MPO: +1.72%). MPO and maximal heart rate were significantly different between A and OR groups. A significant slower reaction time (RT) (+3.35%) was found in OR subjects, whereas RT decreased (-4.59%) in A subjects. The change in MPO was negatively correlated with change in RT in the cognitive test (R 2 = .52). This study showed that the use of objective, inexpensive, and easy-to-interpret physical and cognitive tests can facilitate the monitoring of training adaptations in professional female athletes.

Mobile phone use while cycling: incidence and effects on behaviour and safety.

PubMed

de Waard, Dick; Schepers, Paul; Ormel, Wieke; Brookhuis, Karel

2010-01-01

The effects of mobile phone use on cycling behaviour were studied. In study 1, the prevalence of mobile phone use while cycling was assessed. In Groningen 2.2% of cyclists were observed talking on their phone and 0.6% were text messaging or entering a phone number. In study 2, accident-involved cyclists responded to a questionnaire. Only 0.5% stated that they were using their phone at the time of the accident. In study 3, participants used a phone while cycling. The content of the conversation was manipulated and participants also had to enter a text message. Data were compared with just cycling and cycling while listening to music. Telephoning coincided with reduced speed, reduced peripheral vision performance and increased risk and mental effort ratings. Text messaging had the largest negative impact on cycling performance. Higher mental workload and lower speed may account for the relatively low number of people calling involved in accidents. STATEMENT OF RELEVANCE: Although perhaps mainly restricted to flat countries with a large proportion of cyclists, mobile phone use while cycling has increased and may be a threat to traffic safety, similar to phone use while driving a car. In this study, the extent of the problem was assessed by observing the proportion of cyclists using mobile phones, sending questionnaires to accident-involved cyclists and an experimental study was conducted on the effects of mobile phone use while cycling.

Sports massage with ozonised oil or non-ozonised oil: Comparative effects on recovery parameters after maximal effort in cyclists.

PubMed

Paoli, Antonio; Bianco, Antonino; Battaglia, Giuseppe; Bellafiore, Marianna; Grainer, Alessandro; Marcolin, Giuseppe; Cardoso, Claudia C; Dall'aglio, Roberto; Palma, Antonio

2013-11-01

To study the effects of passive rest (PR) and sports massage with (SMOZO) and without (SM) ozonised oil on sports performance psycho-physiological indices in competitive amateur cyclists after 3 pre-fatiguing Wingate cycle and post-recovery ramp tests. An intra-subjects experimental design with repeated measures. Department of Human Anatomy and Physiology, University of Padua. Fifteen male competitive cyclists (age: 27 ± 3.5 years, body weight: 77.6 ± 8.3 kg, height: 178 ± 7.7 cm) were studied. Subjects' power output (P), heart rate (HR), Visual Analogue Scale (VAS) score and blood lactate (BL) clearance in response to PR, SMOZO and SM recoveries were compared. There were no significant differences in cyclists' heart rate patterns in the three experimental conditions (p > 0.05). After SMOZO recovery, athletes showed a higher Pmax (p < 0.05) and a lower perceived fatigue VAS score (p < 0.033) in the ramp test. Blood lactate decreased more at T2 (mid-time point of treatment) and T3 (final time point of treatment) than T1 (beginning of treatment) compared to SM and PR conditions. These findings suggest that use of ozonised oil during sports massage increases blood lactate removal, improves performance and reduces the perception of fatigue in cyclists from 3 Wingate tests. Copyright © 2012 Elsevier Ltd. All rights reserved.

Pulse oximeter for cyclists in smartphone

NASA Astrophysics Data System (ADS)

Martins, L.; Gaidos, O.; dos Santos, I.

2015-01-01

The monitoring of cyclists during physical activity is an important factor to improve their performance. We discuss a new approaches based on smartphone for monitoring physiological signal wirelessly for cyclists, using a pulse oximeter sensor attached to the rider's forehead. This paper presents a wireless pulse Oximeter that was developed with a Nellcor's module, which uses the Standard Host Interface Protocol (SHIP) for communication with the Bluetooth module and sends data for a Smartphone with Android O.S. Then these data are shown in the screen: the heartbeat and saturation percentage. The application was created with App Inventor and the data are sent to Google Maps via Twitter. The results demonstrate the possibility of developing a successful prototype.

Variability of Respiration and Metabolism: Responses to Submaximal Cycling and Running.

ERIC Educational Resources Information Center

Armstrong, Lawrence E.; Costill, David L.

1985-01-01

This investigation examined day-to-day variations in metabolic measurements during submaximal running and cycling. Significant differences were found in the oxygen uptake (VO2) of runners and cyclists and the minute ventilation (VE) of cyclists while running, but blood lactic acid (HLA) did not differ day to day. (Author/MT)

Neighborhood Social Inequalities in Road Traffic Injuries: The Influence of Traffic Volume and Road Design

PubMed Central

Gauvin, Lise; Plante, Céline; Fournier, Michel; Morency, Catherine

2012-01-01

Objectives. We examined the extent to which differential traffic volume and road geometry can explain social inequalities in pedestrian, cyclist, and motor vehicle occupant injuries across wealthy and poor urban areas. Methods. We performed a multilevel observational study of all road users injured over 5 years (n = 19 568) at intersections (n = 17 498) in a large urban area (Island of Montreal, Canada). We considered intersection-level (traffic estimates, major roads, number of legs) and area-level (population density, commuting travel modes, household income) characteristics in multilevel Poisson regressions that nested intersections in 506 census tracts. Results. There were significantly more injured pedestrians, cyclists, and motor vehicle occupants at intersections in the poorest than in the richest areas. Controlling for traffic volume, intersection geometry, and pedestrian and cyclist volumes greatly attenuated the event rate ratios between intersections in the poorest and richest areas for injured pedestrians (−70%), cyclists (−44%), and motor vehicle occupants (−44%). Conclusions. Roadway environment can explain a substantial portion of the excess rate of road traffic injuries in the poorest urban areas. PMID:22515869

Public bike sharing in New York City: helmet use behavior patterns at 25 Citi Bike™ stations.

PubMed

Basch, Corey H; Ethan, Danna; Zybert, Patricia; Afzaal, Sarah; Spillane, Michael; Basch, Charles E

2015-06-01

Urban public bicycle sharing programs are on the rise in the United States. Launched in 2013, NYC's public bicycle share program, Citi Bike™ is the fastest growing program of its kind in the nation, with nearly 100,000 members and more than 330 docking stations across Manhattan and Brooklyn. The purpose of this study was to assess helmet use behavior among Citi Bike™ riders at 25 of the busiest docking stations. The 25 Citi Bike™ Stations varied greatly in terms of usage: total number of cyclists (N = 96-342), commute versus recreation (22.9-79.5% commute time riders), weekday versus weekend (6.0-49.0% weekend riders). Helmet use ranged between 2.9 and 29.2% across sites (median = 7.5 %). A total of 4,919 cyclists were observed, of whom 545 (11.1%) were wearing helmets. Incoming cyclists were more likely to wear helmets than outgoing cyclists (11.0 vs 5.9%, p = .000). NYC's bike share program endorses helmet use, but relies on education to encourage it. Our data confirm that, to date, this strategy has not been successful.

Not just contact sports: significant numbers of sports-related concussions in cycling.

PubMed

Helmich, Ingo; von Götz, Daniel; Emsermann, Carina; Xuanjin, Fu; Griese, Anne; Lauterbach, Ilka; Lausberg, Hedda

2018-04-04

Although sports-related concussions (SRCs) / mild traumatic brain injuries (mTBIs) in contact sports have recently received much attention, investigation of SRCs in cycling - a sport yielding some of the highest percentages of SRC - remains strikingly limited. In particular, rates of incidence, cycling-specific causes, and potential long-term effects of SRC have not been examined in this sport. Here, a retrospective online survey was used to investigate the incidence and potential long-term effects of SRCs among cyclists. A cycling-specific questionnaire was developed and administered to 2792 cyclists via an online survey. First, participants were asked about their acute symptomatology, and secondly, cycling-specific items and concussion history were addressed. Of the 999 cyclists whom completed the questionnaire, 23.8% had experienced a concussion. Incidence of concussion was significantly higher in cyclists who were club members, who cycled more than 200 kilometers per week, and who wore a helmet. Cyclists with a history of concussion complained significantly more often about headaches, pressure in the head, sensitivity to light, confusion, and irritability. Concussions in cycling are a serious injury with a high incidence relative to other sports. Although wearing a helmet reduces the risk of severe brain injury, interesting, the present results show a relation between helmet use, participation in cycling clubs, and increased concussion incidence. These data are in line with the growing number of findings showing that athletes with a history of concussion report more symptoms.

[A spatially explicit analysis of traffic accidents involving pedestrians and cyclists in Berlin].

PubMed

Lakes, Tobia

2017-12-01

In many German cities and counties, sustainable mobility concepts that strengthen pedestrian and cyclist traffic are promoted. From the perspectives of urban development, traffic planning and public healthcare, a spatially differentiated analysis of traffic accident data is decisive. 1) The identification of spatial and temporal patterns of the distribution of accidents involving cyclists and pedestrians, 2) the identification of hotspots and exploration of possible underlying causes and 3) the critical discussion of benefits and challenges of the results and the derivation of conclusions. Spatio-temporal distributions of data from accident statistics in Berlin involving pedestrians and cyclists from 2011 to 2015 were analysed with geographic information systems (GIS). While the total number of accidents remains relatively stable for pedestrian and cyclist accidents, the spatial distribution analysis shows, however, that there are significant spatial clusters (hotspots) of traffic accidents with a strong concentration in the inner city area. In a critical discussion, the benefits of geographic concepts are identified, such as spatially explicit health data (in this case traffic accident data), the importance of the integration of other data sources for the evaluation of the health impact of areas (traffic accident statistics of the police), and the possibilities and limitations of spatial-temporal data analysis (spatial point-density analyses) for the derivation of decision-supported recommendations and for the evaluation of policy measures of health prevention and of health-relevant urban development.

Major features of immunesenescence, including reduced thymic output, are ameliorated by high levels of physical activity in adulthood.

PubMed

Duggal, Niharika Arora; Pollock, Ross D; Lazarus, Norman R; Harridge, Stephen; Lord, Janet M

2018-04-01

It is widely accepted that aging is accompanied by remodelling of the immune system including thymic atrophy and increased frequency of senescent T cells, leading to immune compromise. However, physical activity, which influences immunity but declines dramatically with age, is not considered in this literature. We assessed immune profiles in 125 adults (55-79 years) who had maintained a high level of physical activity (cycling) for much of their adult lives, 75 age-matched older adults and 55 young adults not involved in regular exercise. The frequency of naïve T cells and recent thymic emigrants (RTE) were both higher in cyclists compared with inactive elders, and RTE frequency in cyclists was no different to young adults. Compared with their less active counterparts, the cyclists had significantly higher serum levels of the thymoprotective cytokine IL-7 and lower IL-6, which promotes thymic atrophy. Cyclists also showed additional evidence of reduced immunesenescence, namely lower Th17 polarization and higher B regulatory cell frequency than inactive elders. Physical activity did not protect against all aspects of immunesenescence: CD28 -ve CD57 +ve senescent CD8 T-cell frequency did not differ between cyclists and inactive elders. We conclude that many features of immunesenescence may be driven by reduced physical activity with age. © 2018 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

[BODY COMPOSITION AND SOMATOTYPE IN UNIVERSITY TRIATHLETES].

PubMed

Guillén Rivas, Laura; Mielgo-Ayuso, Juan; Norte-Navarro, Aurora; Cejuela, Roberto; Cabañas, María Dolores; Martínez-Sanz, José Miguel

2015-08-01

the triathlon is an endurance sport and individual that consists of three different disciplines: swimming, cycling and running. The aim of the study was to describe and analyze the anthropometric characteristics, body composition and somatotype in male college triathletes. observational and descriptive study of anthropometric characteristics, body composition and somatotype of 39 male college athletes from 24 ± 4,5 years, participants in the championship of Spain university triathlon sprint mode (Alicante 2010), from different universities Spanish. According to anthropometric measurement techniques adopted by the International Society for the Advancement of Kinanthropometry (ISAK) and the Spanish Group Cineantropometría (GREC) by an accredited assessor ISAK Level II. we find athletes of stunting, where you destacanvalores below normal in the subscapularis, supraspinatus, triceps and biceps skinfold, percentage of muscle mass (45.27 ± 3.29%) and fat mass (10.22 ± 2.92%) and bone (16.65 ± 1.34%) and where mesomorphy somatotipo predominates. the triathletes and runners have lower size that cyclists and swimmers. Triathletes and cyclists show a similar weight, less than swimmers line, and more than 10km runners. Iliac crest skinfold, abdominal and thigh front cyclists are less than triathletes. The percentage of fat mass of runners triathletes and swimmers are similar, however the muscle mass of athletes usually less than cyclists but similar to other forms. Somatotype resembles triathlete cyclist (mesomorph). The corridor is ectomorph and mesomorph-swimmer can range from a ectomorph mesomorph. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Can the Lamberts and Lambert Submaximal Cycle Test Reflect Overreaching in Professional Cyclists?

PubMed

Decroix, Lieselot; Lamberts, Robert P; Meeusen, Romain

2018-01-01

The Lamberts and Lambert Submaximal Cycle Test (LSCT) consists of 3 stages during which cyclists cycle for 6 min at 60%, 6 min at 80%, and 3 min at 90% of their maximal heart rate, followed by 1-min recovery. To determine if the LSCT is able to reflect a state of functional overreaching in professional female cyclists during an 8-d training camp and the following recovery days. Six professional female cyclists performed an LSCT on days 1, 5, and 8 of the training camp and 3 d after the training camp. During each stage of the LSCT, power output and rating of perceived exertion (RPE) were determined. Training diaries and Profile of Mood States (POMS) were also completed. At the middle and the end of the training camp, increased power output during the 2nd and 3rd stages of the LSCT was accompanied with increased RPE during these stages and/or the inability to reach 90% of maximal heart rate. All athletes reported increased feelings of fatigue and muscle soreness, while changes in energy balance, calculated from the POMS, were less indicative of a state of overreaching. After 3 d of recovery, all parameters of the LSCT returned to baseline, indicating a state of functional overreaching during the training camp. The LSCT is able to reflect a state of overreaching in elite professional female cyclists during an 8-d training camp and the following recovery days.

Drivers' Visual Search Behavior Toward Vulnerable Road Users at Junctions as a Function of Cycling Experience.

PubMed

Robbins, Chloe Jade; Chapman, Peter

2018-06-01

The current study investigated the behavior and visual attention of two groups of drivers with differing pedal cycling experience (pedal cyclists and nonpedal cyclists) towards vulnerable road users at junctions in a driving simulator. Pedal cyclists and motorcyclists are involved in a disproportionate number of crashes given the distance they travel, with a high proportion of these crashes occurring at junctions. Many studies have found that car drivers who also hold a motorcycle license have increased awareness towards motorcycles. The task involved approaching a T-junction and turning right when it was deemed to be safe. In Study 1, the junction was controlled by a give way sign, and in Study 2, the junction was controlled by a stop sign. Each T-junction contained a target vehicle (car, motorcycle, or pedal cycle), approaching from a near, medium, or far distance from the junction. Participants did not look at pedal cycles approaching from a far distance for as long as they looked at approaching motorcycles and cars, despite all vehicles travelling at identical speeds. No differences were found between pedal cyclists and nonpedal cyclists on any visual attention measures, indicating that pedal cycling experience was not associated with differences in drivers' attention toward pedal cycles. Findings have implications for road safety, demonstrating subtle differences in drivers' everyday visual attention toward differing vehicle types. This research has the potential to inform the development of in-car technical assistive systems, improving the safety of vulnerable road users at junctions.

Optimism about safety and group-serving interpretations of safety among pedestrians and cyclists in relation to road use in general and under low light conditions.

PubMed

King, M J; Wood, J M; Lacherez, P F; Marszalek, R P

2012-01-01

Drivers are known to be optimistic about their risk of crash involvement, believing that they are less likely to be involved in a crash than other drivers. However, little comparative research has been conducted among other road users. In addition, optimism about crash risk is conceptualised as applying only to an individual's assessment of his or her personal risk of crash involvement. The possibility that the self-serving nature of optimism about safety might be generalised to the group-level as a cyclist or a pedestrian, i.e., becoming group-serving rather than self-serving, has been overlooked in relation to road safety. This study analysed a subset of data collected as part of a larger research project on the visibility of pedestrians, cyclists and road workers, focusing on a set of questionnaire items administered to 406 pedestrians, 838 cyclists and 622 drivers. The items related to safety in various scenarios involving drivers, pedestrians and cyclists, allowing predictions to be derived about group differences in agreement with items based on the assumption that the results would exhibit group-serving bias. Analysis of the responses indicated that specific hypotheses about group-serving interpretations of safety and responsibility were supported in 22 of the 26 comparisons. When the nine comparisons relevant to low lighting conditions were considered separately, seven were found to be supported. The findings of the research have implications for public education and for the likely acceptance of messages which are inconsistent with current assumptions and expectations of pedestrians and cyclists. They also suggest that research into group-serving interpretations of safety, even for temporary roles rather than enduring groups, could be fruitful. Further, there is an implication that gains in safety can be made by better educating road users about the limitations of their visibility and the ramifications of this for their own road safety, particularly in low light. 2010 Elsevier Ltd. All rights reserved.

Visual Impairment does not Limit Training Effects in Development of Aerobic and Anaerobic Capacity in Tandem Cyclists

PubMed Central

Malwina, Kamelska Anna; Krzysztof, Mazurek; Piotr, Zmijewski

2015-01-01

The study aimed to investigate the differences in the effects of 7-month training on aerobic and anaerobic capacity in tandem cycling athletes with and without visual impairment. In this study, Polish elite (n=13) and sub-elite (n=13) visually impaired (VI) (n=13; 40.8 ±12.8 years) and properly sighted (PS) (n=13; 36.7 ±12.2 years) tandem-cycling athletes participated voluntarily in 7-month routine training. The following pre-/post-training measurements were conducted on separate days: maximal oxygen uptake (VO2max) was estimated with age correction using the Physical Working Capacity test on a bicycle ergometer according to the Astrand-Ryhming method. Maximal power output (Pmax) was evaluated using the Quebec test on a bicycle ergometer. At baseline, VO2max (47.8 ±14.1 vs 42.0 ±8.3 ml/kg/min, respectively) and Pmax (11.5 ±1.5 vs 11.5 ±1.0 W/kg) did not differ significantly between PS and VI cyclists. However, differences in aerobic capacity were considered as clinically significant. Two-way ANOVA revealed that after 7 month training, there were statistically significant increases in VO2max (p=0.003) and Pmax (p=0.009) among VI (VO2max, +9.1%; Pmax, +6.3%) and PS (VO2max, +9.1%; Pmax, +11.7%) cyclists, however, no time × visual impairment interaction effect was found (VO2max, p=0.467; Pmax, p=0.364). After training, VO2max (p=0.03), but not Pmax (p=0.13), was significantly greater in elite compared to sub-elite tandem cyclists. VI and PS tandem cyclists showed similar rates of improvement in VO2max and Pmax after 7-month training. VO2max was a significant determinant of success in tandem cycling. This is one of the first studies providing reference values for aerobic and anaerobic capacity in visually impaired cyclists. PMID:26834877

The Science of Cycling

ERIC Educational Resources Information Center

Crompton, Zoe; Daniels, Shelley

2014-01-01

Children are engaged by finding out about science in the real world (Harlen, 2010). Many children will be cyclists or will have seen or heard about the success of British cyclists in the Olympics and the Tour de France. This makes cycling a good hook to draw children into learning science. It is also a good cross-curricular topic, with strong…

Measuring Cycling Effort.

ERIC Educational Resources Information Center

Jahnke, Thomas; Hamson, Mike

1999-01-01

Investigates the basic mechanics of cycling with a simple reckoning of how much effort is needed from the cyclist. The work done by the cyclist is quantified when the ride is on the flat and also when pedaling uphill. Proves that by making use of the available gears on a mountain bike, cycling uphill can be accomplished without pain. (Author/ASK)

Does the Friel Anaerobic Threshold Test Accurately Detect Heart Rate Deflection in Trained Cyclists?

PubMed

Yuen, Willie K; Schreiner, Shad R; Hoover, Donald L; Loudon, Janice K; Billinger, Sandra A

The Friel Anaerobic Threshold Test (FATT) has been used to determine anaerobic threshold (AT). The FATT suggests AT occurs near the heart rate deflection point (HRDP) at a rating of perceived exertion (RPE) of 17. The primary purpose of this study was to determine 1) whether the HRDP could be determined using the FATT, 2) examine differences between HRVT and HR that coincided Borg's rating of perceived exertion (RPE) of 17, and 3) if riding position (hoods or aero) would influence performance. Fourteen male cyclists (30.4 ± 7.41years of age; 151.8 ± 60.4 cycled miles/week) participated in the study. Each subject performed the FATT on two occasions within one week. The findings of this study suggest that the FATT can determine HRDP in trained cyclists while riding in the hoods position but not the aero position. No significant difference was found between the hoods and aero position for HRVT as measured by the metabolic cart. Our data suggest that HR at an RPE of 15 more accurately reflects the HRVT than the RPE of 17. A low, non-significant correlation was found for both the hoods and aero (0.41 and 0.44, respectively; p > 0.20) for the HR at RPE of 17. The findings of this study suggest that the FATT can determine HRDP in trained cyclists. However, HRDP was identified in the cyclists preferred riding position. When performing the FATT, HRVT at an RPE of 15 should be used to estimate VT over the suggested RPE of 17.

Nutritional intake and anthropometric changes of professional road cyclists during a 4-day competition.

PubMed

Sánchez-Muñoz, C; Zabala, M; Muros, J J

2016-07-01

Appropriate nutrition through adequate dietary intake of total calories, macronutrients, and micronutrients is an essential component of optimizing the performance of all elite athletes. The aim of this study was to describe the food intake, body composition, and biochemical profile of professional cyclists during the Tour of Andalusia, a four-stage race covering a total distance of 647.6 km. Nutritional data were collected by trained investigators who weighed all of the food and fluid ingested by the cyclists. The nutritional intake of the cyclists was as follows: CHO, 12.8 ± 1.7 g/kg of body weight (BW; 62.3%); fat, 2.1 ± 0.2 g/kg BW (23.2%); proteins, 3.0 ± 0.3 g/kg BW (14.5%); total kcal was 5644.3 ± 593.1. Intake of all micronutrients, except for folate and potassium [which were 93.7% and 91.3% of Recommended Dietary Allowances (RDA)] exceeded the RDA/I. Percentage of body fat and fat weight significantly decreased (P < 0.05) while weight of muscle mass remained unchanged after the Tour. Concentrations of urea, aspartate aminotransferase, alanine aminotransferase, creatine kinase, myoglobin, and high-density lipoproteins significantly increased (P < 0.05) after the Tour. To our knowledge, this is the first study to describe both nutritional intake and the body and biochemical composition of a sample of professional road cyclists during a top-class cycling race. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of Beta-Hydroxy Beta-Methylbutyrate on the Onset of Blood Lactate Accumulation and VO2peak in Endurance-Trained Cyclists.

ERIC Educational Resources Information Center

Vukovich, Matthew D.; Dreifort, Geri D.

2001-01-01

Examined the effect of beta-hydroxy beta-methylbutyrate (HMB) supplementation on maximal oxygen consumption (VO2peak) and onset of blood lactate accumulation (OBLA) in endurance-trained cyclists. Acute exercise did not affect plasma HMB concentrations. OBLA increased with HMB and leucine, with blood glucose significantly greater during the HMB…

Sleep/wake behaviour of endurance cyclists before and during competition.

PubMed

Lastella, Michele; Roach, Gregory Daniel; Halson, Shona Leigh; Martin, David Thomas; West, Nicholas Peter; Sargent, Charli

2015-01-01

Good sleep is critical for optimising recovery and athletic performance. Yet, few studies have investigated how athletes sleep before and during competition. The aim of this study was to determine whether such sleep is poorer than that before a usual training day. Twenty-one male endurance cyclists' (age: 19.9 ± 1.7 years) sleep/wake behaviour was assessed using wrist activity monitors for 11 nights, including a six-night baseline training phase, three nights before competition and two nights during competition. Cyclists had less sleep on the night before competition (6.5 ± 0.9 h) and during the first night of competition (6.8 ± 0.8 h) than at baseline (7.4 ± 0.6 h). Cyclists also went to bed and woke up earlier during competition than at baseline. Competition schedules and competition itself can disrupt the sleep/wake behaviour of athletes during competition. Future investigations should examine sleep during three stages of competition (i.e. before, during and after competition). This will help coaches develop a greater understanding of how sleep changes during different phases of competition and enable them to plan post-competition training programmes to ensure appropriate rest and recovery is obtained.

Model of cyclist accident characteristics in the city of Malang and Blitar

NASA Astrophysics Data System (ADS)

Arifin, M. Z.; Agustin, I. W.

2018-01-01

Utilization of bicycles as an environmentally friendly mode of transportation is reconcerned as the development of sustainable transportation programs. The use of bicycles in some developed countries such as the Netherlands is 27 per cent of total travel, while for developing countries such as Indonesia, cyclists are less than 1% of total travel with low educated characteristics (65 per cent) and low income (48 per cent). Cyclist reduces dependencies on petroleum and environmental pollution as well as lessen the occurrence of congestion and traffic accidents involving motor vehicles. It was necessary to know the behavior and interaction of bicycle riders with other vehicle users in a heterogeneous traffic flow. The main purpose of the research is to create a model of bicycle accidents to increase the road traffic safety in Malang city and Blitar city. The research used analyses of frequency, the road’s level of service, and multiple linear regression. The results showed that there was a need for a development basis of a special lane for bicycle. It aims to reduce the level and number of cyclist accidents and to achieve transportation safety as well as to raise public awareness in traffic safety.

The psychology of elite cycling: a systematic review.

PubMed

Spindler, David J; Allen, Mark S; Vella, Stewart A; Swann, Christian

2018-09-01

This systematic review sought to synthesise what is currently known about the psychology of elite cycling. Nine electronic databases were searched in March 2017 for studies reporting an empirical test of any psychological construct in an elite cycling sample. Fourteen studies (total n = 427) met inclusion criteria. Eight studies were coded as having high risk of bias. Themes extracted included mood, anxiety, self-confidence, pain, and cognitive function. Few studies had similar objectives meaning that in many instances findings could not be synthesised in a meaningful way. Nevertheless, there was some cross-study evidence that elite cyclists have more positive mood states (relative to normative scores), pre-race anxiety impairs performance (among male cyclists), and associative strategies are perceived as helpful for pain management. Among single studies coded as having low risk of bias, evidence suggests that implicit beliefs affect decision making performance, elite cyclists are less susceptible to mental fatigue (than non-elite cyclists), and better leadership skills relates to greater social labouring. Limitations include non-standardisation of measures, lack of follow-up data, small sample sizes, and overall poor research quality. The findings of this systematic review might be used to inform research and theory development on the psychology of elite endurance cycling.

The association between commuter cycling and sickness absence.

PubMed

Hendriksen, Ingrid J M; Simons, Monique; Garre, Francisca Galindo; Hildebrandt, Vincent H

2010-08-01

To study the association between commuter cycling and all-cause sickness absence, and the possible dose-response relationship between absenteeism and the distance, frequency and speed of commuter cycling. Cross-sectional data about cycling in 1236 Dutch employees were collected using a self-report questionnaire. Company absenteeism records were checked over a one-year period (May 2007-April 2008). Propensity scores were used to make groups comparable and to adjust for confounders. Zero-inflated Poisson models were used to assess differences in absenteeism between cyclists and non-cyclists. The mean total duration of absenteeism over the study year was more than 1 day shorter in cyclists than in non-cyclists. This can be explained by the higher proportion of people with no absenteeism in the cycling group. A dose-response relationship was observed between the speed and distance of cycling and absenteeism. Compared to people who cycle a short distance (

Sensor design for outdoor racing bicycle field testing for human vibration comfort evaluation

NASA Astrophysics Data System (ADS)

Vanwalleghem, Joachim; De Baere, Ives; Loccufier, Mia; Van Paepegem, Wim

2013-09-01

This paper is concerned with the vibrational comfort evaluation of the cyclist when cycling a rough surface. Outdoor comfort tests have so far only been done through instrumenting the bicycle with accelerometers. This work instruments a racing bicycle with custom-made contact force sensors and velocity sensors to acquire human comfort through the absorbed power method. Comfort evaluation is assessed at the hand-arm and seat interface of the cyclist with the bicycle. By means of careful finite-element analysis for designing the force gauges at the handlebar and the seat combined with precise calibration of both force and velocity sensors, all sensors have proven to work properly. Initial field tests are focused on the proper functioning of the designed sensors and their suitability for vibration comfort measurements. Tests on a cobblestone road reveal that the outcome of the absorbed power values is within the same range as those from laboratory tests found in the literature. This sensor design approach for outdoor testing with racing bicycles may give a new interpretation on evaluating the cyclist's comfort since the vibrational load is not only quantified in terms of acceleration but also in terms of force and velocity at the bicycle-cyclist contact points.

Recent trends in cyclist fatalities in Australia.

PubMed

Boufous, Soufiane; Olivier, Jake

2016-08-01

The study examines trends in bicycling fatalities reported to the Australian police between 1991 and 2013. Trends were estimated using Poisson regression modelling. Overall, cycling fatalities decreased by 1.9% annually between 1991 and 2013. However, while deaths following multivehicle crashes decreased at a rate of 2.9% per annum (95% CI -4.0% to -1.8%), deaths from single vehicle crashes increased by 5.8% per annum (95% CI 4.1% to 7.5%). Over the study period, the average age of cyclists who died in single vehicle crashes (45.3 years, 95% CI 41.5 to 49.1) was significantly higher than cyclists who died in multivehicle crashes (36.2 years, 95% CI 34.7 to 37.7). The average age of deceased cyclists increased significantly for both types of crashes. The observed increase in single vehicle crashes need to be closely monitored in Australia and internationally. In-depth studies are needed to investigate the circumstances of fatal single bicycle crashes in order to develop appropriate countermeasures. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Cyclists’ experiences of harassment from motorists: findings from a survey of cyclists in Queensland, Australia

PubMed Central

Heesch, Kristiann C; Sahlqvist, Shannon; Garrard, Jan

2013-01-01

Objective Harassment from motorists is a major constraint on cycling that has been under-researched. We examined incidence and correlates of harassment of cyclists. Methods Cyclists in Queensland, Australia were surveyed in 2009 about their experiences of harassment while cycling, from motor vehicle occupants. Respondents also indicated the forms of harassment they experienced. Logistic regression modeling was used to examine gender and other correlates of harassment. Results Of 1830 respondents, 76% of men and 72% of women reported harassment in the previous 12 months. The most reported forms of harassment were driving too close (66%), shouting abuse (63%), and making obscene gestures/sexual harassment (45%). Older age, overweight/obesity, less cycling experience (<2 years) and less frequent cycling (<3 days/week) were associated with less likelihood of harassment, while living in highly advantaged areas (SEIFA deciles 8 or 9), cycling for recreation, and cycling for competition were associated with increased likelihood of harassment. Gender was not associated with reports of harassment. Conclusions Efforts to decrease harassment should include a closer examination of the circumstances that give rise to harassment, as well as fostering road environments and driver attitudes and behaviors that recognize that cyclists are legitimate road users. PMID:22001076

Gender stereotypes and superior conformity of the self in a sample of cyclists.

PubMed

Félonneau, Marie-Line; Causse, Elsa; Constant, Aymery; Contrand, Benjamin; Messiah, Antoine; Lagarde, Emmanuel

2013-01-01

In the field of driving, people tend to think they are more competent and more cautious than others. This is the superior conformity of the self (SCS). Our main hypothesis was that, among cyclists, women would show a higher SCS on cautiousness, though men would show a higher SCS concerning competence. 1799 cyclists provided a self-assessment of their own cautiousness and of other people's cautiousness. The same procedure was used for competence. Consistent with the hypothesis, the SCS was gender-specific: it was more prominent for women concerning cautiousness and more prominent for men concerning competence. These results could explain why people tend to ignore the safety campaigns. They also indicate the importance of adapting messages concerning safety measures to gender. Copyright © 2012 Elsevier Ltd. All rights reserved.

Trends in local newspaper reporting of London cyclist fatalities 1992-2012: the role of the media in shaping the systems dynamics of cycling

PubMed Central

Macmillan, Alex; Roberts, Alex; Woodcock, James; Aldred, Rachel; Goodman, Anna

2016-01-01

Background Successfully increasing cycling across a broad range of the population would confer important health benefits, but many potential cyclists are deterred by fears about traffic danger. Media coverage of road traffic crashes may reinforce this perception. As part of a wider effort to model the system dynamics of urban cycling, in this paper we examined how media coverage of cyclist fatalities in London changed across a period when the prevalence of cycling doubled. We compared this with changes in the coverage of motorcyclist fatalities as a control group. Methods Police records of traffic crashes (STATS19) were used to identify all cyclist and motorcyclist fatalities in London between 1992 and 2012. We searched electronic archives of London's largest local newspaper to identify relevant articles (January 1992–April 2014), and sought to identify which police-reported fatalities received any media coverage. We repeated this in three smaller English cities. Results Across the period when cycling trips doubled in London, the proportion of fatalities covered in the local media increased from 6% in 1992–1994 to 75% in 2010–2012. By contrast, the coverage of motorcyclist fatalities remained low (4% in 1992–1994 versus 5% in 2010–2012; p = 0.007 for interaction between mode and time period). Comparisons with other English cities suggested that the changes observed in London might not occur in smaller cities with lower absolute numbers of crashes, as in these settings fatalities are almost always covered regardless of mode share (79–100% coverage for both cyclist and motorcyclist fatalities). Conclusion In large cities, an increase in the popularity (and therefore ‘newsworthiness’) of cycling may increase the propensity of the media to cover cyclist fatalities. This has the potential to give the public the impression that cycling has become more dangerous, and thereby initiate a negative feedback loop that dampens down further increases in cycling. Understanding these complex roles of the media in shaping cycling trends may help identify effective policy levers to achieve sustained growth in cycling. PMID:26551734

Trends in local newspaper reporting of London cyclist fatalities 1992-2012: the role of the media in shaping the systems dynamics of cycling.

PubMed

Macmillan, Alex; Roberts, Alex; Woodcock, James; Aldred, Rachel; Goodman, Anna

2016-01-01

Successfully increasing cycling across a broad range of the population would confer important health benefits, but many potential cyclists are deterred by fears about traffic danger. Media coverage of road traffic crashes may reinforce this perception. As part of a wider effort to model the system dynamics of urban cycling, in this paper we examined how media coverage of cyclist fatalities in London changed across a period when the prevalence of cycling doubled. We compared this with changes in the coverage of motorcyclist fatalities as a control group. Police records of traffic crashes (STATS19) were used to identify all cyclist and motorcyclist fatalities in London between 1992 and 2012. We searched electronic archives of London's largest local newspaper to identify relevant articles (January 1992-April 2014), and sought to identify which police-reported fatalities received any media coverage. We repeated this in three smaller English cities. Across the period when cycling trips doubled in London, the proportion of fatalities covered in the local media increased from 6% in 1992-1994 to 75% in 2010-2012. By contrast, the coverage of motorcyclist fatalities remained low (4% in 1992-1994 versus 5% in 2010-2012; p=0.007 for interaction between mode and time period). Comparisons with other English cities suggested that the changes observed in London might not occur in smaller cities with lower absolute numbers of crashes, as in these settings fatalities are almost always covered regardless of mode share (79-100% coverage for both cyclist and motorcyclist fatalities). In large cities, an increase in the popularity (and therefore 'newsworthiness') of cycling may increase the propensity of the media to cover cyclist fatalities. This has the potential to give the public the impression that cycling has become more dangerous, and thereby initiate a negative feedback loop that dampens down further increases in cycling. Understanding these complex roles of the media in shaping cycling trends may help identify effective policy levers to achieve sustained growth in cycling. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Influence of acute dietary nitrate supplementation on 50 mile time trial performance in well-trained cyclists.

PubMed

Wilkerson, Daryl P; Hayward, Giles M; Bailey, Stephen J; Vanhatalo, Anni; Blackwell, Jamie R; Jones, Andrew M

2012-12-01

Dietary nitrate supplementation has been reported to improve short distance time trial (TT) performance by 1-3 % in club-level cyclists. It is not known if these ergogenic effects persist in longer endurance events or if dietary nitrate supplementation can enhance performance to the same extent in better trained individuals. Eight well-trained male cyclists performed two laboratory-based 50 mile TTs: (1) 2.5 h after consuming 0.5 L of nitrate-rich beetroot juice (BR) and (2) 2.5 h after consuming 0.5 L of nitrate-depleted BR as a placebo (PL). BR significantly elevated plasma [NO(2) (-)] (BR: 472 ± 96 vs. PL: 379 ± 94 nM; P < 0.05) and reduced completion time for the 50 mile TT by 0.8 % (BR: 136.7 ± 5.6 vs. PL: 137.9 ± 6.4 min), which was not statistically significant (P > 0.05). There was a significant correlation between the increased post-beverage plasma [NO(2) (-)] with BR and the reduction in TT completion time (r = -0.83, P = 0.01). Power output (PO) was not different between the conditions at any point (P > 0.05) but oxygen uptake ([Formula: see text]O(2)) tended to be lower in BR (P = 0.06), resulting in a significantly greater PO/[Formula: see text]O(2) ratio (BR: 67.4 ± 5.5 vs. PL: 65.3 ± 4.8 W L min(-1); P < 0.05). In conclusion, acute dietary supplementation with beetroot juice did not significantly improve 50 mile TT performance in well-trained cyclists. It is possible that the better training status of the cyclists in this study might reduce the physiological and performance response to NO(3) (-) supplementation compared with the moderately trained cyclists tested in earlier studies.

INTERVENTION AT THE FOOT-SHOE-PEDAL INTERFACE IN COMPETITIVE CYCLISTS

PubMed Central

Vicenzino, Bill; Sisto, Sue Ann

2016-01-01

ABSTRACT Background Competitive cyclists are susceptible to injury from the highly repetitive nature of pedaling during training and racing. Deviation from an optimal movement pattern is often cited as a factor contributing to tissue stress with specific concern for excessive frontal plane knee motion. Wedges and orthoses are increasingly used at the foot-shoe-pedal-interface (FSPI) in cycling shoes to alter the kinematics of the lower limb while cycling. Determination of the effect of FSPI alteration on cycling kinematics may offer a simple, inexpensive tool to reduce anterior knee pain in recreational and competitive cyclists. There have been a limited number of experimental studies examining the effect of this intervention in cyclists, and there is little agreement upon which FSPI interventions can prevent or treat knee injury. The purpose of this review is to provide a broader review of the literature than has been performed to date, and to critically examine the literature examining the evidence for FSPI intervention in competitive cyclists. Methods Current literature examining the kinematic response to intervention at the FSPI while cycling was reviewed. A multi-database search was performed in PubMed, EBSCO, Scopus, CINAHL and SPORTdiscus. Eleven articles were reviewed, and a risk of bias assessment performed according to guidelines developed by the Cochrane Bias Methods Group. Papers with a low risk of bias were selected for review, but two papers with higher risk of bias were included as there were few high quality studies available on this topic. Results Seven of the eleven papers had low bias in sequence generation i.e. random allocation to the test condition, only one paper had blinding to group allocation, all papers had detailed but non-standardized methodology, and incomplete data reporting, but were generally free of other bias sources. Conclusions Wedges and orthoses at the FSPI alter kinematics of the lower limb while cycling, although conclusions about their efficacy and response to long-term use are limited. Further high quality experimental studies are needed examining cyclists using standardized methodology and products currently used to alter SPFI function. Level of Evidence 3 PMID:27525187

Bicycle helmet size, adjustment, and stability.

PubMed

Thai, Kim T; McIntosh, Andrew S; Pang, Toh Yen

2015-01-01

One of the main requirements of a protective bicycle helmet is to provide and maintain adequate coverage to the head. A poorly fitting or fastened helmet may be displaced during normal use or even ejected during a crash. The aims of the current study were to identify factors that influence the size of helmet worn, identify factors that influence helmet position and adjustment, and examine the effects of helmet size worn and adjustment on helmet stability. Recreational and commuter cyclists in Sydney were surveyed to determine how helmet size and/or adjustment affected helmet stability in the real world. Anthropometric characteristics of the head were measured and, to assess helmet stability, a test analogous to the requirements of the Australian bicycle helmet standard was undertaken. Two hundred sixty-seven cyclists were recruited across all age groups and 91% wore an AS/NZS 2063-compliant helmet. The main ethnic group was Europeans (71%) followed by Asians (18%). The circumferences of the cyclists' heads matched well the circumference of the relevant ISO headform for the chosen helmet size, but the head shapes differed with respect to ISO headforms. Age and gender were associated with wearing an incorrectly sized helmet and helmet adjustment. Older males (>55 years) were most likely to wear an incorrectly sized helmet. Adult males in the 35-54 year age group were most likely to wear a correctly adjusted helmet. Using quasistatic helmet stability tests, it was found that the correctness of adjustment, rather than size, head dimensions, or shape, significantly affected helmet stability in all test directions. Bicycle helmets worn by recreational and commuter cyclists are often the wrong size and are often worn and adjusted incorrectly, especially in children and young people. Cyclists need to be encouraged to adjust their helmets correctly. Current headforms used in standards testing may not be representative of cyclists' head shapes. This may create challenges to helmet suppliers if on one hand they optimize the helmet to meet tests on ISO-related headforms while on the other seeking to offer greater range of sizes.

The effect of vigorous running and cycling on serum COMP, lubricin, and femoral cartilage thickness: a pilot study.

PubMed

Roberts, Harry M; Moore, Jonathan P; Griffith-McGeever, Claire L; Fortes, Matthew B; Thom, Jeanette M

2016-08-01

Our aim was to investigate lubricin, cartilage oligomeric matrix protein (COMP), and femoral cartilage deformation in response to different biomechanical loading of the knee joint (running vs cycling). Serum lubricin and COMP concentrations (enzyme-linked immunosorbent assay), and femoral cartilage thickness (suprapatellar transverse ultrasonography) were determined in 11 male runners (age: 40 ± 6 years; weight: 76 ± 8 kg) and 11 male cyclists (35 ± 12 years; 75 ± 5 kg) at baseline, immediately after, and 30 min after vigorous exercise (time trial: 10-km run or 25-km cycle). At baseline, lubricin (runners: 104.0 ± 19.8 ng/ml; cyclists: 119.1 ± 23.9 ng/ml) and COMP (runners: 804.1 ± 87.5 ng/ml; cyclists: 693.0 ± 84.7 ng/ml) did not significantly differ; however, vigorous exercise was accompanied by an increase in lubricin (cyclists: 39.4 %; p < 0.05; runners: 56.9 %; p < 0.05) and COMP (cyclists: 32.1 %; p < 0.05; runners: 14.2 %; p = 0.14) that returned toward baseline following 30 min of rest (p < 0.05). No between-group differences were observed for baseline cartilage thickness at the intercondyle notch, medial condyle, and lateral condyle, and vigorous exercise did not result in significant change for either group. In the absence of ultrasonographic knee cartilage deformation, the response of serum lubricin and COMP following acute vigorous exercise indicates an increase in joint lubrication and cartilage metabolism, respectively, which appears largely independent of exercise modality.

A Monetary Reward Alters Pacing but Not Performance in Competitive Cyclists.

PubMed

Skorski, Sabrina; Thompson, Kevin G; Keegan, Richard J; Meyer, Tim; Abbiss, Chris R

2017-01-01

Money has frequently been used as an extrinsic motivator since it is assumed that humans are willing to invest more effort for financial reward. However, the influence of a monetary reward on pacing and performance in trained athletes is not well-understood. Therefore, the aim of this study was to analyse the influence of a monetary reward in well-trained cyclists on their pacing and performance during short and long cycling time trials (TT). Twentythree cyclists (6 ♀, 17 ♂) completed 4 self-paced time trials (TTs, 2 short: 4 km and 6 min; 2 long: 20 km and 30 min); in a randomized order. Participants were separated into parallel, non-randomized "rewarded" and "non-rewarded" groups. Cyclists in the rewarded group received a monetary reward based on highest mean power output across all TTs. Cyclists in the non-rewarded group did not receive a monetary reward. Overall performance was not significantly different between groups in short or long TTs ( p > 0.48). Power output showed moderatly lower effect sizes at comencement of the short TTs ( P meandiff = 36.6 W; d > 0.44) and the 20 km TT ( P meandiff = 22.6 W; d = 0.44) in the rewarded group. No difference was observed in pacing during the 30 min TT ( p = 0.95). An external reward seems to have influenced pacing at the commencement of time trials. Participants in the non-rewarded group adopted a typical parabolic shaped pattern, whereas participants in the rewarded group started trials more conservatively. Results raise the possibility that using money as an extrinsic reward may interfere with regulatory processes required for effective pacing.

Accident rates amongst regular bicycle riders in Tasmania, Australia.

PubMed

Palmer, Andrew J; Si, Lei; Gordon, Jared M; Saul, Tim; Curry, Beverley A; Otahal, Petr; Hitchens, Peta L

2014-11-01

To characterise the demographics, cycling habits and accident rates of adult cyclists in Tasmania. Volunteers ≥18 years of age who had cycled at least once/week over the previous month provided information on demographics; cycling experience; bicycles owned; hours/km/trips cycled per week; cycling purpose; protective equipment used; and major (required third-party medical treatment or resulted ≥1 day off work) or minor (interfered with individuals' regular daily activities and/or caused financial costs) accidents while cycling. Over 8-months, 136 cyclists (70.6% male) completed the telephone survey. Mean (standard deviation) age was 45.4 (12.1) years with 17.1 (11.4) years of cycling experience. In the week prior to interview, cyclists averaged 6.6 trips/week (totalling 105.7km or 5.0h). The most common reason for cycling was commuting/transport (34% of trips), followed by training/health/fitness (28%). The incidence of major and minor cycling accidents was 1.6 (95% CI 1.1-2.0) and 3.7 (2.3-5.0) per 100,000km, respectively. Male sex was associated with a significantly lower minor accident risk (incidence rate ratio=0.34, p=0.01). Mountain biking was associated with a significantly higher risk of minor accident compared with road or racing, touring, and city or commuting biking (p<0.05). Physical activity of regular cyclists' exceeds the level recommended for maintenance of health and wellbeing; cyclists also contributed substantially to the local economy. Accident rates are higher in this sample than previously reported in Tasmania and internationally. Mountain biking was associated with higher risks of both major and minor accidents compared to road/racing bike riding. Copyright © 2014 Elsevier Ltd. All rights reserved.

Reactive fibroblastic and myofibroblastic proliferation of the vulva (Cyclist's Nodule): A hitherto poorly described vulval lesion occurring in cyclists.

PubMed

McCluggage, W Glenn; Smith, John H F

2011-01-01

Perineal nodules occurring in male cyclists are reported in the literature, although the histologic features are not extensively documented. There has been little description of similar lesions in the female population. We describe 4 cases in which a vulval nodule or swelling developed in competitive female cyclists aged 15 to 45 years. The lesions were unilateral and occurred on the right or left labium majus (2 cases each). The histologic features were similar in all cases and consisted of a haphazard admixture of adipose tissue, variably cellular hyalinized tissue containing bland spindle-shaped fibroblasts, blood vessels, and nerve fibers. In some areas, thick cords of fibrous tissue imparted a keloid-like appearance. Other histologic features included plump mesenchymal cells with round or ovoid nuclei and abundant eosinophilic cytoplasm resulting in an epithelioid, plasmacytoid, or ganglion-like appearance (2 cases), a lymphocytic infiltrate around blood vessels (3 cases), foci of fat necrosis (1 case), and collections of elastic fibers (2 cases). One case recurred, the histologic features of the recurrent lesion being identical to the original. The overall morphologic appearances, especially in the cases with plump mesenchymal cells, bore some resemblance to proliferative fasciitis. Immunohistochemically, the cells were estrogen receptor positive and the plump mesenchymal cells were smooth muscle actin positive, in keeping with myofibroblasts. Desmin, S100, CD34, and HMGA2 were negative. Pathologists should be aware of this pseudoneoplastic lesion occurring on the vulva, which arises in a specific clinical setting and has the potential to be misdiagnosed as a variety of other mesenchymal lesions. We term this lesion as reactive fibroblastic and myofibroblastic proliferation of the vulva or "cyclist's nodule."

Promoting Safe Walking and Cycling to Improve Public Health: Lessons From The Netherlands and Germany

PubMed Central

Pucher, John; Dijkstra, Lewis

2003-01-01

Objectives. We examined the public health consequences of unsafe and inconvenient walking and bicycling conditions in American cities to suggest improvements based on successful policies in The Netherlands and Germany. Methods. Secondary data from national travel and crash surveys were used to compute fatality trends from 1975 to 2001 and fatality and injury rates for pedestrians and cyclists in The Netherlands, Germany, and the United States in 2000. Results. American pedestrians and cyclists were much more likely to be killed or injured than were Dutch and German pedestrians and cyclists, both on a per-trip and on a per-kilometer basis. Conclusions. A wide range of measures are available to improve the safety of walking and cycling in American cities, both to reduce fatalities and injuries and to encourage walking and cycling. PMID:12948971

Inverse relationship between VO2max and economy/efficiency in world-class cyclists.

PubMed

Lucía, Alejandro; Hoyos, Jesus; Pérez, Margarita; Santalla, Alfredo; Chicharro, José L

2002-12-01

To determine the relationship that exists between VO2max and cycling economy/efficiency during intense, submaximal exercise in world-class road professional cyclists. METHODS Each of 11 male cyclists (26+/-1 yr (mean +/- SEM); VO2max: 72.0 +/- 1.8 mL x kg(-1) x min(-1)) performed: 1) a ramp test for O2max determination and 2) a constant-load test of 20-min duration at the power output eliciting 80% of subjects' VO2max during the previous ramp test (mean power output of 385 +/- 7 W). Cycling economy (CE) and gross mechanical efficiency (GE) were calculated during the constant-load tests. CE and GE averaged 85.2 +/- 2.3 W x L(-1) x min(-1) and 24.5 +/- 0.7%, respectively. An inverse, significant correlation was found between 1) VO2max (mL x kg(-0.32) x min(-1)) and both CE (r = -0.71; P = 0.01) and GE (-0.72; P = 0.01), and 2) VO2max (mL x kg(-1) x min(-1)) and both CE (r = -0.65; P = 0.03) and GE (-0.64; P = 0.03). A high CE/GE seems to compensate for a relatively low VO2max in professional cyclists.

Environmental supports for walking/biking and traffic safety: income and ethnicity disparities.

PubMed

Yu, Chia-Yuan

2014-10-01

The present study investigates the influence of income, ethnicity, and built environmental characteristics on the percentages of workers who walk/bike as well as on pedestrian/cyclist crash rates. Furthermore, income and ethnicity disparities are also explored. This study chose 162 census tracts in Austin as the unit of analysis. To explore income and ethnicity differences in built environments, this study examined the associations of the poverty rate, the percentage of white population, and the percentage of Hispanic population to each built environmental variable. Path models were applied to examine environmental supports of walking/biking and pedestrian/cyclist safety. Areas with high poverty rates had more biking trips and experienced more cyclist crashes, while areas with a high percentage of white population generated more walking trips and fewer pedestrian crashes. Sidewalk completeness and mixed land uses promoted walking to work but increased the crash risk for pedestrians as well. In terms of biking behaviors, road density and transit stop density both increased biking trips and cyclist crashes. Environmental designs that both encourage walking/biking trips and generate more safety threats should attract more attention from policy makers. Policies should also be more devoted to enhancing the mobility and health for areas with high poverty rates. Copyright © 2014 Elsevier Inc. All rights reserved.

Cycling infrastructure for reducing cycling injuries in cyclists.

PubMed

Mulvaney, Caroline A; Smith, Sherie; Watson, Michael C; Parkin, John; Coupland, Carol; Miller, Philip; Kendrick, Denise; McClintock, Hugh

2015-12-10

Cycling is an attractive form of transport. It is beneficial to the individual as a form of physical activity that may fit more readily into an individual's daily routine, such as for cycling to work and to the shops, than other physical activities such as visiting a gym. Cycling is also beneficial to the wider community and the environment as a result of fewer motorised journeys. Cyclists are seen as vulnerable road users who are frequently in close proximity to larger and faster motorised vehicles. Cycling infrastructure aims to make cycling both more convenient and safer for cyclists. This review is needed to guide transport planning. To:1. evaluate the effects of different types of cycling infrastructure on reducing cycling injuries in cyclists, by type of infrastructure;2. evaluate the effects of cycling infrastructure on reducing the severity of cycling injuries in cyclists;3. evaluate the effects of cycling infrastructure on reducing cycling injuries in cyclists with respect to age, sex and social group. We ran the most recent search on 2nd March 2015. We searched the Cochrane Injuries Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE (OvidSP), Embase Classic + Embase(OvidSP), PubMed and 10 other databases. We searched websites, handsearched conference proceedings, screened reference lists of included studies and previously published reviews and contacted relevant organisations. We included randomised controlled trials, cluster randomised controlled trials, controlled before-after studies, and interrupted time series studies which evaluated the effect of cycling infrastructure (such as cycle lanes, tracks or paths, speed management, roundabout design) on cyclist injury or collision rates. Studies had to include a comparator, that is, either no infrastructure or a different type of infrastructure. We excluded studies that assessed collisions that occurred as a result of competitive cycling. Two review authors examined the titles and abstracts of papers obtained from searches to determine eligibility. Two review authors extracted data from the included trials and assessed the risk of bias. We carried out a meta-analysis using the random-effects model where at least three studies reported the same intervention and outcome. Where there were sufficient studies, as a secondary analysis we accounted for changes in cyclist exposure in the calculation of the rate ratios. We rated the quality of the evidence as 'high', 'moderate', 'low' or 'very low' according to the GRADE approach for the installation of cycle routes and networks. We identified 21 studies for inclusion in the review: 20 controlled before-after (CBA) studies and one interrupted time series (ITS) study. These evaluated a range of infrastructure including cycle lanes, advanced stop lines, use of colour, cycle tracks, cycle paths, management of the road network, speed management, cycle routes and networks, roundabout design and packages of measures. No studies reported medically-attended or self-reported injuries. There was no evidence that cycle lanes reduce the rate of cycle collisions (rate ratio 1.21, 95% CI 0.70 to 2.08). Taking into account cycle flow, there was no difference in collisions for cyclists using cycle routes and networks compared with cyclists not using cycle routes and networks (RR 0.40, 95% CI 0.15 to 1.05). There was statistically significant heterogeneity between the studies (I² = 75%, Chi² = 8.00 df = 2, P = 0.02) for the analysis adjusted for cycle flow. We judged the quality of the evidence regarding cycle routes and networks as very low and we are very uncertain about the estimate. These analyses are based on findings from CBA studies.From data presented narratively, the use of 20 mph speed restrictions in urban areas may be effective at reducing cyclist collisions. Redesigning specific parts of cycle routes that may be particularly busy or complex in terms of traffic movement may be beneficial to cyclists in terms of reducing the risk of collision. Generally, the conversion of intersections to roundabouts may increase the number of cycle collisions. In particular, the conversion of intersections to roundabouts with cycle lanes marked as part of the circulating carriageway increased cycle collisions. However, the conversion of intersections with and without signals to roundabouts with cycle paths may reduce the odds of collision. Both continuing a cycle lane across the mouth of a side road with a give way line onto the main road, and cycle tracks, may increase the risk of injury collisions in cyclists. However, these conclusions are uncertain, being based on a narrative review of findings from included studies. There is a lack of evidence that cycle paths or advanced stop lines either reduce or increase injury collisions in cyclists. There is also insufficient evidence to draw any robust conclusions concerning the effect of cycling infrastructure on cycling collisions in terms of severity of injury, sex, age, and level of social deprivation of the casualty.In terms of quality of the evidence, there was little matching of intervention and control sites. In many studies, the comparability of the control area to the intervention site was unclear and few studies provided information on other cycling infrastructures that may be in place in the control and intervention areas. The majority of studies analysed data routinely collected by organisations external to the study team, thus reducing the risk of bias in terms of systematic differences in assessing outcomes between the control and intervention groups. Some authors did not take regression-to-mean effects into account when examining changes in collisions. Longer data collection periods pre- and post-installation would allow for regression-to-mean effects and also seasonal and time trends in traffic volume to be observed. Few studies adjusted cycle collision rates for exposure. Generally, there is a lack of high quality evidence to be able to draw firm conclusions as to the effect of cycling infrastructure on cycling collisions. There is a lack of rigorous evaluation of cycling infrastructure.

Pattern of energy expenditure during simulated competition.

PubMed

Foster, Carl; De Koning, Jos J; Hettinga, Floor; Lampen, Joanne; La Clair, Kerry L; Dodge, Christopher; Bobbert, Maarten; Porcari, John P

2003-05-01

To determine how athletes spontaneously use their energetic reserves when the only instruction was to finish in minimal time, and whether experience from repeated performance changes the strategy of recreational athletes. Recreational road cyclists/speed skaters (N = 9) completed three laboratory time trials of 1500 m on a windload braked cycle. The pattern of energy use was calculated from total work and from the work attributable to aerobic metabolism, which allowed computation of anaerobic energy use. Regional level speed skaters (N = 8) also performed a single 1500-m time trial with the same protocol and measurements. The serial trials were completed in (mean +/- SD) 133.8 +/- 6.6, 133.9 +/- 5.8, 133.8 +/- 5.5 s (P > 0.05 among trials); and in 125.7 +/- 10.9 s in the skaters (P < 0.05 vs cyclists). The [OV0312]O(2peak) during the terminal 200 m was similar within trials (3.23 +/- 0.44, 3.34 +/- 0.44, 3.30 +/- 0.51 (P > 0.05)) versus 3.91 +/- 0.68 L.min-1 in the skaters (P < 0.05 vs cyclists). In all events, the initial power output and anaerobic energy use was high and decayed to a more or less constant value ( approximately 25% of peak) over the remainder of the event. Contrary to predictions based on an assumed "all out" starting strategy, the subjects reserved some of their ability to perform anaerobic work for a terminal acceleration. The total work accomplished was not different between trials (43.53, 43.78, and 47.48 kJ in the recreational athletes, or between the cyclists and skaters (47.79 kJ). The work attributable to anaerobic sources was not different between the rides (20.67, 20.53, and 21.12 kJ in the recreational athletes). In the skaters, the work attributable to anaerobic sources was significantly larger versus the cyclists (24.67 kJ). Energy expenditure during high-intensity cycling seems: 1) to be expended in a manner that allows the athlete to preserve an anaerobic energetic contribution throughout an event, 2) does not appear to have a large learning effect in already well trained cyclists, and 3) anaerobic energy expenditure may be the performance discriminating factor among groups of athletes.

The effect of topical thiocolchicoside in preventing and reducing the increase of muscle tone, stiffness, and soreness: A real-life study on top-level road cyclists during stage competition.

PubMed

Gervasi, Marco; Sisti, Davide; Benelli, Piero; Fernández-Peña, Eneko; Calcabrini, Cinzia; Rocchi, Marco B L; Lanata, Luigi; Bagnasco, Michela; Tonti, Andrea; Vilberto, Stocchi; Sestili, Piero

2017-07-01

In professional road cyclists, the majority of overuse injuries affect the lower limbs and are mostly represented by contractures or muscle shortening, characterized by an increase of tone and stiffness and a variation of elasticity. Treatment and prevention of these specific conditions may include physical, supplementary, and pharmacologic support. The aim of this real-life study was to determine: first, the alterations of tone, stiffness, elasticity, and soreness of rectus femoris (RF) and biceps femoris (BF) in top class cyclists engaged in 3 multistage races, and second, whether any variable in the management of the athletes may affect the prevention and/or reduction of such alterations.Twenty-three professional cyclists competing in 3 international, cycling stage races were assessed. Athletes could receive, upon the approval of the medical staff, physical, dietary, and/or pharmacological management which could include treatments with topical over-the-counter myorelaxants to prevent and/or reduce muscle contractures. MyotonPro was used to daily measure tone, stiffness, and elasticity in RF and BF in relaxed and contracted state after every stage. In parallel, BF and RF soreness was also assessed with a Likert scale.All athletes received the same general massage management; none of them received dietary supplements; some of the athletes were treated with a topical myorelaxant thiocolchicoside (TCC 0.25%) foam 3 times daily. TCC was identified as the only variable able to affect these muscle parameters in the cyclists. Tone, stiffness (regardless of the state), and soreness significantly increased over time either in BF or RF in all athletes. In the group of athletes that used TCC (n = 11; TCC+) the increase in tone, stiffness, and soreness was significantly lower than in the group not receiving TCC (n = 12; No-TCC). Elasticity varied coherently with tone and stiffness.A very intense and protracted sport activity increases muscular tone, stiffness, and soreness over time. Topical TCC foam significantly attenuates these alterations and might represent an efficient strategy both to prevent and manage contractures and their consequences in professional cyclists as well in athletes from other disciplines involving similar workloads.

Determination of Anaerobic Threshold by Monitoring the O2 Pulse Changes in Endurance Cyclists.

PubMed

Nikooie, Rohollah

2016-06-01

The purpose of this study was to determine the validity of anaerobic threshold (AnT)-equivalent to the second turn point for lactate (LTP2)-estimation using the O2 pulse changes in highly trained endurance cyclists who do not show heart rate deflection point (HRDP) during incremental testing. Sixteen endurance cyclists (age, 24.8 ± 4.7 years) and fifteen active men (age, 24.8 ± 3.7 years) performed an incremental cycling test to exhaustion. Pulmonary oxygen uptake (V[Combining Dot Above]O2) and other hemodynamic variables, heart rate, and blood lactate concentration were measured continuously throughout the test. O2 pulse anaerobic threshold (O2 pulse-AnT) was defined as the second turn point in O2 pulse-workload curve. LTP2 was considered as gold standard assessment of AnT and was applied to confirm the validity of O2 pulse-AnT. Intraclass correlation coefficients and the Bland-Altman method were used to determine the relationship and agreement between the O2 corresponding to LTP2 and O2 pulse-AnT, respectively. The active men and 68.7% of the endurance cyclists showed HRDP, whereas all subjects showed O2 pulse-AnT during incremental testing. In both groups, the values for V[Combining Dot Above]O2 corresponding to LTP2 were not significantly different from the V[Combining Dot Above]O2 at O2 pulse-AnT. The V[Combining Dot Above]O2 at LTP2 and O2 pulse-AnT were highly correlated (endurance cyclists: R = 0.68; standard error of estimate [SEE] = 3.74 ml·kg·min and active men: R = 0.58; SEE = 2.91 ml·kg·min) and Bland-Altman plot revealed the limit of agreement of O2 at LTP2 and O2 pulse-AnT differences between 5.1 and 8.6 ml·kg·min (95% CI). In summary, results of this study showed that the second turn point in the O2 pulse-workload curve occurs around LTP2. Therefore, using O2 pulse-AnT is recommended for the noninvasive determination of AnT in highly trained endurance cyclists who do not show HRDP during incremental exercise.

Factors Associated with Pre-Event Hydration Status and Drinking Behavior of Middle-Aged Cyclists.

PubMed

Yates, B A; Ellis, L A; Butts, C L; McDermott, B P; Williamson, K H; Armstrong, L E

2018-01-01

Water is an essential nutrient for thermoregulation, metabolism, cognition, and overall physiological homeostatic function. However, aging adults display a blunted thirst mechanism and subsequently have an increased risk for dehydration or hyponatremia. Fluid consumption behaviors are modifiable and the importance of practicing adequate drinking behaviors for aging adults is amplified during exercise. Identification of aging adult's hydration beliefs and how they attain hydration advice could provide valuable information into ways to promote better drinking habits to reduce fluid imbalances. Thus, this investigation evaluated the knowledge, beliefs and behaviors of middle-aged cyclists (MA) that were associated with hydration status and drinking behavior, before and during a 164-km mass-participation event (ambient temperature, 33.3±2.8ºC(mean±SD)). This cross-sectional field study retrospectively grouped participants by their second urine specific gravity (Usg) measurement of the event morning prior to a mass participation cycling event. Usg was assessed via handheld refractometer. The Hotter N' Hell Hundred 164-km cycling event in Wichita Falls, Texas during the month of August. 36 male recreational cyclists (age, 53±9 y(mean±SD)). Participants were grouped according their urine specific gravity as either slightly hyperhydrated (SH; n=12, Usg≤1.014), euhydrated (EUH; n=12, Usg, 1.015-1.020), or slightly dehydrated (SD; n=12, Usg≥1.021). Exercise histories and questionnaires were recorded 24-48 h prior to the cycling event. Regardless of pre-event hydration status, all groups experienced a similar body mass loss during the 164-km event and finished with statistically similar exercise times; also, drinking behavior within all groups was influenced by multiple factors. The primary factors associated with MA cyclist drinking behavior were trial and error/personal history and thirst; further, the majority of cyclists (≥65%) in SH, EUH, and SD believed that dehydration affects performance negatively. The least important factors included rehydration recommendations from scientific and sports medicine organizations, plus information from sports drink manufacturers. Considering the complexity of the present findings and the physiological changes that accompany aging such as delayed thirst perception, we recommend that MA cyclists formulate an individualized drinking plan that is based on observations during exercise.

Effect of choline supplementation on fatigue in trained cyclists.

PubMed

Spector, S A; Jackman, M R; Sabounjian, L A; Sakkas, C; Landers, D M; Willis, W T

1995-05-01

The availability of choline, the precurser of the neurotransmitter, acetylcholine, in the diet is sufficient to provide the body's requirements under normal conditions. However, preliminary evidence indicates that depletion of choline may limit performance, while oral supplementation may delay fatigue during prolonged efforts. A double-blind cross-over design was used to determine the relationship between plasma choline and fatigue during supramaximal brief and submaximal prolonged activities. Twenty male cyclists (ages 23-29) with maximal aerobic power (VO2max) between 58 and 81 ml.min-1.kg-1 were randomly divided into BRIEF (N = 10) and PROLONGED (N = 10) groups. One hour after drinking a beverage with or without choline bitartrate (2.43 g), cyclists began riding at a power output equivalent to approximately 150% (BRIEF) and 70% (PROLONGED) of VO2max at a cadence of 80-90 rpm. Time to exhaustion, indirect calorimetry and serum choline, lactate, and glucose were measured. Increases in choline levels of 37 and 52% were seen within one hour of ingestion for BRIEF and PROLONGED groups, respectively. Neither group depleted choline during exercise under the choline or placebo conditions. Fatigue times and work performed under either test condition for the BRIEF or PROLONGED groups were similar. Consequently, trained cyclists do not deplete choline during supramaximal brief or prolonged submaximal exercise, nor do they benefit from choline supplementation to delay fatigue under these conditions.

Relationship between power-duration parameters and mechanical and anthropometric properties of the thigh in elite cyclists.

PubMed

Kordi, Mehdi; Menzies, Campbell; Parker Simpson, Len

2018-03-01

The curvature constant (W') and asymptote (critical power; CP) of the power-duration relationship are important parameters for explaining cycling performance. Short-duration endurance cycling events rely more heavily on the W'; however, the full mechanistic underpinning of this parameter is yet to be determined. Evidence suggests both muscle volume and muscle strength may contribute to the magnitude of W'. Therefore, the present study investigated the relationship between power-duration parameters (CP and W') and (1) anthropometric and (2) mechanical properties of thigh muscles in a sample of elite cyclists. Eleven elite male cyclists had gross thigh volume (T VOL ), quadriceps muscle volume (Q VOL ), vastus lateralis (VL) muscle pennation angle (PA) and VL muscle thickness (MT) measured. Additionally, maximum torque production of the knee extensors (F MAX ) was assessed. The relationship between these anthropometric and mechanical measures and both the CP and W' were determined. W' showed a very strong positive and significant relationship with F MAX (r = 0.87, p < 0.001) and a large positive and significant relationship with T VOL (r = 0.60, p =  0.05). No other anthropometric characteristics were related to the W'. The CP was not associated with any mechanical or anthropometric parameter. In addition to muscle size, the maximal evocable force of a muscle (group) appears to be linked to the magnitude of the W' in elite cyclists.

Women’s bike seats: a pressing matter for competitive female cyclists

PubMed Central

Guess, Marsha K.; Partin, Sarah N.; Schrader, Steven; Lowe, Brian; LaCombe, Julie; Reutman, Susan; Wang, Andrea; Toennis, Christine; Melman, Arnold; Mikhail, Madgy; Connell, Kathleen A.

2011-01-01

Introduction There are numerous genital complaints in women cyclists, including pain, numbness and edema of pelvic floor structures. Debate ensues about the best saddle design for protection of the pelvic floor. Aim To investigate the relationships between saddle design, seat pressures and genital nerve function in female, competitive cyclists. Methods We previously compared genital sensation in healthy, premenopausal, competitive women bicyclists and runners. The 48 cyclists from our original study comprise the study group in this sub-analysis. Main Outcome Measures (1) Genital vibratory thresholds (VT) were determined using the Medoc Vibratory Sensation Analyzer 3000. (2) Saddle pressures as determined using a specially designed map sensor. Results More than half of the participants (54.8%) used traditional saddles and the remainder (45.2%), rode with cut-out saddles. On bivariate analysis, use of traditional saddles was associated with lower mean perineal saddle pressures (MPSP) than riding on cut-out saddles. Peak perineal saddle pressures (PPSP) were also lower; however, the difference did not reach statistical significance. Saddle design did not affect mean or peak total saddle pressures (MTSP, PTSP). Saddle width was significantly associated with PPSP, MTSP and PTSP, but not with MPSP. Women riding cut-out saddles had, on average, a 4 and 11 kPa increase in MPSP and PPSP, respectively, compared to women using traditional saddles (p= 0.008 and p= 0.010), after adjustment for other variables. Use of wider saddles was associated with lower PPSP and MTSP after adjustment. Although an inverse correlation was seen between saddle pressures and VTs on bivariate analysis, these differences were not significant after adjusting for age. Conclusion Cut-out and narrower saddles negatively affect saddle pressures in female cyclists. Effects of saddle design on pudendal nerve sensory function were not apparent in this cross-sectional analysis. Longitudinal studies evaluating the long-term effects of saddle pressure on the integrity of the pudendal nerve, pelvic floor and sexual function are warranted. PMID:21834869

Women's bike seats: a pressing matter for competitive female cyclists.

PubMed

Guess, Marsha K; Partin, Sarah N; Schrader, Steven; Lowe, Brian; LaCombe, Julie; Reutman, Susan; Wang, Andrea; Toennis, Christine; Melman, Arnold; Mikhail, Madgy; Connell, Kathleen A

2011-11-01

There are numerous genital complaints in women cyclists, including pain, numbness, and edema of pelvic floor structures. Debate ensues about the best saddle design for protection of the pelvic floor. To investigate the relationships between saddle design, seat pressures, and genital nerve function in female, competitive cyclists. We previously compared genital sensation in healthy, premenopausal, competitive women bicyclists and runners. The 48 cyclists from our original study comprise the study group in this subanalysis. Main outcome measures were: (i) genital vibratory thresholds (VTs) determined using the Medoc Vibratory Sensation Analyzer 3000 and (ii) saddle pressures as determined using a specially designed map sensor. More than half of the participants (54.8%) used traditional saddles, and the remainder (45.2%) rode with cut-out saddles. On bivariate analysis, use of traditional saddles was associated with lower mean perineal saddle pressures (MPSP) than riding on cut-out saddles. Peak perineal saddle pressures (PPSP) were also lower; however, the difference did not reach statistical significance. Saddle design did not affect mean or peak total saddle pressures (MTSP, PTSP). Saddle width was significantly associated with PPSP, MTSP, and PTSP but not with MPSP. Women riding cut-out saddles had, on average, a 4 and 11 kPa increase in MPSP and PPSP, respectively, compared with women using traditional saddles (P = 0.008 and P = 0.010), after adjustment for other variables. Use of wider saddles was associated with lower PPSP and MTSP after adjustment. Although an inverse correlation was seen between saddle pressures and VTs on bivariate analysis, these differences were not significant after adjusting for age. Cut-out and narrower saddles negatively affect saddle pressures in female cyclists. Effects of saddle design on pudendal nerve sensory function were not apparent in this cross-sectional analysis. Longitudinal studies evaluating the long-term effects of saddle pressure on the integrity of the pudendal nerve, pelvic floor, and sexual function are warranted. © 2011 International Society for Sexual Medicine.

Cyclist route choice, traffic-related air pollution, and lung function: a scripted exposure study

PubMed Central

2013-01-01

Background A travel mode shift to active transportation such as bicycling would help reduce traffic volume and related air pollution emissions as well as promote increased physical activity level. Cyclists, however, are at risk for exposure to vehicle-related air pollutants due to their proximity to vehicle traffic and elevated respiratory rates. To promote safe bicycle commuting, the City of Berkeley, California, has designated a network of residential streets as “Bicycle Boulevards.” We hypothesized that cyclist exposure to air pollution would be lower on these Bicycle Boulevards when compared to busier roads and this elevated exposure may result in reduced lung function. Methods We recruited 15 healthy adults to cycle on two routes – a low-traffic Bicycle Boulevard route and a high-traffic route. Each participant cycled on the low-traffic route once and the high-traffic route once. We mounted pollutant monitors and a global positioning system (GPS) on the bicycles. The monitors were all synced to GPS time so pollutant measurements could be spatially plotted. We measured lung function using spirometry before and after each bike ride. Results We found that fine and ultrafine particulate matter, carbon monoxide, and black carbon were all elevated on the high-traffic route compared to the low-traffic route. There were no corresponding changes in the lung function of healthy non-asthmatic study subjects. We also found that wind-speed affected pollution concentrations. Conclusions These results suggest that by selecting low-traffic Bicycle Boulevards instead of heavily trafficked roads, cyclists can reduce their exposure to vehicle-related air pollution. The lung function results indicate that elevated pollutant exposure may not have acute negative effects on healthy cyclists, but further research is necessary to determine long-term effects on a more diverse population. This study and broader field of research have the potential to encourage policy-makers and city planners to expand infrastructure to promote safe and healthy bicycle commuting. PMID:23391029

Associations of Physical Activity, Sports Participation and Active Commuting on Mathematic Performance and Inhibitory Control in Adolescents.

PubMed

Domazet, Sidsel L; Tarp, Jakob; Huang, Tao; Gejl, Anne Kær; Andersen, Lars Bo; Froberg, Karsten; Bugge, Anna

2016-01-01

To examine objectively measured physical activity level, organized sports participation and active commuting to school in relation to mathematic performance and inhibitory control in adolescents. The design was cross-sectional. A convenient sample of 869 sixth and seventh grade students (12-14 years) was invited to participate in the study. A total of 568 students fulfilled the inclusion criteria and comprised the final sample for this study. Mathematic performance was assessed by a customized test and inhibitory control was assessed by a modified Eriksen flanker task. Physical activity was assessed with GT3X and GT3X+ accelerometers presented in sex-specific quartiles of mean counts per minute and mean minutes per day in moderate-to-vigorous physical activity. Active commuting and sports participation was self-reported. Mixed model regression was applied. Total physical activity level was stratified by bicycling status in order to bypass measurement error subject to the accelerometer. Non-cyclists in the 2nd quartile of counts per minute displayed a higher mathematic score, so did cyclists in the 2nd and 3rd quartile of moderate-to-vigorous physical activity relative to the least active quartile. Non-cyclists in the 3rd quartile of counts per minute had an improved reaction time and cyclists in the 2nd quartile of counts per minute and moderate-to-vigorous physical activity displayed an improved accuracy, whereas non-cyclists in the 2nd quartile of counts per minute showed an inferior accuracy relative to the least active quartile. Bicycling to school and organized sports participation were positively associated with mathematic performance. Sports participation and bicycling were positively associated with mathematic performance. Results regarding objectively measured physical activity were mixed. Although, no linear nor dose-response relationship was observed there was no indication of a higher activity level impairing the scholastic or cognitive performance.

Validation of the virtual elevation field test method when assessing the aerodynamics of para-cyclists with a uni-lateral trans-tibial amputation.

PubMed

Dyer, Bryce; Disley, B Xavier

2018-02-01

Lower-limb amputees typically require some form of prosthetic limb to ride a bicycle for recreation or when competing. At elite-level racing speeds, aerodynamic drag can represent the majority of the resistance acting against a cyclists' forward motion. As a result, the reduction of such resistance is beneficial to an amputee whereby the form and function of the prosthetic limb can be optimized through engineering. To measure the performance of such limbs, field testing provides a cost-effective and context-specific method of aerodynamic drag measurement. However, few methods have been formally validated and none have been applied to amputees with lower-limb amputations. In this paper, an elite level para-cyclist wore two different prosthetic limb designs and had their total aerodynamic drag of a wind tunnel reference method statistically correlated against a velodrome-based virtual elevation field test method. The calculated coefficient of variation was in the range of 0.7-0.9% for the wind tunnel method and 2-3% for the virtual elevation method. A 0.03 m 2 difference was identified in the absolute values recorded between the two methods. Ultimately, both methods exhibited high levels of precision, yet relative results to each other. The virtual elevation method is proposed as a suitable technique to assess the aerodynamic drag of amputee para-cyclists. Implications for rehabilitation This assessment method will provide practitioners a reliable means of assessing the impact of changes made to prosthetics design for cyclists with limb absence. The proposed method offers a low cost and geographically accessible solution compared to others proposed in the past. This assessment method has significant potential for impact among prosthetic limb users looking to improve their cycling performance whereas previous attention in this field has been extremely limited.

Cyclist route choice, traffic-related air pollution, and lung function: a scripted exposure study.

PubMed

Jarjour, Sarah; Jerrett, Michael; Westerdahl, Dane; de Nazelle, Audrey; Hanning, Cooper; Daly, Laura; Lipsitt, Jonah; Balmes, John

2013-02-07

A travel mode shift to active transportation such as bicycling would help reduce traffic volume and related air pollution emissions as well as promote increased physical activity level. Cyclists, however, are at risk for exposure to vehicle-related air pollutants due to their proximity to vehicle traffic and elevated respiratory rates. To promote safe bicycle commuting, the City of Berkeley, California, has designated a network of residential streets as "Bicycle Boulevards." We hypothesized that cyclist exposure to air pollution would be lower on these Bicycle Boulevards when compared to busier roads and this elevated exposure may result in reduced lung function. We recruited 15 healthy adults to cycle on two routes - a low-traffic Bicycle Boulevard route and a high-traffic route. Each participant cycled on the low-traffic route once and the high-traffic route once. We mounted pollutant monitors and a global positioning system (GPS) on the bicycles. The monitors were all synced to GPS time so pollutant measurements could be spatially plotted. We measured lung function using spirometry before and after each bike ride. We found that fine and ultrafine particulate matter, carbon monoxide, and black carbon were all elevated on the high-traffic route compared to the low-traffic route. There were no corresponding changes in the lung function of healthy non-asthmatic study subjects. We also found that wind-speed affected pollution concentrations. These results suggest that by selecting low-traffic Bicycle Boulevards instead of heavily trafficked roads, cyclists can reduce their exposure to vehicle-related air pollution. The lung function results indicate that elevated pollutant exposure may not have acute negative effects on healthy cyclists, but further research is necessary to determine long-term effects on a more diverse population. This study and broader field of research have the potential to encourage policy-makers and city planners to expand infrastructure to promote safe and healthy bicycle commuting.

Associations of Physical Activity, Sports Participation and Active Commuting on Mathematic Performance and Inhibitory Control in Adolescents

PubMed Central

Huang, Tao; Gejl, Anne Kær; Froberg, Karsten

2016-01-01

Objectives To examine objectively measured physical activity level, organized sports participation and active commuting to school in relation to mathematic performance and inhibitory control in adolescents. Methods The design was cross-sectional. A convenient sample of 869 sixth and seventh grade students (12–14 years) was invited to participate in the study. A total of 568 students fulfilled the inclusion criteria and comprised the final sample for this study. Mathematic performance was assessed by a customized test and inhibitory control was assessed by a modified Eriksen flanker task. Physical activity was assessed with GT3X and GT3X+ accelerometers presented in sex-specific quartiles of mean counts per minute and mean minutes per day in moderate-to-vigorous physical activity. Active commuting and sports participation was self-reported. Mixed model regression was applied. Total physical activity level was stratified by bicycling status in order to bypass measurement error subject to the accelerometer. Results Non-cyclists in the 2nd quartile of counts per minute displayed a higher mathematic score, so did cyclists in the 2nd and 3rd quartile of moderate-to-vigorous physical activity relative to the least active quartile. Non-cyclists in the 3rd quartile of counts per minute had an improved reaction time and cyclists in the 2nd quartile of counts per minute and moderate-to-vigorous physical activity displayed an improved accuracy, whereas non-cyclists in the 2nd quartile of counts per minute showed an inferior accuracy relative to the least active quartile. Bicycling to school and organized sports participation were positively associated with mathematic performance. Conclusions Sports participation and bicycling were positively associated with mathematic performance. Results regarding objectively measured physical activity were mixed. Although, no linear nor dose-response relationship was observed there was no indication of a higher activity level impairing the scholastic or cognitive performance. PMID:26727211

Yellow and social perceptions of racing cyclists' sportspersonship: Proposing an inter-contextual analysis.

PubMed

Chantal, Yves; Bernache-Assollant, Iouri

2017-03-01

Through inter-contextual designs, the present set of experiments sought to explore whether the colour yellow would impact on social perceptions of sportspersonship exclusively in relation to competitive cycling. In Experiment 1 (N = 149), a silhouette image of a cyclist on a yellow background yielded lower perceptions of sportspersonship in comparison to grey or to the context of motocross, regardless of the colour. That interaction was conceptually replicated in Experiment 2 (N = 146) while changing measures (i.e., adaptation of the World Anti-Doping Code) and the context of comparison to sprinting. Furthermore, female and male observers' scores did not differ significantly thereby suggesting that yellow impacted on perceived sportspersonship similarly across gender. On the whole, those findings suggest that yellow can generate negative impressions of racing cyclists because, with years, this colour took on a meaning of opportunism from frequent pairings with doping. We close with discussing a number of limitations and future research avenues.

Assessment of bicycle-car accidents under four different types of collision.

PubMed

Raslavičius, Laurencas; Bazaras, Liudas; Keršys, Artūras; Lukoševičius, Vaidas; Makaras, Rolandas; Eidukynas, Valdas

2017-03-01

Bicycle riders are among the highest risk group in traffic. A cyclist simulation study captured kinematics and injuries to legs, pelvis, neck, and head for one human body size. We analyzed the number of parameters (forces acting on left and right tibia, head injury criterion, neck tensile force, neck shear force, and pelvic acceleration) for each of the four different cases: bicyclist ride out-residential driveway, motorist overtaking-undetected bicyclist, bicyclist left turn-same direction, and bicyclist right turn-opposite direction. The comparison of simulation outcomes for leg injuries with official hospital records has shown a very good correlation in terms of injury severity prediction. This study concludes that if countermeasures to prevent fatal cyclist injury in car impacts were to be concentrated on mitigating head and neck impact to the windscreen of the car, a dominant share of fatal cyclist crashes and severe traumatic head injury cases at collision speeds exceeding 40 km/h could be prevented.

Comparison of platelet function between sedentary individuals and competitive athletes at rest.

PubMed

Lippi, Giuseppe; Montagnana, Martina; Salvagno, Gian Luca; Franchini, Massimo; Guidi, Gian Cesare

2006-08-17

There are controversial evidences on the effect of different types and workloads of physical exercise on primary hemostasis. In particular, little is known on the chronic influence of a strenuous and regular aerobic training regimen on platelet function. The aim of this investigation was to compare platelet function between sedentary controls and trained athletes at rest and to evaluate whether a greater amount of exercise performed in professional cyclists may contribute to increased platelet chronic responsiveness compared to both elite cyclists and sedentary individuals. Platelet's ability to adhere and aggregate was assayed following a 12-24 h resting period in 49 active professional male road cyclists, 40 elite male cyclists and 43 matched sedentary healthy male volunteers, by the platelet function analyzer 100 (PFA-100). Mean values of the collagen-epinephrine test did not differ between controls and athletes (sedentary controls: 111 +/- 33 s; elite athletes: 113 +/- 26 s, p = 0.93; professional athletes: 120 +/- 33 s; p = 0.33), whereas mean values of the collagen-ADP test displayed a slightly but significant trend towards decreased values when comparing sedentary controls (83 +/- 21 s) with either elite (77 +/- 11 s, p < 0.01) or professional (75 +/- 16 s, p < 0.01) athletes. The trend towards slightly lower collagen-ADP values are suggestive for a modest but significant chronic activation of primary hemostasis, highlighting the need to set appropriate reference ranges for the PFA-100 when evaluating primary hemostasis in physically active subjects.

Effect of concurrent resistance and sprint training on body composition and cardiometabolic health indicators in masters cyclists

PubMed Central

Delvecchio, Luke; Reaburn, Peter; Trapp, Gail; Korhonen, Marko T.

2016-01-01

In older previously sedentary individuals endurance training imposes a more effective stimulus to enhance cardiometabolic health compared with resistance or sprint training. We examined the effect of replacing a portion of endurance training with combined resistance and/or sprint training and how this influences cardiometabolic health indicators in masters endurance cyclists. Twenty-seven well-trained male road cyclists (53.7±8.2 years) were allocated to a resistance and track sprint-cycling training group (RTC, n=10), an endurance and track sprint-cycling group (ETC, n=7) or a control endurance group (CTRL, n=10). Both the RTC and ETC groups completed a 12-week intervention of specific training while the CTRL group maintained their endurance training load. Lower limb lean mass (LLM), trunk fat mass (TFM), fasting blood glucose (FBG), total cholesterol (TC), triglycerides (TG), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured before and after the intervention period. TFM decreased for all groups (P<0.05) while LLM significantly increased for RTC and ETC groups (P<0.05). No significant between group or time effects were observed for FBG, TC, TG, SBP, or DBP. The results suggest that replacing a portion of endurance training with 12 weeks of ETC or RTC training favourably affects body composition by lowering TFM and increasing LLM without negatively affecting cardiometabolic health indicators in well-trained masters endurance cyclists. PMID:27807523

A longitudinal study on the ammonia threshold in junior cyclists

PubMed Central

Yuan, Y; Chan, K

2004-01-01

Objectives: To identify the effect of a one year non-specific training programme on the ammonia threshold of a group of junior cyclists and to correlate ammonia threshold with other common physiological variables. Methods: The cyclists performed tests at three time points (T1, T2, T3) during the year. Follow up tests were conducted every six months after the original test. Ammonia threshold was obtained from a graded exercise with four minute steps. Results: The relatively non-specific one year training programme was effective in inducing an increase in peak VO2 (60.6 (5.9), 65.9 (7.4), and 64.6 (6.5) ml/min/kg at T1, T2, and T3 respectively) and endurance time (18.3 (4.5), 20.1 (5.2), and 27.0 (6.1) minutes at T1, T2, and T3 respectively), but was not effective for the sprint related variables. Ammonia threshold, together with lactate threshold and ventilatory threshold, was not significantly different at the three test times. Only endurance time correlated significantly with ammonia threshold (r  =  0.915, p  =  0.001). Conclusions: The findings suggest that a relatively non-specific one year training programme does not modify the ammonia threshold of junior cyclists. The significant correlation between ammonia threshold and endurance time further confirms that ammonia threshold is a measure of the ability to sustain exercise at submaximal intensities. PMID:15039242

Effect of short-term cold-water immersion on muscle pain sensitivity in elite track cyclists.

PubMed

Klich, Sebastian; Krymski, Igor; Michalik, Kamil; Kawczyński, Adam

2018-05-01

To determine the effect of short-term cold-water immersion (CWI) on muscle pain sensitivity after maximal anaerobic power training in track cyclists. Repeated measures. University Laboratory. 12 elite sprint track cyclists (age 24,75 ± 4,23 years). PPT measurements were made on dominant lower extremity (right) in 20 reference points, including anterior thigh muscles, posterior thigh muscles and posterior cuff muscles. PPT levels were measured: 1) before workout, 2) immediately after workout, but before CWI 3) 1 h after CWI and 4) 12 h after CWI. Mean PPT values for each muscle group per participant were calculated for further statistical analysis. The average PPT for anterior thigh muscles decreased significantly after effort (p = 0.001) and increased significantly 1 h after CWI (p = 0.048). In posterior thigh muscles PPT decreased significantly after effort (p = 0.014) and increased significantly 1 h and 12 h after CWI (p = 0.045 and p = 0.25 respectively). However, in posterior cuff muscles PPT decreased only after effort (p = 0.001). Short-term repeated sprint exercise appears to affect PPT in track cyclists. This study have reported that CWI in 5 °C for 5 min have had a beneficial effect in minimizing PPT 1 h post repeated maximal sprint training. Copyright © 2018 Elsevier Ltd. All rights reserved.

A hazard-based duration model for analyzing crossing behavior of cyclists and electric bike riders at signalized intersections.

PubMed

Yang, Xiaobao; Huan, Mei; Abdel-Aty, Mohamed; Peng, Yichuan; Gao, Ziyou

2015-01-01

This paper presents a hazard-based duration approach to investigate riders' waiting times, violation hazards, associated risk factors, and their differences between cyclists and electric bike riders at signalized intersections. A total of 2322 two-wheeled riders approaching the intersections during red light periods were observed in Beijing, China. The data were classified into censored and uncensored data to distinguish between safe crossing and red-light running behavior. The results indicated that the red-light crossing behavior of most riders was dependent on waiting time. They were inclined to terminate waiting behavior and run against the traffic light with the increase of waiting duration. Over half of the observed riders cannot endure 49s or longer. 25% of the riders can endure 97s or longer. Rider type, gender, waiting position, conformity tendency and crossing traffic volume were identified to have significant effects on riders' waiting times and violation hazards. Electric bike riders were found to be more sensitive to the external risk factors such as other riders' crossing behavior and crossing traffic volume than cyclists. Moreover, unobserved heterogeneity was examined in the proposed models. The finding of this paper can explain when and why cyclists and electric bike riders run against the red light at intersections. The results of this paper are useful for traffic design and management agencies to implement strategies to enhance the safety of riders. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effect on road safety of a modal shift from car to bicycle.

PubMed

Stipdonk, Henk; Reurings, Martine

2012-01-01

To describe and apply a method to assess the effect on road safety of a modal shift from cars to bicycles. Ten percent of all car trips shorter than 7.5 km were assumed to be replaced by bicycle trips. Single-vehicle and multivehicle crashes involving cars and/or bicycles were considered. The safety of car occupants and cyclists was taken into account as well as the safety of other road users involved in such crashes. The computations were carried out by age and gender. Assuming constant risk (casualties per distance traveled), the expected number of accidents is proportional to the mobility shift. Several types of risk were considered: the risk of being injured as a car driver or cyclist and the risk of being involved as a car driver or cyclist in a crash in which another road user is injured. The results indicated that the total gain of the modal shift was negative for fatalities, which means that there was a net increase in the number of fatalities. The modal shift was advantageous for young drivers and disadvantageous for elderly drivers. In addition, it was more positive for males than for females. The turning point was around the age of 35. For hospitalized casualties, due to the strong influence of the many hospitalized cyclists in nonmotorized vehicle crashes, there was a strong negative overall effect, and the modal shift resulted in a positive effect for 18- and 19-year-old males only. Overall, a small increase (up to 1%) in the number of cyclist fatalities and a greater increase of 3.5 percent in the number of inpatients was expected. The increase in casualties was mainly due to the proportion of single-vehicle bicycle crashes with serious injuries in relation to the total number of injured cyclists. The effect of the modal shift was shown to depend on age and gender, resulting in fewer casualties for younger drivers and for women. It is possible to provide a first approximation of the effect on road safety of a mobility shift from cars to bicycles. This approximation indicates that, in general, road safety does not benefit from this modal shift. The effect differs for gender and age groups. Elderly drivers are safer inside a car than on a bicycle. For the number of hospitalized casualties, the modal shift increases the number of casualties for practically all ages and both genders.

Influence of Prior Intense Exercise and Cold Water Immersion in Recovery for Performance and Physiological Response during Subsequent Exercise

PubMed Central

Christensen, Peter M.; Bangsbo, Jens

2016-01-01

Athletes in intense endurance sports (e.g., 4000-m track cycling) often perform maximally (~4 min) twice a day due to qualifying and finals being placed on the same day. The purpose of the present study was to evaluate repeated performance on the same day in a competitive setting (part A) and the influence from prior intense exercise on subsequent performance and physiological response to moderate and maximal exercise with and without the use of cold water immersion (CWI) in recovery (part B). In part A, performance times during eight World championships for male track cyclists were extracted from the qualifying and final races in 4000-m individual pursuit. In part B, twelve trained cyclists with an average (±SD) ⩒O2-peak of 67 ± 5 mL/min/kg performed a protocol mimicking a qualifying race (QUAL) followed 3 h later by a performance test (PT) with each exercise period encompassing intense exercise for ~4 min preceded by an identical warm-up period in both a control setting (CON) and using cold water immersion in recovery (CWI; 15 min at 15°C). Performance was lowered (P < 0.001) from qualification to finals (259 ± 3 vs. 261 ± 3 s) for the track cyclists during World championships in part A. In part B, mean power in PT was not different in CWI relative to CON (406 ± 43 vs. 405 ± 38 W). Peak ⩒O2 (5.04 ± 0.50 vs. 5.00 ± 0.49 L/min) and blood lactate (13 ± 3 vs. 14 ± 3 mmol/L) did not differ between QUAL and PT and cycling economy and potassium handling was not impaired by prior intense exercise. In conclusion, performance is reduced with repeated maximal exercise in world-class track cyclists during 4000-m individual pursuit lasting ~4 min, however prior intense exercise do not appear to impair peak ⩒O2, peak lactate, cycling economy, or potassium handling in trained cyclists and CWI in recovery does not improve subsequent performance. PMID:27445857

Dietary Nitrate Fails to Improve 1 and 4 km Cycling Performance in Highly Trained Cyclists.

PubMed

McQuillan, Joseph A; Dulson, Deborah K; Laursen, Paul B; Kilding, Andrew E

2017-06-01

We aimed to compare the effects of two different dosing durations of dietary nitrate (NO 3 - ) supplementation on 1 and 4 km cycling time-trial performance in highly trained cyclists. In a double-blind crossover-design, nine highly trained cyclists ingested 140ml of NO 3 - -rich beetroot juice containing ~8.0mmol [NO 3 - ], or placebo, for seven days. Participants completed a range of laboratory-based trials to quantify physiological and perceptual responses and cycling performance: time-trials on day 3 and 6 (4km) and on day 4 and 7 (1km) of the supplementation period. Relative to placebo, effects following 3- and 4-days of NO 3 - supplementation were unclear for 4 (-0.8; 95% CL, ± 2.8%, p = .54) and likely harmful for 1km (-1.9; ± 2.5% CL, p = .17) time-trial mean power. Effects following 6- and 7-days of NO 3 - supplementation resulted in unclear effects for 4 (0.1; ± 2.2% CL, p = .93) and 1km (-0.9; ± 2.6%CL, p = .51) time-trial mean power. Relative to placebo, effects for 40, 50, and 60% peak power output were unclear for economy at days 3 and 6 of NO 3 - supplementation (p > .05). Dietary NO 3 - supplementation appears to be detrimental to 1km time-trial performance in highly trained cyclists after 4-days. While, extending NO 3 - dosing to ≥ 6-days reduced the magnitude of harm in both distances, overall performance in short duration cycling time-trials did not improve relative to placebo.

The effects of 16 weeks of intensive cycling training on seminal oxidants and antioxidants in male road cyclists.

PubMed

Maleki, Behzad Hajizadeh; Tartibian, Bakhtyar; Vaamonde, Diana

2014-07-01

To examine the effects of 16 weeks of intensive cycling training on seminal reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), catalase, and total antioxidant capacity (TAC) in male road cyclists. Repeated measures design. The Exercise Physiology Laboratory of the Urmia University. Twenty-four healthy nonprofessional male road cyclists (aged 17-26 years) participated in this study. All subjects participated in 16 weeks of intensive cycling training. The semen samples were collected, respectively, at baseline (T1), immediately (T2), 12 (T3), and 24 (T4) hours after the last training session in week 8; immediately (T5), 12 (T6), and 24 (T7) hours after the last training session in week 16; and 7 (T8) and 30 (T9) days after the last training session in week 16. Total antioxidant capacity and SOD were measured by colorimetric assay. The levels of ROS were measured by a chemiluminescence assay. Malondialdehyde levels were measured by thiobarbituric acid reactive substance assay. Catalase was measured by monitoring the initial rate of disappearance of hydrogen peroxide (initial concentration 10 mM) at 240 nm. The levels of seminal ROS and MDA increased (P < 0.008) and remained high after 30 days of recovery. The levels of seminal SOD, catalase, and TAC decreased (P < 0.008) and remained low after 30 days of recovery (P < 0.008). Sixteen weeks of intensive cycling training may have deleterious consequences for spermatozoa and hence may affect sperm healthy parameters in male cyclists.

Can cycling safety be improved by opening all unidirectional cycle paths for cycle traffic in both directions? A theoretical examination of available literature and data.

PubMed

Methorst, Rob; Schepers, Paul; Kamminga, Jaap; Zeegers, Theo; Fishman, Elliot

2017-08-01

Many studies have found bicycle-motor vehicle crashes to be more likely on bidirectional cycle paths than on unidirectional cycle paths because drivers do not expect cyclists riding at the right side of the road. In this paper we discuss the hypothesis that opening all unidirectional cycle paths for cycle traffic in both directions prevent this lack of expectancy and accordingly improves cycling safety. A new national standard requires careful consideration because a reversal is difficult once cyclists are used to their new freedom of route choice. We therefore explored the hypothesis using available data, research, and theories. The results show that of the length of cycle paths along distributor roads in the Netherlands, 72% is bidirectional. If drivers would become used to cyclists riding at the left side of the road, this result raises the question of why bidirectional cycle paths in the Netherlands still have a poor safety record compared to unidirectional cycle paths. Moreover, our exploration suggested that bidirectional cycle paths have additional safety problems. It increases the complexity of unsignalized intersections because drivers have to scan more directions in a short period of time. Moreover, there are some indications that the likelihood of frontal crashes between cyclists increases. We reject the hypothesis that opening all unidirectional cycle paths for cycle traffic in both directions will improve cycle safety. We recommend more attention for mitigating measures given the widespread application of bidirectional cycle paths in the Netherlands. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of car-to-bicycle approach patterns for developing active safety devices.

PubMed

Matsui, Yasuhiro; Oikawa, Shoko; Hitosugi, Masahito

2016-05-18

To reduce the severity of injuries and the number of cyclist deaths in traffic accidents, active safety devices providing cyclist detection are considered to be effective countermeasures. The features of car-to-bicycle collisions need to be known in detail to develop such safety devices. The study investigated near-miss situations captured by drive recorders installed in passenger cars. Because similarities in the approach patterns between near-miss incidents and real-world fatal cyclist accidents in Japan were confirmed, we analyzed the 229 near-miss incident data via video capturing bicycles crossing the road in front of forward-moving cars. Using a video frame captured by a drive recorder, the time to collision (TTC) was calculated from the car's velocity and the distance between the car and bicycle at the moment when the bicycle initially appeared. The average TTC in the cases where bicycles emerged from behind obstructions was shorter than that in the cases where drivers had unobstructed views of the bicycles. In comparing the TTC of car-to-bicycle near-miss incidents to the previously obtained results of car-to-pedestrian near-miss incidents, it was determined that the average TTC in car-to-bicycle near-miss incidents was significantly longer than that in car-to-pedestrian near-miss incidents. When considering the TTC in the test protocol of evaluation for safety performance of active safety devices, we propose individual TTCs for evaluation of cyclist and pedestrian detections, respectively. In the test protocols, the following 2 scenarios should be employed: bicycle emerging from behind an unobstructed view and bicycle emerging from behind obstructions.

Subgroups of adolescents differing in physical and social environmental preferences towards cycling for transport: A latent class analysis.

PubMed

Verhoeven, Hannah; Ghekiere, Ariane; Van Cauwenberg, Jelle; Van Dyck, Delfien; De Bourdeaudhuij, Ilse; Clarys, Peter; Deforche, Benedicte

2018-07-01

In order to be able to tailor environmental interventions to adolescents at risk for low levels of physical activity, the aim of the present study is to identify subgroups of adolescents with different physical and social environmental preferences towards cycling for transport and to determine differences in individual characteristics between these subgroups. In this experimental study, 882 adolescents (12-16 years) completed 15 choice tasks with manipulated photographs. Participants chose between two possible routes to cycle to a friend's house which differed in seven physical micro-environmental factors, cycling distance and co-participation in cycling (i.e. cycling alone or with a friend). Latent class analysis was performed. Data were collected from March till October 2016 across Flanders (Belgium). Three subgroups could be identified. Subgroup 1 attached most importance to separation of the cycle path and safety-related aspects. Subgroup 2 attached most importance to being able to cycle together with a friend and had the highest percentage of regular cyclists. In subgroup 3, the importance of cycling distance clearly stood out. This subgroup included the lowest percentage of regular cyclists. Results showed that in order to stimulate the least regular cyclists, and thus also the subgroup most at risk for low levels of active transport, cycling distances should be as short as possible. In general, results showed that providing well-separated cycle paths which enable adolescents to cycle side by side and introducing shortcuts for cyclists may encourage different subgroups of adolescents to cycle for transport without discouraging other subgroups. Copyright © 2018 Elsevier Inc. All rights reserved.

Influence of hamstring muscles extensibility on spinal curvatures and pelvic tilt in highly trained cyclists.

PubMed

Muyor, José M; Alacid, Fernando; López-Miñarro, Pedro A

2011-09-01

The purpose of this study was to determine the influence of hamstring muscles extensibility in standing, maximal trunk flexion with knees extended and on the bicycle in lower handlebar-hands position of highly trained cyclists. Ninety-six cyclists were recruited for the study (mean ± SD, age: 30.36 ± 5.98 years). Sagittal spinal curvatures and pelvic tilt were measured in the standing position, maximal trunk flexion with knees extended (sit-and-reach test) and while sitting on a bicycle in lower handlebar-hand position using a Spinal Mouse system. Hamstring muscles extensibility was determined in both legs by passive straight leg raise test (PSLR). The sample was divided into three groups according to PSLR angle: (1) reduced extensibility (PSLR < 80º; n = 30), (2) moderate hamstring extensibility group (PSLR = 80º - 90º; n = 35), and (3) high hamstring extensibility (PSLR = > 90º; n = 31). ANOVA analysis showed significant differences among groups for thoracic (p < 0.001) and pelvic tilt (p < 0.001) angles in the sit-and-reach test. No differences were found between groups for standing and on the bicycle position. Post hoc analysis showed significant differences in all pairwise comparisons for thoracic angle (p < 0.01) and pelvic angle (p < 0.001) in the sit-and-reach test. No differences were found in lumbar angle in any posture. In conclusion, the hamstring muscles extensibility influence the thoracic and pelvic postures when maximal trunk flexion with knees extended is performed, but not when cyclists are seated on their bicycles.

Influence of Hamstring Muscles Extensibility on Spinal Curvatures and Pelvic Tilt in Highly Trained Cyclists

PubMed Central

Muyor, José M.; Alacid, Fernando; López-Miñarro, Pedro A.

2011-01-01

The purpose of this study was to determine the influence of hamstring muscles extensibility in standing, maximal trunk flexion with knees extended and on the bicycle in lower handlebar-hands position of highly trained cyclists. Ninety-six cyclists were recruited for the study (mean ± SD, age: 30.36 ± 5.98 years). Sagittal spinal curvatures and pelvic tilt were measured in the standing position, maximal trunk flexion with knees extended (sit-and-reach test) and while sitting on a bicycle in lower handlebar-hand position using a Spinal Mouse system. Hamstring muscles extensibility was determined in both legs by passive straight leg raise test (PSLR). The sample was divided into three groups according to PSLR angle: (1) reduced extensibility (PSLR < 80º; n = 30), (2) moderate hamstring extensibility group (PSLR = 80º – 90º; n = 35), and (3) high hamstring extensibility (PSLR = > 90º; n = 31). ANOVA analysis showed significant differences among groups for thoracic (p < 0.001) and pelvic tilt (p < 0.001) angles in the sit-and-reach test. No differences were found between groups for standing and on the bicycle position. Post hoc analysis showed significant differences in all pairwise comparisons for thoracic angle (p < 0.01) and pelvic angle (p < 0.001) in the sit-and-reach test. No differences were found in lumbar angle in any posture. In conclusion, the hamstring muscles extensibility influence the thoracic and pelvic postures when maximal trunk flexion with knees extended is performed, but not when cyclists are seated on their bicycles PMID:23486997

Optimal cycling time trial position models: aerodynamics versus power output and metabolic energy.

PubMed

Fintelman, D M; Sterling, M; Hemida, H; Li, F-X

2014-06-03

The aerodynamic drag of a cyclist in time trial (TT) position is strongly influenced by the torso angle. While decreasing the torso angle reduces the drag, it limits the physiological functioning of the cyclist. Therefore the aims of this study were to predict the optimal TT cycling position as function of the cycling speed and to determine at which speed the aerodynamic power losses start to dominate. Two models were developed to determine the optimal torso angle: a 'Metabolic Energy Model' and a 'Power Output Model'. The Metabolic Energy Model minimised the required cycling energy expenditure, while the Power Output Model maximised the cyclists׳ power output. The input parameters were experimentally collected from 19 TT cyclists at different torso angle positions (0-24°). The results showed that for both models, the optimal torso angle depends strongly on the cycling speed, with decreasing torso angles at increasing speeds. The aerodynamic losses outweigh the power losses at cycling speeds above 46km/h. However, a fully horizontal torso is not optimal. For speeds below 30km/h, it is beneficial to ride in a more upright TT position. The two model outputs were not completely similar, due to the different model approaches. The Metabolic Energy Model could be applied for endurance events, while the Power Output Model is more suitable in sprinting or in variable conditions (wind, undulating course, etc.). It is suggested that despite some limitations, the models give valuable information about improving the cycling performance by optimising the TT cycling position. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparison of platelet function between sedentary individuals and competitive athletes at rest

PubMed Central

Lippi, Giuseppe; Montagnana, Martina; Salvagno, Gian Luca; Franchini, Massimo; Guidi, Gian Cesare

2006-01-01

Background There are controversial evidences on the effect of different types and workloads of physical exercise on primary hemostasis. In particular, little is known on the chronic influence of a strenuous and regular aerobic training regimen on platelet function. Methods The aim of this investigation was to compare platelet function between sedentary controls and trained athletes at rest and to evaluate whether a greater amount of exercise performed in professional cyclists may contribute to increased platelet chronic responsiveness compared to both elite cyclists and sedentary individuals. Platelet's ability to adhere and aggregate was assayed following a 12–24 h resting period in 49 active professional male road cyclists, 40 elite male cyclists and 43 matched sedentary healthy male volunteers, by the platelet function analyzer 100 (PFA-100). Results and discussion Mean values of the collagen-epinephrine test did not differ between controls and athletes (sedentary controls: 111 ± 33 s; elite athletes: 113 ± 26 s, p = 0.93; professional athletes: 120 ± 33 s; p = 0.33), whereas mean values of the collagen-ADP test displayed a slightly but significant trend towards decreased values when comparing sedentary controls (83 ± 21 s) with either elite (77 ± 11 s, p < 0.01) or professional (75 ± 16 s, p < 0.01) athletes. Conclusion The trend towards slightly lower collagen-ADP values are suggestive for a modest but significant chronic activation of primary hemostasis, highlighting the need to set appropriate reference ranges for the PFA-100 when evaluating primary hemostasis in physically active subjects. PMID:16916446

Energy expenditure during bicycling.

PubMed

McCole, S D; Claney, K; Conte, J C; Anderson, R; Hagberg, J M

1990-02-01

This study was designed to measure the O2 uptake (VO2) of cyclists while they rode outdoors at speeds from 32 to 40 km/h. Regression analyses of data from 92 trials using the same wheels, tires, and tire pressure with the cyclists riding in their preferred gear and in an aerodynamic position indicated the best equation (r = 0.84) to estimate VO2 in liters per minute VO2 = -4.50 + 0.17 rider speed + 0.052 wind speed + 0.022 rider weight where rider and wind speed are expressed in kilometers per hour and rider weight in kilograms. Following another rider closely, i.e., drafting, at 32 km/h reduced VO2 by 18 +/- 11%; the benefit of drafting a single rider at 37 and 40 km/h was greater (27 +/- 8%) than that at 32 km/h. Drafting one, two, or four riders in a line at 40 km/h resulted in the same reduction in VO2 (27 +/- 7%). Riding at 40 km/h at the back of a group of eight riders reduced VO2 by significantly more (39 +/- 6%) than drafting one, two, or four riders in a line; drafting a vehicle at 40 km/h resulted in the greatest decrease in VO2 (62 +/- 6%). VO2 was also 7 +/- 4% lower when the cyclists were riding an aerodynamic bicycle. An aerodynamic set of wheels with a reduced number of spokes and one set of disk wheels were the only wheels to reduce VO2 significantly while the cyclists were riding a conventional racing bicycle at 40 km/h.(ABSTRACT TRUNCATED AT 250 WORDS)

Riding position and lumbar spine angle in recreational cyclists: A pilot study

PubMed Central

SCHULZ, SAMANTHA J.; GORDON, SUSAN J.

2010-01-01

This pilot study investigated the reliability of an inclinometer to assess lumbar spine angle in three different cycling positions, and explored the relationship between lumbar spine angle and riding position, anthropometry, bike measures and low back pain (LBP). Cyclists were recruited from two cycle clubs. Anthropometric variables and bike setup were measured before participants’ bikes were secured in a wind trainer. Cyclists then adopted three positions for riding, upright on the handlebars, on the brake levers and on the drops, according to a random allocation. The angle of the lumbar spine was measured; using an inclinometer, at zero minutes and after cyclists had completed 10 minutes of cycling. Intra-measurer reliability for inclinometer use to measure lumbar spine angle in each position was excellent (ICC=0.97). The angle of the lumbar spine changed significantly over 10 minutes in the brake position (p=0.004). Lumbar spine angle at 10 minutes was significantly different between the brake and drop positions (p=0.018, p<0.05), and between upright and drop positions (p=0.012, p<0.05). Lumbar spine angle was not related to anthropometric measures. The change in lumbar spine angle varied from one degree of extension to 12 degrees of flexion, with increased flexion occurring in 95% of trials. An inclinometer has excellent intra-measurer reliability to measure lumbar spine angle in cycling positions. Future research with a sample of 72 or more participants is required to determine if there is a significant relationship between LBP and lumbar spine angle in different cycling positions. PMID:27182345

Game-based situation awareness training for child and adult cyclists

PubMed Central

Airaksinen, Jasmiina; Kanerva, Kaisa; Rissanen, Anna; Ränninranta, Riikka; Åberg, Veera

2017-01-01

Safe cycling requires situation awareness (SA), which is the basis for recognizing and anticipating hazards. Children have poorer SA than adults, which may put them at risk. This study investigates whether cyclists' SA can be trained with a video-based learning game. The effect of executive working memory on SA was also studied. Thirty-six children (9–10 years) and 22 adults (21–48 years) played the game. The game had 30 video clips filmed from a cyclist's perspective. Each clip was suddenly masked and two or three locations were presented. The player's task was to choose locations with a potential hazard and feedback was given for their answers. Working memory capacity (WMC) was tested with a counting span task. Children's and adults' performance improved while playing the game, which suggests that playing the game trains SA. Adults performed better than children, and they also glanced at hazards more while the video was playing. Children expectedly had a lower WMC than adults, but WMC did not predict performance within the groups. This indicates that SA does not depend on WMC when passively viewing videos. PMID:28405369

Exposure assessment of a cyclist to PM10 and ultrafine particles.

PubMed

Berghmans, P; Bleux, N; Int Panis, L; Mishra, V K; Torfs, R; Van Poppel, M

2009-02-01

Estimating personal exposure to air pollution is a crucial component in identifying high-risk populations and situations. It will enable policy makers to determine efficient control strategies. Cycling is again becoming a favorite mode of transport both in developing and in developed countries due to increasing traffic congestion and environmental concerns. In Europe, it is also seen as a healthy sports activity. However, due to high levels of hazardous pollutants in the present day road microenvironment the cyclist might be at a higher health risk due to higher breathing rate and proximity to the vehicular exhaust. In this paper we present estimates of the exposure of a cyclist to particles of various size fractions including ultrafine particles (UFP) in the town of Mol (Flanders, Belgium). The results indicate relatively higher UFP concentration exposure during morning office hours and moderate UFP levels during afternoon. The major sources of UFP and PM(10) were identified, which are vehicular emission and construction activities, respectively. We also present a dust mapping technique which can be a useful tool for town planners and local policy makers.

Competitor presence reduces internal attentional focus and improves 16.1km cycling time trial performance.

PubMed

Williams, Emily L; Jones, Hollie S; Andy Sparks, S; Marchant, David C; Midgley, Adrian W; Mc Naughton, Lars R

2015-07-01

Whilst the presence of a competitor has been found to improve performance, the mechanisms influencing the change in selected work rates during direct competition have been suggested but not specifically assessed. The aim was to investigate the physiological and psychological influences of a visual avatar competitor during a 16.1-km cycling time trial performance, using trained, competitive cyclists. Randomised cross-over design. Fifteen male cyclists completed four 16.1km cycling time trials on a cycle ergometer, performing two with a visual display of themselves as a simulated avatar (FAM and SELF), one with no visual display (DO), and one with themselves and an opponent as simulated avatars (COMP). Participants were informed the competitive avatar was a similar ability cyclist but it was actually a representation of their fastest previous performance. Increased performance times were evident during COMP (27.8±2.0min) compared to SELF (28.7±1.9min) and DO (28.4±2.3min). Greater power output, speed and heart rate were apparent during COMP trial than SELF (p<0.05) and DO (p≤0.06). There were no differences between SELF and DO. Ratings of perceived exertion were unchanged across all conditions. Internal attentional focus was significantly reduced during COMP trial (p<0.05), suggesting reduced focused on internal sensations during an increase in performance. Competitive cyclists performed significantly faster during a 16.1-km competitive trial than when performing maximally, without a competitor. The improvement in performance was elicited due to a greater external distraction, deterring perceived exertion. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Regional variations in pedal cyclist injuries in New Zealand: safety in numbers or risk in scarcity?

PubMed

Tin, Sandar Tin; Woodward, Alistair; Thornley, Simon; Ameratunga, Shanthi

2011-08-01

To assess regional variations in rates of traffic injuries to pedal cyclists resulting in death or hospital inpatient treatment, in relation to time spent cycling and time spent travelling in a car. Cycling injuries were identified from the Mortality Collection and the National Minimum Dataset. Time spent cycling and time spent travelling as a driver or passenger in a car/van/ute/SUV were computed from National Household Travel Surveys. There are 16 census regions in New Zealand, some of which were combined for this analysis to ensure an adequate sample size, resulting in eight regional groups. Analyses were undertaken for 1996-99 and 2003-07. Injury rates, per million hours spent cycling, varied widely across regions (11 to 33 injuries during 1996-99 and 12 to 78 injuries during 2003-07). The injury rate increased with decreasing per capita time spent cycling. The rate also increased with increasing per capita time spent travelling in a car. There was an inverse association between the injury rate and the ratio of time spent cycling to time spent travelling in a car. The expected number of cycling injuries increased with increasing total time spent cycling but at a decreasing rate particularly after adjusting for total time spent travelling in a car. The findings indicate a 'risk in scarcity' effect for New Zealand cyclists such that risk profiles of cyclists are likely to deteriorate if fewer people use a bicycle and more use a car. Cooperative efforts to promote cycling and its safety and to restrict car use may reverse the risk in scarcity effect. © 2011 The Authors. ANZJPH © 2011 Public Health Association of Australia.

The road most travelled: the geographic distribution of road traffic injuries in England.

PubMed

Steinbach, Rebecca; Edwards, Phil; Grundy, Chris

2013-06-05

Both road safety campaigns and epidemiological research into social differences in road traffic injury risk often assume that road traffic injuries occur close to home. While previous work has examined distance from home to site of collision for child pedestrians in local areas, less is known about the geographic distribution of road traffic injuries from other modes. This study explores the distribution of the distance between home residence and collision site (crash distance) by mode of transport, geographic area, and social characteristics in England. Using 10 years of road casualty data collected by the police, we examined the distribution of crash distance by age, sex, injury severity, area deprivation, urban/rural status, year, day of week, and, in London only, ethnic group. 54% of pedestrians, 39% of cyclists, 17% of powered two-wheeler riders and 16% of car occupants were injured within 1 km of home. 82% of pedestrians, 83% of cyclists, 54% of powered two-wheeler and 53% of car occupants were injured within 5 km of home. We found some social and geographic differences in crash distance: for all transport modes injuries tended to occur closer to home in more deprived or urban areas; younger and older pedestrians and cyclists were also injured closer to home. Crash distance appears to have increased over time for pedestrian, cyclist and car occupant injuries, but has decreased over time for powered two-wheeler injuries. Injuries from all travel modes tend to occur quite close to home, supporting assumptions made in epidemiological and road safety education literature. However, the trend for increasing crash distance and the social differences identified may have methodological implications for future epidemiological studies on social differences in injury risk.

Effect of Endurance Training on The Lactate and Glucose Minimum Intensities

PubMed Central

Junior, Pedro B.; de Andrade, Vitor L.; Campos, Eduardo Z.; Kalva-Filho, Carlos A.; Zagatto, Alessandro M.; de Araújo, Gustavo G.; Papoti, Marcelo

2018-01-01

Due to the controversy about the sensitive of lactate minimum intensity (LMI) to training and the need to develop other tool for aerobic fitness evaluation, the purpose of this study was to analyze the sensitivity of glucose minimum intensity (GMI) and LMI to endurance training. Eight trained male cyclists (21.4 ± 1.9 years, 67.6 ± 7.5 kg and 1.72 ± 0.10 m) were evaluated twice, before and after 12 weeks of training. GMI and LMI were calculated, respectively, by the lowest blood glucose and lactate values attained during an incremental test performed after a hyperlactemia induction, and VO2max was determined during standard incremental effort. The training was prescribed in three different zones and controlled by heart rate (HR). The training distribution was equivalent to 59.7%, 25.0% and 15.3% below, at and above anaerobic threshold HR respectively. The anaerobic threshold evaluated by GMI and LMI improvement 9.89 ± 4.35% and 10.28 ± 9.89 respectively, after training, but the VO2max 2.52 ± 1.81%. No differences were found between GMI and LMI in pre (218.2 ± 22.1 vs 215.0 ± 18.6 W) and post (240.6 ± 22.9 vs 237.5 ± 18.8 W) training situations. LMI and GMI were sensitive to 12-week aerobic training in cyclist; thus, both protocols can be used to assess aerobic adaptation, athletes diagnostic and prescribe training. Key points The lactate and glucose minimum intensities (GMI) can be used for monitoring training effects on cyclists Although both GMI and lactate minimum intensities are important index of aerobic fitness, they cannot be used to determine aerobic fitness. The polarized training was effective for improvements of maximal oxygen uptake on trained cyclists. PMID:29535585

Minute ventilation of cyclists, car and bus passengers: an experimental study.

PubMed

Zuurbier, Moniek; Hoek, Gerard; van den Hazel, Peter; Brunekreef, Bert

2009-10-27

Differences in minute ventilation between cyclists, pedestrians and other commuters influence inhaled doses of air pollution. This study estimates minute ventilation of cyclists, car and bus passengers, as part of a study on health effects of commuters' exposure to air pollutants. Thirty-four participants performed a submaximal test on a bicycle ergometer, during which heart rate and minute ventilation were measured simultaneously at increasing cycling intensity. Individual regression equations were calculated between heart rate and the natural log of minute ventilation. Heart rates were recorded during 280 two hour trips by bicycle, bus and car and were calculated into minute ventilation levels using the individual regression coefficients. Minute ventilation during bicycle rides were on average 2.1 times higher than in the car (individual range from 1.3 to 5.3) and 2.0 times higher than in the bus (individual range from 1.3 to 5.1). The ratio of minute ventilation of cycling compared to travelling by bus or car was higher in women than in men. Substantial differences in regression equations were found between individuals. The use of individual regression equations instead of average regression equations resulted in substantially better predictions of individual minute ventilations. The comparability of the gender-specific overall regression equations linking heart rate and minute ventilation with one previous American study, supports that for studies on the group level overall equations can be used. For estimating individual doses, the use of individual regression coefficients provides more precise data. Minute ventilation levels of cyclists are on average two times higher than of bus and car passengers, consistent with the ratio found in one small previous study of young adults. The study illustrates the importance of inclusion of minute ventilation data in comparing air pollution doses between different modes of transport.

Particulate matter exposure of bicycle path users in a high-altitude city

NASA Astrophysics Data System (ADS)

Fajardo, Oscar A.; Rojas, Nestor Y.

2012-01-01

It is necessary to evaluate cyclists' exposure to particulate matter and if they are at a higher risk due to their increased breathing rate and their exposure to freshly emitted pollutants. The aim of this pilot study was to determine cyclists' exposure to PM 10 in a highly-polluted, high-altitude city such as Bogotá, and comment on the appropriateness of building bicycle paths alongside roads with heavy traffic in third world cities. A total of 29 particulate matter (PM 10) measurements, taken at two sampling sites using Harvard impactors, were used for estimating the exposure of users of the 80th street bicycle path to this pollutant. PM 10 dose could be considered as being high, especially due to high concentrations and cyclists' increased inhalation rates. A random survey was conducted over 73 bicycle path users to determine cyclists' time, distance and speed on the bicycle path on a daily and weekly basis, their level of effort when cycling and general characteristics, such as this population's gender and age. Based on this information, the PM 10 average daily dose (ADD c) for different bicycle path users and the ratio between ADD c and a reference ADD for people at rest exposed to an indoor concentration of 25 μg m -3 were estimated. The average increase in ADD was 6%-9% when riding with light effort and by 12%-18% when riding with moderate effort. The most enthusiastic bicycle path users showed ADD c/ADD r ratios as high as 1.30 when riding with light effort and 1.64 when riding with moderate effort, thereby significantly increasing their PM 10 exposure-associated health risks.

Severe street and mountain bicycling injuries in adults: a comparison of the incidence, risk factors and injury patterns over 14 years

PubMed Central

Roberts, Derek J.; Ouellet, Jean-Francois; Sutherland, Francis R.; Kirkpatrick, Andrew W.; Lall, Rohan N.; Ball, Chad G.

2013-01-01

Background Street and mountain bicycling are popular recreational activities and prevalent modes of transportation with the potential for severe injury. The purpose of this investigation was to compare the incidence, risk factors and injury patterns among adults with severe street versus mountain bicycling injuries. Methods We conducted a retrospective cohort study using the Southern Alberta Trauma Database of all adults who were severely injured (injury severity score [ISS] ≥ 12) while street or mountain bicycling between Apr. 1, 1995, and Mar. 31, 2009. Results Among 11 772 severely injured patients, 258 (2.2%) were injured (mean ISS 17, hospital stay 6 d, mortality 7%) while street (n = 209) or mountain bicycling (n = 49). Street cyclists were often injured after being struck by a motor vehicle, whereas mountain bikers were frequently injured after faulty jump attempts, bike tricks and falls (cliffs, roadsides, embankments). Mountain cyclists were admitted more often on weekends than weekdays (61.2% v. 45.0%, p = 0.040). Injury patterns were similar for both cohorts (all p > 0.05), with trauma to the head (67.4%), extremities (38.4%), chest (34.1%), face (26.0%) and abdomen (10.1%) being common. Spinal injuries, however, were more frequent among mountain cyclists (65.3% v. 41.1%, p = 0.003). Surgical intervention was required in 33.3% of patients (9.7% open reduction internal fixation, 7.8% spinal fixation, 7.0% craniotomy, 5.8% facial repair and 2.7% laparotomy). Conclusion With the exception of spine injuries, severely injured cyclists display similar patterns of injury and comparable outcomes, regardless of style (street v. mountain). Helmets and thoracic protection should be advocated for injury prevention. PMID:23706856

Is the Functional Threshold Power (FTP) a Valid Surrogate of the Lactate Threshold?

PubMed

Valenzuela, Pedro L; Morales, Javier S; Foster, Carl; Lucia, Alejandro; de la Villa, Pedro

2018-05-10

This study aimed to analyze the relationship between the Functional Threshold Power (FTP) and the Lactate Threshold (LT). 20 male cyclists performed an incremental test in which the LT was determined. At least 48 h later, they performed a 20-minute time trial and 95% of the mean power output (P20) was defined as FTP. Participants were divided into recreational (Peak Power Output [PPO] < 4.5 W∙kg -1 , n=11) or trained cyclists (PPO > 4.5 W∙kg -1 , n=9) according to their fitness status. The FTP (240 ± 35 W) was overall not significantly different (effect size[ES]=0.20, limits of agreement [LoA]=-2.4 ± 11.5%) from the LT (246 ± 24 W), and both markers were strongly correlated (r=0.95, p<0.0001). Accounting for the participants' fitness status, no significant differences were found between FTP and LT ([ES]=0.22; LoA=2.1 ± 7.8%) in TC, but FTP was significantly lower than the LT (p=0.0004, ES=0.81; LoA=-6.5 ± 8.3%) in RC. A significant relationship was found between relative PPO and the bias between FTP and the LT markers (r=0.77, p<0.0001). The FTP is a valid field test-based marker for the assessment of endurance fitness. However, caution should be taken when using the FTP interchangeably with the LT as the bias between markers seems to depend on the athletes' fitness status. Whereas the FTP provides a good estimate of the LT in trained cyclists, in recreational cyclists FTP may underestimate LT.

Renal function and plasma volume following ultramarathon cycling.

PubMed

Neumayr, G; Pfister, R; Hoertnagl, H; Mitterbauer, G; Prokop, W; Joannidis, M

2005-01-01

In recreational cyclists marathon cycling influences renal function only on a minimal scale. Respective information on extreme ultramarathon cycling in better trained athletes is not available. The objective was to evaluate the renal and haematological effects of ultraendurance cycling in the world's best ultramarathon cyclists. Creatinine (CR), urea, haemoglobin (Hb), haematocrit (Hct) and plasma volume (PV) were investigated in 16 male ultramarathon cyclists during the 1st Race Across the Alps in 2001 (distance: 525 km; cumulative altitude difference: 12,600 m). All renal functional parameters were normal pre-exercise. During the race serum CR, urea and uric acid rose significantly by 33, 97 % and 18 % (p <0.001 respectively) and nearly normalised again on the following day. The decline in calculated CR clearance was 25 %. There was a negative correlation (r=- 0.575, p=0.02) between the rise in serum CR and the athlete's training kilometers. The serum urea/CR ratio rose above 40 in 12 athletes (75 %). Mean fractional sodium excretion and fractional uric acid excretion fell below 0.5 % (p <0.001) and 7 %, indicating reduced renal perfusion. The deflection of the renal functional parameters was temporary and nearly gone after 24 hours of recovery. Hct declined during the race from 0.44 to 0.42, and continued falling on the next day (0.42 --> 0.40; p <0.001). The corresponding rises in calculated PV were + 8 % and + 22 %. The study affirms that in world class cyclists the enormous strains of ultramarathon cycling influence renal function only on a minimal scale. The impact on the PV, however, is pronounced leading to marked haemodilution post-exercise. This very temporary "impairment of renal function" seems to be the physiological response to ultramarathon cycling and may be attenuated to some extent by preceding high-volume training.

Improvement of Performance and Reduction of Fatigue With Low-Level Laser Therapy in Competitive Cyclists.

PubMed

Lanferdini, Fábio J; Bini, Rodrigo R; Baroni, Bruno M; Klein, Kelli D; Carpes, Felipe P; Vaz, Marco A

2018-01-01

Evidence indicates that low-level laser therapy (LLLT) minimizes fatigue effects on muscle performance. However, the ideal LLLT dosage to improve athletes'performance during sports activities such as cycling is still unclear. Therefore, the goal of this study was to investigate the effects of different LLLT dosages on cyclists'performance in time-to-exhaustion tests. In addition, the effects of LLLT on the frequency content of the EMG signals to assess fatigue mechanisms were examined. Twenty male competitive cyclists participated in a crossover, randomized, double-blind, placebo-controlled trial. They performed an incremental cycling test to exhaustion (on day 1) followed by 4 time-to-exhaustion tests (on days 2-5) at their individual maximal power output. Before each time-to-exhaustion test, different dosages of LLLT (135, 270, and 405 J/thigh, respectively) or placebo were applied at the quadriceps muscle bilaterally. Power output and muscle activation from both lower limbs were recorded throughout the tests. Increased performance in time-to-exhaustion tests was observed with the LLLT-135 J (∼22 s; P < .01), LLLT-270 J (∼13 s; P = .03), and LLLT-405 J (∼13 s; P = .02) compared to placebo (149 ± 23 s). Although LLLT-270 J and LLLT-405 J did not show significant differences in muscle activation compared with placebo, LLLT-135 J led to an increased high-frequency content compared with placebo in both limbs at the end of the exhaustion test (P ≤ .03). In conclusion, LLLT increased time to exhaustion in competitive cyclists, suggesting this intervention as a possible nonpharmacological ergogenic agent in cycling. Among the different dosages, LLLT-135 J seems to promote the best effects.

Reliability of sprint test indices in well-trained cyclists.

PubMed

Coleman, D A; Wiles, J D; Nunn, M; Smith, M F

2005-06-01

The study aim was to assess reliability of repeated laboratory sprint tests in well-trained endurance cyclists. Eleven male cyclists (mean +/- standard deviation: 27 +/- 6 yr, 1.79 +/- 0.04 m, 70.1 +/- 3.3 kg) performed a maximal 30-second sprint test on four separate occasions using their own bicycle fitted with an SRM powermeter on a Kingcycle air-braked ergometer. Peak power output (W (peak)), mean power (W (mean)) and an index of fatigue (FI) were calculated. Three minutes post sprint, capillarised blood lactate measurements were taken and analysed. No significant differences (p > 0.05) were found between trials for W (peak), W (mean), FI and blood lactate concentration. Repeatability of W (peak), W (mean), and fatigue index improved across trials 2 and 3 when compared to trials 1 and 2. The highest CV for these variables was recorded between trials 3 and 4. The CV for W (peak) was 4.5 +/- 1.6 %, W (mean) 2.4 +/- 1.2 %, and FI 17.2 +/- 7.1 %. Intraclass reliability coefficients were 0.93 (95 % CI 0.84 - 0.98), 0.94 (95 % CI 0.86 - 0.98) and 0.89 (95 % CI 0.69 - 0.95) respectively. Blood lactate concentration ranged between 5.35 and 14.52 mmol.l(-1), with a mean CV of 12.1 +/- 4.2 %. The CV for trials 2 and 3 revealed the highest CV for blood lactate concentration (15.1 %). The lowest CV for this variable (10.2 %) was recorded between trials 3 and 4. The intraclass reliability coefficient for blood lactate concentration was 0.79 (95 % CI 0.58 - 0.93). The results of this study indicate that there is no improvement in the reliability of sprint test indices when assessing well-trained, experienced cyclists, riding on their own cycle equipment.

Characteristics of single-vehicle crashes with e-bikes in Switzerland.

PubMed

Hertach, Patrizia; Uhr, Andrea; Niemann, Steffen; Cavegn, Mario

2018-08-01

In Switzerland, the usage and accident numbers of e-bikes have strongly increased in recent years. According to official statistics, single-vehicle accidents constitute an important crash type. Up to date, very little is known about the mechanisms and causes of these crashes. To gain more insight, a survey was conducted among 3658 e-cyclists in 2016. The crash risk and injury severity were analysed using logistic regression models. 638 (17%) e-cyclists had experienced a single-vehicle accident in road traffic since the beginning of their e-bike use. Risk factors were high riding exposure, male sex, and using the e-bike mainly for the purpose of getting to work or school. There was no effect of age on the crash risk. Skidding, falling while crossing a threshold, getting into or skidding on a tram/railway track and evasive actions were the most important accident mechanisms. The crash causes mentioned most often were a slippery road surface, riding too fast for the situation and inability to keep the balance. Women, elderly people, riders of e-bikes with a pedal support up to 45 km/h and e-cyclists who considered themselves to be less fit in comparison to people of the same age had an increased risk of injury. This study confirms the high relevance of single-vehicle crashes with e-bikes. Measures to prevent this type of accident could include the sensitisation of e-cyclists regarding the most common accident mechanisms and causes, a regular maintenance of bicycle pathways, improvements regarding tram and railway tracks and technological advancements of e-bikes. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Using data mining techniques to predict the severity of bicycle crashes.

PubMed

Prati, Gabriele; Pietrantoni, Luca; Fraboni, Federico

2017-04-01

To investigate the factors predicting severity of bicycle crashes in Italy, we used an observational study of official statistics. We applied two of the most widely used data mining techniques, CHAID decision tree technique and Bayesian network analysis. We used data provided by the Italian National Institute of Statistics on road crashes that occurred on the Italian road network during the period ranging from 2011 to 2013. In the present study, the dataset contains information about road crashes occurred on the Italian road network during the period ranging from 2011 to 2013. We extracted 49,621 road accidents where at least one cyclist was injured or killed from the original database that comprised a total of 575,093 road accidents. CHAID decision tree technique was employed to establish the relationship between severity of bicycle crashes and factors related to crash characteristics (type of collision and opponent vehicle), infrastructure characteristics (type of carriageway, road type, road signage, pavement type, and type of road segment), cyclists (gender and age), and environmental factors (time of the day, day of the week, month, pavement condition, and weather). CHAID analysis revealed that the most important predictors were, in decreasing order of importance, road type (0.30), crash type (0.24), age of cyclist (0.19), road signage (0.08), gender of cyclist (0.07), type of opponent vehicle (0.05), month (0.04), and type of road segment (0.02). These eight most important predictors of the severity of bicycle crashes were included as predictors of the target (i.e., severity of bicycle crashes) in Bayesian network analysis. Bayesian network analysis identified crash type (0.31), road type (0.19), and type of opponent vehicle (0.18) as the most important predictors of severity of bicycle crashes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cycling on rollers: influence of tyre pressure and cross section on power requirements.

PubMed

Reiser, Raoul; Watt, Jon; Peterson, Michael

2003-07-01

The resistance against a cyclist while riding on rollers is due mainly to rolling resistance produced by the deformation of the tyre as it rolls against small diameter drums. Resistance is then combined with wheel speed to set power output. The effect of tyre pressure and cross-section on power was investigated by systematically altering the pressure (552 kPa, 690 kPa, and 827 KPa) in a 20c, 23c, 25c, and 28c tyre of the same design while riding at a wheel speed of 45 kph. Average power over 1 minute was measured with a Power Tap Hub (Tune Corporation, Cambridge, Massachusetts, USA) on five occasions. Statistical significance was evaluated at p < 0.05. Power requirements increased significantly with each reduction in tyre pressure for all tyres and pressures except the 25c between 690 and 827 kPa. The 20c tyre required significantly more power from the cyclist at each tested tyre pressure when compared to the other tyres (which were not different from each other). The differences in resistance from tyre size were not observed when ridden on the road. Additionally, a slightly different tyre design from the same manufacturer responded similarly in the 20c, but was significantly different in the 23c size. It was also observed that power requirements increased significantly when both the wheels were ridden on the rollers as compared to just the rear wheel. These results indicate that the power requirements may be significantly altered by the cyclist by adjusting tyre pressure, tyre cross-section size, tyre type, and with the number of wheels contacting the rollers. However, the magnitude of these power requirements may not be suitable for intense workouts of trained cyclists.

The generalized force-velocity relationship explains why the preferred pedaling rate of cyclists exceeds the most efficient one.

PubMed

Kohler, Götz; Boutellier, Urs

2005-05-01

The most efficient pedaling rate (lowest oxygen consumption) at a workload of 50-300 W has been reported to be in the range of 42-60 rpm. By contrast, most competitive cyclists prefer a pedaling rate of more than 90 rpm. The reason for this difference is still unknown. We assume that the high pedaling rate preferred by cyclists can be explained by the inherent properties of muscle fibers. To obtain statements which do not depend on muscle's cross-section and length, we generalized Hill's characteristic equations where muscle force and heat liberation are related to shortening velocity. A pedaling rate of f (etamax) yields to maximal efficiency, whereas the higher pedaling rate f (Pmax) leads to maximal power. The ratio f (Pmax)/f (etamax) between these two pedaling rates ranges from 1.7 to 2.4, and it depends on the muscle's fiber-type composition. In sprints and competitions of very short duration, f (Pmax) is more advantageous because energy supply is not the predominant limiting factor. The price to be paid for the most powerful pedaling rate is lower efficiency and higher energy cost. In longer exercises, economy is more important and the optimal pedaling rate shifts toward f (etamax). We conclude that the optimal pedaling rate, representing the fastest race performance, is not fixed but depends on race duration; it ranges between f (etamax) and f (Pmax). Our results are not only of interest for competitive cyclists but also for investigations using cycle ergometers: maximum power might not be reached by using a pedaling rate near the most efficient one.

Severe street and mountain bicycling injuries in adults: a comparison of the incidence, risk factors and injury patterns over 14 years.

PubMed

Roberts, Derek J; Ouellet, Jean-Francois; Sutherland, Francis R; Kirkpatrick, Andrew W; Lall, Rohan N; Ball, Chad G

2013-06-01

Street and mountain bicycling are popular recreational activities and prevalent modes of transportation with the potential for severe injury. The purpose of this investigation was to compare the incidence, risk factors and injury patterns among adults with severe street versus mountain bicycling injuries. We conducted a retrospective cohort study using the Southern Alberta Trauma Database of all adults who were severely injured (injury severity score [ISS] ≥ 12) while street or mountain bicycling between Apr. 1, 1995, and Mar. 31, 2009. Among 11 772 severely injured patients, 258 (2.2%) were injured (mean ISS 17, hospital stay 6 d, mortality 7%) while street (n = 209) or mountain bicycling (n = 49). Street cyclists were often injured after being struck by a motor vehicle, whereas mountain bikers were frequently injured after faulty jump attempts, bike tricks and falls (cliffs, roadsides, embankments). Mountain cyclists were admitted more often on weekends than weekdays (61.2% v. 45.0%, p = 0.040). Injury patterns were similar for both cohorts (all p > 0.05), with trauma to the head (67.4%), extremities (38.4%), chest (34.1%), face (26.0%) and abdomen (10.1%) being common. Spinal injuries, however, were more frequent among mountain cyclists (65.3% v. 41.1%, p = 0.003). Surgical intervention was required in 33.3% of patients (9.7% open reduction internal fixation, 7.8% spinal fixation, 7.0% craniotomy, 5.8% facial repair and 2.7% laparotomy). With the exception of spine injuries, severely injured cyclists display similar patterns of injury and comparable outcomes, regardless of style (street v. mountain). Helmets and thoracic protection should be advocated for injury prevention.

The electrocardiogram of athletes Comparison with untrained subjects1

PubMed Central

Van Ganse, W.; Versee, L.; Eylenbosch, W.; Vuylsteek, K.

1970-01-01

The resting electrocardiograms of 30 cyclists currently involved in competitive sport were compared with those of an equal number of healthy controls matched for age, height, and weight. The cyclists had significantly lower heart rates, longer PQ,QRS, and QTc intervals, higher T waves in lead II, left axis deviation of the T wave, higher R waves in the right and deeper S waves in the left praecordial leads, and deeper S waves in the right and higher R waves in the left praecordial leads. The possible significance of these findings should be assessed by prolonged prospective studies in athletes and untrained control subjects. PMID:4245411

Bicycle Use and Cyclist Safety Following Boston’s Bicycle Infrastructure Expansion, 2009–2012

PubMed Central

Angriman, Federico; Bellows, Alexandra L.; Taylor, Kathryn

2016-01-01

Objectives. To evaluate changes in bicycle use and cyclist safety in Boston, Massachusetts, following the rapid expansion of its bicycle infrastructure between 2007 and 2014. Methods. We measured bicycle lane mileage, a surrogate for bicycle infrastructure expansion, and quantified total estimated number of commuters. In addition, we calculated the number of reported bicycle accidents from 2009 to 2012. Bicycle accident and injury trends over time were assessed via generalized linear models. Multivariable logistic regression was used to examine factors associated with bicycle injuries. Results. Boston increased its total bicycle lane mileage from 0.034 miles in 2007 to 92.2 miles in 2014 (P < .001). The percentage of bicycle commuters increased from 0.9% in 2005 to 2.4% in 2014 (P = .002) and the total percentage of bicycle accidents involving injuries diminished significantly, from 82.7% in 2009 to 74.6% in 2012. The multivariable logistic regression analysis showed that for every 1-year increase in time from 2009 to 2012, there was a 14% reduction in the odds of being injured in an accident. Conclusions. The expansion of Boston’s bicycle infrastructure was associated with increases in both bicycle use and cyclist safety. PMID:27736203

Esophageal reflux in conditioned runners, cyclists, and weightlifters.

PubMed

Collings, Kimberly L; Pierce Pratt, F; Rodriguez-Stanley, Sheila; Bemben, Michael; Miner, Philip B

2003-05-01

Gastroesophageal reflux disease is a disorder in which gastric contents move from stomach to esophagus. Exercise is a recognized contributing factor to reflux in healthy volunteers and is reported to be proportional to exercise intensity and the type of exercise. Our aim was to explore changes in physiology occurring in conditioned runners, cyclists, and weightlifters. Ten subjects from each sport with >3-month history of exercise-induced heartburn were enrolled. Subjects underwent evaluation of fasting and fed esophageal pH, heart rate, GI symptom, and perceived exertion during standardized exercise routines at 65% (60 min) and 85% (20 min) of their maximal capabilities. Weightlifters experienced the most heartburn and reflux: 18.51 +/- 17.34% time esophageal pH

Prevention of bicycle accidents.

PubMed

Simpson, A H; Mineiro, J

1992-01-01

To elucidate the way of reducing the number of bicycle accidents. A prospective study of all casualties from bicycle accidents attending an accident unit for a 29-month period was performed (1831 patients). A more detailed questionnaire on the causes of accidents was used for the last 12 months of the study (818 patients). In the 0-7 and 8-12 years age groups, 87.5 per cent and 66.2 per cent, respectively, were due to cyclist error. The 8-12-year-old cyclists were twice as likely to have caused the accident if they had not had formal training (risk ratio = 2.0). Over the age of 18 years, 41.4 per cent were due to another road user. A motor vehicle was involved in 633 of the 1831 accidents. Children under the age of 8 years should not be allowed on public roads. Older children should only be allowed on the roads after formal training. This should become part of the school curriculum. A campaign to increase the awareness of motorists would be expected to reduce the number of cycle accidents. It would be beneficial to dedicate more roads and tracks to cycle use. Cyclists should be encouraged to wear more protective gear.

Increasing bicycle helmet use in the community. Measuring response to a wide-scale, 2-year effort.

PubMed

Morris, B A; Trimble, N E; Fendley, S J

1994-06-01

To determine whether a wide-scale, long-term community promotional effort would increase the use of bicycle helmets among children. Over 2 years, a non-profit group coordinated a range of activities to promote helmet use. On one date before the intervention began and three dates during the intervention, observers surveyed students riding bicycles. Cyclists were observed at 5 elementary schools, three secondary schools, and two community college entrances. A total of 851 cyclists were observed, 536 of them at elementary schools in a convenience sample. Print, radio, and television advertising; posters; pamphlets; bicycle rodeos; and a play were used in a public awareness campaign. Health promotion activities included education, social marketing, community development, and legislative action. Number of cyclists and whether they wore helmets. Combining the two observation dates for each year, helmet use increased from 5.4% in 1990 to 15.4% in 1991. The greatest increase was observed among elementary school students, the group most at risk of serious head injury or death. Overall, girls were twice as likely to wear helmets as boys. Wide-scale, long-term community promotion appears to be effective in increasing the use of bicycle helmets.

Protein intake during training sessions has no effect on performance and recovery during a strenuous training camp for elite cyclists.

PubMed

Hansen, Mette; Bangsbo, Jens; Jensen, Jørgen; Krause-Jensen, Matilde; Bibby, Bo Martin; Sollie, Ove; Hall, Ulrika Andersson; Madsen, Klavs

2016-01-01

Training camps for top-class endurance athletes place high physiological demands on the body. Focus on optimizing recovery between training sessions is necessary to minimize the risk of injuries and improve adaptations to the training stimuli. Carbohydrate supplementation during sessions is generally accepted as being beneficial to aid performance and recovery, whereas the effect of protein supplementation and timing is less well understood. We studied the effects of protein ingestion during training sessions on performance and recovery of elite cyclists during a strenuous training camp. In a randomized, double-blinded study, 18 elite cyclists consumed either a whey protein hydrolysate-carbohydrate beverage (PRO-CHO, 14 g protein/h and 69 g CHO/h) or an isocaloric carbohydrate beverage (CHO, 84 g/h) during each training session for six days (25-29 h cycling in total). Diet and training were standardized and supervised. The diet was energy balanced and contained 1.7 g protein/kg/day. A 10-s peak power test and a 5-min all-out performance test were conducted before and after the first training session and repeated at day 6 of the camp. Blood and saliva samples were collected in the morning after overnight fasting during the week and analyzed for biochemical markers of muscle damage, stress, and immune function. In both groups, 5-min all-out performance was reduced after the first training session and at day 6 compared to before the first training session, with no difference between groups. Peak power in the sprint test did not change significantly between tests or between groups. In addition, changes in markers for muscle damage, stress, and immune function were not significantly influenced by treatment. Intake of protein combined with carbohydrate during cycling at a training camp for top cyclists did not result in marked performance benefits compared to intake of carbohydrates when a recovery drink containing adequate protein and carbohydrate was ingested immediately after each training session in both groups. These findings suggest that the addition of protein to a carbohydrate supplement consumed during exercise does not improve recovery or performance in elite cyclists despite high demands of daily exhaustive sessions during a one-week training camp.

One night of partial sleep deprivation impairs recovery from a single exercise training session.

PubMed

Rae, Dale E; Chin, Tayla; Dikgomo, Kagiso; Hill, Lee; McKune, Andrew J; Kohn, Tertius A; Roden, Laura C

2017-04-01

The effects of sleep deprivation on physical performance are well documented, but data on the consequence of sleep deprivation on recovery from exercise are limited. The aim was to compare cyclists' recovery from a single bout of high-intensity interval training (HIIT) after which they were given either a normal night of sleep (CON, 7.56 ± 0.63 h) or half of their usual time in bed (DEP, 3.83 ± 0.33 h). In this randomized cross-over intervention study, 16 trained male cyclists (age 32 ± 7 years), relative peak power output (PPO 4.6 ± 0.7 W kg -1 ) performed a HIIT session at ±18:00 followed by either the CON or DEP sleep condition. Recovery from the HIIT session was assessed the following day by comparing pre-HIIT variables to those measured 12 and 24 h after the session. Following a 2-week washout, cyclists repeated the trial, but under the alternate sleep condition. PPO was reduced more 24 h after the HIIT session in the DEP (ΔPPO -0.22 ± 0.22 W kg -1 ; range -0.75 to 0.1 W kg -1 ) compared to the CON condition (ΔPPO -0.05 ± 0.09 W kg -1 , range -0.19 to 0.17 W kg -1 , p = 0.008, d = -2.16). Cyclists were sleepier (12 h: p = 0.002, d = 1.90; 24 h: p = 0.001, d = 1.41) and felt less motivated to train (12 h, p = 0.012, d = -0.89) during the 24 h recovery phase when the HIIT session was followed by the DEP condition. The exercise-induced 24 h reduction in systolic blood pressure observed in the CON condition was absent in the DEP condition (p = 0.039, d = 0.75). One night of partial sleep deprivation impairs recovery from a single HIIT session in cyclists. Further research is needed to understand the mechanisms behind this observation.

Effectiveness of two interventions in preventing traffic accidents: a systematic review.

PubMed

Porchia, B R; Baldasseroni, A; Dellisanti, C; Lorini, C; Bonaccorsi, G

2014-01-01

The prevention of road traffic accidents should be considered a serious public health concern, since they are the eighth leading cause of death globally and the main cause of death for young people aged 15-29. Evidences from many countries show that successes in preventing road traffic injuries can be achieved through concerted efforts at national level. The aim of our study was to assess the effectiveness of two interventions to prevent road traffic accidents: the introduction of graduated driver licensing (GDL) and the interventions to improve pedestrian and cyclist visibility. Our search started with a scoping review on the interventions to prevent road traffic accidents to allow the development of a logical framework of traffic accidents. Specific and answerable questions formulated according to PICO scheme and combinations of keywords were used to perform a systematic search in the following databases: Pubmed, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects (DARE), Health Evidence, Transport Research International Documentation (TRID) and Google. References of selected papers were searched. Only systematic reviews and meta-analyses were eligible. No temporal limits or linguistic filters were applied. 160 systematic reviews and meta-analyses were found for the question of the introduction of GDL program and 188 on the improvement of visibility in cyclists and pedestrians. After selection, four papers were included in qualitative synthesis for each question. All included studies underwent quality evaluation. GDL programs seem to be effective in reducing crash rates among young drivers, in particular in 16 year-old. Programs with more restrictions seem also to reduce fatal events. To improve visibility of pedestrians and cyclists, street lighting has been suggested as an intervention able to improve driver's visual capabilities and ability to detect roadway hazards and to prevent car crashes. Visibility aids (fluorescent materials, lamps, flashing lights and retroreflective materials) have the potential to increase visibility and enable drivers to detect pedestrians and cyclists earlier. The two interventions seem to be effective, but further examinations are needed to measure long-term effects. It is necessary to provide feasible studies in local context to estimate the impact of introduction of GDL programs or of some of their components and to improve interventions to increase visibility of pedestrians and cyclists.

Injury incidence rates of cyclists compared to pedestrians, car occupants and powered two-wheeler riders, using a medical registry and mobility data, Rhône County, France.

PubMed

Blaizot, Stéphanie; Papon, Francis; Haddak, Mohamed Mouloud; Amoros, Emmanuelle

2013-09-01

In France, the bicycle's modal share is stabilizing after a decline; in some of France's major cities, it has even increased since the 1990s. It is hence relevant to improve the knowledge of the injury risk associated with cycling, compared with other means of transport such as car, walking and powered two-wheeler (PTW) riding. The injury incidence rates were estimated by the ratio between accident data and mobility (exposure) data. Two accident data sources were used: police data and hospital-based data (outpatients and inpatients) from the Rhône road trauma Registry. This provides four injury categories: all-injury, hospitalization, serious-injury and fatal-injury. Exposure data were estimated from a regional household travel survey (RTS), using three measures of mobility: number of trips, distance traveled and time spent traveling. The survey was carried out from November 2005 to April 2006, on weekdays, outside school and public holidays; this seasonality was corrected using the 2007-2008 national household travel survey (NTS) that covered an entire year. Only information involving accidents and trips in, and residents of, the Rhône County (1.6 million inhabitants, including the city Lyon) were included in our study. Trends of injury rates were also evaluated in Greater Lyon, using previous travel surveys. The PTW riders had the highest all-injury, hospitalization, serious-injury and fatal-injury rates, followed by cyclists, and lastly by pedestrians and car occupants. The rates between men and women seemed similar among pedestrians and among car occupants. For car occupants, pedestrians and cyclists, the age group 18-25 years had higher all-injury rate compared with the age group 25-65 years. On the contrary, the age group≥65 years seemed to have higher hospitalization and serious-injury rates, compared with the age group 25-65 years. For cyclists, the injury rates seemed higher in non-dense areas than in dense areas. Between 1996-1997 and 2005-2006 and with regards to time spent traveling, the all-injury, serious-injury and fatal-injury rates seemed to have decreased for car occupants and cyclists. The higher risk for PTW riders is confirmed and quantified; it is very high. Decrease in injury rates seems more marked for cyclists; this may indicate the "safety in numbers" effect. Countermeasures for improving road safety could be implemented, especially for vulnerable road user types. However, they will not be sufficient to fill in the gap between the much higher risk for PTW riders and that of car occupants. Exposure-based injury rates can be a tool for monitoring and evaluating the effectiveness of policies and programs, and for comparisons between countries. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cyclists' attitudes toward policies encouraging bicycle travel: findings from the Taupo Bicycle Study in New Zealand.

PubMed

Tin Tin, Sandar; Woodward, Alistair; Thornley, Simon; Langley, John; Rodgers, Anthony; Ameratunga, Shanthi

2010-03-01

Utility cycling provides substantial health, environmental and economic benefits. Despite a favourable trend in leisure-time cycling, cycling is infrequently used for everyday travel needs in New Zealand. This study investigated cyclists' attitudes toward environmental and policy measures that would encourage them to cycle more, particularly for a trip to work. A cross-sectional analysis was undertaken using baseline data obtained from the Taupo Bicycle Study, a web-based longitudinal study. The study population comprised 2469 cyclists, aged 16 years or over, who had enrolled in the 2006 Wattyl Lake Taupo Cycle Challenge. The majority (88%) reported the provision of bicycle lanes as an important factor that would encourage them to cycle more often, followed by bicycle paths (76%), better bicycle security (64%), reduced motor vehicle speed (55%) and bike friendly public transport (38%). Of those who reported travelling to work at least once a week (N = 2223), varying proportions reported shower facilities at work (61%), fewer difficult intersections (43%), rising fuel costs (41%), fewer car parks (27%), bike designed to commute (26%) and rising cost of car parking (25%) as important factors that would encourage them to cycle to work more often. There were important differences in these perceived influences defined by the participants' socio-demographic characteristics and current cycling habits.

Full suspension mountain bike improves off-road cycling performance.

PubMed

Nishii, T; Umemura, Y; Kitagawa, K

2004-12-01

The purpose of the present study was to determine the effects of suspension systems on the cycling performance of cyclists during off-road bicycling. Eight elite male cyclists (67.8+/-5.8 ml/min/kg of (.-)VO(2max)) performed 30-minute riding tests on bicycles with 2 different suspension setups: front suspension (FS) and front and rear suspension (FRS). Heart rate, blood lactate concentration, pedaling power, cadence, cycling velocity, and completed distance during the trial were measured creatin kinase (CK), lactic dehydrogenase (LDH) and glutamic-oxaloacetic transaminase (GOT) were measured before and after the trials. The average cadence during the trial was significantly higher (p<0.05) with the FRS (73.6+/-6.1 rpm) than the FS (70.2+/-6.2 rpm). Subjects rode significantly faster (p<0.05) on FRS (24.1+/-2.6 km/h) than FS bikes (22.9+/-2.4 km/h), although no significant difference was observed in pedaling power (240.7+/-26.6 W vs 242.2+/-28.8 W, FS vs FRS, respectively). Serum creatin kinase increased significantly (p<0.05) at 24 h after the trial when cyclists exercised with the FS bike. We conclude that the FRS improved cycling performance over rough terrain. FRS might therefore be more suitable for cross-country mountain bike races.

A health impact assessment of a proposed bill to decrease speed limits on local roads in Massachusetts (U.S.A.).

PubMed

James, Peter; Ito, Kate; Banay, Rachel F; Buonocore, Jonathan J; Wood, Benjamin; Arcaya, Mariana C

2014-10-02

Decreasing traffic speeds increases the amount of time drivers have to react to road hazards, potentially averting collisions, and makes crashes that do happen less severe. Boston's regional planning agency, the Metropolitan Area Planning Council (MAPC), in partnership with the Massachusetts Department of Public Health (MDPH), conducted a Health Impact Assessment (HIA) that examined the potential health impacts of a proposed bill in the state legislature to lower the default speed limits on local roads from 30 miles per hour (mph) to 25 mph. The aim was to reduce vehicle speeds on local roads to a limit that is safer for pedestrians, cyclists, and children. The passage of this proposed legislation could have had far-reaching and potentially important public health impacts. Lower default speed limits may prevent around 18 fatalities and 1200 serious injuries to motorists, cyclists and pedestrians each year, as well as promote active transportation by making local roads feel more hospitable to cyclists and pedestrians. While a lower speed limit would increase congestion and slightly worsen air quality, the benefits outweigh the costs from both a health and economic perspective and would save the state approximately $62 million annually from prevented fatalities and injuries.

A Health Impact Assessment of a Proposed Bill to Decrease Speed Limits on Local Roads in Massachusetts (U.S.A.)

PubMed Central

James, Peter; Ito, Kate; Banay, Rachel F.; Buonocore, Jonathan J.; Wood, Benjamin; Arcaya, Mariana C.

2014-01-01

Decreasing traffic speeds increases the amount of time drivers have to react to road hazards, potentially averting collisions, and makes crashes that do happen less severe. Boston’s regional planning agency, the Metropolitan Area Planning Council (MAPC), in partnership with the Massachusetts Department of Public Health (MDPH), conducted a Health Impact Assessment (HIA) that examined the potential health impacts of a proposed bill in the state legislature to lower the default speed limits on local roads from 30 miles per hour (mph) to 25 mph. The aim was to reduce vehicle speeds on local roads to a limit that is safer for pedestrians, cyclists, and children. The passage of this proposed legislation could have had far-reaching and potentially important public health impacts. Lower default speed limits may prevent around 18 fatalities and 1200 serious injuries to motorists, cyclists and pedestrians each year, as well as promote active transportation by making local roads feel more hospitable to cyclists and pedestrians. While a lower speed limit would increase congestion and slightly worsen air quality, the benefits outweigh the costs from both a health and economic perspective and would save the state approximately $62 million annually from prevented fatalities and injuries. PMID:25279544

A new crank arm based load cell, with built-in conditioning circuit and strain gages, to measure the components of the force applied by a cyclist.

PubMed

Pigatto, Andre V; Moura, Karina O A; Favieiro, Gabriela W; Balbinot, Alexandre

2016-08-01

This report describes the development of a force platform based on instrumented load cells with built-in conditioning circuit and strain gages to measure and acquire the components of the force that is applied to the bike crank arm during pedaling in real conditions, and save them on a SD Card. To accomplish that, a complete new crank arm 3D solid model was developed in the SolidWorks, with dimensions equivalent to a commercial crank set and compatible with a conventional road bike, but with a compartment to support all the electronics necessary to measure 3 components of the force applied to the pedal during pedaling. After that, a 6082 T6 Aluminum Crankset based on the solid model was made and instrumented with three Wheatstone bridges each. The signals were conditioned on a printed circuit board, made on SMD technology, and acquired using a microcontroller with a DAC. Static deformation analysis showed a linearity error below 0.6% for all six channels. Dynamic analysis showed a natural frequency above 136Hz. A one-factor experiment design was performed with 5 amateur cyclists. ANOVA showed that the cyclist weight causes significant variation on the force applied to the bicycle pedal and its bilateral symmetry.

Road crossing behavior under traffic light conflict: Modulating effects of green light duration and signal congruency.

PubMed

Lange, Florian; Haiduk, Michael; Boos, Moritz; Tinschert, Peter; Schwarze, Anke; Eggert, Frank

2016-10-01

A large number of pedestrians and cyclists regularly ignore the traffic lights to cross the road illegally. In a recent analysis, illegal road crossing behavior has been shown to be enhanced in the presence of incongruent stimulus configurations. Pedestrians and cyclists are more likely to cross against a red light when exposed to an irrelevant conflicting green light. Here, we present experimental and observational data on the factors moderating the risk associated with incongruent traffic lights. In an observational study, we demonstrated that the conflict-related increase in illegal crossing rates is reduced when pedestrian and cyclist green light periods are long. In a laboratory experiment, we manipulated the color of the irrelevant signals to expose participants to different degrees of incongruency. Results revealed that individuals' performance gradually varied as a function of incongruency, suggesting that the negative impact of a conflicting green light can be reduced by slightly adjusting its color. Our findings highlight that the observation of real-world behavior at intersections and the experimental analysis of psychological processes under controlled laboratory conditions can complement each other in identifying risk factors of risky road crossing behavior. Based on this combination, our study elaborates on promising measures to improve safety at signalized intersections. Copyright © 2016 Elsevier Ltd. All rights reserved.

Power output measurement during treadmill cycling.

PubMed

Coleman, D A; Wiles, J D; Davison, R C R; Smith, M F; Swaine, I L

2007-06-01

The study aim was to consider the use of a motorised treadmill as a cycling ergometry system by assessing predicted and recorded power output values during treadmill cycling. Fourteen male cyclists completed repeated cycling trials on a motorised treadmill whilst riding their own bicycle fitted with a mobile ergometer. The speed, gradient and loading via an external pulley system were recorded during 20-s constant speed trials and used to estimate power output with an assumption about the contribution of rolling resistance. These values were then compared with mobile ergometer measurements. To assess the reliability of measured power output values, four repeated trials were conducted on each cyclist. During level cycling, the recorded power output was 257.2 +/- 99.3 W compared to the predicted power output of 258.2 +/- 99.9 W (p > 0.05). For graded cycling, there was no significant difference between measured and predicted power output, 268.8 +/- 109.8 W vs. 270.1 +/- 111.7 W, p > 0.05, SEE 1.2 %. The coefficient of variation for mobile ergometer power output measurements during repeated trials ranged from 1.5 % (95 % CI 1.2 - 2.0 %) to 1.8 % (95 % CI 1.5 - 2.4 %). These results indicate that treadmill cycling can be used as an ergometry system to assess power output in cyclists with acceptable accuracy.

New functional pavements for pedestrians and cyclists.

PubMed

Wallqvist, V; Kjell, G; Cupina, E; Kraft, L; Deck, C; Willinger, R

2017-08-01

When many fields of pedestrian and cyclist safety have been extensively studied, the surfacing has long been left unquestioned, despite being developed for another mode of transport and being one of the main causes for falls and fall injuries. In this project new surfacing materials for pedestrian and cyclist safety have been produced. Focusing on augmenting previously largely disregarded parameters as impact absorption, comfort and visibility at the same time as avoiding deteriorating of crucial parameters as friction and wear resistance. Rubber content, binder type, and pigment addition have been varied and evaluated. The results demonstrate that by increasing rubber content of the mixtures the head injury criterion (HIC) value and injury risk can be decreased while maintaining frictional properties according to existing criteria. Assembly of test-lanes demonstrate that some developed materials experience lower flow and component separation than standard materials due to rubber addition, calling for further optimisation of construction procedure linked to content development. Initial trials on the test-lanes indicate that a polyurethane (PU) based material has high cycling comfort, visibility and can be modified with phosphorescence properties. For standard asphalt, impact absorption might be inflicted by modification of bitumen alone but is mostly augmented by rubber addition. The results also indicate that rubber content can decrease ice formation on the materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

Increasing bicycle helmet use in the community. Measuring response to a wide-scale, 2-year effort.

PubMed Central

Morris, B. A.; Trimble, N. E.; Fendley, S. J.

1994-01-01

OBJECTIVE: To determine whether a wide-scale, long-term community promotional effort would increase the use of bicycle helmets among children. DESIGN: Over 2 years, a non-profit group coordinated a range of activities to promote helmet use. On one date before the intervention began and three dates during the intervention, observers surveyed students riding bicycles. SETTING: Cyclists were observed at 5 elementary schools, three secondary schools, and two community college entrances. PARTICIPANTS: A total of 851 cyclists were observed, 536 of them at elementary schools in a convenience sample. INTERVENTIONS: Print, radio, and television advertising; posters; pamphlets; bicycle rodeos; and a play were used in a public awareness campaign. Health promotion activities included education, social marketing, community development, and legislative action. MAIN OUTCOME MEASURES: Number of cyclists and whether they wore helmets. RESULTS: Combining the two observation dates for each year, helmet use increased from 5.4% in 1990 to 15.4% in 1991. The greatest increase was observed among elementary school students, the group most at risk of serious head injury or death. Overall, girls were twice as likely to wear helmets as boys. CONCLUSIONS: Wide-scale, long-term community promotion appears to be effective in increasing the use of bicycle helmets. PMID:8019189

Impact of Ramadan intermittent fasting on cognitive function in trained cyclists: a pilot study.

PubMed

Chamari, K; Briki, W; Farooq, A; Patrick, T; Belfekih, T; Herrera, C P

2016-03-01

This study assessed selected measures of cognitive function in trained cyclists who observed daylight fasting during Ramadan. Eleven cyclists volunteered to participate (age: 21.6±4.8 years, VO2max: 57.7±5.6 ml kg(-1)·min(-1)) and were followed for 2 months. Cognitive function (Cambridge Neuropsychological Test Automated Battery (CANTAB), Reaction Time index (RTI) and Rapid Visual Information Processing (RVP) tests) and sleep architecture (ambulatory EEG) were assessed: before Ramadan (BR), in the 1st week (RA1) and 4th week of Ramadan (RA4), and 2 weeks post-Ramadan (PR). Both cognitive tests were performed twice per day: before and after Ramadan at 8-10 a.m. and 4-6 p.m., and during Ramadan at 4-6 p.m. and 0-2 a.m., respectively. Training load (TL) by the rating of perceived exertion (RPE) method and wellness (Hooper index) were measured daily. If the TL increased over the study period, this variable was stable during Ramadan. The perceived fatigue and delayed onset muscle soreness (DOMS) increased at RA4. Sleep patterns and architecture showed clear disturbances, with significant increases in the number of awakenings and light sleep durations during Ramadan (RA1 and RA4), together with decreased durations of deep and REM sleep stages at PR. RTI (simple and multiple reaction index) reaction and movement times did not vary over the study period. The RVP test showed reduced false alarms during Ramadan, suggesting reduced impulsivity. Overall accuracy significantly increased at RA1, RA4 and PR compared to baseline. At RA4, the accuracy was higher at 0-2 a.m. compared to 4-6 p.m. Despite the observed disturbances in sleep architecture, Ramadan fasting did not negatively impact the cognitive performance of trained cyclists from the Middle East.

Impact of Ramadan intermittent fasting on cognitive function in trained cyclists: a pilot study

PubMed Central

Briki, W; Farooq, A; Patrick, T; Belfekih, T; Herrera, CP

2015-01-01

This study assessed selected measures of cognitive function in trained cyclists who observed daylight fasting during Ramadan. Eleven cyclists volunteered to participate (age: 21.6±4.8 years, VO2max: 57.7±5.6 ml kg−1·min−1) and were followed for 2 months. Cognitive function (Cambridge Neuropsychological Test Automated Battery (CANTAB), Reaction Time index (RTI) and Rapid Visual Information Processing (RVP) tests) and sleep architecture (ambulatory EEG) were assessed: before Ramadan (BR), in the 1st week (RA1) and 4th week of Ramadan (RA4), and 2 weeks post-Ramadan (PR). Both cognitive tests were performed twice per day: before and after Ramadan at 8-10 a.m. and 4-6 p.m., and during Ramadan at 4-6 p.m. and 0-2 a.m., respectively. Training load (TL) by the rating of perceived exertion (RPE) method and wellness (Hooper index) were measured daily. If the TL increased over the study period, this variable was stable during Ramadan. The perceived fatigue and delayed onset muscle soreness (DOMS) increased at RA4. Sleep patterns and architecture showed clear disturbances, with significant increases in the number of awakenings and light sleep durations during Ramadan (RA1 and RA4), together with decreased durations of deep and REM sleep stages at PR. RTI (simple and multiple reaction index) reaction and movement times did not vary over the study period. The RVP test showed reduced false alarms during Ramadan, suggesting reduced impulsivity. Overall accuracy significantly increased at RA1, RA4 and PR compared to baseline. At RA4, the accuracy was higher at 0-2 a.m. compared to 4-6 p.m. Despite the observed disturbances in sleep architecture, Ramadan fasting did not negatively impact the cognitive performance of trained cyclists from the Middle East. PMID:26985134

No Effect of Acute and 6-Day Nitrate Supplementation on VO2 and Time-Trial Performance in Highly Trained Cyclists.

PubMed

Nyakayiru, Jean M; Jonvik, Kristin L; Pinckaers, Philippe J M; Senden, Joan; van Loon, Luc J C; Verdijk, Lex B

2017-02-01

While the majority of studies reporting ergogenic effects of dietary nitrate have used a multiday supplementation protocol, some studies suggest that a single dose of dietary nitrate before exercise can also improve subsequent performance. We aimed to compare the impact of acute and 6-day sodium nitrate supplementation on oxygen uptake (V̇O 2 ) and time-trial performance in trained cyclists. Using a randomized, double-blind, cross-over design, 17 male cyclists (25 ± 4 y, V̇O 2peak 65 ± 4 ml·kg -1 ·min -1 , W max 411 ± 35 W) were subjected to 3 different trials; 5 days placebo and 1 day sodium nitrate supplementation (1-DAY); 6 days sodium nitrate supplementation (6-DAY); 6 days placebo supplementation (PLA). Nitrate was administered as 1097 mg sodium nitrate providing 800 mg (~12.9 mmol) nitrate per day. Three hours after ingestion of the last supplemental bolus, indirect calorimetry was performed while subjects performed 30 min of exercise at 45% W max and 30 min at 65% W max on a cycle ergometer, followed by a 10 km time-trial. Immediately before exercise, plasma [nitrate] and [nitrite] increased to a similar extent during the 6-DAY and 1-DAY trial, but not with PLA (plasma nitrite: 501 ± 205, 553 ± 278, and 239 ± 74 nM, respectively; p < .001). No differences were observed between interventions in V̇O 2 during submaximal exercise, or in time to complete the time-trial (6-DAY: 1004 ± 61, 1-DAY: 1022 ± 72, PLA: 1017 ± 71 s; p = .28). We conclude that both acute and 6-days of sodium nitrate supplementation do not alter V̇O 2 during submaximal exercise or improve time-trial performance in highly trained cyclists, despite increasing plasma [nitrate] and [nitrite].

Highly increased Troponin I levels following high-intensity endurance cycling may detect subclinical coronary artery disease in presumably healthy leisure sport cyclists: The North Sea Race Endurance Exercise Study (NEEDED) 2013.

PubMed

Skadberg, Øyvind; Kleiven, Øyunn; Bjørkavoll-Bergseth, Magnus; Melberg, Tor; Bergseth, Rolf; Selvåg, Jone; Auestad, Bjørn; Greve, Ole J; Dickstein, Kenneth; Aarsland, Torbjørn; Ørn, Stein

2017-05-01

Background Circulating cardiac troponin levels increase following prolonged intense physical exercise. The aim of this study was to identify participants with highly elevated cardiac troponins after prolonged, high intensity exercise, and to evaluate these for subclinical coronary artery disease. Methods and results Ninety-seven recreational cyclists without known cardiovascular disease or diabetes, participating in a 91 km mountain bike race were included, 74 (76%) were males, age: 43 ± 10 years, race duration: 4.2 (3.6-4.7) h. Blood samples, rest electrocardiogram and physical examination were obtained 24 h prior to, and at 0, 3 and 24 h following the race. Median cardiac troponin I level at baseline: 3.4 (2.1-4.9) ng/l (upper limit of normal: 30.0 ng/l). There was a highly significant ( p < 0.0001) increase in circulating cardiac troponin I in all participants: immediately following the race; 50.5 (28.5-71.9) ng/l, peaking at 3 h 69.3 (42.3-97.7) ng/l and declining at 24 h: 14.2 (8.5-27.9) ng/l. No cyclist had symptoms or rest electrocardiogram changes compatible with coronary artery disease during or following the race. Coronary artery disease was detected by coronary angiography in the three cyclists with the three of the four highest cardiac troponin values (>370 ng/l) at 3 and 24 h following the race. Computed tomographic coronary angiography was performed in an additional 10 riders with the subsequently highest cardiac troponin I values, without identifying underlying coronary artery disease. Conclusions This study suggests that there is a pathologic cardiac troponin I response following exercise in individuals with subclinical coronary artery disease. This response may be associated with an excessive cardiac troponin I increase at 3 and 24 h following prolonged high-intensity exercise.

Applied physiology of cycling.

PubMed

Faria, I E

1984-01-01

Historically, the bicycle has evolved through the stages of a machine for efficient human transportation, a toy for children, a finely-tuned racing machine, and a tool for physical fitness development, maintenance and testing. Recently, major strides have been made in the aerodynamic design of the bicycle. These innovations have resulted in new land speed records for human powered machines. Performance in cycling is affected by a variety of factors, including aerobic and anaerobic capacity, muscular strength and endurance, and body composition. Bicycle races range from a 200m sprint to approximately 5000km. This vast range of competitive racing requires special attention to the principle of specificity of training. The physiological demands of cycling have been examined through the use of bicycle ergometers, rollers, cycling trainers, treadmill cycling, high speed photography, computer graphics, strain gauges, electromyography, wind tunnels, muscle biopsy, and body composition analysis. These techniques have been useful in providing definitive data for the development of a work/performance profile of the cyclist. Research evidence strongly suggests that when measuring the cyclist's aerobic or anaerobic capacity, a cycling protocol employing a high pedalling rpm should be used. The research bicycle should be modified to resemble a racing bicycle and the cyclist should wear cycling shoes. Prolonged cycling requires special nutritional considerations. Ingestion of carbohydrates, in solid form and carefully timed, influences performance. Caffeine appears to enhance lipid metabolism. Injuries, particularly knee problems which are prevalent among cyclists, may be avoided through the use of proper gearing and orthotics. Air pollution has been shown to impair physical performance. When pollution levels are high, training should be altered or curtailed. Effective training programmes simulate competitive conditions. Short and long interval training, blended with long distance tempo cycling, will exploit both the anaerobic and aerobic systems. Strength training, to be effective, must be performed with the specific muscle groups used in cycling, and at specific angles of involvement.

Comparison of particulate matter dose and acute heart rate variability response in cyclists, pedestrians, bus and train passengers.

PubMed

Nyhan, Marguerite; McNabola, Aonghus; Misstear, Bruce

2014-01-15

Exposure to airborne particulate matter (PM) has been linked to cardiovascular morbidity and mortality. Heart rate variability (HRV) is a measure of the change in cardiac autonomic function, and consistent links between PM exposure and decreased HRV have been documented in studies. This study quantitatively assesses the acute relative variation of HRV with predicted PM dose in the lungs of commuters. Personal PM exposure, HR and HRV were monitored in 32 young healthy cyclists, pedestrians, bus and train passengers. Inhaled and lung deposited PM doses were determined using a numerical model of the human respiratory tract which accounted for varying ventilation rates between subjects and during commutes. Linear mixed models were used to examine air pollution dose and HRV response relationships in 122 commutes sampled. Elevated PM2.5 and PM10 inhaled and lung deposited doses were significantly (p<0.05) associated with decreased HRV indices. Percent declines in SDNN (standard deviation of normal RR intervals) relative to resting, due to an inter-quartile range increase in PM10 lung deposited dose were stronger in cyclists (-6.4%, 95% CI: -11.7, -1.3) and pedestrians (-5.8%, 95% CI: -11.3, -0.5), in comparison to bus (-3.2%, 95% CI: -6.4, -0.1) and train (-1.8%, -7.5, 3.8) passengers. A similar trend was observed in the case of PM2.5 lung deposited dose and results for rMSSD (the square root of the squared differences of successive normal RR intervals) followed similar trends to SDNN. Inhaled and lung deposited doses accounting for varying ventilation rates between modes, individuals and during commutes have been neglected in other studies relating PM to HRV. The findings here indicate that exercise whilst commuting has an influence on inhaled PM and PM lung deposited dose, and these were significantly associated with acute declines in HRV, especially in pedestrians and cyclists. © 2013.

Arginine and antioxidant supplement on performance in elderly male cyclists: a randomized controlled trial.

PubMed

Chen, Steve; Kim, Woosong; Henning, Susanne M; Carpenter, Catherine L; Li, Zhaoping

2010-03-23

Human exercise capacity declines with advancing age. These changes often result in loss of physical fitness and more rapid senescence. Nitric oxide (NO) has been implicated in improvement of exercise capacity through vascular smooth muscle relaxation in both coronary and skeletal muscle arteries, as well as via independent mechanisms. Antioxidants may prevent nitric oxide inactivation by oxygen free radicals. The purpose of this study was to investigate the effects of an L-arginine and antioxidant supplement on exercise performance in elderly male cyclists. This was a two-arm prospectively randomized double-blinded and placebo-controlled trial. Sixteen male cyclists were randomized to receive either a proprietary supplement (Niteworks(R), Herbalife International Inc., Century City, CA) or a placebo powder. Exercise parameters were assessed by maximal incremental exercise testing performed on a stationary cycle ergometer using breath-by-breath analysis at baseline, week one and week three. There was no difference between baseline exercise parameters. In the supplemented group, anaerobic threshold increased by 16.7% (2.38 +/- 0.18 L/min, p < 0.01) at week 1, and the effect was sustained by week 3 with a 14.2% (2.33 +/- 0.44 L/min, p < 0.01). In the control group, there was no change in anaerobic threshold at weeks 1 and 3 compared to baseline (1.88 +/- 0.20 L/min at week 1, and 1.86 +/- 0.21 L/min at week 3). The anaerobic threshold for the supplement groups was significantly higher than that of placebo group at week 1 and week 3. There were no significant changes noted in VO2 max between control and intervention groups at either week 1 or week 3 by comparison to baseline. An arginine and antioxidant-containing supplement increased the anaerobic threshold at both week one and week three in elderly cyclists. No effect on VO2 max was observed. This study indicated a potential role of L-arginine and antioxidant supplementation in improving exercise performance in elderly.

Low-level laser therapy improves the VO2 kinetics in competitive cyclists.

PubMed

Lanferdini, Fábio J; Krüger, Renata L; Baroni, Bruno M; Lazzari, Caetano; Figueiredo, Pedro; Reischak-Oliveira, Alvaro; Vaz, Marco A

2018-04-01

Some evidence supports that low-level laser therapy (LLLT) reduces neuromuscular fatigue, so incrementing sports performance. A previous randomized controlled trial of our group showed increased exercise tolerance in male competitive cyclists treated with three different LLLT doses (3, 6, and 9 J/diode; or 135, 270, and 405 J/thigh) before time-to-exhaustion cycling tests. Now, the present study was designed to evaluate the effects of these LLLT doses on the VO 2 kinetics of athletes during cycling tests. Twenty male competitive cyclists (29 years) participated in a crossover, randomized, double-blind, and placebo-controlled trial. On the first day, the participants performed an incremental cycling test to exhaustion to determine maximal oxygen uptake (VO 2MAX ) and maximal power output (PO MAX ), as well as a familiarization with the time-to-exhaustion test. In the following days (2 to 5), all participants performed time-to-exhaustion tests at PO MAX . Before the exhaustion test, different doses of LLLT (3, 6, and 9 J/diode; or 135, 270, and 405 J/thigh, respectively) or placebo were applied bilaterally to the quadriceps muscle. All exhaustion tests were monitored online by an open-circuit spirometry system in order to analyze the VO 2 amplitude, VO 2 delay time, time constant (tau), and O 2 deficit. Tau and O 2 deficit were decreased with LLLT applications compared to the placebo condition (p < 0.05). No differences (p > 0.05) were found between the experimental conditions for VO 2 amplitude and VO 2 delay time. In conclusion, LLLT decreases tau and O 2 deficit during time-to-exhaustion tests in competitive cyclists, and these changes in VO 2 kinetics response can be one of the possible mechanisms to explain the ergogenic effect induced by LLLT.

Age-related changes in physical and perceptual markers of recovery following high-intensity interval cycle exercise.

PubMed

Borges, Nattai R; Reaburn, Peter R; Doering, Thomas M; Argus, Christos K; Driller, Matthew W

2018-05-29

The purpose of this study was to compare physical performance, perceptual and haematological markers of recovery in well-trained masters and young cyclists across 48 h following a bout of repeated high-intensity interval exercise. Nine masters (mean ± SD; age = 55.6 ± 5.0 years) and eight young (age = 25.9 ± 3.0 years) cyclists performed a high-intensity interval exercise session consisting of 6 × 30 s intervals at 175% peak power output with 4.5 min rest between efforts. Maximal voluntary contraction (MVC), 10 s sprint (10SST), 30-min time trial (30TT) performance, creatine kinase concentration (CK) and perceptual measures of motivation, total recovery, fatigue and muscle soreness were collected at baseline and at standardised time points across the 48 h recovery period. No significant group-time interactions were observed for performance of MVC, 10SST, 30TT and CK (P > 0.05). A significant reduction in 10SST peak power was found in both masters (P = 0.002) and young (P = 0.003) cyclists at 1 h post exercise, however, both groups physically recovered at similar rates. Neither group showed significant (P > 0.05) or practically meaningful increases in CK (%∆ < 10%). A significant age-related difference was found for perceptual fatigue (P = 0.01) and analysis of effect size (ES) showed that perceptual recovery was delayed with masters cyclists reporting lower motivation (ES ±90%CI = 0.69 ± 0.77, moderate), greater fatigue (ES = 0.75 ± 0.93, moderate) and muscle soreness (ES = 0.61 ± 0.70, moderate) after 48 h of recovery. The delay in perceived recovery may have negative effects on long-term participation to systematic training.

Urban cyclist exposure to fine particle pollution in a rapidly growing city

NASA Astrophysics Data System (ADS)

Luce, B. W.; Barrett, T. E.; Ponette-González, A.

2017-12-01

Urban cyclists are exposed to elevated atmospheric concentrations of fine particulate matter (particles <2.5 µm or PM2.5). Major urban sources of PM2.5 include the incomplete combustion of fossil fuels from vehicle exhaust, which is emitted directly into cyclists' "breathing zone." In cities, human exposure to PM2.5 is a concern because its small size allows it to be inhaled deeper into the lungs than most particles. The aim of this research is to determine "hotspots" (locations with high PM2.5 concentrations) within the Dallas-Fort Worth Metroplex, Texas, where urban cyclists are most exposed to fine particle pollution. Recent research indicates that common exposure hotspots include traffic signals, junctions, bus stations, parking lots, and inclined streets. To identify these and other hotspots, a bicycle equipped with a low-cost, portable, battery-powered particle counter (Dylos 1700) coupled with a Trimble Geo 5T handheld Global Positioning System (GPS; ≤1 m ± resolution) will be used to map and measure particle mass concentrations along predetermined routes. Measurements will be conducted during a consecutive four-month period (Sep-Dec) during morning and evening rush hours when PM2.5 levels are generally highest, as well as during non-rush hour times to determine background concentrations. PM2.5 concentrations will be calculated from particle counts using an equation developed by Steinle et al. (2015). In addition, traffic counts will be conducted along the routes coinciding with the mobile monitoring times. We will present results on identified "hotspots" of high fine particle concentrations and PM2.5 exposure in the City of Denton, where particle pollution puts urban commuters most at risk, as well as average traffic counts from monitoring times. These data can be used to determine pollution mitigation strategies in rapidly growing urban areas.

Comparisons of personal exposure to PM2.5 and CO by different commuting modes in Beijing, China.

PubMed

Huang, Jing; Deng, Furong; Wu, Shaowei; Guo, Xinbiao

2012-05-15

Epidemiological studies have shown that commuting in traffic is associated with adverse health effects. It is vital to investigate commuters' exposure to traffic-related air pollutants before considering potential health risks. However, there are relatively few publications considering commuters' personal exposure in China. We carried out a field investigation measuring commuters' personal exposure to particulate matter ≤2.5 μm in aerodynamic diameter (PM(2.5)) and carbon monoxide (CO) by three commuting modes in Beijing. Both PM(2.5) and CO personal concentrations and whole trip exposures were compared among the three commuting modes. After controlling confounding factors, we found that taxi commuters were exposed to lower concentrations of PM(2.5) (31.64±20.77 μg/m(3)) compared with bus commuters (42.40±23.36 μg/m(3)) and cyclists (49.10±26.60 μg/m(3)). By contrast, CO personal concentrations were significantly higher when commuting by taxi (5.21±1.52 ppm) than by bus (2.41±0.99 ppm) and bicycle (1.90±0.55 ppm). However, when inhalation rates and trip duration were taken into consideration, cyclists experienced the highest whole trip exposures to both PM(2.5) and CO (p<0.05). We also found fixed site monitoring data were not appropriate surrogates for personal exposure while commuting, especially during traffic heavy times. PM(2.5) and CO personal concentrations were greatly influenced by the commuting mode. Furthermore, the highest whole trip exposures to PM(2.5) and CO which cyclists experienced indicates it is not preferable to commute by bicycle in a relatively high air polluted environment. Cyclists are possibly subject to greater health risks than other commuters. Thus further research needs to be conducted to investigate the health risks associated with cycling. Copyright © 2012 Elsevier B.V. All rights reserved.

The effect of crash characteristics on cyclist injuries: An analysis of Virginia automobile-bicycle crash data.

PubMed

Robartes, Erin; Chen, T Donna

2017-07-01

This paper examines bicyclist, automobile driver, vehicle, environmental, and roadway characteristics that influence cyclist injury severity in order to determine which factors should be addressed to mitigate the worst bicyclist injuries. An ordered probit model is used to examine single bicycle-single vehicle crashes from Virginia police crash report data from 2010 to 2014. Five injury severity levels are considered: fatalities, severe injuries, minor or possible injuries, no apparent injuries, and no injury. The results of this study most notably found automobile driver intoxication to increase the probability of a cyclist fatality six fold and double the risk of a severe injury, while bicyclist intoxication increases the probability of a fatality by 36.7% and doubles the probability of severe injury. Additionally, bicycle and automobile speeds, obscured automobile driver vision, specific vehicle body types (SUV, truck, and van), vertical roadway grades and horizontal curves elevate the probability of more severe bicyclist injuries. Model results encourage consideration of methods to reduce the impact of biking and driving while intoxicated such as analysis of bicycling under the influence laws, education of drunk driving impacts on bicyclists, and separation of vehicles and bicycles on the road. Additionally, the results encourage consideration of methods to improve visibility of bicyclists and expectation of their presence on the road. Copyright © 2017 Elsevier Ltd. All rights reserved.

Variation in plasma amino acid concentrations during a cycling competition.

PubMed

Medelli, J; Lounana, J; Hill, D

2003-06-01

The variations in plasma concentrations of 24 amino acids (AAs) were measured, taking into account modifications in plasma volume, in 7 male subjects, professional cyclists, during the first 2 stages (EI and EII) of the competition "4 Days of Dunkirk 1999". Blood samples were taken before the start and at the end of each stage. At the end of EI a significant reduction (p<0.02) in alpha-aminobutyric acid was observed (-38%) and a significant increase (Wilcoxon 0.01

Changes in circulating cytokines and markers of muscle damage in elite cyclists during a multi-stage competition.

PubMed

Córdova Martínez, Alfredo; Martorell Pons, Miquel; Sureda Gomila, Antoni; Tur Marí, Josep A; Pons Biescas, Antoni

2015-09-01

The purpose of this study was to determine the changes in the basal and post-exercise plasma markers of muscular damage, lipid peroxidation and cytokines in eight male well-trained semiprofessional cyclists, in response to a three consecutive-day cycling competition. Serum markers of oxidative and muscular damage - creatine kinase activity, lactate dehydrogenase activity, myoglobin and malondialdehyde (MDA), creatinine and nitrite levels - followed a sawtooth-type representation throughout the competition. MDA showed an accumulative pattern, evidenced in the post-race values of the third stage which were significantly higher with respect to the values of the first stage. Cortisol levels were significantly influenced by an interaction between the exercise and the stage factors, with higher values on the 4th day. Plasma cytokine levels were only determined before the first stage and post-race, after the third stage. The exercise increased TNFα, IL6, IL2 and IFNγ levels, whereas IL1β was unchanged. In conclusion, cyclist stages induced oxidative and cellular muscle damage which is partially recovered to basal values by the next morning. Repetitive stages during the cycling competition accumulated plasma muscular damage and lipid peroxidation markers and pro-inflammatory cytokines, probably as a result of local inflammatory responses. © 2014 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

Impact of Bicycle Route Type on Exposure to Traffic-Related Air Pollution

PubMed Central

MacNaughton, Piers; Melly, Steven; Vallarino, Jose; Adamkiewicz, Gary; Spengler, John D.

2017-01-01

Cyclists are exposed to traffic-related air pollution (TRAP) during their commutes due to their proximity to vehicular traffic. Two of the main components of TRAP are black carbon (BC) and nitrogen dioxide (NO2), which have both been causally associated with increased mortality. To assess the impact of cyclists’ exposure to TRAP, a battery-powered mobile monitoring station was designed to sample air pollutants along five bike routes in Boston, Massachusetts. The bike routes were categorized into three types: bike paths, which are separated from vehicle traffic; bike lanes, which are adjacent to traffic; and designated bike lanes, which are shared traffic lanes for buses and cyclists. Bike lanes were found to have significantly higher concentrations of BC and NO2 than bike paths in both adjusted and unadjusted generalized linear models. Higher concentrations were observed in designated bike lanes than bike paths; however, this association was only significant for NO2. After adjusting for traffic density, background concentration, and proximity to intersections, bike lanes were found to have concentrations of BC and NO2 that were approximately 33% higher than bike paths. Distance from the road, vegetation barriers, and reduced intersection density appear to influence these variations. These findings suggest that cyclists can reduce their exposure to TRAP during their commute by using bike paths preferentially over bike lanes regardless of the potential increase of traffic near these routes. PMID:24840278

Noncircular Chainrings Do Not Influence Maximum Cycling Power.

PubMed

Leong, Chee-Hoi; Elmer, Steven J; Martin, James C

2017-12-01

Noncircular chainrings could increase cycling power by prolonging the powerful leg extension/flexion phases, and curtailing the low-power transition phases. We compared maximal cycling power-pedaling rate relationships, and joint-specific kinematics and powers across 3 chainring eccentricities (CON = 1.0; LOW ecc  = 1.13; HIGH ecc  = 1.24). Part I: Thirteen cyclists performed maximal inertial-load cycling under 3 chainring conditions. Maximum cycling power and optimal pedaling rate were determined. Part II: Ten cyclists performed maximal isokinetic cycling (120 rpm) under the same 3 chainring conditions. Pedal and joint-specific powers were determined using pedal forces and limb kinematics. Neither maximal cycling power nor optimal pedaling rate differed across chainring conditions (all p > .05). Peak ankle angular velocity for HIGH ecc was less than CON (p < .05), while knee and hip angular velocities were unaffected. Self-selected ankle joint-center trajectory was more eccentric than HIGH ecc with an opposite orientation that increased velocity during extension/flexion and reduced velocity during transitions. Joint-specific powers did not differ across chainring conditions, with a small increase in power absorbed during ankle dorsiflexion with HIGH ecc . Multiple degrees of freedom in the leg, crank, and pedal system allowed cyclists to manipulate ankle angular velocity to maintain their preferred knee and hip actions, suggesting maximizing extension/flexion and minimizing transition phases may be counterproductive for maximal power.

Visual Object Recognition with 3D-Aware Features in KITTI Urban Scenes

PubMed Central

Yebes, J. Javier; Bergasa, Luis M.; García-Garrido, Miguel Ángel

2015-01-01

Driver assistance systems and autonomous robotics rely on the deployment of several sensors for environment perception. Compared to LiDAR systems, the inexpensive vision sensors can capture the 3D scene as perceived by a driver in terms of appearance and depth cues. Indeed, providing 3D image understanding capabilities to vehicles is an essential target in order to infer scene semantics in urban environments. One of the challenges that arises from the navigation task in naturalistic urban scenarios is the detection of road participants (e.g., cyclists, pedestrians and vehicles). In this regard, this paper tackles the detection and orientation estimation of cars, pedestrians and cyclists, employing the challenging and naturalistic KITTI images. This work proposes 3D-aware features computed from stereo color images in order to capture the appearance and depth peculiarities of the objects in road scenes. The successful part-based object detector, known as DPM, is extended to learn richer models from the 2.5D data (color and disparity), while also carrying out a detailed analysis of the training pipeline. A large set of experiments evaluate the proposals, and the best performing approach is ranked on the KITTI website. Indeed, this is the first work that reports results with stereo data for the KITTI object challenge, achieving increased detection ratios for the classes car and cyclist compared to a baseline DPM. PMID:25903553

Visual Object Recognition with 3D-Aware Features in KITTI Urban Scenes.

PubMed

Yebes, J Javier; Bergasa, Luis M; García-Garrido, Miguel Ángel

2015-04-20

Driver assistance systems and autonomous robotics rely on the deployment of several sensors for environment perception. Compared to LiDAR systems, the inexpensive vision sensors can capture the 3D scene as perceived by a driver in terms of appearance and depth cues. Indeed, providing 3D image understanding capabilities to vehicles is an essential target in order to infer scene semantics in urban environments. One of the challenges that arises from the navigation task in naturalistic urban scenarios is the detection of road participants (e.g., cyclists, pedestrians and vehicles). In this regard, this paper tackles the detection and orientation estimation of cars, pedestrians and cyclists, employing the challenging and naturalistic KITTI images. This work proposes 3D-aware features computed from stereo color images in order to capture the appearance and depth peculiarities of the objects in road scenes. The successful part-based object detector, known as DPM, is extended to learn richer models from the 2.5D data (color and disparity), while also carrying out a detailed analysis of the training pipeline. A large set of experiments evaluate the proposals, and the best performing approach is ranked on the KITTI website. Indeed, this is the first work that reports results with stereo data for the KITTI object challenge, achieving increased detection ratios for the classes car and cyclist compared to a baseline DPM.

Validity of a device designed to measure braking power in bicycle disc brakes.

PubMed

Miller, Matthew C; Fink, Philip W; Macdermid, Paul William; Perry, Blake G; Stannard, Stephen R

2017-07-21

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 (r 2  = 0.989; p < 0.0001) and the dirt path (r 2  = 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.

Comparative Outcomes of Traumatic Brain Injury from Biking Accidents With or Without Helmet Use.

PubMed

Dagher, Jehane H; Costa, Camille; Lamoureux, Julie; de Guise, Elaine; Feyz, Mitra

2016-01-01

To determine if health outcomes and demographics differ according to helmet status between persons with cycling-related traumatic brain injuries (TBI). This is a retrospective study of 128 patients admitted to the Montreal General Hospital following a TBI that occurred while cycling from 2007-2011. Information was collected from the Quebec trauma registry and the coroner's office in cases of death from cycling accidents. The independent variables collected were socio-demographic, helmet status, clinical and neurological patient information. The dependent variables evaluated were length of stay (LOS), extended Glasgow outcome scale (GOS-E), injury severity scale (ISS), discharge destination and death. 25% of cyclists wore a helmet. The helmet group was older, more likely to be university educated, married and retired. Unemployment, longer intensive care unit (ICU) stay, severe intracranial bleeding and neurosurgical interventions were more common in the no helmet group. There was no significant association between the severity of the TBI, ISS scores, GOS-E or death and helmet wearing. The median age of the subjects who died was higher than those who survived. Cyclists without helmets were younger, less educated, single and unemployed. They had more severe TBIs on imaging, longer LOS in ICU and more neurosurgical interventions. Elderly cyclists admitted to the hospital appear to be at higher risk of dying in the event of a TBI.

Impairment of Performance Variables After In-Season Strength-Training Cessation in Elite Cyclists.

PubMed

Rønnestad, Bent R; Hansen, Joar; Hollan, Ivana; Spencer, Matt; Ellefsen, Stian

2016-09-01

The current study investigated the effects of 8 wk of strength-training cessation after 25 wk of strength training on strength- and cycling-performance characteristics. Elite cyclists were randomly assigned to either 25 wk of endurance training combined with heavy strength training (EXP, n = 7, maximal oxygen uptake [V̇O 2max ] 77 ± 6 mL . kg -1 . min -1 ; 3 × 4-10 RM, 1 to 2 d/wk) or to endurance training only (CON, n = 7, V̇O 2max 73 ± 5 mL . kg -1 . min -1 ). Thereafter, both groups performed endurance training only for 8 wk, coinciding with the initial part of the competition season. Data were assessed for practical significance using magnitude-based inferences. During the 25-wk preparatory period, EXP had a larger positive impact on maximal isometric half-squat force, squat jump (SJ), maximal aerobic power (W max ), power output at 4 mmol/L [La], and mean power in 30-s Wingate test than did CON (ES = 0.46-0.74). Conversely, during the 8-wk competition period EXP had a reduction in SJ, W max , and mean power in the 30-s Wingate test compared with CON (ES = 0.49-0.84). The present findings suggest rapid decline of adaptations on termination of strength training during the first 8 wk of the competition period in elite cyclists.

Mechanisms, injuries and helmet use in cyclists presenting to an inner city emergency department.

PubMed

Dinh, Michael M; Kastelein, Christopher; Hopkins, Roy; Royle, Timothy J; Bein, Kendall J; Chalkley, Dane R; Ivers, Rebecca

2015-08-01

The objectives of the present study were to describe the injury profiles of cyclists presenting to an ED and determine the risk of significant head injury associated with bicycle helmet use. This was a retrospective single trauma centre study of all adult cyclists presenting to an inner city ED and undergoing a trauma team review between January 2012 and June 2014. The outcome of interest was significant head injury defined as any head injury with an Abbreviated Injury Scale score of two or more. Variables analysed included demographic characteristics, helmet use at time of incident, location, time and the presence of intoxication. The most common body regions were upper limb injuries (57%), followed by head injuries (43%), facial injuries (30%) and lower limb injuries (24%). A lower proportion of people wearing helmets had significant head injury (17% vs 31%, P = 0.018) or facial injury (26% vs 48%, P = 0.0017) compared with non-helmet users. After adjustment for important covariates, helmet use was associated with a 70% decrease in the odds of significant head injury (odds ratio 0.34, 95% confidence interval 0.15, 0.76, P = 0.008). Head injuries were common after inner city cycling incidents. The use of helmets was associated with a reduction in significant head injury. © 2015 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

VO2max and ventilatory threshold of trained cyclists are not affected by 28-day L-arginine supplementation.

PubMed

Sunderland, Kyle L; Greer, Felicia; Morales, Jacobo

2011-03-01

The ergogenic effect of L-arginine on an endurance-trained population is not well studied. The few studies that have investigated L-arginine on this population have not been conducted in a laboratory setting or measured aerobic variables. The purpose of the current study is to determine if 28 days of L-arginine supplementation in trained male cyclists affects VO2max and ventilatory threshold (VT). Eighteen (18) endurance-trained male cyclists (mean ± SD, age: 36.3 ± 7.9 years; height: 182.4 ± 4.6 cm; and body mass: 79.5 ± 4.7 kg) performed a graded exercise test (GXT; 50 W + 25 W·min) before and after 28 days of supplementation with L-arginine (ARG; 2 × 6 g·d) or placebo (PLA; cornstarch). The GXT was conducted on the subject's own bicycle using the RacerMate CompuTrainer (Seattle, WA, USA). VO2 was continuously recorded using the ParvoMedics TrueOne 2400 metabolic cart (Salt Lake City, UT, USA) and VT was established by plotting the ventilatory equivalent for O2 (VE/VO2) and the ventilatory equivalent for CO2 (VE/VCO2) and identifying the point at which VE/VO2 increases with no substantial changes in VE/VCO2. L-arginine supplementation had no effect from initial VO2max (PL, 58.7 ± 7.1 ml·kg·min; ARG, 63.5 ± 7.3 ml·kg·min) to postsupplement VO2max (PL, 58.9 ± 6.0 ml·kg·min; ARG, 63.2 ± 7.2 ml·kg·min). Also, no effect was seen from initial VT (PL, 75.7 ± 4.6% VO2max; ARG, 76.0 ± 5.3% VO2max) to postsupplement VT (PL, 74.3 ± 8.1% VO2max; ARG, 74.2 ± 6.4% VO2max). These results indicate that L-arginine does not impact VO2max or VT in trained male cyclists.

Arginine and antioxidant supplement on performance in elderly male cyclists: a randomized controlled trial

PubMed Central

2010-01-01

Background Human exercise capacity declines with advancing age. These changes often result in loss of physical fitness and more rapid senescence. Nitric oxide (NO) has been implicated in improvement of exercise capacity through vascular smooth muscle relaxation in both coronary and skeletal muscle arteries, as well as via independent mechanisms. Antioxidants may prevent nitric oxide inactivation by oxygen free radicals. The purpose of this study was to investigate the effects of an L-arginine and antioxidant supplement on exercise performance in elderly male cyclists. Methods This was a two-arm prospectively randomized double-blinded and placebo-controlled trial. Sixteen male cyclists were randomized to receive either a proprietary supplement (Niteworks®, Herbalife International Inc., Century City, CA) or a placebo powder. Exercise parameters were assessed by maximal incremental exercise testing performed on a stationary cycle ergometer using breath-by-breath analysis at baseline, week one and week three. Results There was no difference between baseline exercise parameters. In the supplemented group, anaerobic threshold increased by 16.7% (2.38 ± 0.18 L/min, p < 0.01) at week 1, and the effect was sustained by week 3 with a 14.2% (2.33 ± 0.44 L/min, p < 0.01). In the control group, there was no change in anaerobic threshold at weeks 1 and 3 compared to baseline (1.88 ± 0.20 L/min at week 1, and 1.86 ± 0.21 L/min at week 3). The anaerobic threshold for the supplement groups was significantly higher than that of placebo group at week 1 and week 3. There were no significant changes noted in VO2 max between control and intervention groups at either week 1 or week 3 by comparison to baseline. Conclusion An arginine and antioxidant-containing supplement increased the anaerobic threshold at both week one and week three in elderly cyclists. No effect on VO2 max was observed. This study indicated a potential role of L-arginine and antioxidant supplementation in improving exercise performance in elderly. PMID:20331847

Effect of antioxidant supplementation on exercise-induced cardiac troponin release in cyclists: a randomized trial.

PubMed

Klinkenberg, Lieke J J; Res, Peter T; Haenen, Guido R; Bast, Aalt; van Loon, Luc J C; van Dieijen-Visser, Marja P; Meex, Steven J R

2013-01-01

Cardiac troponin is the biochemical gold standard to diagnose acute myocardial infarction. Interestingly however, elevated cardiac troponin concentrations are also frequently observed during and after endurance-type exercise. Oxidative stress associated with prolonged exercise has been proposed to contribute to cardiac troponin release. Therefore, the aim of this study was to assess the effect of 4 week astaxanthin supplementation (a potent cartenoid antioxidant) on antioxidant capacity and exercise-induced cardiac troponin release in cyclists. Thirty-two well-trained male cyclists (age 25±5, weight 73±7 kg, maximum O2 uptake 60±5 mL·kg(-1)·min(-1), Wmax 5.4±0.5 W·kg(-1); mean ± SD) were repeatedly subjected to a laboratory based standardized exercise protocol before and after 4 weeks of astaxanthin (20 mg/day), or placebo supplementation in a double-blind randomized manner. Blood samples were obtained at baseline, at 60 min of cycling and immediately post-exercise (≈ 120 min). The pre-supplementation cycling trial induced a significant rise of median cardiac troponin T concentrations from 3.2 (IQR 3.0-4.2) to 4.7 ng/L (IQR 3.7-6.7), immediately post-exercise (p<0.001). Four weeks of astaxanthin supplementation significantly increased mean basal plasma astaxanthin concentrations from non-detectable values to 175±86 µg·kg(-1). However, daily astaxanthin supplementation had no effect on exercise-induced cardiac troponin T release (p = 0.24), as measured by the incremental area under the curve. Furthermore, the elevation in basal plasma astaxanthin concentrations was not reflected in changes in antioxidant capacity markers (trolox equivalent antioxidant capacity, uric acid, and malondialdehyde). Markers of inflammation (high-sensitivity C-reactive protein) and exercise-induced skeletal muscle damage (creatine kinase) were equally unaffected by astaxanthin supplementation. Despite substantial increases in plasma astaxanthin concentrations, astaxanthin supplementation did not improve antioxidant capacity in well-trained cyclists. Accordingly, exercise-induced cardiac troponin T concentrations were not affected by astaxanthin supplementation. ClinicalTrials.gov NCT01241877.

Bicycling crashes on streetcar (tram) or train tracks: mixed methods to identify prevention measures.

PubMed

Teschke, Kay; Dennis, Jessica; Reynolds, Conor C O; Winters, Meghan; Harris, M Anne

2016-07-22

Streetcar or train tracks in urban areas are difficult for bicyclists to negotiate and are a cause of crashes and injuries. This study used mixed methods to identify measures to prevent such crashes, by examining track-related crashes that resulted in injuries to cyclists, and obtaining information from the local transit agency and bike shops. We compared personal, trip, and route infrastructure characteristics of 87 crashes directly involving streetcar or train tracks to 189 crashes in other circumstances in Toronto, Canada. We complemented this with engineering information about the rail systems, interviews of personnel at seven bike shops about advice they provide to customers, and width measurements of tires on commonly sold bikes. In our study, 32 % of injured cyclists had crashes that directly involved tracks. The vast majority resulted from the bike tire being caught in the rail flangeway (gap in the road surface alongside rails), often when cyclists made unplanned maneuvers to avoid a collision. Track crashes were more common on major city streets with parked cars and no bike infrastructure, with left turns at intersections, with hybrid, racing and city bikes, among less experienced and less frequent bicyclists, and among women. Commonly sold bikes typically had tire widths narrower than the smallest track flangeways. There were no track crashes in route sections where streetcars and trains had dedicated rights of way. Given our results, prevention efforts might be directed at individual knowledge, bicycle tires, or route design, but their potential for success is likely to differ. Although it may be possible to reach a broader audience with continued advice about how to avoid track crashes, the persistence and frequency of these crashes and their unpredictable circumstances indicates that other solutions are needed. Using tires wider than streetcar or train flangeways could prevent some crashes, though there are other considerations that lead many cyclists to have narrower tires. To prevent the majority of track-involved injuries, route design measures including dedicated rail rights of way, cycle tracks (physically separated bike lanes), and protected intersections would be the best strategy.

Using mental mapping to unpack perceived cycling risk.

PubMed

Manton, Richard; Rau, Henrike; Fahy, Frances; Sheahan, Jerome; Clifford, Eoghan

2016-03-01

Cycling is the most energy-efficient mode of transport and can bring extensive environmental, social and economic benefits. Research has highlighted negative perceptions of safety as a major barrier to the growth of cycling. Understanding these perceptions through the application of novel place-sensitive methodological tools such as mental mapping could inform measures to increase cyclist numbers and consequently improve cyclist safety. Key steps to achieving this include: (a) the design of infrastructure to reduce actual risks and (b) targeted work on improving safety perceptions among current and future cyclists. This study combines mental mapping, a stated-preference survey and a transport infrastructure inventory to unpack perceptions of cycling risk and to reveal both overlaps and discrepancies between perceived and actual characteristics of the physical environment. Participants translate mentally mapped cycle routes onto hard-copy base-maps, colour-coding road sections according to risk, while a transport infrastructure inventory captures the objective cycling environment. These qualitative and quantitative data are matched using Geographic Information Systems and exported to statistical analysis software to model the individual and (infra)structural determinants of perceived cycling risk. This method was applied to cycling conditions in Galway City (Ireland). Participants' (n=104) mental maps delivered data-rich perceived safety observations (n=484) and initial comparison with locations of cycling collisions suggests some alignment between perception and reality, particularly relating to danger at roundabouts. Attributing individual and (infra)structural characteristics to each observation, a Generalised Linear Mixed Model statistical analysis identified segregated infrastructure, road width, the number of vehicles as well as gender and cycling experience as significant, and interactions were found between individual and infrastructural variables. The paper concludes that mental mapping is a highly useful tool for assessing perceptions of cycling risk with a strong visual aspect and significant potential for public participation. This distinguishes it from more traditional cycling safety assessment tools that focus solely on the technical assessment of cycling infrastructure. Further development of online mapping tools is recommended as part of bicycle suitability measures to engage cyclists and the general public and to inform 'soft' and 'hard' cycling policy responses. Copyright © 2015 Elsevier Ltd. All rights reserved.

Factors Influencing Injury Severity of Bicyclists Involved in Crashes with Motor Vehicles: Bike Lanes, Alcohol, Lighting, Speed, and Helmet Use.

PubMed

Helak, Kelsey; Jehle, Dietrich; McNabb, Daniel; Battisti, Amanda; Sanford, Steward; Lark, Mary Claire

2017-07-01

In 2014, 726 bicyclists were killed and an additional 50,000 were injured in crashes with motor vehicles. The number of cyclists in the United States is increasing, and as a result there has been a call for more bike lanes. We examined the difference in the severity of injury of bicyclists involved in motor vehicle crashes when riding in the traffic lane compared with riding in a bike lane or on a paved shoulder. We also controlled for other safety factors, including alcohol use, travel speed, posted speed, helmet usage, and lighting conditions to determine their impact on bicyclist safety. Single-year National Automotive Sampling System-General Estimates System files were used to analyze data regarding the bike lanes, and multiyear data were used to analyze the additional factors. Univariate and multiple regression analyses controlling for confounders were performed on the data. When adjusting for speed limit, alcohol use by driver, weather conditions, time of day, and helmet use, the cyclist's position had no significant effect on the severity of injury ( P = 0.57). The severity of injury was significantly greater when the driver or bicyclist had been drinking alcohol ( P < 0.0001 and P < 0.003, respectively). Bicyclists were more severely injured when vehicles moved at greater speeds and the posted speed limit was higher ( P < 0.0001 for both). Also, injury severity was found to be significantly higher when lighting conditions were "dark" ( P < 0.0001). Our findings suggest that simply having a dedicated space for bicyclists, such as a bike lane or a paved shoulder, does not reduce the severity of injuries sustained when a crash with a motor vehicle takes place. Cyclist safety could be improved by implementing changes that affect vehicle speed, alcohol use by drivers, and lighting conditions. Moreover, emergency physicians should be aware that when they receive a report of a cyclist being struck by a car in a bike lane, they should prepare to treat injuries of severity similar to those received by a bicyclist hit by a vehicle in traffic.

Cross-comparison of three surrogate safety methods to diagnose cyclist safety problems at intersections in Norway.

PubMed

Laureshyn, Aliaksei; Goede, Maartje de; Saunier, Nicolas; Fyhri, Aslak

2017-08-01

Relying on accident records as the main data source for studying cyclists' safety has many drawbacks, such as high degree of under-reporting, the lack of accident details and particularly of information about the interaction processes that led to the accident. It is also an ethical problem as one has to wait for accidents to happen in order to make a statement about cyclists' (un-)safety. In this perspective, the use of surrogate safety measures based on actual observations in traffic is very promising. In this study we used video data from three intersections in Norway that were all independently analysed using three methods: the Swedish traffic conflict technique (Swedish TCT), the Dutch conflict technique (DOCTOR) and the probabilistic surrogate measures of safety (PSMS) technique developed in Canada. The first two methods are based on manual detection and counting of critical events in traffic (traffic conflicts), while the third considers probabilities of multiple trajectories for each interaction and delivers a density map of potential collision points per site. Due to extensive use of microscopic data, PSMS technique relies heavily on automated tracking of the road users in video. Across the three sites, the methods show similarities or are at least "compatible" with the accident records. The two conflict techniques agree quite well for the number, type and location of conflicts, but some differences with no obvious explanation are also found. PSMS reports many more safety-relevant interactions including less severe events. The location of the potential collision points is compatible with what the conflict techniques suggest, but the possibly significant share of false alarms due to inaccurate trajectories extracted from video complicates the comparison. The tested techniques still require enhancement, with respect to better adjustment to analysis of the situations involving cyclists (and vulnerable road users in general) and further validation. However, we believe this to be a future direction for the road safety analysis as the number of accidents is constantly decreasing and the quality of accident data does not seem to improve. Copyright © 2016 Elsevier Ltd. All rights reserved.

The impact of transportation infrastructure on bicycling injuries and crashes: a review of the literature

PubMed Central

2009-01-01

Background Bicycling has the potential to improve fitness, diminish obesity, and reduce noise, air pollution, and greenhouse gases associated with travel. However, bicyclists incur a higher risk of injuries requiring hospitalization than motor vehicle occupants. Therefore, understanding ways of making bicycling safer and increasing rates of bicycling are important to improving population health. There is a growing body of research examining transportation infrastructure and the risk of injury to bicyclists. Methods We reviewed studies of the impact of transportation infrastructure on bicyclist safety. The results were tabulated within two categories of infrastructure, namely that at intersections (e.g. roundabouts, traffic lights) or between intersections on "straightaways" (e.g. bike lanes or paths). To assess safety, studies examining the following outcomes were included: injuries; injury severity; and crashes (collisions and/or falls). Results The literature to date on transportation infrastructure and cyclist safety is limited by the incomplete range of facilities studied and difficulties in controlling for exposure to risk. However, evidence from the 23 papers reviewed (eight that examined intersections and 15 that examined straightaways) suggests that infrastructure influences injury and crash risk. Intersection studies focused mainly on roundabouts. They found that multi-lane roundabouts can significantly increase risk to bicyclists unless a separated cycle track is included in the design. Studies of straightaways grouped facilities into few categories, such that facilities with potentially different risks may have been classified within a single category. Results to date suggest that sidewalks and multi-use trails pose the highest risk, major roads are more hazardous than minor roads, and the presence of bicycle facilities (e.g. on-road bike routes, on-road marked bike lanes, and off-road bike paths) was associated with the lowest risk. Conclusion Evidence is beginning to accumulate that purpose-built bicycle-specific facilities reduce crashes and injuries among cyclists, providing the basis for initial transportation engineering guidelines for cyclist safety. Street lighting, paved surfaces, and low-angled grades are additional factors that appear to improve cyclist safety. Future research examining a greater variety of infrastructure would allow development of more detailed guidelines. PMID:19845962

Tendinitis (image)

MedlinePlus

... fibrous structure that joins muscle to bone. Tendinitis pain in the knee is located in the front of the knee. ... going up and down stairs or inclines. Tendinitis knee pain can happen in runners, skiers, and cyclists.

Automatic Counting of Pedestrians and Cyclists.

DOT National Transportation Integrated Search

2016-01-01

On September 2014, U.S. Secretary of Transportation Anthony Foxx : unveiled a new Transportation Action Plan [1] to increase active, no-motorized : transportation. On it, the Department of Transportation reinforced its commitment : to making safe ...

Video markers tracking methods for bike fitting

NASA Astrophysics Data System (ADS)

Rajkiewicz, Piotr; Łepkowska, Katarzyna; Cygan, Szymon

2015-09-01

Sports cycling is becoming increasingly popular over last years. Obtaining and maintaining a proper position on the bike has been shown to be crucial for performance, comfort and injury avoidance. Various techniques of bike fitting are available - from rough settings based on body dimensions to professional services making use of sophisticated equipment and expert knowledge. Modern fitting techniques use mainly joint angles as a criterion of proper position. In this work we examine performance of two proposed methods for dynamic cyclist position assessment based on video data recorded during stationary cycling. Proposed methods are intended for home use, to help amateur cyclist improve their position on the bike, and therefore no professional equipment is used. As a result of data processing, ranges of angles in selected joints are provided. Finally strengths and weaknesses of both proposed methods are discussed.

Bicycling for transportation and health: the role of infrastructure.

PubMed

Dill, Jennifer

2009-01-01

This paper aims to provide insight on whether bicycling for everyday travel can help US adults meet the recommended levels of physical activity and what role public infrastructure may play in encouraging this activity. The study collected data on bicycling behavior from 166 regular cyclists in the Portland, Oregon metropolitan area using global positioning system (GPS) devices. Sixty percent of the cyclists rode for more than 150 minutes per week during the study and nearly all of the bicycling was for utilitarian purposes, not exercise. A disproportionate share of the bicycling occurred on streets with bicycle lanes, separate paths, or bicycle boulevards. The data support the need for well-connected neighborhood streets and a network of bicycle-specific infrastructure to encourage more bicycling among adults. This can be accomplished through comprehensive planning, regulation, and funding.

[Reconstruction of Vehicle-human Crash Accident and Injury Analysis Based on 3D Laser Scanning, Multi-rigid-body Reconstruction and Optimized Genetic Algorithm].

PubMed

Sun, J; Wang, T; Li, Z D; Shao, Y; Zhang, Z Y; Feng, H; Zou, D H; Chen, Y J

2017-12-01

To reconstruct a vehicle-bicycle-cyclist crash accident and analyse the injuries using 3D laser scanning technology, multi-rigid-body dynamics and optimized genetic algorithm, and to provide biomechanical basis for the forensic identification of death cause. The vehicle was measured by 3D laser scanning technology. The multi-rigid-body models of cyclist, bicycle and vehicle were developed based on the measurements. The value range of optimal variables was set. A multi-objective genetic algorithm and the nondominated sorting genetic algorithm were used to find the optimal solutions, which were compared to the record of the surveillance video around the accident scene. The reconstruction result of laser scanning on vehicle was satisfactory. In the optimal solutions found by optimization method of genetic algorithm, the dynamical behaviours of dummy, bicycle and vehicle corresponded to that recorded by the surveillance video. The injury parameters of dummy were consistent with the situation and position of the real injuries on the cyclist in accident. The motion status before accident, damage process by crash and mechanical analysis on the injury of the victim can be reconstructed using 3D laser scanning technology, multi-rigid-body dynamics and optimized genetic algorithm, which have application value in the identification of injury manner and analysis of death cause in traffic accidents. Copyright© by the Editorial Department of Journal of Forensic Medicine

Within-Season Distribution of External Training and Racing Workload in Professional Male Road Cyclists.

PubMed

Metcalfe, Alan J; Menaspà, Paolo; Villerius, Vincent; Quod, Marc; Peiffer, Jeremiah J; Govus, Andrew D; Abbiss, Chris R

2017-04-01

To describe the within-season external workloads of professional male road cyclists for optimal training prescription. Training and racing of 4 international competitive professional male cyclists (age 24 ± 2 y, body mass 77.6 ± 1.5 kg) were monitored for 12 mo before the world team-time-trial championships. Three within-season phases leading up to the team-time-trial world championships on September 20, 2015, were defined as phase 1 (Oct-Jan), phase 2 (Feb-May), and phase 3 (June-Sept). Distance and time were compared between training and racing days and over each of the various phases. Times spent in absolute (<100, 100-300, 400-500, >500 W) and relative (0-1.9, 2.0-4.9, 5.0-7.9, >8 W/kg) power zones were also compared for the whole season and between phases 1-3. Total distance (3859 ± 959 vs 10911 ± 620 km) and time (240.5 ± 37.5 vs 337.5 ± 26 h) were lower (P < .01) in phase 1 than phase 2. Total distance decreased (P < .01) from phase 2 to phase 3 (10911 ± 620 vs 8411 ± 1399 km, respectively). Mean absolute (236 ± 12.1 vs 197 ± 3 W) and relative (3.1 ± 0 vs 2.5 ± 0 W/kg) power output were higher (P < .05) during racing than training, respectively. Volume and intensity differed between training and racing over each of 3 distinct within-season phases.

Computational fluid dynamics analysis of cyclist aerodynamics: performance of different turbulence-modelling and boundary-layer modelling approaches.

PubMed

Defraeye, Thijs; Blocken, Bert; Koninckx, Erwin; Hespel, Peter; Carmeliet, Jan

2010-08-26

This study aims at assessing the accuracy of computational fluid dynamics (CFD) for applications in sports aerodynamics, for example for drag predictions of swimmers, cyclists or skiers, by evaluating the applied numerical modelling techniques by means of detailed validation experiments. In this study, a wind-tunnel experiment on a scale model of a cyclist (scale 1:2) is presented. Apart from three-component forces and moments, also high-resolution surface pressure measurements on the scale model's surface, i.e. at 115 locations, are performed to provide detailed information on the flow field. These data are used to compare the performance of different turbulence-modelling techniques, such as steady Reynolds-averaged Navier-Stokes (RANS), with several k-epsilon and k-omega turbulence models, and unsteady large-eddy simulation (LES), and also boundary-layer modelling techniques, namely wall functions and low-Reynolds number modelling (LRNM). The commercial CFD code Fluent 6.3 is used for the simulations. The RANS shear-stress transport (SST) k-omega model shows the best overall performance, followed by the more computationally expensive LES. Furthermore, LRNM is clearly preferred over wall functions to model the boundary layer. This study showed that there are more accurate alternatives for evaluating flow around bluff bodies with CFD than the standard k-epsilon model combined with wall functions, which is often used in CFD studies in sports. 2010 Elsevier Ltd. All rights reserved.

The most economical cadence increases with increasing workload.

PubMed

Foss, Øivind; Hallén, Jostein

2004-08-01

Several studies have suggested that the most economical cadence in cycling increases with increasing workload. However, none of these studies have been able to demonstrate this relationship with experimental data. The purpose of this study was to test the hypothesis that the most economical cadence in elite cyclists increases with increasing workload and to explore the effect of cadence on performance. Six elite road cyclists performed submaximal and maximal tests at four different cadences (60, 80, 100 and 120 rpm) on separate days. Respiratory data was measured at 0, 50, 125, 200, 275 and 350 W during the submaximal test and at the end of the maximal test. The maximal test was carried out as an incremental test, conducted to reveal differences in maximal oxygen uptake and time to exhaustion (short-term performance) between cadences. The results showed that the lowest oxygen uptake, i.e. the best work economy, shifted from 60 rpm at 0 W to 80 rpm at 350 W ( P<0.05). No difference was found in maximal oxygen uptake among cadences ( P>0.05), while the best performance was attained at the same cadence that elicited the best work economy (80 rpm) at 350 W ( P<0.05). This study demonstrated that the most economical cadence increases with increasing workload in elite cyclists. It was further shown that work economy and performance are related during short efforts (approximately 5 min) over a wide range of cadences.

Exposure to particulate matter in traffic: A comparison of cyclists and car passengers

NASA Astrophysics Data System (ADS)

Int Panis, Luc; de Geus, Bas; Vandenbulcke, Grégory; Willems, Hanny; Degraeuwe, Bart; Bleux, Nico; Mishra, Vinit; Thomas, Isabelle; Meeusen, Romain

2010-06-01

Emerging evidence suggests that short episodes of high exposure to air pollution occur while commuting. These events can result in potentially adverse health effects. We present a quantification of the exposure of car passengers and cyclists to particulate matter (PM). We have simultaneously measured concentrations (PNC, PM2.5 and PM10) and ventilatory parameters (minute ventilation (VE), breathing frequency and tidal volume) in three Belgian locations (Brussels, Louvain-la-Neuve and Mol) for 55 persons (38 male and 17 female). Subjects were first driven by car and then cycled along identical routes in a pairwise design. Concentrations and lung deposition of PNC and PM mass were compared between biking trips and car trips. Mean bicycle/car ratios for PNC and PM are close to 1 and rarely significant. The size and magnitude of the differences in concentrations depend on the location which confirms similar inconsistencies reported in literature. On the other hand, the results from this study demonstrate that bicycle/car differences for inhaled quantities and lung deposited dose are large and consistent across locations. These differences are caused by increased VE in cyclists which significantly increases their exposure to traffic exhaust. The VE while riding a bicycle is 4.3 times higher compared to car passengers. This aspect has been ignored or severely underestimated in previous studies. Integrated health risk evaluations of transport modes or cycling policies should therefore use exposure estimates rather than concentrations.

Lead Quantification in Urine Samples of Athletes by Coupling DLLME with UV-Vis Spectrophotometry.

PubMed

Faraji, Hakim; Helalizadeh, Masoumeh

2017-04-01

Urine lead level is one of the most employed measures of lead exposure and risk. The urine samples used in this study were obtained from ten healthy male cyclists. Dispersive liquid-liquid microextraction combined with ultraviolet and visible spectrophotometry was utilized for preconcentration, extraction, and determination of lead in urine samples. Optimization of the independent variables was carried out based on chemometric methods in three steps. According to the screening and optimization study, 133 μL of CCl 4 (extracting solvent), 1.34 mL ethanol (dispersing solvent), pH 2.0, 0.00 % of salt, and 0.1 % O,O-diethyl dithiophosphoric (chelating agent) were used as the optimum independent variables for microextraction and determination of lead. Under the optimized conditions, R 2 was 0.9991, and linearity range was 0.01-100 μg L -1 . Precision was evaluated in terms of repeatability and intermediate precision, with relative standard deviations being <9.1 and <15.3 %, respectively. The accuracy was estimated using urine samples of cyclists as real samples and it was confirmed. The relative error of ≤5 % was considered significant in the method specificity study. The lead concentration mean for the cyclists was 3.79 μg L -1 in urine samples. As a result, the proposed method is a robust technique to quantify lead concentrations higher than 11.6 ng L -1 in urine samples.

Dose–response associations between cycling activity and risk of hypertension in regular cyclists: The UK Cycling for Health Study

PubMed Central

Hollingworth, M; Harper, A; Hamer, M

2015-01-01

Most population studies on physical activity and health have involved largely inactive men and women, thus making it difficult to infer if health benefits occur at exercise levels above the current minimum guidelines. The aim was to examine associations between cycling volume and classical cardiovascular risk markers, including hypertension and hypercholesterolemia, in a population sample of habitual cyclists. A nationwide sample comprising 6949 men and women (aged 47.6 years on average) completed questions about their cycling levels, demographics and health. Nearly the entire sample (96.3%) achieved the current minimum physical activity recommendation through cycling alone. There was a dose–response association between cycling volume and risk of diagnosed hypertension (P-trend =0.001), with odds ratios of 0.98 (95% confidence interval (CI), 0.80–1.21), 0.86 (0.70, 1.06), 0.67 (95% CI, 0.53–0.83) across categories of 23–40, 40–61 and >61 metabolic equivalent hours/week (MET-h/week) compared with <23 MET-h/week. These associations persisted in models adjusted for age, sex, smoking, alcohol, body mass index (BMI) and other moderatevigorous physical activities. We also observed inverse associations between cycling volume and other risk factors including BMI and hypercholesterolemia. In summary, results from a population sample of cyclists suggest that additional cardiovascular health benefits can be achieved beyond the current minimum physical activity recommendation. PMID:25273856

Low-stress bicycling and network connectivity.

DOT National Transportation Integrated Search

2012-05-01

For a bicycling network to attract the widest possible segment of the population, its most fundamental attribute should be low-stress connectivity, that is, providing routes between peoples origins and destinations that do not require cyclists to ...

Gluconeogenesis during endurance exercise in cyclists habituated to a long‐term low carbohydrate high‐fat diet

PubMed Central

Webster, Christopher C.; Noakes, Timothy D.; Chacko, Shaji K.; Swart, Jeroen; Kohn, Tertius A.

2016-01-01

Key points Blood glucose is an important fuel for endurance exercise. It can be derived from ingested carbohydrate, stored liver glycogen and newly synthesized glucose (gluconeogenesis).We hypothesized that athletes habitually following a low carbohydrate high fat (LCHF) diet would have higher rates of gluconeogenesis during exercise compared to those who follow a mixed macronutrient diet.We used stable isotope tracers to study glucose production kinetics during a 2 h ride in cyclists habituated to either a LCHF or mixed macronutrient diet.The LCHF cyclists had lower rates of total glucose production and hepatic glycogenolysis but similar rates of gluconeogenesis compared to those on the mixed diet.The LCHF cyclists did not compensate for reduced dietary carbohydrate availability by increasing glucose synthesis during exercise but rather adapted by altering whole body substrate utilization. Abstract Endogenous glucose production (EGP) occurs via hepatic glycogenolysis (GLY) and gluconeogenesis (GNG) and plays an important role in maintaining euglycaemia. Rates of GLY and GNG increase during exercise in athletes following a mixed macronutrient diet; however, these processes have not been investigated in athletes following a low carbohydrate high fat (LCHF) diet. Therefore, we studied seven well‐trained male cyclists that were habituated to either a LCHF (7% carbohydrate, 72% fat, 21% protein) or a mixed diet (51% carbohydrate, 33% fat, 16% protein) for longer than 8 months. After an overnight fast, participants performed a 2 h laboratory ride at 72% of maximal oxygen consumption. Glucose kinetics were measured at rest and during the final 30 min of exercise by infusion of [6,6‐2H2]‐glucose and the ingestion of 2H2O tracers. Rates of EGP and GLY both at rest and during exercise were significantly lower in the LCHF group than the mixed diet group (Exercise EGP: LCHF, 6.0 ± 0.9 mg kg−1 min−1, Mixed, 7.8 ± 1.1 mg kg−1 min−1, P < 0.01; Exercise GLY: LCHF, 3.2 ± 0.7 mg kg−1 min−1, Mixed, 5.3 ± 0.9 mg kg−1 min−1, P < 0.01). Conversely, no difference was detected in rates of GNG between groups at rest or during exercise (Exercise: LCHF, 2.8 ± 0.4 mg kg−1 min−1, Mixed, 2.5 ± 0.3 mg kg−1 min−1, P = 0.15). We conclude that athletes on a LCHF diet do not compensate for reduced glucose availability via higher rates of glucose synthesis compared to athletes on a mixed diet. Instead, GNG remains relatively stable, whereas glucose oxidation and GLY are influenced by dietary factors. PMID:26918583

Gluconeogenesis during endurance exercise in cyclists habituated to a long-term low carbohydrate high-fat diet.

PubMed

Webster, Christopher C; Noakes, Timothy D; Chacko, Shaji K; Swart, Jeroen; Kohn, Tertius A; Smith, James A H

2016-08-01

Blood glucose is an important fuel for endurance exercise. It can be derived from ingested carbohydrate, stored liver glycogen and newly synthesized glucose (gluconeogenesis). We hypothesized that athletes habitually following a low carbohydrate high fat (LCHF) diet would have higher rates of gluconeogenesis during exercise compared to those who follow a mixed macronutrient diet. We used stable isotope tracers to study glucose production kinetics during a 2 h ride in cyclists habituated to either a LCHF or mixed macronutrient diet. The LCHF cyclists had lower rates of total glucose production and hepatic glycogenolysis but similar rates of gluconeogenesis compared to those on the mixed diet. The LCHF cyclists did not compensate for reduced dietary carbohydrate availability by increasing glucose synthesis during exercise but rather adapted by altering whole body substrate utilization. Endogenous glucose production (EGP) occurs via hepatic glycogenolysis (GLY) and gluconeogenesis (GNG) and plays an important role in maintaining euglycaemia. Rates of GLY and GNG increase during exercise in athletes following a mixed macronutrient diet; however, these processes have not been investigated in athletes following a low carbohydrate high fat (LCHF) diet. Therefore, we studied seven well-trained male cyclists that were habituated to either a LCHF (7% carbohydrate, 72% fat, 21% protein) or a mixed diet (51% carbohydrate, 33% fat, 16% protein) for longer than 8 months. After an overnight fast, participants performed a 2 h laboratory ride at 72% of maximal oxygen consumption. Glucose kinetics were measured at rest and during the final 30 min of exercise by infusion of [6,6-(2) H2 ]-glucose and the ingestion of (2) H2 O tracers. Rates of EGP and GLY both at rest and during exercise were significantly lower in the LCHF group than the mixed diet group (Exercise EGP: LCHF, 6.0 ± 0.9 mg kg(-1)  min(-1) , Mixed, 7.8 ± 1.1 mg kg(-1)  min(-1) , P < 0.01; Exercise GLY: LCHF, 3.2 ± 0.7 mg kg(-1)  min(-1) , Mixed, 5.3 ± 0.9 mg kg(-1)  min(-1) , P < 0.01). Conversely, no difference was detected in rates of GNG between groups at rest or during exercise (Exercise: LCHF, 2.8 ± 0.4 mg kg(-1)  min(-1) , Mixed, 2.5 ± 0.3 mg kg(-1)  min(-1) , P = 0.15). We conclude that athletes on a LCHF diet do not compensate for reduced glucose availability via higher rates of glucose synthesis compared to athletes on a mixed diet. Instead, GNG remains relatively stable, whereas glucose oxidation and GLY are influenced by dietary factors. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Application of demographic analysis to pedestrian safety : [project summary].

DOT National Transportation Integrated Search

2017-05-01

FDOT has been working diligently to improve its facilities for pedestrians and cyclists, including : initiatives like the Complete Streets Policy and Implementation Plan. However, one of the : challenges facing FDOT is targeting those areas of greate...

Development of an analytical framework to rank pedestrian and cyclist projects.

DOT National Transportation Integrated Search

2015-10-01

Worsening traffic congestion and air pollution, rising road maintenance and construction costs, and escalating health risks from obesity to cardiovascular disease are among major motives triggering the attention of transportation authorities to walki...

Moderate association of anthropometry, but not training volume, with race performance in male ultraendurance cyclists.

PubMed

Knechtle, Beat; Wirth, Andrea; Knechtle, Patrizia; Rosemann, Thomas

2009-09-01

In 28 male Caucasian nonprofessional ultracyclists, we investigated whether anthropometry or training volume had an influence on race speed in the 600 km at the Swiss Cycling Marathon 2007. Anthropometric parameters (age, body mass, body height, skinfold thicknesses) were determined before the race to calculate body mass index and percent body fat. In addition, participants, using a training diary, recorded their training volume in hours and kilometers in the 3 months before the race. The influence of anthropometry and training volume on speed in the race as the dependent variable was investigated in a multiple linear regression model. Anthropometry showed a moderate association with speed in the race (r2 = .178, p < .05), whereas training volume showed no association (r2 = .000, p > .05). We concluded that anthropometry had a greater influence on race performance than training volume in recreational ultraendurance cyclists.

Effect of bike lane infrastructure improvements on ridership in one New Orleans neighborhood.

PubMed

Parker, Kathryn M; Rice, Janet; Gustat, Jeanette; Ruley, Jennifer; Spriggs, Aubrey; Johnson, Carolyn

2013-02-01

Incorporating cycling into daily life is one way to increase physical activity. This study examined the impact of building new bike lanes in New Orleans to determine whether more people were cycling on the street and with the flow of traffic after bike lanes were built. Through direct observation of one intervention and two adjacent streets, observers counted cyclists riding on the street and sidewalk, with and against traffic, before and after installation of the lanes. Data were tallied separately for adults, children, males, females, and by race for each location. There was an increase in cyclists on all three streets after the installation of the bike lanes, with the largest increase on the street with the new lane. Additionally, the proportion of riders cycling with traffic increased after the lanes were striped. Bike lanes can have a positive impact in creating a healthy neighborhood.

A relationship between attractiveness and performance in professional cyclists

PubMed Central

Postma, Erik

2014-01-01

Females often prefer to mate with high quality males, and one aspect of quality is physical performance. Although a preference for physically fitter males is therefore predicted, the relationship between attractiveness and performance has rarely been quantified. Here, I test for such a relationship in humans and ask whether variation in (endurance) performance is associated with variation in facial attractiveness within elite professional cyclists that finished the 2012 Tour de France. I show that riders that performed better were more attractive, and that this preference was strongest in women not using a hormonal contraceptive. Thereby, I show that, within this preselected but relatively homogeneous sample of the male population, facial attractiveness signals endurance performance. Provided that there is a relationship between performance-mediated attractiveness and reproductive success, this suggests that human endurance capacity has been subject to sexual selection in our evolutionary past. PMID:24501269

Aerodynamics of a cycling team in a time trial: does the cyclist at the front benefit?

NASA Astrophysics Data System (ADS)

Íñiguez-de-la Torre, A.; Íñiguez, J.

2009-11-01

When seasonal journeys take place in nature, birds and fishes migrate in groups. This provides them not only with security but also a considerable saving of energy. The power they need to travel requires overcoming aerodynamic or hydrodynamic drag forces, which can be substantially reduced when the group travels in an optimal arrangement. Also in this area, humans imitate nature, which is especially evident in the practice of outdoor sports and motor competitions. Cycle races, in which speeds of up to 15 m s-1 are frequent, offer great opportunities to appreciate the advantage of travelling in a group. Here we present a brief analysis of the aerodynamics of a cycling team in a time-trial challenge, showing how each rider is favoured according to his position in the group. We conclude that the artificial tail wind created by the team also benefits the cyclist at the front by about 5%.

The effects of salmeterol on power output in nonasthmatic athletes.

PubMed

McDowell, S L; Fleck, S J; Storms, W W

1997-04-01

Salmeterol xinafoate is a new aerosol inhalant that is used in the treatment of asthma. It is currently banned by the International Olympic Committee because of the concern that it may lend an unfair competitive advantage to the user. The purpose of this study was to determine whether salmeterol improves short-term anaerobic performance in elite nonasthmatic track cyclists. Eleven elite track cyclists volunteered to perform a 30-second all-out cycle ergometer test 3 hours after receiving either 42 micrograms of salmeterol xinafoate or placebo applied in a double-blind crossover procedure. During the ergometer test, peak power output, total work, time to peak power, and percent fatigue (decline in power output) were measured. Pulmonary measurements were also taken before and at various time points after inhalation and the ergometer test. A methacholine challenge was administered to each subject before participation in the study to ensure that none of the subjects had any reactive airway diseases. There were no significant differences (p > 0.05) between the placebo and salmeterol trials for peak power output, total work performed during the 30-second test, percent fatigue, and time to peak power. No differences between trials were observed for the pulmonary function test variables at any of the time points. Blood lactate concentrations before and after administration of drug or placebo were also not significantly different between trials. Additionally, salmeterol did not affect the maximal heart rate achieved during the test as compared with the placebo. Short-term salmeterol use within the prescribed dosage was not shown to increase short-term power output in nonasthmatic cyclists.

Differences in Pedaling Technique in Cycling: A Cluster Analysis.

PubMed

Lanferdini, Fábio J; Bini, Rodrigo R; Figueiredo, Pedro; Diefenthaeler, Fernando; Mota, Carlos B; Arndt, Anton; Vaz, Marco A

2016-10-01

To employ cluster analysis to assess if cyclists would opt for different strategies in terms of neuromuscular patterns when pedaling at the power output of their second ventilatory threshold (PO VT2 ) compared with cycling at their maximal power output (PO MAX ). Twenty athletes performed an incremental cycling test to determine their power output (PO MAX and PO VT2 ; first session), and pedal forces, muscle activation, muscle-tendon unit length, and vastus lateralis architecture (fascicle length, pennation angle, and muscle thickness) were recorded (second session) in PO MAX and PO VT2 . Athletes were assigned to 2 clusters based on the behavior of outcome variables at PO VT2 and PO MAX using cluster analysis. Clusters 1 (n = 14) and 2 (n = 6) showed similar power output and oxygen uptake. Cluster 1 presented larger increases in pedal force and knee power than cluster 2, without differences for the index of effectiveness. Cluster 1 presented less variation in knee angle, muscle-tendon unit length, pennation angle, and tendon length than cluster 2. However, clusters 1 and 2 showed similar muscle thickness, fascicle length, and muscle activation. When cycling at PO VT2 vs PO MAX , cyclists could opt for keeping a constant knee power and pedal-force production, associated with an increase in tendon excursion and a constant fascicle length. Increases in power output lead to greater variations in knee angle, muscle-tendon unit length, tendon length, and pennation angle of vastus lateralis for a similar knee-extensor activation and smaller pedal-force changes in cyclists from cluster 2 than in cluster 1.

Alcohol consumption and cycling in contrast to driving.

PubMed

Hagemeister, Carmen; Kronmaier, Markus

2017-08-01

In Germany, the legal blood alcohol limit for cyclists is much higher (0.16 percent) than the limit for drivers (0.05 percent) - as long as no crash has occurred. The proportion of police-recorded crashes with personal damage under the influence is higher for cyclists than drivers, and the blood alcohol concentrations are higher for cyclists than drivers. 63 women and 204 men who drive a car and use a bike and drink alcohol participated in the online study. In the sample, cycling under the influence (CUI) was more frequent and was observed more frequently among friends than driving under the influence (DUI). Persons who use a particular vehicle type more often in general and when they visit friends also use it more often after alcohol consumption. Persons who drink alcohol more often cycle more often after alcohol consumption. In all aspects covered, drink cycling was seen as more acceptable and less dangerous than drink driving. Persons who cycle more often under the influence observe drink cycling more often among their friends. They think they are less of a danger to themselves and others when cycling after alcohol consumption, and they agree less with the statement that one should leave one's bike parked after alcohol consumption. The attitudes that drinking is unsafe for one's own driving and that one should leave one's car parked are important predictors of (non-)drink driving. For cycling, the most important predictors are bike use frequency and observing drink cycling among friends. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of physical activities that induce moderate external loading on bone metabolism in male athletes.

PubMed

Maïmoun, L; Mariano-Goulart, D; Couret, I; Manetta, J; Peruchon, E; Micallef, J P; Verdier, R; Rossi, M; Leroux, J L

2004-09-01

Sports characterized by little or moderate weight bearing or impact have a low osteogenic effect. However, the action of such sports on bone turnover remains unclear. The objective of this study was to determine the effect on bone remodelling of physical activities that induce moderate external loading on the skeleton. Thirty-eight male athletes aged 18-39 years (cyclists, n = 11; swimmers, n = 13; triathletes, n = 14) and 10 age-matched sedentary controls aged 22-35 years participated in the study. The study combined measurement of bone mineral density by dual-energy X-ray absorptiometry and bone turnover assessment from specific biochemical markers: serum bone-specific alkaline phosphatase, osteocalcin, urinary type I collagen C-telopeptide and calcium. Compared with the controls and swimmers, adjusted bone mineral density was higher (P < 0.05) in triathletes at the total proximal femur and lower limbs. No differences in bone mineral density were found between cyclists, swimmers and controls. Compared with controls, osteocalcin was higher (P < 0.05) in triathletes and swimmers and urinary type I collagen C-telopeptide was higher in swimmers only. Serum bone-specific alkaline phosphatase was lower (P < 0.05) in cyclists than in all other groups. In conclusion, an osteogenic effect was found only in triathletes, mainly at bone sites under high mechanical stress. Bone turnover differed in athletes compared with controls, suggesting that bone turnover may be sport-practice dependent. Despite some encouraging observations, it was not possible to show that changes in the bone remodelling process were sport-discipline dependent.

Analysing a cycling grand tour: Can we monitor fatigue with intensity or load ratios?

PubMed

Sanders, Dajo; Heijboer, Mathieu; Hesselink, Matthijs K C; Myers, Tony; Akubat, Ibrahim

2018-06-01

This study evaluated the changes in ratios of different intensity (rating of perceived exertion; RPE, heart rate; HR, power output; PO) and load measures (session-RPE; sRPE, individualized TRIMP; iTRIMP, Training Stress Score™; TSS) in professional cyclists. RPE, PO and HR data was collected from twelve professional cyclists (VO 2max 75 ± 6 ml∙min∙kg -1 ) during a two-week baseline training period and during two cycling Grand Tours. Subjective:objective intensity (RPE:HR, RPE:PO) and load (sRPE:iTRIMP, sRPE:TSS) ratios and external:internal intensity (PO:HR) and load (TSS:iTRIMP) ratios were calculated for every session. Moderate to large increases in the RPE:HR, RPE:PO and sRPE:TSS ratios (d = 0.79-1.79) and small increases in the PO:HR and sRPE:iTRIMP ratio (d = 0.21-0.41) were observed during Grand Tours compared to baseline training data. Differences in the TSS:iTRIMP ratio were trivial to small (d = 0.03-0.27). Small to moderate week-to-week changes (d = 0.21-0.63) in the PO:HR, RPE:PO, RPE:HR, TSS:iTRIMP, sRPE:iTRIMP and sRPE:TSS were observed during the Grand Tour. Concluding, this study shows the value of using ratios of intensity and load measures in monitoring cyclists. Increases in ratios could reflect progressive fatigue that is not readily detected by changes in solitary intensity/load measures.

A Study of Bicycle and Passenger Car Collisions Based on Insurance Claims Data

PubMed Central

Isaksson-Hellman, Irene

2012-01-01

In Sweden, bicycle crashes are under-reported in the official statistics that are based on police reports. Statistics from hospital reports show that cyclists constitute the highest percentage of severely injured road users compared to other road user groups. However, hospital reports lack detailed information about the crash. To get a more comprehensive view, additional data are needed to accurately reflect the casualty situation for cyclists. An analysis based on 438 cases of bicycle and passenger car collisions is presented, using data collected from insurance claims. The most frequent crash situations are described with factors as to where and when collisions occur, age and gender of the involved cyclists and drivers. Information on environmental circumstances such as road status, weather- and light conditions, speedlimits and traffic environment is also included. Based on the various crash events, a total of 32 different scenarios have been categorized, and it was found that more than 75% were different kinds of intersection related situations. From the data, it was concluded that factors such as estimated impact speed and age significantly influence injury severity. The insurance claims data complement the official statistics and provide a more comprehensive view of bicycle and passenger car collisions by considering all levels of crash and injury severity. The detailed descriptions of the crash situations also provide an opportunity to find countermeasures to prevent or mitigate collisions. The results provide a useful basis, and facilitates the work of reducing the number of bicycle and passenger car collisions with serious consequences. PMID:23169111

V02 'overshoot' during moderate-intensity exercise in endurance-trained athletes: the influence of exercise modality.

PubMed

Kilding, Andrew E; Jones, Andrew M

2008-02-01

The purpose of this study was to investigate the influence of exercise modality on the 'overshoot' in V(O2) that has been reported following the onset of moderate-intensity (below the gas exchange threshold, GET) exercise in endurance athletes. Seven trained endurance cyclists and seven trained endurance runners completed six square-wave transitions to a work-rate or running speed requiring 80% of mode-specific GET during both cycle and treadmill running exercise. The kinetics of V(O2) was assessed using non-linear regression and any overshoot in V(O2) was quantified as the integrated volume (IV) of O(2) consumed above the steady-state requirement. During cycling, an overshoot in V(O2) was evident in all seven cyclists (IV = 136 +/- 41 ml) and in four runners (IV = 81 +/- 94 ml). During running, an overshoot in V(O2) was evident in four runners (IV = 72 +/- 61 ml) but no cyclists. These data challenge the notion that V(O2) always rises towards a steady-state with near-exponential kinetics in this exercise intensity domain. The greater incidence of the V(O2) overshoot during cycling (11/14 subjects) compared to running (4/14 subjects) indicates that the overshoot phenomenon is related to an interaction between high levels of aerobic fitness and exercise modality. We speculate that a transient loss in muscle efficiency as a consequence of a non-constant ATP requirement following the onset of constant-work-rate exercise or an initially excessive recruitment of motor units (relative to the work-rate) might contribute to the overshoot phenomenon.

An immersive virtual peer for studying social influences on child cyclists' road-crossing behavior.

PubMed

Babu, Sabarish V; Grechkin, Timofey Y; Chihak, Benjamin; Ziemer, Christine; Kearney, Joseph K; Cremer, James F; Plumert, Jodie M

2011-01-01

The goal of our work is to develop a programmatically controlled peer to bicycle with a human subject for the purpose of studying how social interactions influence road-crossing behavior. The peer is controlled through a combination of reactive controllers that determine the gross motion of the virtual bicycle, action-based controllers that animate the virtual bicyclist and generate verbal behaviors, and a keyboard interface that allows an experimenter to initiate the virtual bicyclist's actions during the course of an experiment. The virtual bicyclist's repertoire of behaviors includes road following, riding alongside the human rider, stopping at intersections, and crossing intersections through specified gaps in traffic. The virtual cyclist engages the human subject through gaze, gesture, and verbal interactions. We describe the structure of the behavior code and report the results of a study examining how 10- and 12-year-old children interact with a peer cyclist that makes either risky or safe choices in selecting gaps in traffic. Results of our study revealed that children who rode with a risky peer were more likely to cross intermediate-sized gaps than children who rode with a safe peer. In addition, children were significantly less likely to stop at the last six intersections after the experience of riding with the risky than the safe peer during the first six intersections. The results of the study and children's reactions to the virtual peer indicate that our virtual peer framework is a promising platform for future behavioral studies of peer influences on children's bicycle riding behavior. © 2011 IEEE Published by the IEEE Computer Society

Upper Body Compression Garment: Physiological Effects While Cycling in a Hot Environment.

PubMed

Leoz-Abaurrea, Iker; Aguado-Jiménez, Roberto

2017-06-01

The purpose of the present study was to investigate the effects of an upper body compression garment (UBCG) on physiologic and perceptual responses while cycling in a hot environment. Twenty recreational road cyclists were pair-matched for age, anthropometric data, and fitness level (V̇O 2max ) and randomly assigned to a control (CON) group (n=10) of cyclists who wore a conventional t-shirt or to a group (n=10) of cyclists who wore UBCG. Test session consisted of cycling at a fixed load (~50% V̇O 2max ) for 30 minutes at an ambient temperature of ~40ºC (39.9±0.4ºC), followed by 10 minutes of recovery. Significantly greater (P = .002) rectal temperature (T rec ) was observed at the end of exercise in the UBCG group (38.3±0.2ºC) versus CON group (37.9±0.3ºC). Significantly greater heart rate (HR) was observed in the UBCG group at minute 15 (P = .01) and at the end of exercise (187±9 vs 173±10 beats/min; P = .004) for UBCG and CON, respectively. Furthermore, participants who wore UBCG perceived a significantly greater (P = .03) thermal sensation at the end of exercise. During recovery HR and T rec remained significantly greater (P < .05) in the UBCG group. The use of an UBCG increased cardiovascular and thermoregulatory strain during cycling in a hot environment and did not aid during recovery. Copyright © 2017 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Influence of standing position on mechanical and energy costs in uphill cycling.

PubMed

Bouillod, Anthony; Pinot, Julien; Valade, Aurélien; Cassirame, Johan; Soto-Romero, Georges; Grappe, Frédéric

2018-04-27

This study was designed to examine the influence of standing position (vs. seated) during uphill cycling on both mechanical cost (MC) and energy cost (EC) in elite cyclists. For the study, thirteen elite cyclists (VO 2max : 71.4 ± 8.0 ml·min -1 ·kg -1 ) performed, in a randomised order, three sets of exercises. Each set comprised 2 min of exercise, alternating every 30 s between seated and standing postures, using different slopes and intensity levels on a motorised treadmill. MC was calculated from the measurement of power output and speed, whereas EC was calculated from the measurement of oxygen consumption and speed. MC was significantly higher (+4.3%, p < 0.001) in standing position compared to seated position when all slopes and intensities were considered. However, EC was not significantly affected by the change in position. The standing position also induced a significant increase in rolling resistance power (p < 0.001), rolling resistance coefficient (p < 0.001) and lateral sways (p < 0.001). The significant increase in MC observed in standing position was due to a higher rolling resistance induced by bicycle sways and a shift forward of the centre of mass compared to seated position. This result should lead bicycle tire manufacturers to reduce the increase in rolling resistance between the two positions. Considering the relationship observed between the MC and bicycle sways, cyclists would be well advised to decrease the bicycle sways in order to reduce the MC of locomotion. Copyright © 2018 Elsevier Ltd. All rights reserved.

Validity and reliability of the Hexoskin® wearable biometric vest during maximal aerobic power testing in elite cyclists.

PubMed

Elliot, Catherine A; Hamlin, Michael J; Lizamore, Catherine A

2017-07-28

The purpose of this study was to investigate the validity and reliability of the Hexoskin® vest for measuring respiration and heart rate (HR) in elite cyclists during a progressive test to exhaustion. Ten male elite cyclists (age 28.8 ± 12.5 yr, height 179.3 ± 6.0 cm, weight 73.2 ± 9.1 kg, V˙ O2max 60.7 ± 7.8 ml.kg.min mean ± SD) conducted a maximal aerobic cycle ergometer test using a ramped protocol (starting at 100W with 25W increments each min to failure) during two separate occasions over a 3-4 day period. Compared to the criterion measure (Metamax 3B) the Hexoskin® vest showed mainly small typical errors (1.3-6.2%) for HR and breathing frequency (f), but larger typical errors (9.5-19.6%) for minute ventilation (V˙E) during the progressive test to exhaustion. The typical error indicating the reliability of the Hexoskin® vest at moderate intensity exercise between tests was small for HR (2.6-2.9%) and f (2.5-3.2%) but slightly larger for V˙E (5.3-7.9%). We conclude that the Hexoskin® vest is sufficiently valid and reliable for measurements of HR and f in elite athletes during high intensity cycling but the calculated V˙E value the Hexoskin® vest produces during such exercise should be used with caution due to the lower validity and reliability of this variable.

The effect of the oxygen uptake-power output relationship on the prediction of supramaximal oxygen demands.

PubMed

Muniz-Pumares, Daniel; Pedlar, Charles; Godfrey, Richard; Glaister, Mark

2017-01-01

The aim of this study was to investigate the relationship between oxygen uptake (V̇O2) and power output at intensities below and above the lactate threshold (LT) in cyclists; and to determine the reliability of supramaximal power outputs linearly projected from these relationships. Nine male cyclists (mean±standard deviation age: 41±8 years; mass: 77±6 kg, height: 1.79±0.05 m and V̇O2max: 54±7 mL∙kg-1∙min-1) completed two cycling trials each consisting of a step test (10×3 min stages at submaximal incremental intensities) followed by a maximal test to exhaustion. The lines of best fit for V̇O2 and power output were determined for: the entire step test; stages below and above the LT, and from rolling clusters of five consecutive stages. Lines were projected to determine a power output predicted to elicit 110% peak V̇O2. There were strong linear correlations (r≥0.953; P<0.01) between V̇O2 and power output using the three approaches; with the slope, intercept, and projected values of these lines unaffected (P≥0.05) by intensity. The coefficient of variation of the predicted power output at 110% V̇O2max was 6.7% when using all ten submaximal stages. Cyclists exhibit a linear V̇O2 and power output relationship when determined using 3 min stages, which allows for prediction of a supramaximal intensity with acceptable reliability.

Cycling Injuries in Southwest Colorado: A Comparison of Road vs Trail Riding Injury Patterns.

PubMed

Kotlyar, Simon

2016-06-01

To describe the epidemiology of injuries sustained in cyclists and compare the injury patterns in road vs trail biking accidents. A retrospective chart review was performed of injured road and trail cyclists presenting to a rural mountain resort-based medical center during a 3-year study period. Of 304 patients, 70% were male, with 67% sustaining trail injuries and 33% sustaining road cycling injuries. There was a bimodal age distribution. Prehospital care was activated in 16% of patients. The most common injuries were lacerations and abrasions (64%), upper extremity fractures (26%), head injuries (9%), and thoracic trauma (6%). Head injury was more common in road- vs trail-related trauma (16% vs 6%; P = .005), whereas thoracic injury was more common in trail riders (7% vs 2%; P = .053). Head injury and lower extremit y fracture were the most common reasons for patient transfer. Patients with head injuries who did not use a helmet were more likely to require transfer to a neurosurgical unit (38% vs 17%; P = .296); however, this difference did not meet statistical significance. Lacerations and abrasions are the most common injuries sustained in cycling. Quantifying the role of protective extremity gear in reducing these injury patterns may be of interest for future studies. Protective helmet use may be important in reducing morbidity from cycling-related head trauma; however, more data are needed. Prehospital care providers responding to the injured trail cyclist should be equipped to manage laceration, fracture, head injury, and thoracic trauma in the field. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Heat acclimatization does not improve VO2max or cycling performance in a cool climate in trained cyclists.

PubMed

Karlsen, A; Racinais, S; Jensen, M V; Nørgaard, S J; Bonne, T; Nybo, L

2015-06-01

This study investigated if well-trained cyclists improve V ˙ O 2 m a x and performance in cool conditions following heat acclimatization through natural outdoor training in hot conditions. Eighteen trained male cyclists were tested for physiological adaptations, V ˙ O 2 m a x , peak aerobic power output, exercise efficiency, and outdoor time trial (TT) performance (43.4 km in cool environment, ∼5-13 °C) before and after 2 weeks of training in a cool (CON, n = 9) or hot (∼35 °C, HA, n = 9) environment. After heat acclimatization, TT performance in the heat was improved by 16%; however, there was no change in the HA group in V ˙ O 2 m a x (4.79 ± 0.21 L/min vs 4.82 ± 0.35 L/min), peak aerobic power output (417 ± 16 W vs 422 ± 17 W), and outdoor TT performance in cool conditions (300 ± 14 W/69 ± 3 min vs 302 ± 9 W/69 ± 4 min). The present study shows that 2 weeks of heat acclimatization was associated with marked improvements in TT performance in the heat. However, for the well-trained endurance athletes, this did not transfer to an improved aerobic exercise capacity or outdoor TT performance in cool conditions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Evaluation of transportation microenvironments through assessment of cyclists' exposure to traffic related particulate matter.

DOT National Transportation Integrated Search

2011-03-01

Urban residents spend a considerable amount of outdoor time in transportation microenvironments as pedestrians, bicycle commuters, public transit users, residents and workers situated along roadways, and commuters within vehicles. Within these transp...

Evaluation of bike boxes at signalized intersections.

DOT National Transportation Integrated Search

2011-01-01

This report presents a before-after study of bike boxes at 10 signalized intersections in Portland, Oregon. The bike boxes, also known as advanced stop lines or advanced stop boxes, were installed to increase visibility of cyclists and reduce conflic...

Evaluation of transit bus turn warning systems for pedestrians and cyclists.

DOT National Transportation Integrated Search

2015-05-01

As part of a cooperative agreement with the Federal Transit Administration (FTA), the Tri-County Metropolitan Transportation District of Oregon (TriMet) conducted a demonstration test of three commercially-available pedestrian turn warning systems fo...

Bicycle accidents among teenagers

DOT National Transportation Integrated Search

2001-10-01

The report shows that knowledge of traffic rules does not contribute to reduce the accident risk, or injury risk of young cyclists. Running red lights and cycling in the wrong direction in one-way traffic increase accident and injury risk. Using cycl...

Cycling in the African American Community : safety training guidelines and findings.

DOT National Transportation Integrated Search

2013-08-01

This report is a program users manual for the Cycling in the African American Community (CAAC) safety training intervention. The CAAC safety training intervention was designed to nudge more African Americans, who are often beginning cyclists...

Fiber Type-Specific Satellite Cell Content in Cyclists Following Heavy Training with Carbohydrate and Carbohydrate-Protein Supplementation

PubMed Central

McKenzie, Alec I.; D'Lugos, Andrew C.; Saunders, Michael J.; Gworek, Keith D.; Luden, Nicholas D.

2016-01-01

The central purpose of this study was to evaluate the fiber type-specific satellite cell and myonuclear responses of endurance-trained cyclists to a block of intensified training, when supplementing with carbohydrate (CHO) vs. carbohydrate-protein (PRO). In a crossover design, endurance-trained cyclists (n = 8) performed two consecutive training periods, once supplementing with CHO (de facto “control” condition) and the other with PRO. Each training period consisted of 10 days of intensified cycle training (ICT–120% increase in average training duration) followed by 10 days of recovery (RVT–reduced volume training; 33% volume reduction vs. normal training). Skeletal muscle biopsies were obtained from the vastus lateralis before and after ICT and again following RVT. Immunofluorescent microscopy was used to quantify SCs (Pax7+), myonuclei (DAPI+), and myosin heavy chain I (MyHC I). Data are expressed as percent change ± 90% confidence limits. The 10-day block of ICTCHO increased MyHC I SC content (35 ± 28%) and myonuclear density (16 ± 6%), which remained elevated following RVTCHO (SC = 69 ± 50% vs. PRE; Nuclei = 17 ± 15% vs. PRE). MyHC II SC and myonuclei were not different following ICTCHO, but were higher following RVTCHO (SC = +33 ± 31% vs. PRE; Nuclei = 15 ± 14% vs. PRE), indicating a delayed response compared to MyHC I fibers. The MyHC I SC pool increased following ICTPRO (37 ± 37%), but without a concomitant increase in myonuclei. There were no changes in MyHC II SC or myonuclei following ICTPRO. Collectively, these trained endurance cyclists possessed a relatively large pool of SCs that facilitated rapid (MyHC I) and delayed (MyHC II) satellite cell proliferation and myonuclear accretion under carbohydrate conditions. The current findings strengthen the growing body of evidence demonstrating alterations in satellite cell number in the absence of hypertrophy. Satellite cell pool expansion is typically viewed as an advantageous response to exercise. However, when coupled with our previous report that PRO possibly enhanced whole muscle recovery and increased MyHC I and II fiber size, the limited satellite cell/myonuclear response observed with carbohydrate-protein seem to indicate that protein supplementation may have minimized the necessity for satellite cell involvement, thereby suggesting that protein may benefit skeletal muscle during periods of heavy training. PMID:27899900

Measuring pedestrian exposure and risk in high-risk areas : final report.

DOT National Transportation Integrated Search

2016-11-01

For the past three years, UDOT has been studying characteristics of high- and low-risk intersections for pedestrians : and cyclists in an effort to better understand what creates a dangerous environment for non-motorized travelers. : This research ha...

Risk Assessment of Non-Motorized Access to Rail Transit Stations

DOT National Transportation Integrated Search

2018-01-01

Over the past decade, the agency has undertaken multiple efforts to better understand the various components that contribute to safety for vulnerable road users. One major destination type that attracts a large number of pedestrians and cyclists is t...

Expanding transportation systems management and operations (TSM&O) from planning to construction primer : [summary].

DOT National Transportation Integrated Search

2016-01-01

Floridas increasing population leads to more road users of all types: pedestrians, cyclists, public : transit, trucks, and automobiles. Because funds and right-of-way are often unavailable to : increase highway capacity through expansion, effectiv...

Development of a portable bicycle/pedestrian monitoring system for safety enhancement.

DOT National Transportation Integrated Search

2017-02-02

The objective of this project was to develop a portable automated system to collect continuous video data on pedestrian and cyclist behavior at midblock locations throughout the metro Atlanta area. The system analyzes the collected video data and aut...

An illustrated analysis of North Carolina traffic crash statistics for 2006

DOT National Transportation Integrated Search

2006-01-01

This books purpose is to serve as a resource for traffic safety experts, : public officials and those interested in making North Carolinas roadways, : sidewalks and pedal-cyclist paths safe for all of us who travel on them. It : presents detail...

Utilizing ego-centric video to conduct naturalistic bicycling studies.

DOT National Transportation Integrated Search

2016-10-01

Existing data collection methods are mostly designed for videos captured by stationary cameras and are not designed to follow cyclists along a : route or to integrate other sensor data. The goals of this research are: a) to develop a platform to coll...

Five-Kilometers Time Trial: Preliminary Validation of a Short Test for Cycling Performance Evaluation.

PubMed

Dantas, Jose Luiz; Pereira, Gleber; Nakamura, Fabio Yuzo

2015-09-01

The five-kilometer time trial (TT5km) has been used to assess aerobic endurance performance without further investigation of its validity. This study aimed to perform a preliminary validation of the TT5km to rank well-trained cyclists based on aerobic endurance fitness and assess changes of the aerobic endurance performance. After the incremental test, 20 cyclists (age = 31.3 ± 7.9 years; body mass index = 22.7 ± 1.5 kg/m(2); maximal aerobic power = 360.5 ± 49.5 W) performed the TT5km twice, collecting performance (time to complete, absolute and relative power output, average speed) and physiological responses (heart rate and electromyography activity). The validation criteria were pacing strategy, absolute and relative reliability, validity, and sensitivity. Sensitivity index was obtained from the ratio between the smallest worthwhile change and typical error. The TT5km showed high absolute (coefficient of variation < 3%) and relative (intraclass coefficient correlation > 0.95) reliability of performance variables, whereas it presented low reliability of physiological responses. The TT5km performance variables were highly correlated with the aerobic endurance indices obtained from incremental test (r > 0.70). These variables showed adequate sensitivity index (> 1). TT5km is a valid test to rank the aerobic endurance fitness of well-trained cyclists and to differentiate changes on aerobic endurance performance. Coaches can detect performance changes through either absolute (± 17.7 W) or relative power output (± 0.3 W.kg(-1)), the time to complete the test (± 13.4 s) and the average speed (± 1.0 km.h(-1)). Furthermore, TT5km performance can also be used to rank the athletes according to their aerobic endurance fitness.

Physiological and psychological responses to outdoor vs. laboratory cycling.

PubMed

Mieras, Molly E; Heesch, Matthew W S; Slivka, Dustin R

2014-08-01

The purpose of this study was to determine the physiological and psychological responses to laboratory vs. outdoor cycling. Twelve recreationally trained male cyclists participated in an initial descriptive testing session and 2 experimental trials consisting of 1 laboratory and 1 outdoor session, in a randomized order. Participants were given a standardized statement instructing them to give the same perceived effort for both the laboratory and outdoor 40-km trials. Variables measured include power output, heart rate (HR), core temperature, skin temperature, body weight, urine specific gravity (USG), Rating of Perceived Exertion (RPE), attentional focus, and environmental conditions. Wind speed was higher in the outdoor trial than in the laboratory trial (2.5 ± 0.6 vs. 0.0 ± 0.0 m·s-1, p = 0.02) whereas all other environmental conditions were similar. Power output (208.1 ± 10.2 vs. 163.4 ± 11.8 W, respectively, p < 0.001) and HR (152 ± 4 and 143 ± 6 b·min-1, respectively, p = 0.04) were higher in the outdoor trial than in the laboratory trial. Core temperature was similar, whereas skin temperature was cooler during the outdoor trial than during the laboratory trial (31.4 ± 0.3 vs. 33.0 ± 0.2° C, respectively, p < 0.001), thus creating a larger thermal gradient between the core and skin outdoors. No significant differences in body weight, USG, RPE, or attentional focus were observed between trials. These data indicate that outdoor cycling allows cyclists to exercise at a higher intensity than in laboratory cycling, despite similar environmental conditions and perceived exertion. In light of this, cyclists may want to ride at a higher perceived exertion in indoor settings to acquire the same benefit as they would from an outdoor ride.

Maximal lipidic power in high competitive level triathletes and cyclists

PubMed Central

González‐Haro, C; Galilea, P A; González‐de‐Suso, J M; Drobnic, F; Escanero, J F

2007-01-01

Objective To describe the fat‐oxidation rate in triathlon and different modalities of endurance cycling. Methods 34 endurance athletes (15 male triathletes, 4 female triathletes, 11 road cyclists and 4 male mountain bikers) underwent a progressive cycloergometer test until exhaustion. Relative work intensity (VO2max), minimal lactate concentration (La−min), lactic threshold, individual lactic threshold (ILT), maximal fat‐oxidation rate (Fatmax, Fatmax zone) and minimal fat‐oxidation rate (Fatmin) were determined in each of the groups and were compared by means of one‐way analysis of variance. Results No significant differences were found for Fatmax, Fatmin or for the Fatmax zone expressed as fat oxidation rate (g/min). Intensities −20%, −10% and −5% Fatmax were significantly lower for mountain bikers with respect to road cyclists and female triathletes, expressed as % VO2max. Intensities 20%, 10% and 5% Fatmax were significantly lower for mountain bikers with respect to male triathletes and female triathletes, and for male triathletes in comparison with female triathletes, expressed as % VO2max. Lactic threshold and La−min did not show significant differences with respect to Fatmax. Lactic threshold was found at the same VO2max with respect to the higher part of the Fatmax zone, and La−min at the same VO2max with respect to the lower part of the Fatmax zone. Conclusions The VO2max of Fatmax and the Fatmax zone may explain the different endurance adaptations of the athletes according to their sporting discipline. Lactic threshold and La−min were found at different relative work intensities with respect to those of Fatmax even though they belonged to the Fatmax zone. PMID:17062656

Pacing Strategy, Muscle Fatigue, and Technique in 1500-m Speed-Skating and Cycling Time Trials.

PubMed

Stoter, Inge K; MacIntosh, Brian R; Fletcher, Jared R; Pootz, Spencer; Zijdewind, Inge; Hettinga, Florentina J

2016-04-01

To evaluate pacing behavior and peripheral and central contributions to muscle fatigue in 1500-m speed-skating and cycling time trials when a faster or slower start is instructed. Nine speed skaters and 9 cyclists, all competing at regional or national level, performed two 1500-m time trials in their sport. Athletes were instructed to start faster than usual in 1 trial and slower in the other. Mean velocity was measured per 100 m. Blood lactate concentrations were measured. Maximal voluntary contraction (MVC), voluntary activation (VA), and potentiated twitch (PT) of the quadriceps muscles were measured to estimate central and peripheral contributions to muscle fatigue. In speed skating, knee, hip, and trunk angles were measured to evaluate technique. Cyclists showed a more explosive start than speed skaters in the fast-start time trial (cyclists performed first 300 m in 24.70 ± 1.73 s, speed skaters in 26.18 ± 0.79 s). Both trials resulted in reduced MVC (12.0% ± 14.5%), VA (2.4% ± 5.0%), and PT (25.4% ± 15.2%). Blood lactate concentrations after the time trial and the decrease in PT were greater in the fast-start than in the slow-start trial. Speed skaters showed higher trunk angles in the fast-start than in the slow-start trial, while knee angles remained similar. Despite similar instructions, behavioral adaptations in pacing differed between the 2 sports, resulting in equal central and peripheral contributions to muscle fatigue in both sports. This provides evidence for the importance of neurophysiological aspects in the regulation of pacing. It also stresses the notion that optimal pacing needs to be studied sport specifically, and coaches should be aware of this.

The Positive Effects of Priming Exercise on Oxygen Uptake Kinetics and High-Intensity Exercise Performance Are Not Magnified by a Fast-Start Pacing Strategy in Trained Cyclists

PubMed Central

Caritá, Renato Aparecido Corrêa; Greco, Camila Coelho; Denadai, Benedito Sérgio

2014-01-01

The purpose of this study was to determine both the independent and additive effects of prior heavy-intensity exercise and pacing strategies on the VO2 kinetics and performance during high-intensity exercise. Fourteen endurance cyclists (VO2max  = 62.8±8.5 mL.kg−1.min−1) volunteered to participate in the present study with the following protocols: 1) incremental test to determine lactate threshold and VO2max; 2) four maximal constant-load tests to estimate critical power; 3) six bouts of exercise, using a fast-start (FS), even-start (ES) or slow-start (SS) pacing strategy, with and without a preceding heavy-intensity exercise session (i.e., 90% critical power). In all conditions, the subjects completed an all-out sprint during the final 60 s of the test as a measure of the performance. For the control condition, the mean response time was significantly shorter (p<0.001) for FS (27±4 s) than for ES (32±5 s) and SS (32±6 s). After the prior exercise, the mean response time was not significantly different among the paced conditions (FS = 24±5 s; ES = 25±5 s; SS = 26±5 s). The end-sprint performance (i.e., mean power output) was only improved (∼3.2%, p<0.01) by prior exercise. Thus, in trained endurance cyclists, an FS pacing strategy does not magnify the positive effects of priming exercise on the overall VO2 kinetics and short-term high-intensity performance. PMID:24740278

Angular position of the cleat according to torsional parameters of the cyclist's lower limb.

PubMed

Ramos-Ortega, Javier; Domínguez, Gabriel; Castillo, José Manuel; Fernández-Seguín, Lourdes; Munuera, Pedro V

2014-05-01

The aim of this work was to study the relationship of torsional and rotational parameters of the lower limb with a specific angular position of the cleat to establish whether these variables affect the adjustment of the cleat. Correlational study. Motion analysis laboratory. Thirty-seven male cyclists of high performance. The variables studied of the cyclist's lower limb were hip rotation (internal and external), tibial torsion angle, Q angle, and forefoot adductus angle. The cleat angle was measured through a photograph of the sole and with an Rx of this using the software AutoCAD 2008. The variables were photograph angle (photograph), the variable denominated cleat-tarsus minor angle, and a variable denominated cleat-second metatarsal angle (Rx). Analysis included the intraclass correlation coefficient for the reliability of the measurements, Student's t test performed on the dependent variables to compare side, and the multiple linear regression models were calculated using the software SPSS 15.0 for Windows. The Student's t test performed on the dependent variables to compare side showed no significant differences (P = 0.209 for the photograph angle, P = 0.735 for the cleat-tarsus minor angle, and P = 0.801 for the cleat-second metatarsal angle). Values of R and R2 for the photograph angle model were 0.303 and 0.092 (P = 0.08), the cleat/tarsus minor angle model were 0.683 and 0.466 (P < 0.001), and the cleat/second metatarsal angle model were 0.618 and 0.382, respectively (P < 0.001). The equation given by the model was cleat-tarsus minor angle = 75.094 - (0.521 × forefoot adductus angle) + (0.116 × outward rotation of the hips) + (0.220 × Q angle).

The influence of cadence and power output on force application and in-shoe pressure distribution during cycling by competitive and recreational cyclists.

PubMed

Sanderson, D J; Hennig, E M; Black, A H

2000-03-01

The aim of this study was to determine the response of cyclists to manipulations of cadence and power output in terms of force application and plantar pressure distribution. Two groups of cyclists, 17 recreational and 12 competitive, rode at three nominal cadences (60, 80, 100 rev x min(-1)) and four power outputs (100, 200, 300, 400 W) while simultaneous force and in-shoe pressure data were collected. Two piezoelectric triaxial force transducers mounted in the right pedal measured components of the pedal force and orientation, and a discrete transducer system with 12 transducers recorded the in-shoe pressures. Force application was characterized by calculating peak resultant and peak effective pedal forces and positive and negative impulses. In-shoe pressures were analysed as peak pressures and as the percent relative load. The force data showed no significant group effect but there was a cadence and power main effect. The impulse data showed a significant three-way interaction. Increased cadence resulted in a decreased positive impulse, while increased power output resulted in an increased impulse. The competitive group produced less positive impulse but the difference became less at higher cadences. Few between-group differences were found in pressure, notable only in the pressure under the first metatarsal region. This showed a consistent pattern of in-shoe pressure distribution, where the primary loading structures were the first metatarsal and hallux. There was no indication that pressure at specific sites influenced the pedal force application. The absence of group differences indicated that pressure distribution was not the result of training, but reflected the intrinsic relationship between the foot, the shoe and the pedal.

Effects of Beta-Alanine Supplementation on Brain Homocarnosine/Carnosine Signal and Cognitive Function: An Exploratory Study

PubMed Central

Hobson, Ruth M; Artioli, Guilherme G.; Otaduy, Maria C.; Roschel, Hamilton; Robertson, Jacques; Martin, Daniel; S. Painelli, Vitor; Harris, Roger C.; Gualano, Bruno

2015-01-01

Objectives Two independent studies were conducted to examine the effects of 28 d of beta-alanine supplementation at 6.4 g d-1 on brain homocarnosine/carnosine signal in omnivores and vegetarians (Study 1) and on cognitive function before and after exercise in trained cyclists (Study 2). Methods In Study 1, seven healthy vegetarians (3 women and 4 men) and seven age- and sex-matched omnivores undertook a brain 1H-MRS exam at baseline and after beta-alanine supplementation. In study 2, nineteen trained male cyclists completed four 20-Km cycling time trials (two pre supplementation and two post supplementation), with a battery of cognitive function tests (Stroop test, Sternberg paradigm, Rapid Visual Information Processing task) being performed before and after exercise on each occasion. Results In Study 1, there were no within-group effects of beta-alanine supplementation on brain homocarnosine/carnosine signal in either vegetarians (p = 0.99) or omnivores (p = 0.27); nor was there any effect when data from both groups were pooled (p = 0.19). Similarly, there was no group by time interaction for brain homocarnosine/carnosine signal (p = 0.27). In study 2, exercise improved cognitive function across all tests (P<0.05), although there was no effect (P>0.05) of beta-alanine supplementation on response times or accuracy for the Stroop test, Sternberg paradigm or RVIP task at rest or after exercise. Conclusion 28 d of beta-alanine supplementation at 6.4g d-1 appeared not to influence brain homocarnosine/carnosine signal in either omnivores or vegetarians; nor did it influence cognitive function before or after exercise in trained cyclists. PMID:25875297

Road safety: serious injuries remain a major unsolved problem.

PubMed

Beck, Ben; Cameron, Peter A; Fitzgerald, Mark C; Judson, Rodney T; Teague, Warwick; Lyons, Ronan A; Gabbe, Belinda J

2017-09-18

To investigate temporal trends in the incidence, mortality, disability-adjusted life-years (DALYs), and costs of health loss caused by serious road traffic injury. A retrospective review of data from the population-based Victorian State Trauma Registry and the National Coronial Information System on road traffic-related deaths (pre- and in-hospital) and major trauma (Injury Severity Score > 12) during 2007-2015.Main outcomes and measures: Temporal trends in the incidence of road traffic-related major trauma, mortality, DALYs, and costs of health loss, by road user type. There were 8066 hospitalised road traffic major trauma cases and 2588 road traffic fatalities in Victoria over the 9-year study period. There was no change in the incidence of hospitalised major trauma for motor vehicle occupants (incidence rate ratio [IRR] per year, 1.00; 95% CI, 0.99-1.01; P = 0.70), motorcyclists (IRR, 0.99; 95% CI, 0.97-1.01; P = 0.45) or pedestrians (IRR, 1.00; 95% CI, 0.97-1.02; P = 0.73), but the incidence for pedal cyclists increased 8% per year (IRR, 1.08; 95% CI; 1.05-1.10; P < 0.001). While DALYs declined for motor vehicle occupants (by 13% between 2007 and 2015), motorcyclists (32%), and pedestrians (5%), there was a 56% increase in DALYs for pedal cyclists. The estimated costs of health loss associated with road traffic injuries exceeded $14 billion during 2007-2015, although the cost per patient declined for all road user groups. As serious injury rates have not declined, current road safety targets will be difficult to meet. Greater attention to preventing serious injury is needed, as is further investment in road safety, particularly for pedal cyclists.

Evidence of disturbed sleep and mood state in well-trained athletes during short-term intensified training with and without a high carbohydrate nutritional intervention.

PubMed

Killer, S C; Svendsen, I S; Jeukendrup, A E; Gleeson, M

2017-07-01

Few studies have investigated the effects of exercise training on sleep physiology in well-trained athletes. We investigated changes in sleep markers, mood state and exercise performance in well-trained cyclists undergoing short-term intensified training and carbohydrate nutritional intervention. Thirteen highly-trained male cyclists (age: 25 ± 6y, [Formula: see text]O 2max : 72 ± 5 ml/kg/min) participated in two 9-day periods of intensified training while undergoing a high (HCHO) or moderate (CON) carbohydrate nutritional intervention before, during and after training sessions. Sleep was measured each night via wristwatch actigraphy. Mood state questionnaires were completed daily. Performance was assessed with maximal oxygen uptake ([Formula: see text]. Percentage sleep time fell during intensified training (87.9 ± 1.5 to 82.5 ± 2.3%; p < 0.05) despite an increase in time in bed (456 ± 50 to 509 ± 48 min; p = 0.02). Sleep efficiency decreased during intensified training (83.1 ± 5.3 to 77.8 ± 8.6%; p < 0.05). Actual sleep time was significantly higher in CON than HCHO throughout intensified training. Mood disturbance increased during intensified training and was higher in CON than HCHO (p < 0.05). Performance in the [Formula: see text] exercise protocol fell significantly with intensified training. The main findings of this study were that 9-days of intensified training in highly-trained cyclists resulted in significant and progressive declines in sleep quality, mood state and maximal exercise performance.

Sodium bicarbonate improves 4 km time trial cycling performance when individualised to time to peak blood bicarbonate in trained male cyclists.

PubMed

Gough, Lewis A; Deb, Sanjoy K; Sparks, S Andy; McNaughton, Lars R

2018-08-01

The aim of this study was to investigate the effects of sodium bicarbonate (NaHCO 3 ) on 4 km cycling time trial (TT) performance when individualised to a predetermined time to peak blood bicarbonate (HCO 3 - ). Eleven male trained cyclists volunteered for this study (height 1.82 ± 0.80 m, body mass (BM) 86.4 ± 12.9 kg, age 32 ± 9 years, peak power output (PPO) 382 ± 22 W). Two trials were initially conducted to identify time to peak HCO 3 - following both 0.2 g . kg -1 BM (SBC2) and 0.3 g . kg -1 BM (SBC3) NaHCO 3 . Thereafter, on three separate occasions using a randomised, double-blind, crossover design, participants completed a 4 km TT following ingestion of either SBC2, SBC3, or a taste-matched placebo (PLA) containing 0.07 g . kg -1 BM sodium chloride (NaCl) at the predetermined individual time to peak HCO 3 - . Both SBC2 (-8.3 ± 3.5 s; p < 0.001, d = 0.64) and SBC3 (-8.6 ± 5.4 s; p = 0.003, d = 0.66) reduced the time to complete the 4 km TT, with no difference between SBC conditions (mean difference = 0.2 ± 0.2 s; p = 0.87, d = 0.02). These findings suggest trained cyclists may benefit from individualising NaHCO 3 ingestion to time to peak HCO 3 - to enhance 4 km TT performance.

Fructose and Sucrose Intake Increase Exogenous Carbohydrate Oxidation during Exercise

PubMed Central

Trommelen, Jorn; Fuchs, Cas J.; Beelen, Milou; Lenaerts, Kaatje; Jeukendrup, Asker E.; Cermak, Naomi M.; van Loon, Luc J. C.

2017-01-01

Peak exogenous carbohydrate oxidation rates typically reach ~1 g·min−1 during exercise when ample glucose or glucose polymers are ingested. Fructose co-ingestion has been shown to further increase exogenous carbohydrate oxidation rates. The purpose of this study was to assess the impact of fructose co-ingestion provided either as a monosaccharide or as part of the disaccharide sucrose on exogenous carbohydrate oxidation rates during prolonged exercise in trained cyclists. Ten trained male cyclists (VO2peak: 65 ± 2 mL·kg−1·min−1) cycled on four different occasions for 180 min at 50% Wmax during which they consumed a carbohydrate solution providing 1.8 g·min−1 of glucose (GLU), 1.2 g·min−1 glucose + 0.6 g·min−1 fructose (GLU + FRU), 0.6 g·min−1 glucose + 1.2 g·min−1 sucrose (GLU + SUC), or water (WAT). Peak exogenous carbohydrate oxidation rates did not differ between GLU + FRU and GLU + SUC (1.40 ± 0.06 vs. 1.29 ± 0.07 g·min−1, respectively, p = 0.999), but were 46% ± 8% higher when compared to GLU (0.96 ± 0.06 g·min−1: p < 0.05). In line, exogenous carbohydrate oxidation rates during the latter 120 min of exercise were 46% ± 8% higher in GLU + FRU or GLU + SUC compared with GLU (1.19 ± 0.12, 1.13 ± 0.21, and 0.82 ± 0.16 g·min−1, respectively, p < 0.05). We conclude that fructose co-ingestion (0.6 g·min−1) with glucose (1.2 g·min−1) provided either as a monosaccharide or as sucrose strongly increases exogenous carbohydrate oxidation rates during prolonged exercise in trained cyclists. PMID:28230742

Fructose and Sucrose Intake Increase Exogenous  Carbohydrate Oxidation during Exercise.

PubMed

Trommelen, Jorn; Fuchs, Cas J; Beelen, Milou; Lenaerts, Kaatje; Jeukendrup, Asker E; Cermak, Naomi M; van Loon, Luc J C

2017-02-20

Peak exogenous carbohydrate oxidation rates typically reach ~1 g∙min-1 during exercise when ample glucose or glucose polymers are ingested. Fructose co-ingestion has been shown to further increase exogenous carbohydrate oxidation rates. The purpose of this study was to assess the impact of fructose co-ingestion provided either as a monosaccharide or as part of the disaccharide sucrose on exogenous carbohydrate oxidation rates during prolonged exercise in trained cyclists. Ten trained male cyclists (VO2peak: 65 ± 2 mL∙kg-1∙min-1) cycled on four different occasions for 180 min at 50% Wmax during which they consumed a carbohydrate solution providing 1.8 g∙min-1 of glucose (GLU), 1.2 g∙min-1 glucose + 0.6 g∙min-1 fructose (GLU + FRU), 0.6 g∙min-1 glucose + 1.2 g∙min-1 sucrose (GLU + SUC), or water (WAT). Peak exogenous carbohydrate oxidation rates did not differ between GLU + FRU and GLU + SUC (1.40 ± 0.06 vs. 1.29 ± 0.07 g∙min-1, respectively, p = 0.999), but were 46% ± 8% higher when compared to GLU (0.96 ± 0.06 g∙min-1: p < 0.05). In line, exogenous carbohydrate oxidation rates during the latter 120 min of exercise were 46% ± 8% higher in GLU + FRU or GLU + SUC compared with GLU (1.19 ± 0.12, 1.13 ± 0.21, and 0.82 ± 0.16 g∙min-1, respectively, p < 0.05). We conclude that fructose co-ingestion (0.6 g∙min-1) with glucose (1.2 g∙min-1) provided either as a monosaccharide or as sucrose strongly increases exogenous carbohydrate oxidation rates during prolonged exercise in trained cyclists.

Effects of beta-alanine supplementation on brain homocarnosine/carnosine signal and cognitive function: an exploratory study.

PubMed

Solis, Marina Yazigi; Cooper, Simon; Hobson, Ruth M; Artioli, Guilherme G; Otaduy, Maria C; Roschel, Hamilton; Robertson, Jacques; Martin, Daniel; S Painelli, Vitor; Harris, Roger C; Gualano, Bruno; Sale, Craig

2015-01-01

Two independent studies were conducted to examine the effects of 28 d of beta-alanine supplementation at 6.4 g d(-1) on brain homocarnosine/carnosine signal in omnivores and vegetarians (Study 1) and on cognitive function before and after exercise in trained cyclists (Study 2). In Study 1, seven healthy vegetarians (3 women and 4 men) and seven age- and sex-matched omnivores undertook a brain 1H-MRS exam at baseline and after beta-alanine supplementation. In study 2, nineteen trained male cyclists completed four 20-Km cycling time trials (two pre supplementation and two post supplementation), with a battery of cognitive function tests (Stroop test, Sternberg paradigm, Rapid Visual Information Processing task) being performed before and after exercise on each occasion. In Study 1, there were no within-group effects of beta-alanine supplementation on brain homocarnosine/carnosine signal in either vegetarians (p = 0.99) or omnivores (p = 0.27); nor was there any effect when data from both groups were pooled (p = 0.19). Similarly, there was no group by time interaction for brain homocarnosine/carnosine signal (p = 0.27). In study 2, exercise improved cognitive function across all tests (P < 0.05), although there was no effect (P>0.05) of beta-alanine supplementation on response times or accuracy for the Stroop test, Sternberg paradigm or RVIP task at rest or after exercise. 28 d of beta-alanine supplementation at 6.4 g d(-1) appeared not to influence brain homocarnosine/carnosine signal in either omnivores or vegetarians; nor did it influence cognitive function before or after exercise in trained cyclists.

High-intensity Interval Training in Different Exercise Modes: Lessons from Time to Exhaustion.

PubMed

Sousa, Ana Catarina; Fernandes, Ricardo J; Boas, Joao Paulo Vilas; Figueiredo, Pedro

2018-06-20

To provide information for high-intensity interval training (HIIT) load, we compared the temporal variables of VO 2 response at, and after, a time sustained at the exercise intensity corresponding to VO 2max (Tlim) in different exercise modes. Forty-five trained male swimmers (11), rowers (13), runners (10) and cyclists (11) completed an incremental protocol to determine the velocity (vVO 2max ) or power (wVO 2max ) at VO 2max and a square wave exercise from rest to 100% of vVO 2max /wVO 2max . The temporal variables of VO 2 response were examined using a breath-by-breath gas analyzer. VO 2 responses were not different between exercise modes, except for the percentage of VO 2max at 50% of Tlim, which was ~6% higher in rowing compared to cycling (97.70±2.90 vs 92.40±5.69%, p =0.013). During the recovery period, both swimmers and rowers evidenced higher percentages of VO 2max compared to cyclists at 30 s (65.1±10.4 and 65.7±5.6 vs 52.7±5.6%) and 60 s (41.7±10.8 and 38.4±5.4 vs 30.4±1.8%) time periods, all for p< 0.01. Furthermore, swimmers presented higher time values to reach 50% VO 2max compared to runners and cyclists (51.1±15.6 vs 38.1±6.7 and 33.8±4.7%; p <0.001). When training at 100% of VO 2max intensity, fixed intervals for HIIT could be set freely. However, recovery periods based on time or intensity are exercise-mode dependent. © Georg Thieme Verlag KG Stuttgart · New York.

Effect of Heat and Heat Acclimatization on Cycling Time Trial Performance and Pacing

PubMed Central

RACINAIS, SEBASTIEN; PÉRIARD, JULIEN D.; KARLSEN, ANDERS; NYBO, LARS

2015-01-01

ABSTRACT Purpose This study aimed to determine the effects of heat acclimatization on performance and pacing during outdoor cycling time trials (TT, 43.4 km) in the heat. Methods Nine cyclists performed three TT in hot ambient conditions (TTH, approximately 37°C) on the first (TTH-1), sixth (TTH-2), and 14th (TTH-3) days of training in the heat. Data were compared with the average of two TT in cool condition (approximately 8°C) performed before and after heat acclimatization (TTC). Results TTH-1 (77 ± 6 min) was slower (P = 0.001) than TTH-2 (69 ± 5 min), and both were slower (P < 0.01) than TTC and TTH-3 (66 ± 3 and 66 ± 4 min, respectively), without differences between TTC and TTH-3 (P > 0.05). The cyclists initiated the first 20% of all TT at a similar power output, irrespective of climate and acclimatization status; however, during TTH-1, they subsequently had a marked decrease in power output, which was partly attenuated after 6 d of acclimatization and was further reduced after 14 d. HR was higher during the first 20% of TTH-1 than that in the other TT (P < 0.05), but there were no differences between conditions from 30% onward. Final rectal temperature was similar in all TTH (40.2°C ± 0.4°C, P = 1.000) and higher than that in TTC (38.5°C ± 0.6°C, P < 0.001). Conclusions After 2 wk of acclimatization, trained cyclists are capable of completing a prolonged TT in a similar time in the heat compared with cool conditions, whereas in the unacclimatized state, they experienced a marked decrease in power output during the TTH. PMID:24977692

The effect of post-exercise hydrotherapy on subsequent exercise performance and heart rate variability.

PubMed

Stanley, Jamie; Buchheit, Martin; Peake, Jonathan M

2012-03-01

We investigated the effect of hydrotherapy on time-trial performance and cardiac parasympathetic reactivation during recovery from intense training. On three occasions, 18 well-trained cyclists completed 60 min high-intensity cycling, followed 20 min later by one of three 10-min recovery interventions: passive rest (PAS), cold water immersion (CWI), or contrast water immersion (CWT). The cyclists then rested quietly for 160 min with R-R intervals and perceptions of recovery recorded every 30 min. Cardiac parasympathetic activity was evaluated using the natural logarithm of the square root of mean squared differences of successive R-R intervals (ln rMSSD). Finally, the cyclists completed a work-based cycling time trial. Effects were examined using magnitude-based inferences. Differences in time-trial performance between the three trials were trivial. Compared with PAS, general fatigue was very likely lower for CWI (difference [90% confidence limits; -12% (-18; -5)]) and CWT [-11% (-19; -2)]. Leg soreness was almost certainly lower following CWI [-22% (-30; -14)] and CWT [-27% (-37; -15)]. The change in mean ln rMSSD following the recovery interventions (ln rMSSD(Post-interv)) was almost certainly higher following CWI [16.0% (10.4; 23.2)] and very likely higher following CWT [12.5% (5.5; 20.0)] compared with PAS, and possibly higher following CWI [3.7% (-0.9; 8.4)] compared with CWT. The correlations between performance, ln rMSSD(Post-interv) and perceptions of recovery were unclear. A moderate correlation was observed between ln rMSSD(Post-interv) and leg soreness [r = -0.50 (-0.66; -0.29)]. Although the effects of CWI and CWT on performance were trivial, the beneficial effects on perceptions of recovery support the use of these recovery strategies.

Effect of heat and heat acclimatization on cycling time trial performance and pacing.

PubMed

Racinais, Sebastien; Périard, Julien D; Karlsen, Anders; Nybo, Lars

2015-03-01

This study aimed to determine the effects of heat acclimatization on performance and pacing during outdoor cycling time trials (TT, 43.4 km) in the heat. Nine cyclists performed three TT in hot ambient conditions (TTH, approximately 37°C) on the first (TTH-1), sixth (TTH-2), and 14th (TTH-3) days of training in the heat. Data were compared with the average of two TT in cool condition (approximately 8°C) performed before and after heat acclimatization (TTC). TTH-1 (77 ± 6 min) was slower (P = 0.001) than TTH-2 (69 ± 5 min), and both were slower (P < 0.01) than TTC and TTH-3 (66 ± 3 and 66 ± 4 min, respectively), without differences between TTC and TTH-3 (P > 0.05). The cyclists initiated the first 20% of all TT at a similar power output, irrespective of climate and acclimatization status; however, during TTH-1, they subsequently had a marked decrease in power output, which was partly attenuated after 6 d of acclimatization and was further reduced after 14 d. HR was higher during the first 20% of TTH-1 than that in the other TT (P < 0.05), but there were no differences between conditions from 30% onward. Final rectal temperature was similar in all TTH (40.2°C ± 0.4°C, P = 1.000) and higher than that in TTC (38.5°C ± 0.6°C, P < 0.001). After 2 wk of acclimatization, trained cyclists are capable of completing a prolonged TT in a similar time in the heat compared with cool conditions, whereas in the unacclimatized state, they experienced a marked decrease in power output during the TTH.

Medical and Scientific Aspects of Cycling.

ERIC Educational Resources Information Center

Burke, Edmund R., Ed.; Newsom, Mary M., Ed.

The 24 contributions to this volume were written by coaches, sport scientists, and medical authorities who surveyed recent research on biomechanics, physiology, psychology, nutrition, treatment of injuries, and training techniques for cyclists. There are four sections: (1) biomechanics and physiology; (2) research: techniques and results; (3)…

Examining the design and developmental factors associated with crashes involving pedestrians, cyclists, and motorists in urban environments.

DOT National Transportation Integrated Search

2012-05-01

"Using a parcel-level database of crash incidence and urban form developed for the San Antonio-Bexar : County metropolitan region, this study examined how urban form-related variables affect the incidence of : crashes involving pedestrians, bicyclist...

Narratives of marginalized cyclists : understanding obstacles to utilitarian cycling among women and minorities in Portland, OR : final report.

DOT National Transportation Integrated Search

2017-05-01

Research has demonstrated that everyday or utilitarian forms of cycling are most likely to generate positive : population-level health impacts (Garrard et al., 2012), yet significant deterrents to routine cycling remain, : particularly for women and ...

Energy Efficiency Handbook for Driver's Education.

ERIC Educational Resources Information Center

Berlowitz, Dan; And Others

Presented are suggestions to help the automobile driver attain the saving of fuel and money. Discussed are starting and stopping; anticipation of traffic conditions; use of accessories; trip planning; and accomodation of pedestrians and cyclists. Additional topics covered include systematic car maintenance and safety considerations. (RE)

Conservative care of De Quervain's tenosynovitis/ tendinopathy in a warehouse worker and recreational cyclist: a case report.

PubMed

Howell, Emily R

2012-06-01

This case study was conducted to evaluate the conservative management of a patient presenting with right sided wrist and thumb pain diagnosed as De Quervain's tenosynovitis/tendinopathy. A 49-year-old female warehouse worker and recreational cyclist with right-sided De Quervain's tenosynovitis/tendinopathy that began after a long-distance cycling trip. Treatment included ultrasound, soft tissue and myofascial release therapy, tool assisted fascial stripping or "guasha", acupuncture, mobilizations and kinesiology taping. Home advice included icing, rest, wrist bracing, elevation and eccentric rehabilitation exercises. The positive outcome was a complete resolution of the patient's complaint. This case demonstrates how De Quervain's disease is a challenging condition to treat with conservative methods and can be aggravated with new exacerbating factors as treatment continues. In this case, the addition of the active care (including eccentric exercises and self-care) helped to reinforce the passive care given in the office and accelerate the recovery.

Laboratory versus outdoor cycling conditions: differences in pedaling biomechanics.

PubMed

Bertucci, William; Grappe, Frederic; Groslambert, Alain

2007-05-01

The aim of our study was to compare crank torque profile and perceived exertion between the Monark ergometer (818 E) and two outdoor cycling conditions: level ground and uphill road cycling. Seven male cyclists performed seven tests in seated position at different pedaling cadences: (a) in the laboratory at 60, 80, and 100 rpm; (b) on level terrain at 80 and 100 rpm; and (c) on uphill terrain (9.25% grade) at 60 and 80 rpm. The cyclists exercised for 1 min at their maximal aerobic power. The Monark ergometer and the bicycle were equipped with the SRM Training System (Schoberer, Germany) for the measurement of power output (W), torque (Nxm), pedaling cadence (rpm), and cycling velocity (kmxh-1). The most important findings of this study indicate that at maximal aerobic power the crank torque profiles in the Monark ergometer (818 E) were significantly different (especially on dead points of the crank cycle) and generate a higher perceived exertion compared with road cycling conditions.

Healthy competition: A qualitative study investigating persuasive technologies and the gamification of cycling.

PubMed

Barratt, Paul

2017-07-01

Changing socio-technical practices occurring within cycling are leading the pursuit, and its participants, to become ever more embedded into the networked digital world. GPS enabled mobile-technologies have introduced a new element of competition into recreational riding, whether on the road, competing over timed virtual segments, or online dissecting and comparing the data that has been logged and shared via dedicated ride-logging applications. In order to understand these technologies qualitative study using reflective diaries and semi-structured interviews has been conducted with experienced club cyclists who had fully experienced the effects of their arrival. These riders claim that the applications influence their route choice and motivate them to cycle more frequently, and at a greater intensity although the engagement changes over time. This paper explores how this increased motivation to exercise and compete is instigated, manifested and maintained in the everyday practices of cyclists, as well as the negative consequences of gamification. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Pediatric victims of traffic accidents admitted to a university hospital: epidemiological and clinical aspects].

PubMed

Feitas, Juliana Pontes Pinto; Ribeiro, Lindioneza Adriano; Jorge, Miguel Tanús

2007-12-01

This study analyzes epidemiological and clinic characteristics of victims of traffic accidents. Data were obtained from medical records of children under 15 years of age (n = 1,123) admitted to a university hospital in Uberlândia, Minas Gerais State, Brazil, from 1999 to 2003. Mean age was eight years, 65.7% were boys, 76.6% were cyclists or pedestrians, 45.9% suffered head injuries, and 9% remained in hospital for more than two weeks. Fourteen (1.2%) died, 78.6% of these within 48 hours of hospitalization, and 85.7% with brain injuries. Among the passengers of motorcycles and larger vehicles, 58.8% were not using security devices properly at the time of the accident. Among the cyclists, 61% suffered isolated limb injuries. Meanwhile, pedestrians tended to suffer multiple lesions (57.5%) and be admitted to intensive care (7.1%), and represented 66.7% of the deaths. Epidemiological data on pediatric traffic victims can be useful for accident prevention programs.

Energy and macronutrient intake of a female vegan cyclist during an 8-day mountain bike stage race

PubMed Central

Kornexl, Elmar

2014-01-01

This report describes the dietary intake of a vegan mountain biker (height, 161 cm; weight, 49.6 kg; body mass index, 19.1 kg/m2; relative peak power output, 4.6 W/kg) during the Transalp Challenge 2004 (altitude climbed, 22,500 m; total distance, 662 km), illustrating an aggressive dietary strategy that allowed the cyclist to be competitive. She finished the 8-stage event in 42 hours (mixed category, rank 16; 514 minutes behind the winners of this category), cycling with an average heart rate of 79.5% of laboratory-determined maximum, spending 892 minutes and 1627 minutes at intensities below and above 80%, respectively. During racing, the consumption of energy was 69.3 MJ (1.65 MJ/h), 65.76 MJ from carbohydrates (92 g/h), which was 35% of calories and 40% of carbohydrate total intake, and the fluid ingested was 3 L/day (570 mL/h), 55% of the total fluid consumed. PMID:24381405

Energy and macronutrient intake of a female vegan cyclist during an 8-day mountain bike stage race.

PubMed

Wirnitzer, Katharina C; Kornexl, Elmar

2014-01-01

This report describes the dietary intake of a vegan mountain biker (height, 161 cm; weight, 49.6 kg; body mass index, 19.1 kg/m(2); relative peak power output, 4.6 W/kg) during the Transalp Challenge 2004 (altitude climbed, 22,500 m; total distance, 662 km), illustrating an aggressive dietary strategy that allowed the cyclist to be competitive. She finished the 8-stage event in 42 hours (mixed category, rank 16; 514 minutes behind the winners of this category), cycling with an average heart rate of 79.5% of laboratory-determined maximum, spending 892 minutes and 1627 minutes at intensities below and above 80%, respectively. During racing, the consumption of energy was 69.3 MJ (1.65 MJ/h), 65.76 MJ from carbohydrates (92 g/h), which was 35% of calories and 40% of carbohydrate total intake, and the fluid ingested was 3 L/day (570 mL/h), 55% of the total fluid consumed.

Variability in Laboratory vs. Field Testing of Peak Power, Torque, and Time of Peak Power Production Among Elite Bicycle Motocross Cyclists.

PubMed

Rylands, Lee P; Roberts, Simon J; Hurst, Howard T

2015-09-01

The aim of this study was to ascertain the variation in elite male bicycle motocross (BMX) cyclists' peak power, torque, and time of power production during laboratory and field-based testing. Eight elite male BMX riders volunteered for the study, and each rider completed 3 maximal sprints using both a Schoberer Rad Messtechnik (SRM) ergometer in the laboratory and a portable SRM power meter on an Olympic standard indoor BMX track. The results revealed a significantly higher peak power (p ≤ 0.001, 34 ± 9%) and reduced time of power production (p ≤ 0.001, 105 ± 24%) in the field tests when compared with laboratory-derived values. Torque was also reported to be lower in the laboratory tests but not to an accepted level of significance (p = 0.182, 6 ± 8%). These results suggest that field-based testing may be a more effective and accurate measure of a BMX rider's peak power, torque, and time of power production.

V-Alert: Description and Validation of a Vulnerable Road User Alert System in the Framework of a Smart City.

PubMed

Hernandez-Jayo, Unai; De-la-Iglesia, Idoia; Perez, Jagoba

2015-07-29

V-Alert is a cooperative application to be deployed in the frame of Smart Cities with the aim of reducing the probability of accidents involving Vulnerable Road Users (VRU) and vehicles. The architecture of V-Alert combines short- and long-range communication technologies in order to provide more time to the drivers and VRU to take the appropriate maneuver and avoid a possible collision. The information generated by mobile sensors (vehicles and cyclists) is sent over this heterogeneous communication architecture and processed in a central server, the Drivers Cloud, which is in charge of generating the messages that are shown on the drivers' and cyclists' Human Machine Interface (HMI). First of all, V-Alert has been tested in a simulated scenario to check the communications architecture in a complex scenario and, once it was validated, all the elements of V-Alert have been moved to a real scenario to check the application reliability. All the results are shown along the length of this paper.

Effects of multibuffer supplementation on acid-base balance and 2,3-diphosphoglycerate following repetitive anaerobic exercise.

PubMed

Kraemer, W J; Gordon, S E; Lynch, J M; Pop, M E; Clark, K L

1995-12-01

The purpose of this investigation was to determine the effects of a 3.5-day dietary multibuffer supplement (containing predominantly inorganic phosphate, or Pi, along with bicarbonate and carnosine, i.e., PhosFuel) on repetitive (four trials separated by 2 min rest) Wingate test (WT) performances and whole blood 2,3-diphosphoglycerate (2,3-DPG) concentrations in 10 recreationally trained road cyclists (T) and 10 normally active but untrained (UT) men. A 2-week washout period was utilized between experimental sessions. Venous blood samples were obtained via cannula once before exercise (baseline), immediately post each WT, and 3 min after the final WT (recovery). The data indicate that this supplement does not affect acid-base status with following intense anaerobic exercise and does not improve repetitive WT performance. However, the supplement does enhance post-exercise levels of 2,3-DPG and the 2,3-DPG/Hb ratio in recreationally trained cyclists while improving acute recovery of peak power in these men.

Real Time Bicycle Simulation Study of Bicyclists’ Behaviors and their Implication on Safety

DOT National Transportation Integrated Search

2017-06-30

The main goal of this study was to build a bicycle simulator and study the interaction between cyclists and other roadway users. The simulator developed was used in conjunction with Oculus Rift goggles to create a virtual cycling environment. The vir...

The effect of altitude on cycling performance: a challenge to traditional concepts.

PubMed

Hahn, A G; Gore, C J

2001-01-01

Acute exposure to moderate altitude is likely to enhance cycling performance on flat terrain because the benefit of reduced aerodynamic drag outweighs the decrease in maximum aerobic power [maximal oxygen uptake (VO2max)]. In contrast, when the course is mountainous, cycling performance will be reduced at moderate altitude. Living and training at altitude, or living in an hypoxic environment (approximately 2500 m) but training near sea level, are popular practices among elite cyclists seeking enhanced performance at sea level. In an attempt to confirm or refute the efficacy of these practices, we reviewed studies conducted on highly-trained athletes and, where possible, on elite cyclists. To ensure relevance of the information to the conditions likely to be encountered by cyclists, we concentrated our literature survey on studies that have used 2- to 4-week exposures to moderate altitude (1500 to 3000 m). With acclimatisation there is strong evidence of decreased production or increased clearance of lactate in the muscle, moderate evidence of enhanced muscle buffering capacity (beta m) and tenuous evidence of improved mechanical efficiency (ME) of cycling. Our analysis of the relevant literature indicates that, in contrast to the existing paradigm, adaptation to natural or simulated moderate altitude does not stimulate red cell production sufficiently to increase red cell volume (RCV) and haemoglobin mass (Hb(mass)). Hypoxia does increase serum erthyropoietin levels but the next step in the erythropoietic cascade is not clearly established; there is only weak evidence of an increase in young red blood cells (reticulocytes). Moreover, the collective evidence from studies of highly-trained athletes indicates that adaptation to hypoxia is unlikely to enhance sea level VO2max. Such enhancement would be expected if RCV and Hb(mass) were elevated. The accumulated results of 5 different research groups that have used controlled study designs indicate that continuous living and training at moderate altitude does not improve sea level performance of high level athletes. However, recent studies from 3 independent laboratories have consistently shown small improvements after living in hypoxia and training near sea level. While other research groups have attributed the improved performance to increased RCV and VO2max, we cite evidence that changes at the muscle level (beta m and ME) could be the fundamental mechanism. While living at altitude but training near sea level may be optimal for enhancing the performance of competitive cyclists, much further research is required to confirm its benefit. If this benefit does exist, it probably varies between individuals and averages little more than 1%.

Low cadence interval training at moderate intensity does not improve cycling performance in highly trained veteran cyclists

PubMed Central

Kristoffersen, Morten; Gundersen, Hilde; Leirdal, Stig; Iversen, Vegard V.

2014-01-01

Purpose: The aim of the present study was to investigate effects of low cadence training at moderate intensity on aerobic capacity, cycling performance, gross efficiency, freely chosen cadence, and leg strength in veteran cyclists. Method: Twenty-two well trained veteran cyclists [age: 47 ± 6 years, maximal oxygen consumption (VO2max): 57.9 ± 3.7 ml · kg−1 · min−1] were randomized into two groups, a low cadence training group and a freely chose cadence training group. Respiratory variables, power output, cadence and leg strength were tested before and after a 12 weeks training intervention period. The low cadence training group performed 12 weeks of moderate [73–82% of maximal heart rate (HRmax)] interval training (5 × 6 min) with a cadence of 40 revolutions per min (rpm) two times a week, in addition to their usual training. The freely chosen cadence group added 90 min of training at freely chosen cadence at moderate intensity. Results: No significant effects of the low cadence training on aerobic capacity, cycling performance, power output, cadence, gross efficiency, or leg strength was found. The freely chosen cadence group significantly improved both VO2max (58.9 ± 2.4 vs. 62.2 ± 3.2 ml · kg−1 · min−1), VO2 consumption at lactate threshold (49.4 ± 3.8 vs. 51.8 ± 3.5 ml · kg−1 · min−1) and during the 30 min performance test (52.8 ± 3.0 vs. 54.7 ± 3.5 ml · kg−1 · min−1), and power output at lactate threshold (284 ± 47 vs. 294 ± 48 W) and during the 30 min performance test (284 ± 42 vs. 297 ± 50 W). Moreover, a significant difference was seen when comparing the change in freely chosen cadence from pre- to post between the groups during the 30 min performance test (2.4 ± 5.0 vs. −2.7 ± 6.2). Conclusion: Twelve weeks of low cadence (40 rpm) interval training at moderate intensity (73–82% of HRmax) twice a week does not improve aerobic capacity, cycling performance or leg strength in highly trained veteran cyclists. However, adding training at same intensity (% of HRmax) and duration (90 min weekly) at freely chosen cadence seems beneficial for performance and physiological adaptations. PMID:24550843

Improving safety of vulnerable road users : effectiveness of environment and in-vehicle warning systems at intermodal interchanges.

DOT National Transportation Integrated Search

2014-01-01

In 2009, there were over 114,000 fatalities and injuries in the U.S. among vulnerable road users (VRUs; pedestrians and pedal cyclists; NHTSA, 2010). 4,092 pedestrians were killed in pedestrian-vehicle crashes. Pedestrian risk at intermodal interchan...

Bicycle Safety in Action.

ERIC Educational Resources Information Center

National Commission on Safety Education, Washington, DC.

This material was designed to assist schools in teaching bicycle safety. As the population grows and competition for road space increases, it is more imperative than ever that we concentrate attention on the need for caution among pupil cyclists. The pamphlet: (1) discusses the role of bicycle safety in classroom instruction and in student…

Gluconeogenesis during endurance exercise in cyclists habituated to a long-term low carbohydrate high fat diet

USDA-ARS?s Scientific Manuscript database

Endogenous glucose production (EGP) occurs via hepatic glycogenolysis (GLY) and gluconeogenesis (GNG) and plays an important role in maintaining euglycemia. Rates of GLY and GNG increase during exercise in athletes following a mixed macronutrient diet; however these processes have not been investiga...

TEFL/TESL Newsletter, Volume 4, Number 4.

ERIC Educational Resources Information Center

Australian Dept. of Education, Canberra. Language Teaching Branch.

This issue is devoted to driving and traffic safety. Based on information found in drivers' manuals from the various Australian states, instructions are given vis-a-vis pedestrians, cyclists and motorcyclists, driving regulations, seat belts, alcohol and drugs, lines and signs, and registration and licensing. Sample questions and suggested…

Gearing Up for Mountain Biking.

ERIC Educational Resources Information Center

Jahnke, Thomas; Hamson, Mike

1999-01-01

Examines the gear system of a mountain bike to discover any redundancy in the many gear settings available to the cyclist. Suggests a best strategy for changing up through the gears on a typical 21-gear system and an adjustment to the available gears that would result in a smoother change. (Author/ASK)

Mountain Bicycling in the Urban-Wildland Interface

Treesearch

Arthur W. Magill

1992-01-01

Mountain bicycling is a rapidly growing sport exerting substantial pressure on recreation areas in the urban-wildland interface. In 1983 there were under a million mountain bike users, today there are 15 million. Little is known about the bicyclists, but hikers and equestrians have complained about encounters with cyclists speeding down trails with little regard for...

Agreement of Power Measures between Garmin Vector and SRM Cycle Power Meters

ERIC Educational Resources Information Center

Novak, Andrew R.; Dascombe, Benjamin J.

2016-01-01

This study aimed to determine if the Garmin Vector (Schaffhausen, Switzerland) power meter produced acceptable measures when compared with the Schoberer Rad Messetechnik (SRM; Julich, Germany) power meter across a range of high-intensity efforts. Twenty-one well-trained cyclists completed power profiles (seven maximal mean efforts between 5 and…

Exploring the Aerodynamic Drag of a Moving Cyclist

ERIC Educational Resources Information Center

Theilmann, Florian; Reinhard, Christopher

2016-01-01

Although the physics of cycling itself is a complex mixture of aerodynamics, physiology, mechanics, and heuristics, using cycling as a context for teaching physics has a tradition of certainly more than 30 years. Here, a possible feature is the discussion of the noticeable resistant forces such as aerodynamic drag and the associated power…

76 FR 52046 - Final Policy Statement on the Eligibility of Pedestrian and Bicycle Improvements Under Federal...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-19

... cyclists, lower greenhouse gas emissions, reduced dependence on fossil fuels, increased trip-chaining, and... traffic use fewer resources and affect the environment less than any other form of transport.'' \\6\\ If we... gas emissions, reduced dependence on fossil fuels, increased trip- chaining, increased overall health...

Digital Physical Activity Data Collection and Use by Endurance Runners and Distance Cyclists

ERIC Educational Resources Information Center

Lee, Victor R.; Drake, Joel

2013-01-01

The introduction of sensor technologies to sports has allowed athletes to quantify and track their performance, adding an information-based layer to athletic practices. This information layer is particularly prevalent in practices involving formal competition and high levels of physical endurance, such as biking and running. We interviewed 20…

Sex, Drugs, and Kinesiology: A Useful Partnership for Sport's Most Pressing Issues

ERIC Educational Resources Information Center

Gleaves, John; Llewellyn, Matthew; Wrynn, Alison

2015-01-01

From the gender controversy of South African runner Caster Semenya to the doping practices of disgraced American cyclist Lance Armstrong, recent sporting issues highlight kinesiology's important role and responsibility to sport. Increasingly, sport organizations, such as the International Olympic Committee, the World Anti-Doping Agency, and…

78 FR 40632 - Drawbridge Operation Regulation; Trent River, New Bern, NC

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-08

... navigation position for one hour on two consecutive days to accommodate the annual Bike Multiple Sclerosis... INFORMATION: The Event Director for the Bike Multiple Sclerosis: Historic New Bern Bike Ride, with approval... safe passage for cyclists during the Bike Multiple Sclerosis: Historic New Bern Bike Ride. The US 70...

Mountain Biking with Groups: A "Safe" Activity?

ERIC Educational Resources Information Center

Allen, Terry

2001-01-01

A survey mailed to 200 British mountain bike leaders found that rates of cycling accidents and injuries were greater in forests and woodlands than on terrain where a license is required to lead groups of young cyclists. Excessive speed was mentioned in most accidents, coupled with poor use of breaks in many cases. (SV)

[Mechanism of pelvic girdle injuries in street traffic. Medical-technical accident analysis].

PubMed

Pohlemann, T; Richter, M; Otte, D; Gänsslen, A; Bartram, H; Tscherne, H

2000-04-01

During 1985 and 1993, 7,410 persons were injured in traffic accidents in the area of Hanover. Of these, 306 (4.1%) sustained a pelvic girdle injury. In 139 cases (45%), the pelvic girdle injuries were further classified (Pennal and Tile) and a technical reconstruction of the accident situation was performed. 52% were type A, 27% type B and 21% type C injuries. Some 47% of the casualties were vehicle occupants, 31% pedestrians, 12% motorcyclists and 10% cyclists. In restrained vehicle occupants pelvic girdle injuries occurred mostly in accidents with a delta-v of more than 30 km/h, whereas in unrestrained vehicle occupants, pedestrians and cyclists they also occurred with lower delta-v or collision speed. The percentage of type B and C injuries increased with higher velocities. In addition to further improvements in passive safety, lower collision speed or delta-v is necessary to reduce or prevent pelvic girdle injuries. The reconstruction of pelvic girdle injury mechanism in traffic accidents is possible, when both technical and medical parameters are considered.

Are car daytime running lights detrimental to motorcycle conspicuity?

PubMed

Cavallo, Viola; Pinto, Maria

2012-11-01

For a long time, motorcycles were the only vehicles with daytime running lights (DRLs), but this conspicuity advantage has been questioned due to the rapidly increasing introduction of DRLs on cars as well. The present experiment was designed to assess effects of car DRLs on motorcycle perception in a situation that specifically brought attentional conspicuity to bear. Photographs representing complex urban traffic scenes were displayed briefly (250 ms) to 24 participants who had to detect vulnerable road users (motorcyclists, cyclists, pedestrians) appearing at different locations and distances. Car DRLs hampered motorcycle perception compared to conditions where car lights were not on, especially when the motorcycle was at a greater distance from the observer and when it was located in the central part of the visual scene. Car DRLs also hampered the perception of cyclists and pedestrians. Although the globally positive safety effect of car DRLs is generally acknowledged, our study suggests that more attention should be paid to motorcyclists and other vulnerable road users when introducing car DRLs. Several means of improving motorcycle conspicuity in car DRL environments are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cycling biomechanics: a literature review.

PubMed

Wozniak Timmer, C A

1991-01-01

Submitted in partial fulfillment for a Master of Science degree at the University of Pittsburgh, School of Health Related Professions, Pittsburgh, PA 1.5213 This review of current literature on cycling biomechanics emphasizes lower extremity muscle actions and joint excursions, seat height, pedal position, pedaling rate, force application, and pedaling symmetry. Guidelines are discussed for optimal seat height, pedal position, and pedaling rate. Force application in the power and recovery phases of cycling and the relationship of force application to pedaling symmetry are discussed. The need for a biomechanical approach to cycling exists since a great deal of the literature is primarily physiologic in nature. The purpose of this review is to make cyclists and their advisors aware of the biomechanics of cycling and guidelines to follow. This approach is also important because cycling is a very common form of exercise prescribed by physical therapists for clinic or home programs. Biomechanical aspects of cycling should be considered by cyclists at any level of participation and by physical therapists in order for goal-oriented, efficient cycling to occur. J Orthop Sports Phys Ther 1991;14(3):106-113.

A new crank arm-based load cell for the 3D analysis of the force applied by a cyclist.

PubMed

Balbinot, Alexandre; Milani, Cleiton; Nascimento, Jussan da Silva Bahia

2014-12-03

This report describes a new crank arm-based force platform designed to evaluate the three-dimensional force applied to the pedals by cyclists in real conditions. The force platform was designed to be fitted on a conventional competition bicycle crankset while data is transmitted wirelessly through a Bluetooth™ module and also stored on a SD card. A 3D solid model is created in the SolidWorks (Dassault Systèmes SOLIDWORKS Corp.) to analyze the static and dynamic characteristics of the crank arm by using the finite elements technique. Each crankset arm is used as a load cell based on strain gauges configured as three Wheatstone bridges. The signals are conditioned on a printed circuit board attached directly to the structure. The load cell showed a maximum nonlinearity error between 0.36% and 0.61% and a maximum uncertainty of 2.3% referred to the sensitivity of each channel. A roller trainer equipped with an optical encoder was also developed, allowing the measurement of the wheel's instantaneous velocity.

3D digital headform models of Australian cyclists.

PubMed

Ellena, Thierry; Skals, Sebastian; Subic, Aleksandar; Mustafa, Helmy; Pang, Toh Yen

2017-03-01

Traditional 1D anthropometric data have been the primary source of information used by ergonomists for the dimensioning of head and facial gear. Although these data are simple to use and understand, they only provide univariate measures of key dimensions. 3D anthropometric data, however, describe the complete shape characteristics of the head surface, but are complicated to interpret due to the abundance of information they contain. Consequently, current headform standards based on 1D measurements may not adequately represent the actual head shape variations of the intended user groups. The purpose of this study was to introduce a set of new digital headform models representative of the adult cyclists' community in Australia. Four models were generated based on an Australian 3D anthropometric database of head shapes and a modified hierarchical clustering algorithm. Considerable shape differences were identified between our models and the current headforms from the Australian standard. We conclude that the design of head and facial gear based on current standards might not be favorable for optimal fitting results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Community-based programmes to promote use of bicycle helmets in children aged 0-14 years: a systematic review.

PubMed

Spinks, Anneliese; Turner, Cathy; McClure, Rod; Acton, Caroline; Nixon, Jim

2005-09-01

Hospital-based research has shown that wearing a helmet reduces the risk of head injury in bicycle riders. These studies have provided the impetus for community-wide interventions to increase the numbers of cyclists who wear helmets; however, the effectiveness of such programmes is undetermined. This study employs extensive search strategies to review the scientific literature to establish the effectiveness of community-wide programmes to increase helmet use among cyclists. Thirteen community-wide intervention studies using substantive methodologies were located in 16 published papers. The community-wide interventions include mandating helmet wearing, education campaigns, distribution of free or subsidized helmets or, more frequently, combinations of all of these methods of influence. All studies reported success in influencing helmet wearing across communities. However, none of the studies reveals enough detail of the mix or techniques employed in the interventions to replicate the interventions. While it is encouraging that all of the studies showed positive results, the way forward for further implementation of helmet wearing is for adequate documentation of successful interventions.

Potential errors in body composition as estimated by whole body scintillation counting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lykken, G.I.; Lukaski, H.C.; Bolonchuk, W.W.

Vigorous exercise has been reported to increase the apparent potassium content of athletes measured by whole body gamma ray scintillation counting of /sup 40/K. The possibility that this phenomenon is an artifact was evaluated in three cyclists and one nonathlete after exercise on the road (cyclists) or in a room with a source of radon and radon progeny (nonathlete). The apparent /sup 40/K content of the thighs of the athletes and whole body of the nonathlete increased after exercise. Counts were also increased in both windows detecting /sup 214/Bi, a progeny of radon. /sup 40/K and /sup 214/Bi counts weremore » highly correlated (r . 0.87, p less than 0.001). The apparent increase in /sup 40/K was accounted for by an increase in counts associated with the 1.764 MeV gamma ray emissions from /sup 214/Bi. Thus a failure to correct for radon progeny would cause a significant error in the estimate of lean body mass by /sup 40/K counting.« less

Potential errors in body composition as estimated by whole body scintillation counting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lykken, G.I.; Lukaski, H.C.; Bolonchuk, W.W.

Vigorous exercise has been reported to increase the apparent potassium content of athletes measured by whole body gamma ray scintillation counting of /sup 40/K. The possibility that this phenomenon is an artifact was evaluated in three cyclists and one nonathlete after exercise on the road (cyclists) or in a room with a source of radon and radon progeny (nonathlete). The apparent /sup 40/K content of the thighs of the athletes and whole body of the nonathlete increased after exercise. Counts were also increased in both windows detecting /sup 214/Bi, a progeny of radon. /sup 40/K and /sup 214/Bi counts weremore » highly correlated (r = 0.87, p < 0.001). The apparent increase in /sup 40/K was accounted for by an increase in counts associated with the 1.764 MeV gamma ray emissions from /sup 214/Bi. Thus a failure to correct for radon progeny would cause a significant error in the estimate of lean body mass by /sup 40/K counting.« less

Hip and groin pain in a cyclist resolved after performing a pelvic floor fascial mobilization.

PubMed

Navot, Sivan; Kalichman, Leonid

2016-07-01

Pelvic floor muscle assessment in situations of hip/groin pain in both male and female patients can be a key element in treatment success. We present herein, a 32 year old male professional cyclist, exhibiting right hip and groin pain during cycling and prolonged sitting. The pain commenced after the patient suffered a right hip severe contusion in 2013 causing a tear in the tensor fascia lata and gluteus medius muscle. The patient did not complain of pelvic floor dysfunctions. After receiving several series of conventional physical therapy for the hip/groin pain, the patient experienced partial pain relief and slight improvement of hip range of motion. His pelvic floor muscles and fascial involvement were subsequently assessed. Two sessions of Pelvic Floor Fascial Mobilization (PFFM) were performed and the patient fully recovered. The authors suggest that PFFM, a novel fascial-oriented manual therapy of the pelvic floor approach, can be used for both hip/groin and pelvic floor pain or dysfunction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ulnar nerve lesion at the wrist and sport: A report of 8 cases compared with 45 non-sport cases.

PubMed

Seror, P

2015-04-01

Reporting clinical and electrodiagnostic characteristics of sport-related ulnar neuropathies at the wrist. Eight sport-related and 45 non-sport-related cases from 53 ulnar neuropathies at the wrist cases over 14 years. Sport-related ulnar neuropathies at the wrist cases were due to cycling (5 cases), kayaking (2 cases), and big-game fishing (1 case). No patient had sensory complaints in ulnar digits, and all had motor impairment. Conduction across the wrist with recording on the first dorsal interosseous muscle was impaired in all cases, with conduction block in 5. Two cyclists showed bilateral ulnar neuropathies at the wrist. All cases recovered within 2 to 6 months with sport discontinuation. Distal lesions of the deep motor branch were more frequent in sport- than non-sport-related cases. The 8 sport-related ulnar neuropathies at the wrist cases involved the deep motor branch. Conduction study to the first dorsal interosseous muscle across the wrist is the key to electrodiagnostics. Bilateral cases in cyclists does not require wrist imaging. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

A New Crank Arm-Based Load Cell for the 3D Analysis of the Force Applied by a Cyclist

PubMed Central

Balbinot, Alexandre; Milani, Cleiton; Nascimento, Jussan da Silva Bahia

2014-01-01

This report describes a new crank arm-based force platform designed to evaluate the three-dimensional force applied to the pedals by cyclists in real conditions. The force platform was designed to be fitted on a conventional competition bicycle crankset while data is transmitted wirelessly through a BluetoothTM module and also stored on a SD card. A 3D solid model is created in the SolidWorks (Dassault Systèmes SOLIDWORKS Corp.) to analyze the static and dynamic characteristics of the crank arm by using the finite elements technique. Each crankset arm is used as a load cell based on strain gauges configured as three Wheatstone bridges. The signals are conditioned on a printed circuit board attached directly to the structure. The load cell showed a maximum nonlinearity error between 0.36% and 0.61% and a maximum uncertainty of 2.3% referred to the sensitivity of each channel. A roller trainer equipped with an optical encoder was also developed, allowing the measurement of the wheel's instantaneous velocity. PMID:25479325

Six weeks of a polarized training-intensity distribution leads to greater physiological and performance adaptations than a threshold model in trained cyclists.

PubMed

Neal, Craig M; Hunter, Angus M; Brennan, Lorraine; O'Sullivan, Aifric; Hamilton, D Lee; De Vito, Giuseppe; Galloway, Stuart D R

2013-02-15

This study was undertaken to investigate physiological adaptation with two endurance-training periods differing in intensity distribution. In a randomized crossover fashion, separated by 4 wk of detraining, 12 male cyclists completed two 6-wk training periods: 1) a polarized model [6.4 (±1.4 SD) h/wk; 80%, 0%, and 20% of training time in low-, moderate-, and high-intensity zones, respectively]; and 2) a threshold model [7.5 (±2.0 SD) h/wk; 57%, 43%, and 0% training-intensity distribution]. Before and after each training period, following 2 days of diet and exercise control, fasted skeletal muscle biopsies were obtained for mitochondrial enzyme activity and monocarboxylate transporter (MCT) 1 and 4 expression, and morning first-void urine samples were collected for NMR spectroscopy-based metabolomics analysis. Endurance performance (40-km time trial), incremental exercise, peak power output (PPO), and high-intensity exercise capacity (95% maximal work rate to exhaustion) were also assessed. Endurance performance, PPOs, lactate threshold (LT), MCT4, and high-intensity exercise capacity all increased over both training periods. Improvements were greater following polarized rather than threshold for PPO [mean (±SE) change of 8 (±2)% vs. 3 (±1)%, P < 0.05], LT [9 (±3)% vs. 2 (±4)%, P < 0.05], and high-intensity exercise capacity [85 (±14)% vs. 37 (±14)%, P < 0.05]. No changes in mitochondrial enzyme activities or MCT1 were observed following training. A significant multilevel, partial least squares-discriminant analysis model was obtained for the threshold model but not the polarized model in the metabolomics analysis. A polarized training distribution results in greater systemic adaptation over 6 wk in already well-trained cyclists. Markers of muscle metabolic adaptation are largely unchanged, but metabolomics markers suggest different cellular metabolic stress that requires further investigation.

Prevalence of alcohol-impaired driving and riding in northern Ghana.

PubMed

Damsere-Derry, James; Palk, Gavan; King, Mark

2016-01-01

The objective of this study was to determine the roadside prevalence of alcohol-impaired driving among drivers and riders in northern Ghana. The study also verifies motorists' perceptions of their own alcohol use and knowledge of the legal blood alcohol concentration (BAC) limit in Ghana. With the assistance of police, systematic random sampling was used to collect data at roadblocks using a cross-sectional study design. Breathalyzers were used to screen whether motorists had detectable alcohol in their breath and follow-up breath tests were conducted to measure the actual breath alcohol levels among positive participants. In all, 9.7% of the 789 participants had detectable alcohol, among whom 6% exceeded the legal BAC limit of 0.08%. The prevalence of alcohol-impaired driving/riding was highest among cyclists (10% of all cyclists breath-tested) followed by truck drivers (9%) and motorcyclists (7% of all motorcyclists breath-tested). The occurrence of a positive BAC among cyclists was about 8 times higher (odds ratio [OR] = 7.73; P < .001) and it was 2 times higher among motorcyclists (OR = 2.30; P = .039) compared to private car drivers. The likelihood for detecting a positive BAC among male motorists/riders was higher than that among females (OR = 1.67; P = .354). The odds for detecting a positive BAC among weekend motorists/riders was significantly higher than on weekdays (OR = 2.62; P = .001). Alcohol-impaired driving/riding in Ghana is high by international standards. In order to attenuate the harmful effects of alcohol misuse such as alcohol-impaired driving/riding, there is the need to educate road users about how much alcohol they can consume and stay below the legal limit. The police should also initiate random breath testing to instill the deterrence of detection, certainty of apprehension and punishment, and severity and celerity of punishment among drink-driving motorists and riders.

Ten weeks of branched-chain amino acid supplementation improves select performance and immunological variables in trained cyclists.

PubMed

Kephart, Wesley C; Wachs, Taylor D; Mac Thompson, R; Brooks Mobley, C; Fox, Carlton D; McDonald, James R; Ferguson, Brian S; Young, Kaelin C; Nie, Ben; Martin, Jeffrey S; Company, Joseph M; Pascoe, David D; Arnold, Robert D; Moon, Jordan R; Roberts, Michael D

2016-03-01

We examined if supplementing trained cyclists (32 ± 2 year, 77.8 ± 2.6 kg, and 7.4 ± 1.2 year training) with 12 g/day (6 g/day L-Leucine, 2 g/day L-Isoleucine and 4 g/day L-Valine) of either branched-chain amino acids (BCAAs, n = 9) or a maltodextrin placebo (PLA, n = 9) over a 10-week training season affected select body composition, performance, and/or immune variables. Before and after the 10-week study, the following was assessed: (1) 4-h fasting blood draws; (2) dual X-ray absorptiometry body composition; (3) Wingate peak power tests; and (4) 4 km time-trials. No group × time interactions existed for total lean mass (P = 0.27) or dual-leg lean mass (P = 0.96). A significant interaction existed for body mass-normalized relative peak power (19 % increase in the BCAA group pre- to post-study, P = 0.01), and relative mean power (4 % increase in the BCAA group pre- to post-study, P = 0.01). 4 km time-trial time to completion approached a significant interaction (P = 0.08), as the BCAA group improved in this measure by 11 % pre- to post-study, though this was not significant (P = 0.15). There was a tendency for the BCAA group to present a greater post-study serum BCAA: L-Tryptophan ratio compared to the PLA group (P = 0.08). A significant interaction for neutrophil number existed (P = 0.04), as there was a significant 18 % increase within the PLA group from the pre- to post-study time point (P = 0.01). Chronic BCAA supplementation improves sprint performance variables in endurance cyclists. Additionally, given that BCAA supplementation blunted the neutrophil response to intense cycling training, BCAAs may benefit immune function during a prolonged cycling season.

Prevalence of alcohol among nonfatally injured road accident casualties in two level III trauma centers in northern Ghana.

PubMed

Damsere-Derry, James; Palk, Gavan; King, Mark

2018-02-17

Alcohol use is pervasive among motorists on the road in Ghana; however, we do not know the extent to which this behavior is implicated in road accidents in this country. The main objective of this research was to establish the prevalence of alcohol in the blood of nonfatally injured casualties in the emergency departments (EDs) in northern Ghana. Participants were injured road traffic crash victims, namely, pedestrians, cyclists, motorcyclists, and drivers seeking treatment at an ED. The study sites were 2 level III trauma centers located in Wa and Bolgatanga. Participants were screened for alcohol followed by breath tests for positive participants using breathalyzers. Two hundred and sixty-two accident victims visited EDs, 58% of whom were in Wa. Among the victims, 41% were hospitalized and 57% experienced slight injuries. The vast majority (76%) of the casualties were motorcyclists, 13% were pedestrians, 8% were cyclists, and 2% were drivers. Casualties who had detectable alcohol in their blood were predominantly vulnerable road users. In all, 34% of participants had detectable blood alcohol concentrations (BACs) and the mean BAC for all casualties who tested positive and could give definitive BACs was 0.2265 (226 mg/dl). The prevalence of alcohol use was 53% among cyclists, 34% among motorcyclists, 21% among pedestrians, and 17% among drivers. Male casualties were more likely to test positive for alcohol than females. In addition, the prevalence of alcohol was significantly higher among injured casualties in Bolgatanga compared to Wa. There was a high prevalence of alcohol use among nonfatally injured casualties in northern Ghana and injury severity increased with BAC. AUDIT screening in the hospital, alcohol consumption guideline, road safety education with an emphasis on minimizing or eliminating alcohol consumption, and enhanced enforcement of the BAC limit among motorists are recommended.

Commuters' exposure to particulate matter air pollution is affected by mode of transport, fuel type, and route.

PubMed

Zuurbier, Moniek; Hoek, Gerard; Oldenwening, Marieke; Lenters, Virissa; Meliefste, Kees; van den Hazel, Peter; Brunekreef, Bert

2010-06-01

Commuters are exposed to high concentrations of air pollutants, but little quantitative information is currently available on differences in exposure between different modes of transport, routes, and fuel types. The aim of our study was to assess differences in commuters' exposure to traffic-related air pollution related to transport mode, route, and fuel type. We measured particle number counts (PNCs) and concentrations of PM2.5 (particulate matter

Investigating helmet promotion for cyclists: results from a randomised study with observation of behaviour, using a semi-automatic video system.

PubMed

Constant, Aymery; Messiah, Antoine; Felonneau, Marie-Line; Lagarde, Emmanuel

2012-01-01

Half of fatal injuries among bicyclists are head injuries. While helmet use is likely to provide protection, their use often remains rare. We assessed the influence of strategies for promotion of helmet use with direct observation of behaviour by a semi-automatic video system. We performed a single-centre randomised controlled study, with 4 balanced randomisation groups. Participants were non-helmet users, aged 18-75 years, recruited at a loan facility in the city of Bordeaux, France. After completing a questionnaire investigating their attitudes towards road safety and helmet use, participants were randomly assigned to three groups with the provision of "helmet only", "helmet and information" or "information only", and to a fourth control group. Bikes were labelled with a colour code designed to enable observation of helmet use by participants while cycling, using a 7-spot semi-automatic video system located in the city. A total of 1557 participants were included in the study. Between October 15th 2009 and September 28th 2010, 2621 cyclists' movements, made by 587 participants, were captured by the video system. Participants seen at least once with a helmet amounted to 6.6% of all observed participants, with higher rates in the two groups that received a helmet at baseline. The likelihood of observed helmet use was significantly increased among participants of the "helmet only" group (OR = 7.73 [2.09-28.5]) and this impact faded within six months following the intervention. No effect of information delivery was found. Providing a helmet may be of value, but will not be sufficient to achieve high rates of helmet wearing among adult cyclists. Integrated and repeated prevention programmes will be needed, including free provision of helmets, but also information on the protective effect of helmets and strategies to increase peer and parental pressure.

The changing epidemiology of open fractures in vehicle occupants, pedestrians, motorcyclists and cyclists.

PubMed

Winkler, Dennis; Goudie, Stuart T; Court-Brown, Charles M

2018-02-01

To investigate the changing epidemiology of open fractures in vehicle occupants, pedestrians, motorcyclists and cyclists. Data on all non-spinal open fractures admitted to the Royal Infirmary of Edinburgh after a road traffic accident between 1988 and 2010 were collected and analysed to provide information about the changing epidemiology in different patient groups. Demographic information was collected on all patients with the severity of injury being analysed with the Injury Severity Score (ISS), Musculoskeletal Index (MSI) and the number of open fractures. The severity of the open fractures was analysed using the Gustilo classification. The 23-year study period was divided into four shorter periods and the results were compared. There were 696 patients treated in 23 years. Analysis showed that the incidence of RTA open fractures initially fell in both males and females and continued to fall in females during the 23 years. In males it levelled off about 2000. The age of the female patients also fell during the study period but it did not change in males. The only patient group to show an increased incidence of open fractures were cyclists. In vehicle occupants the incidence fell throughout the study period but it levelled off in pedestrians and motorcyclists. There was no difference in the severity of injury in any group during the study period. The most severe open fractures were those of the distal femur and femoral diaphysis although open tibial diaphyseal fractures were the most common fracture in all patient groups. Improved car design and road safety legislation has resulted in a reduction in the incidence of open fractures in vehicle occupants, pedestrians and motorcyclists. The most obvious group to have benefitted from this are older female pedestrians. The only group to show an increase in age during the study period were male motorcyclists. Copyright © 2017 Elsevier Ltd. All rights reserved.

Power output during women's World Cup road cycle racing.

PubMed

Ebert, Tammie R; Martin, David T; McDonald, Warren; Victor, James; Plummer, John; Withers, Robert T

2005-12-01

Little information exists on the power output demands of competitive women's road cycle racing. The purpose of our investigation was to document the power output generated by elite female road cyclists who achieved success in FLAT and HILLY World Cup races. Power output data were collected from 27 top-20 World Cup finishes (19 FLAT and 8 HILLY) achieved by 15 nationally ranked cyclists (mean +/- SD; age: 24.1+/-4.0 years; body mass: 57.9+/-3.6 kg; height: 168.7+/-5.6 cm; VO2max 63.6+/-2.4 mL kg(-1) min(-1); peak power during graded exercise test (GXT(peak power)): 310+/-25 W). The GXT determined GXT(peak power), VO2peak lactate threshold (LT) and anaerobic threshold (AT). Bicycles were fitted with SRM powermeters, which recorded power (W), cadence (rpm), distance (km) and speed (km h(-1)). Racing data were analysed to establish time in power output and metabolic threshold bands and maximal mean power (MMP) over different durations. When compared to HILLY, FLAT were raced at a similar cadence (75+/-8 vs. 75+/-4 rpm, P=0.93) but higher speed (37.6+/-2.6 vs. 33.9+/-2.7 km h(-1), P=0.008) and power output (192+/-21 vs. 169+/-17 W, P=0.04; 3.3+/-0.3 vs. 3.0+/-0.4 W kg(-1), P=0.04). During FLAT races, riders spent significantly more time above 500 W, while greater race time was spent between 100 and 300 W (LT-AT) for HILLY races, with higher MMPs for 180-300 s. Racing terrain influenced the power output profiles of our internationally competitive female road cyclists. These data are the first to define the unique power output requirements associated with placing well in both flat and hilly women's World Cup cycling events.

The effects of honey supplementation on seminal plasma cytokines, oxidative stress biomarkers, and antioxidants during 8 weeks of intensive cycling training.

PubMed

Tartibian, Bakhtyar; Maleki, Behzad Hajizadeh

2012-01-01

The purpose of this study was to examine the effects of natural honey supplementation on seminal plasma cytokines, oxidative stress biomarkers, and antioxidants during 8 weeks of intensive cycling training in male road cyclists. Thirty-nine healthy nonprofessional male road cyclists aged 18-28 years participated in this study. The participants were randomly assigned to exercise + supplement (E + S, n = 20) and exercise (E, n = 19) groups. All subjects participated in 8 weeks of intensive cycling training. Ninety minutes before each training session, subjects in the E + S group supplemented with 70 g of honey, whereas subjects in the E group received 70 g of an artificial sweetener. All subjects had an initial semen sampling at baseline (T(1)). The next 6 semen collections were collected immediately (T(2)) and 12 (T(3)) and 24 hours (T(4)) after the last training session in week 4, as well as immediately (T(5)) and 12 (T(6)) and 24 hours (T(7)) after the last training session in week 8, respectively. In the E group, 8 weeks of intensive cycling training significantly increased seminal interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α, reactive oxygen species (ROS), and malondialdehyde (MDA) levels (P < .008) and significantly decreased the levels of seminal superoxide dismutase (SOD), catalase, and total antioxidant capacity (TAC) (P < .008). Significantly less elevation in seminal IL-1β, IL-6, IL-8, TNF-α, ROS, and MDA levels (P < .008) and significant increases in seminal SOD, catalase, and TAC concentrations were observed after the honey supplementation in the E + S group (P < .008). It may be possible that honey supplementation following long-term intensive cycling training would be effective in attenuating the probable aggravating effects of intensive cycling training on spermatogenesis and fertility capacity in road cyclists.

Ingestion of glucose or sucrose prevents liver but not muscle glycogen depletion during prolonged endurance-type exercise in trained cyclists.

PubMed

Gonzalez, Javier T; Fuchs, Cas J; Smith, Fiona E; Thelwall, Pete E; Taylor, Roy; Stevenson, Emma J; Trenell, Michael I; Cermak, Naomi M; van Loon, Luc J C

2015-12-15

The purpose of this study was to define the effect of glucose ingestion compared with sucrose ingestion on liver and muscle glycogen depletion during prolonged endurance-type exercise. Fourteen cyclists completed two 3-h bouts of cycling at 50% of peak power output while ingesting either glucose or sucrose at a rate of 1.7 g/min (102 g/h). Four cyclists performed an additional third test for reference in which only water was consumed. We employed (13)C magnetic resonance spectroscopy to determine liver and muscle glycogen concentrations before and after exercise. Expired breath was sampled during exercise to estimate whole body substrate use. After glucose and sucrose ingestion, liver glycogen levels did not show a significant decline after exercise (from 325 ± 168 to 345 ± 205 and 321 ± 177 to 348 ± 170 mmol/l, respectively; P > 0.05), with no differences between treatments. Muscle glycogen concentrations declined (from 101 ± 49 to 60 ± 34 and 114 ± 48 to 67 ± 34 mmol/l, respectively; P < 0.05), with no differences between treatments. Whole body carbohydrate utilization was greater with sucrose (2.03 ± 0.43 g/min) vs. glucose (1.66 ± 0.36 g/min; P < 0.05) ingestion. Both liver (from 454 ± 33 to 283 ± 82 mmol/l; P < 0.05) and muscle (from 111 ± 46 to 67 ± 31 mmol/l; P < 0.01) glycogen concentrations declined during exercise when only water was ingested. Both glucose and sucrose ingestion prevent liver glycogen depletion during prolonged endurance-type exercise. Sucrose ingestion does not preserve liver glycogen concentrations more than glucose ingestion. However, sucrose ingestion does increase whole body carbohydrate utilization compared with glucose ingestion. This trial was registered at https://www.clinicaltrials.gov as NCT02110836. Copyright © 2015 the American Physiological Society.

Investigating Helmet Promotion for Cyclists: Results from a Randomised Study with Observation of Behaviour, Using a Semi-Automatic Video System

PubMed Central

Constant, Aymery; Messiah, Antoine; Felonneau, Marie-Line; Lagarde, Emmanuel

2012-01-01

Introduction Half of fatal injuries among bicyclists are head injuries. While helmet use is likely to provide protection, their use often remains rare. We assessed the influence of strategies for promotion of helmet use with direct observation of behaviour by a semi-automatic video system. Methods We performed a single-centre randomised controlled study, with 4 balanced randomisation groups. Participants were non-helmet users, aged 18–75 years, recruited at a loan facility in the city of Bordeaux, France. After completing a questionnaire investigating their attitudes towards road safety and helmet use, participants were randomly assigned to three groups with the provision of “helmet only”, “helmet and information” or “information only”, and to a fourth control group. Bikes were labelled with a colour code designed to enable observation of helmet use by participants while cycling, using a 7-spot semi-automatic video system located in the city. A total of 1557 participants were included in the study. Results Between October 15th 2009 and September 28th 2010, 2621 cyclists' movements, made by 587 participants, were captured by the video system. Participants seen at least once with a helmet amounted to 6.6% of all observed participants, with higher rates in the two groups that received a helmet at baseline. The likelihood of observed helmet use was significantly increased among participants of the “helmet only” group (OR = 7.73 [2.09–28.5]) and this impact faded within six months following the intervention. No effect of information delivery was found. Conclusion Providing a helmet may be of value, but will not be sufficient to achieve high rates of helmet wearing among adult cyclists. Integrated and repeated prevention programmes will be needed, including free provision of helmets, but also information on the protective effect of helmets and strategies to increase peer and parental pressure. PMID:22355384

Maximal oxygen uptake is proportional to muscle fiber oxidative capacity, from chronic heart failure patients to professional cyclists.

PubMed

van der Zwaard, Stephan; de Ruiter, C Jo; Noordhof, Dionne A; Sterrenburg, Renske; Bloemers, Frank W; de Koning, Jos J; Jaspers, Richard T; van der Laarse, Willem J

2016-09-01

V̇o2 max during whole body exercise is presumably constrained by oxygen delivery to mitochondria rather than by mitochondria's ability to consume oxygen. Humans and animals have been reported to exploit only 60-80% of their mitochondrial oxidative capacity at maximal oxygen uptake (V̇o2 max). However, ex vivo quantification of mitochondrial overcapacity is complicated by isolation or permeabilization procedures. An alternative method for estimating mitochondrial oxidative capacity is via enzyme histochemical quantification of succinate dehydrogenase (SDH) activity. We determined to what extent V̇o2 max attained during cycling exercise differs from mitochondrial oxidative capacity predicted from SDH activity of vastus lateralis muscle in chronic heart failure patients, healthy controls, and cyclists. V̇o2 max was assessed in 20 healthy subjects and 28 cyclists, and SDH activity was determined from biopsy cryosections of vastus lateralis using quantitative histochemistry. Similar data from our laboratory of 14 chronic heart failure patients and 6 controls were included. Mitochondrial oxidative capacity was predicted from SDH activity using estimated skeletal muscle mass and the relationship between ex vivo fiber V̇o2 max and SDH activity of isolated single muscle fibers and myocardial trabecula under hyperoxic conditions. Mitochondrial oxidative capacity predicted from SDH activity was related (r(2) = 0.89, P < 0.001) to V̇o2 max measured during cycling in subjects with V̇o2 max ranging from 9.8 to 79.0 ml·kg(-1)·min(-1) V̇o2 max measured during cycling was on average 90 ± 14% of mitochondrial oxidative capacity. We conclude that human V̇o2 max is related to mitochondrial oxidative capacity predicted from skeletal muscle SDH activity. Mitochondrial oxidative capacity is likely marginally limited by oxygen supply to mitochondria. Copyright © 2016 the American Physiological Society.

A Scientific Approach to Improve Physiological Capacity of an Elite Cyclist.

PubMed

Rønnestad, Bent R; Hansen, Joar

2018-03-01

Previous studies in endurance athletes have indicated that block periodization (BP) can be a good alternative to the more traditional organization of training despite the fact that the total volume and intensity of the training are similar. However, these studies usually last only 4-12 wk. The aim of the present single-case study was to investigate the consequences of 58 wk with systematic BP of low-intensity training (LIT), moderate-intensity training (MIT), and high-intensity interval training (HIT) including incorporation of heavy strength training. It is important that a maintenance stimulus on the nonprioritized training modalities was added in the different training blocks. Performance-related variables were tested regularly during the intervention. The studied cyclist started with a maximal oxygen uptake (VO 2 max) of 73.8 mL · kg -1  · min -1 , peak aerobic power (W max ) of 6.14 W/kg, and a power output at 3 mmol/L blood lactate concentration (Power 3la -) of 3.6 W/kg. Total training volume during the 58-wk intervention was 678 h, of which 452 h were LIT (67%), 124 h were MIT (18%), 69 h were HIT (10%), and 34 h were heavy strength training (5%). The weekly training volume had a large range depending on the focus of the training block. After the intervention the cyclist's VO 2 max was 87 mL · kg -1  · min -1 , W max was 7.35 W/kg, and Power 3la - was 4.9 W/kg. This single case indicates that the present training program can be a good alternative to the more traditional organization of long-term training of endurance athletes. However, a general recommendation cannot be given based on this single-case study.

The effect of endurance training on the ventilatory response to exercise in elite cyclists.

PubMed

Hoogeveen, A R

2000-05-01

The purpose of this study was to investigate the effects of endurance training on the ventilatory response to acute incremental exercise in elite cyclists. Fifteen male elite cyclists [mean (SD) age 24.3 (3.3) years, height 179 (6) cm, body mass 71.1 (7.6) kg, maximal oxygen consumption (VO2max) 69 (7) ml x min(-1) x kg(-1)] underwent two exercise tests on a cycle ergometer. The first test was assessed in December, 6 weeks before the beginning of the cycling season. The second test was performed in June, in the middle of the season. During this period the subjects were expected to be in a highly endurance-trained state. The ventilatory response was assessed during an incremental exercise test (20 W x min(-1)). Oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), and heart rate (HR) were assessed at the following points during the test: at workloads of 200 W, 250 W, 300 W, 350 W, 400 W and at the subject's maximal workload, at a respiratory exchange ratio (R) of 1, and at the ventilatory threshold (Th(vent)) determined using the V-slope-method. Post-training, the mean (SD) VO2max was increased from the pre-training level of 69 (7) ml x min(-1) x kg(-1) (range 61.4-78.6) to 78 (6) ml x min(-1) x kg(-1) (range 70.5-86.3). The mean post-training VO2 was significantly higher than the pre training value (P < 0.01) at all work rates, at Th(vent) and at R = 1. VO2 was also higher at all work rates except for 200 W and 250 W. VE was significantly higher at Th(vent) and R = 1. Training had no effect on HR at all workloads examined. An explanation for the higher VO2 cost for the same work rate may be that in the endurance-trained state, the adaptation to an exercise stimulus with higher intensity is faster than for the less-trained state. Another explanation may be that at the same work rate, in the less-endurance-trained state power is generated using a significantly higher anaerobic input. The results of this study suggest the following practical recommendations for training management in elite cyclists: (1) the VO2 for a subject at the same work rate may be an indicator of the endurance-trained state (i.e., the higher the VO2, the higher the endurance-trained capacity), and (2) the need for multiple exercise tests for determining the HR at Th(vent) during a cycling season is doubtful since at Th(vent) this parameter does not differ much following endurance training.

Some Empirical Notes on the Epo Epidemic in Professional Cycling

ERIC Educational Resources Information Center

Lodewijkx, Hein F. M.; Brouwer, Bram

2011-01-01

The 1990-2010 period in professional cycling is labeled by some as the epo epidemic. Surprisingly, performance enhancement by epo and blood doping is not that clear-cut for endurance athletes, leading to the question whether doping indeed strongly influenced cyclists' performances from the 1990s onwards. We examined the records (1947-2008) of the…

TEACHING PHYSICS: Biking around a hollow sphere

NASA Astrophysics Data System (ADS)

Mak, Se-yuen; Yip, Din-yan

1999-11-01

The conditions required for a cyclist riding a motorbike in a horizontal circle on or above the equator of a hollow sphere are derived using concepts of equilibrium and the condition for uniform circular motion. The result is compared with an empirical analysis based on a video show. Some special cases of interest derived from the general solution are elaborated.

Adult Cycling. An Instructor's Manual. Series MR-001, Publication Number 78-016-01.

ERIC Educational Resources Information Center

Charest, Laurie; Condrey, John

This instructor's manual is designed for use by an experienced cyclist to teach a 10-week, 30-hour course. The course provides on-bike and classroom instruction in defensive maneuvers in traffic, long-distance riding, health and physiology, bike maintenance, legal considerations of biking, and route selection. Participants should be at least…

Biking Is Booming

ERIC Educational Resources Information Center

Truesdell, William H.; Wicks, Carol A.

1978-01-01

One hundred thousand bicycle-motor vehicle accidents will occur this year. Close to 1,100 of the mishaps will result in death. Education is the first, last and best hope for cyclists and motorists alike and one facet of bike safety programs is teaching students to understand a machine they may take for granted. Here are some ideas for starters.…

Moderate Association of Anthropometry, but Not Training Volume, with Race Performance in Male Ultraendurance Cyclists

ERIC Educational Resources Information Center

Knechtle, Beat; Wirth, Andrea; Knechtle, Patrizia; Rosemann, Thomas

2009-01-01

In 28 male Caucasian nonprofessional ultracyclists, we investigated whether anthropometry or training volume had an influence on race speed in the 600 km at the Swiss Cycling Marathon 2007. Anthropometric parameters (age, body mass, body height, skinfold thicknesses) were determined before the race to calculate body mass index and percent body…

Changes in Children's Perception-Action Tuning over Short Time Scales: Bicycling across Traffic-Filled Intersections in a Virtual Environment

ERIC Educational Resources Information Center

Plumert, Jodie M.; Kearney, Joseph K.; Cremer, James F.; Recker, Kara M.; Strutt, Jonathan

2011-01-01

This investigation examined short-term changes in child and adult cyclists' gap decisions and movement timing in response to general and specific road-crossing experiences. Children (10- and 12-year-olds) and adults rode a bicycle through a virtual environment with 12 intersections. Participants faced continuous cross traffic and waited for gaps…

Synchronizing Self and Object Movement: How Child and Adult Cyclists Intercept Moving Gaps in a Virtual Environment

ERIC Educational Resources Information Center

Chihak, Benjamin J.; Plumert, Jodie M.; Ziemer, Christine J.; Babu, Sabarish; Grechkin, Timofey; Cremer, James F.; Kearney, Joseph K.

2010-01-01

Two experiments examined how 10- and 12-year-old children and adults intercept moving gaps while bicycling in an immersive virtual environment. Participants rode an actual bicycle along a virtual roadway. At 12 test intersections, participants attempted to pass through a gap between 2 moving, car-sized blocks without stopping. The blocks were…

The Bicyclist's Paradox

ERIC Educational Resources Information Center

Knight, Randy

2008-01-01

It's a situation every avid cyclist knows only too well. If you cycle up a hill and then back down with no net change in elevation, it seems as if your slower uphill speed and faster downhill speed should offset each other. But they don't. Your average speed is less than it would have been had you cycled the same distance on a level road.…

Aerodynamics of a Cycling Team in a Time Trial: Does the Cyclist at the Front Benefit?

ERIC Educational Resources Information Center

Iniguez-de-la Torre, A.; Iniguez, J.

2009-01-01

When seasonal journeys take place in nature, birds and fishes migrate in groups. This provides them not only with security but also a considerable saving of energy. The power they need to travel requires overcoming aerodynamic or hydrodynamic drag forces, which can be substantially reduced when the group travels in an optimal arrangement. Also in…

The Bicycle Illusion: Sidewalk Science Informs the Integration of Motion and Shape Perception

ERIC Educational Resources Information Center

Masson, Michael E. J.; Dodd, Michael D.; Enns, James T.

2009-01-01

The authors describe a new visual illusion first discovered in a natural setting. A cyclist riding beside a pair of sagging chains that connect fence posts appears to move up and down with the chains. In this illusion, a static shape (the chains) affects the perception of a moving shape (the bicycle), and this influence involves assimilation…

Serum Oxidant and Antioxidant Status in Adolescents Undergoing Professional Endurance Sports Training

PubMed Central

Tong, Tom K.; Lin, Hua; Lippi, Giuseppe; Nie, Jinlei; Tian, Ye

2012-01-01

This study evaluated the impact of professional training on serum oxidant and antioxidant status in adolescent endurance athletes and compared it with that of untrained individuals. Firstly, serum thiobarbituric-acid-reactive substances (TBARSs), xanthine oxidase (XO), catalase (CAT), reduced glutathione (GSH), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC) were measured in 67 male runners, cyclists, and untrained adolescents. Seven-day dietary intakes were also assessed. Secondly, for age- and Tanner-stage-matched comparison, 36 out of the 67 subjects (12 for each group) were then selected and investigated. In cyclists, XO, GSH, and CAT were higher as compared with runners and controls. The CAT in runners, but not GSH and XO, was also higher than in controls. TBARS, T-AOC, and SOD did not differ among the study populations. Regarding the inter-individual relationships among serum redox statuses and dietary nutrient intakes, significant correlations were noted in CAT versus carbohydrates, protein, magnesium, and manganese; GSH versus carbohydrates, protein, fat, selenium, zinc, iron, and magnesium; XO versus cholesterol; CAT versus GSH. These findings suggest that the resting blood redox balance in the professional adolescent athletes was well maintained partly by the increase of individual antioxidant in adaptation to chronic exercise. PMID:22577491

Serum oxidant and antioxidant status in adolescents undergoing professional endurance sports training.

PubMed

Tong, Tom K; Lin, Hua; Lippi, Giuseppe; Nie, Jinlei; Tian, Ye

2012-01-01

This study evaluated the impact of professional training on serum oxidant and antioxidant status in adolescent endurance athletes and compared it with that of untrained individuals. Firstly, serum thiobarbituric-acid-reactive substances (TBARSs), xanthine oxidase (XO), catalase (CAT), reduced glutathione (GSH), superoxide dismutase (SOD), and total antioxidant capacity (T-AOC) were measured in 67 male runners, cyclists, and untrained adolescents. Seven-day dietary intakes were also assessed. Secondly, for age- and Tanner-stage-matched comparison, 36 out of the 67 subjects (12 for each group) were then selected and investigated. In cyclists, XO, GSH, and CAT were higher as compared with runners and controls. The CAT in runners, but not GSH and XO, was also higher than in controls. TBARS, T-AOC, and SOD did not differ among the study populations. Regarding the inter-individual relationships among serum redox statuses and dietary nutrient intakes, significant correlations were noted in CAT versus carbohydrates, protein, magnesium, and manganese; GSH versus carbohydrates, protein, fat, selenium, zinc, iron, and magnesium; XO versus cholesterol; CAT versus GSH. These findings suggest that the resting blood redox balance in the professional adolescent athletes was well maintained partly by the increase of individual antioxidant in adaptation to chronic exercise.

Exposure assessment of a cyclist to particles and chemical elements.

PubMed

Ramos, C A; Silva, J R; Faria, T; Wolterbeek, T H; Almeida, S M

2017-05-01

Cycle paths can be used as a route for active transportation or simply to cycle for physical activity and leisure. However, exposure to air pollutants can be boosted while cycling, in urban environments, due to the proximity to vehicular emissions and elevated breathing rates. The objective of this work was to assess the exposure of a cyclist to particles and to chemical elements by combining real-time aerosol mass concentration reading equipment and biomonitoring techniques. PM 10 and PM 2.5 were measured on three cycle paths located in Lisbon, during weekdays and weekends and during rush hours and off-peak hours resulting in a total of 60 campaigns. Lichens were exposed along cycle paths for 3 months, and their element contents were measured by instrumental neutron activation analysis using the k 0 methodology (k 0 -INAA). Using a bicycle commute route of lower traffic intensity and avoiding rush hours or other times with elevated vehicular congestion facilitate a reduction in exposure to pollutants. The implementation of cycle paths in cities is important to stimulate physical activity and active transportation; however, it is essential to consider ambient air and pollutant sources to create safer infrastructures.

Virtopsy -- noninvasive detection of occult bone lesions in postmortem MRI: additional information for traffic accident reconstruction.

PubMed

Buck, Ursula; Christe, Andreas; Naether, Silvio; Ross, Steffen; Thali, Michael J

2009-05-01

In traffic accidents with pedestrians, cyclists or motorcyclists, patterned impact injuries as well as marks on clothes can be matched to the injury-causing vehicle structure in order to reconstruct the accident and identify the vehicle which has hit the person. Therefore, the differentiation of the primary impact injuries from other injuries is of great importance. Impact injuries can be identified on the external injuries of the skin, the injured subcutaneous and fat tissue, as well as the fractured bones. Another sign of impact is a bone bruise. The bone bruise, or occult bone lesion, means a bleeding in the subcortical bone marrow, which is presumed to be the result of micro-fractures of the medullar trabeculae. The aim of this study was to prove that bleeding in the subcortical bone marrow of the deceased can be detected using the postmortem noninvasive magnetic resonance imaging. This is demonstrated in five accident cases, four involving pedestrians and one a cyclist, where bone bruises were detected in different bones as a sign of impact occurring in the same location as the external and soft tissue impact injuries.

Autonomous Intersection Management

DTIC Science & Technology

2009-12-01

is irrelevant. Fortunately, researchers are attacking this problem with many techniques. In 2004, Honda introduced an intelligent night vision system...or less a solved problem . The problem itself is not too difficult: there are no pedestrians or cyclists and vehicles travel in the same direction at...organized according to the following subgoals, each of which is a contribution of the thesis. 1. Problem definition First, this thesis contributes a

The Effects of a Ketogenic Diet on Exercise Metabolism and Physical Performance in Off-Road Cyclists

PubMed Central

Zajac, Adam; Poprzecki, Stanisław; Maszczyk, Adam; Czuba, Miłosz; Michalczyk, Małgorzata; Zydek, Grzegorz

2014-01-01

The main objective of this research was to determine the effects of a long-term ketogenic diet, rich in polyunsaturated fatty acids, on aerobic performance and exercise metabolism in off-road cyclists. Additionally, the effects of this diet on body mass and body composition were evaluated, as well as those that occurred in the lipid and lipoprotein profiles due to the dietary intervention. The research material included eight male subjects, aged 28.3 ± 3.9 years, with at least five years of training experience that competed in off-road cycling. Each cyclist performed a continuous exercise protocol on a cycloergometer with varied intensity, after a mixed and ketogenic diet in a crossover design. The ketogenic diet stimulated favorable changes in body mass and body composition, as well as in the lipid and lipoprotein profiles. Important findings of the present study include a significant increase in the relative values of maximal oxygen uptake (VO2max) and oxygen uptake at lactate threshold (VO2 LT) after the ketogenic diet, which can be explained by reductions in body mass and fat mass and/or the greater oxygen uptake necessary to obtain the same energy yield as on a mixed diet, due to increased fat oxidation or by enhanced sympathetic activation. The max work load and the work load at lactate threshold were significantly higher after the mixed diet. The values of the respiratory exchange ratio (RER) were significantly lower at rest and during particular stages of the exercise protocol following the ketogenic diet. The heart rate (HR) and oxygen uptake were significantly higher at rest and during the first three stages of exercise after the ketogenic diet, while the reverse was true during the last stage of the exercise protocol conducted with maximal intensity. Creatine kinase (CK) and lactate dehydrogenase (LDH) activity were significantly lower at rest and during particular stages of the 105-min exercise protocol following the low carbohydrate ketogenic diet. The alterations in insulin and cortisol concentrations due to the dietary intervention confirm the concept that the glucostatic mechanism controls the hormonal and metabolic responses to exercise. PMID:24979615

The effects of a ketogenic diet on exercise metabolism and physical performance in off-road cyclists.

PubMed

Zajac, Adam; Poprzecki, Stanisław; Maszczyk, Adam; Czuba, Miłosz; Michalczyk, Małgorzata; Zydek, Grzegorz

2014-06-27

The main objective of this research was to determine the effects of a long-term ketogenic diet, rich in polyunsaturated fatty acids, on aerobic performance and exercise metabolism in off-road cyclists. Additionally, the effects of this diet on body mass and body composition were evaluated, as well as those that occurred in the lipid and lipoprotein profiles due to the dietary intervention. The research material included eight male subjects, aged 28.3 ± 3.9 years, with at least five years of training experience that competed in off-road cycling. Each cyclist performed a continuous exercise protocol on a cycloergometer with varied intensity, after a mixed and ketogenic diet in a crossover design. The ketogenic diet stimulated favorable changes in body mass and body composition, as well as in the lipid and lipoprotein profiles. Important findings of the present study include a significant increase in the relative values of maximal oxygen uptake (VO2max) and oxygen uptake at lactate threshold (VO2 LT) after the ketogenic diet, which can be explained by reductions in body mass and fat mass and/or the greater oxygen uptake necessary to obtain the same energy yield as on a mixed diet, due to increased fat oxidation or by enhanced sympathetic activation. The max work load and the work load at lactate threshold were significantly higher after the mixed diet. The values of the respiratory exchange ratio (RER) were significantly lower at rest and during particular stages of the exercise protocol following the ketogenic diet. The heart rate (HR) and oxygen uptake were significantly higher at rest and during the first three stages of exercise after the ketogenic diet, while the reverse was true during the last stage of the exercise protocol conducted with maximal intensity. Creatine kinase (CK) and lactate dehydrogenase (LDH) activity were significantly lower at rest and during particular stages of the 105-min exercise protocol following the low carbohydrate ketogenic diet. The alterations in insulin and cortisol concentrations due to the dietary intervention confirm the concept that the glucostatic mechanism controls the hormonal and metabolic responses to exercise.

Effects of sprint interval training and body weight reduction on power to weight ratio in experienced cyclists.

PubMed

Lunn, William R; Finn, Joan A; Axtell, Robert S

2009-07-01

The purpose of this study was to determine the effect of supramaximal sprint interval training (SIT), body weight reduction, and a combination of both treatments on peak and average anaerobic power to weight ratio (PPOan:Wt, APOan:Wt) by manipulating peak and average anaerobic power output (PPOan, APOan) and body weight (BW) in experienced cyclists. Participants (N = 34, age = 38.0 +/- 7.1 years) were assigned to 4 groups for a 10-week study. One group performed twice-weekly SIT sessions on a cycle ergometer while maintaining body weight (SIT). A second group did not perform SIT but intentionally reduced body weight (WR). A third group simultaneously performed SIT sessions and reduced body weight (SIT+WR). A control group cycled in their normal routine and maintained body weight (CON). The 30-second Wingate Test assessed pretest and posttest POan:Wt scores. There was a significant mean increase (p < 0.05) from pretest to posttest in PPOan:Wt and APOan:Wt (W x kg(-1)) scores in both SIT (10.82 +/- 1.71 to 11.92 +/- 1.77 and 8.05 +/- 0.64 to 8.77 +/- 0.64, respectively) and WR (10.33 +/- 2.91 to 11.29 +/- 2.80 and 7.04 +/- 1.45 to 7.62 +/- 1.24, respectively). PPOan and APOan (W) increased significantly only in SIT (753.7 +/- 121.0 to 834.3 +/- 150.1 and 561.3 +/- 62.5 to 612.7 +/- 69.0, respectively). Body weight (kg) decreased significantly in WR and SIT + WR (80.3 +/- 13.7 to 75.3 +/- 11.9 and 78.9 +/- 10.8 to 73.4 +/- 10.8, respectively). The results demonstrate that cyclists can use SIT sessions and body weight reduction as singular training interventions to effect significant increases in anaerobic power to weight ratio, which has been correlated to enhanced aerobic cycling performance. However, the treatments were not effective as combined interventions, as there was no significant change in either PPOan:Wt or APOan:Wt in SIT + WR.

Intensified training increases salivary free light chains in trained cyclists: Indication that training volume increases oral inflammation.

PubMed

Heaney, Jennifer L J; Killer, Sophie C; Svendsen, Ida S; Gleeson, Michael; Campbell, John P

2018-05-01

Periods of short-term intensified training (IT) are often used by athletes during training cycles over the season and undergoing phases of increased physical stress may impact upon the immune system. This study investigated the effects of a period of IT on free light chains (FLCs) in saliva - an emerging immune biomarker of oral inflammation - and matched serum samples in well-trained athletes. It also examined if IT influences basal FLC levels and FLC flux during acute exercise. Highly trained male cyclists (n = 10) underwent a 9-day period of IT; before and after IT participants performed a 1 h time trial (TT) on a cycle ergometer, with blood and saliva samples collected pre- and post-exercise. FLCs were assessed in serum and saliva, and IgG, IgA, IgM and creatinine were also measured in serum. Weekly training volume increased by 143% (95% CI 114-172%), p < 0.001, during IT compared with pre-trial baseline training. Following IT, the cyclists demonstrated higher salivary FLC levels. Both salivary lambda FLC concentrations (p < 0.05, η 2  = 0.384) and secretion rates, and kappa FLC concentrations and secretion rates increased after IT. Salivary FLCs concentration and secretion rates decreased in response to the TT following IT (p < 0.05, η 2  = 0.387-0.428), but not in response to the TT prior to IT. No significant effects of IT on serum FLCs were observed. There were no significant changes in serum FLCs in response to the TT, before or after the IT period, nor did IT impact upon other serological responses to the TT. In conclusion, IT increased basal salivary FLC parameters and amplified decreases in salivary FLCs in response to acute exercise. Increases in salivary FLC concentration likely reflects alterations to oral inflammation during times of heavy training, and we show for the first time that FLCs may have utility as a marker of exercise stress and oral health status. Copyright © 2018 Elsevier Inc. All rights reserved.

Under-reporting bicycle accidents to police in the COST TU1101 international survey: Cross-country comparisons and associated factors.

PubMed

Shinar, D; Valero-Mora, P; van Strijp-Houtenbos, M; Haworth, N; Schramm, A; De Bruyne, Guido; Cavallo, V; Chliaoutakis, J; Dias, J; Ferraro, O E; Fyhri, A; Sajatovic, A Hursa; Kuklane, K; Ledesma, R; Mascarell, O; Morandi, A; Muser, M; Otte, D; Papadakaki, M; Sanmartín, J; Dulf, D; Saplioglu, M; Tzamalouka, G

2018-01-01

Police crash reports are often the main source for official data in many countries. However, with the exception of fatal crashes, crashes are often underreported in a biased manner. Consequently, the countermeasures adopted according to them may be inefficient. In the case of bicycle crashes, this bias is most acute and it probably varies across countries, with some of them being more prone to reporting accidents to police than others. Assessing if this bias occurs and the size of it can be of great importance for evaluating the risks associated with bicycling. This study utilized data collected in the COST TU1101 action "Towards safer bicycling through optimization of bicycle helmets and usage". The data came from an online survey that included questions related to bicyclists' attitudes, behaviour, cycling habits, accidents, and patterns of use of helmets. The survey was filled by 8655 bicyclists from 30 different countries. After applying various exclusion factors, 7015 questionnaires filled by adult cyclists from 17 countries, each with at least 100 valid responses, remained in our sample. The results showed that across all countries, an average of only 10% of all crashes were reported to the police, with a wide range among countries: from a minimum of 0.0% (Israel) and 2.6% (Croatia) to a maximum of a 35.0% (Germany). Some factors associated with the reporting levels were type of crash, type of vehicle involved, and injury severity. No relation was found between the likelihood of reporting and the cyclist's gender, age, educational level, marital status, being a parent, use of helmet, and type of bicycle. The significant under-reporting - including injury crashes that do not lead to hospitalization - justifies the use of self-report survey data for assessment of bicycling crash patterns as they relate to (1) crash risk issues such as location, infrastructure, cyclists' characteristics, and use of helmet and (2) strategic approaches to bicycle crash prevention and injury reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effects of intensified training on resting metabolic rate (RMR), body composition and performance in trained cyclists

PubMed Central

Lundy, Bronwen; Rogers, Margot A.; Welvaert, Marijke; Halson, Shona; McKune, Andrew

2018-01-01

Background Recent research has demonstrated decreases in resting metabolic rate (RMR), body composition and performance following a period of intensified training in elite athletes, however the underlying mechanisms of change remain unclear. Therefore, the aim of the present study was to investigate how an intensified training period, designed to elicit overreaching, affects RMR, body composition, and performance in trained endurance athletes, and to elucidate underlying mechanisms. Method Thirteen (n = 13) trained male cyclists completed a six-week training program consisting of a “Baseline” week (100% of regular training load), a “Build” week (~120% of Baseline load), two “Loading” weeks (~140, 150% of Baseline load, respectively) and two “Recovery” weeks (~80% of Baseline load). Training comprised of a combination of laboratory based interval sessions and on-road cycling. RMR, body composition, energy intake, appetite, heart rate variability (HRV), cycling performance, biochemical markers and mood responses were assessed at multiple time points throughout the six-week period. Data were analysed using a linear mixed modeling approach. Results The intensified training period elicited significant decreases in RMR (F(5,123.36) = 12.0947, p = <0.001), body mass (F(2,19.242) = 4.3362, p = 0.03), fat mass (F(2,20.35) = 56.2494, p = <0.001) and HRV (F(2,22.608) = 6.5212, p = 0.005); all of which improved following a period of recovery. A state of overreaching was induced, as identified by a reduction in anaerobic performance (F(5,121.87) = 8.2622, p = <0.001), aerobic performance (F(5,118.26) = 2.766, p = 0.02) and increase in total mood disturbance (F(5, 110.61) = 8.1159, p = <0.001). Conclusion Intensified training periods elicit greater energy demands in trained cyclists, which, if not sufficiently compensated with increased dietary intake, appears to provoke a cascade of metabolic, hormonal and neural responses in an attempt to restore homeostasis and conserve energy. The proactive monitoring of energy intake, power output, mood state, body mass and HRV during intensified training periods may alleviate fatigue and attenuate the observed decrease in RMR, providing more optimal conditions for a positive training adaptation. PMID:29444097

Commuters’ Exposure to Particulate Matter Air Pollution Is Affected by Mode of Transport, Fuel Type, and Route

PubMed Central

Zuurbier, Moniek; Hoek, Gerard; Oldenwening, Marieke; Lenters, Virissa; Meliefste, Kees; van den Hazel, Peter; Brunekreef, Bert

2010-01-01

Background Commuters are exposed to high concentrations of air pollutants, but little quantitative information is currently available on differences in exposure between different modes of transport, routes, and fuel types. Objectives The aim of our study was to assess differences in commuters’ exposure to traffic-related air pollution related to transport mode, route, and fuel type. Methods We measured particle number counts (PNCs) and concentrations of PM2.5 (particulate matter ≤ 2.5 μm in aerodynamic diameter), PM10, and soot between June 2007 and June 2008 on 47 weekdays, from 0800 to 1000 hours, in diesel and electric buses, gasoline- and diesel-fueled cars, and along two bicycle routes with different traffic intensities in Arnhem, the Netherlands. In addition, each-day measurements were taken at an urban background location. Results We found that median PNC exposures were highest in diesel buses (38,500 particles/cm3) and for cyclists along the high-traffic intensity route (46,600 particles/cm3) and lowest in electric buses (29,200 particles/cm3). Median PM10 exposure was highest from diesel buses (47 μg/m3) and lowest along the high- and low-traffic bicycle routes (39 and 37 μg/m3). The median soot exposure was highest in gasoline-fueled cars (9.0 × 10−5/m), diesel cars (7.9 × 10−5/m), and diesel buses (7.4 × 10−5/m) and lowest along the low-traffic bicycle route (4.9 × 10−5/m). Because the minute ventilation (volume of air per minute) of cyclists, which we estimated from measured heart rates, was twice the minute ventilation of car and bus passengers, we calculated that the inhaled air pollution doses were highest for cyclists. With the exception of PM10, we found that inhaled air pollution doses were lowest for electric bus passengers. Conclusions Commuters’ rush hour exposures were significantly influenced by mode of transport, route, and fuel type. PMID:20185385

Exercise intensity of cycle-touring events.

PubMed

Neumayr, G; Pfister, R; Mitterbauer, G; Gaenzer, H; Sturm, W; Eibl, G; Hoertnagl, H

2002-10-01

The aim of the study was to analyze the exercise intensity of recreational cyclists participating in a cycling-touring event. In 14 male healthy recreational cyclists heart rate (HR) monitoring was performed during the Otztal Radmarathon 1999 (distance: 230 km; altitude difference: 5500 m) in order to evaluate the HR response and to estimate the cardiopulmonary strains for the less-trained athlete confronted with such a marathon. Four different exercise intensities were defined as percentages of maximal HR (HR(max)) as follows: recovery HR (HR(re)) < 70 % of HR max; moderate aerobic HR (HR(ma)) = 70 - 80 %; intense aerobic HR (HR(ia)) = 80 - 90 %; and anaerobic HR (HR(an)) > 90 %. All athletes finished the competition successfully. The mean racing time was 10 h 14 min, the average speed 22.5 km/h. The mean HR(max) was 188 bpm, the average value of the measured HRs (HR(average)) was 145 bpm resulting in a mean HR(average)/HR(max) ratio of 0.77. Athletes spent 18.5 % (1 h 54 min) of total race time within HR(re), 28 % (2 h 52 min) within HR(ma), 39.5 % (4 h 02 min) within HR(ia), and 14 % (1 h 26 min) within HR(an). The vast majority of exercise was done under "aerobic conditions" (HR(re) + HR(ma) + HR(ia) = 86 % or 8 h 48 min) - confirming the knowledge that the aerobic energy supply is crucial for the performance of long-term exercise. The large amount of high exercise intensities (HR(ia) + HR(an) = 53.5 % or 5 h 30 min), however, features the intense cardiopulmonary strains evoked by such competitions. The HR response was related to the course profile with HRs significantly declining in all subjects to an extent of 10 % during the course of race. Our findings show that the exercise intensity borne by recreational cyclists during a cycle-touring event is high and very similar to that of professionals. With respect to the high cardiovascular strains a thorough medical screening is advisable for any participant of such an event combining both high volume and high intensity loads.

An empirical tool to evaluate the safety of cyclists: Community based, macro-level collision prediction models using negative binomial regression.

PubMed

Wei, Feng; Lovegrove, Gordon

2013-12-01

Today, North American governments are more willing to consider compact neighborhoods with increased use of sustainable transportation modes. Bicycling, one of the most effective modes for short trips with distances less than 5km is being encouraged. However, as vulnerable road users (VRUs), cyclists are more likely to be injured when involved in collisions. In order to create a safe road environment for them, evaluating cyclists' road safety at a macro level in a proactive way is necessary. In this paper, different generalized linear regression methods for collision prediction model (CPM) development are reviewed and previous studies on micro-level and macro-level bicycle-related CPMs are summarized. On the basis of insights gained in the exploration stage, this paper also reports on efforts to develop negative binomial models for bicycle-auto collisions at a community-based, macro-level. Data came from the Central Okanagan Regional District (CORD), of British Columbia, Canada. The model results revealed two types of statistical associations between collisions and each explanatory variable: (1) An increase in bicycle-auto collisions is associated with an increase in total lane kilometers (TLKM), bicycle lane kilometers (BLKM), bus stops (BS), traffic signals (SIG), intersection density (INTD), and arterial-local intersection percentage (IALP). (2) A decrease in bicycle collisions was found to be associated with an increase in the number of drive commuters (DRIVE), and in the percentage of drive commuters (DRP). These results support our hypothesis that in North America, with its current low levels of bicycle use (<4%), we can initially expect to see an increase in bicycle collisions as cycle mode share increases. However, as bicycle mode share increases beyond some unknown 'critical' level, our hypothesis also predicts a net safety improvement. To test this hypothesis and to further explore the statistical relationships between bicycle mode split and overall road safety, future research needs to pursue further development and application of community-based, macro-level CPMs. Copyright © 2012. Published by Elsevier Ltd.

Comparison of Critical Power and W' Derived From 2 or 3 Maximal Tests.

PubMed

Simpson, Len Parker; Kordi, Mehdi

2017-07-01

Typically, accessing the asymptote (critical power; CP) and curvature constant (W') parameters of the hyperbolic power-duration relationship requires multiple constant-power exhaustive-exercise trials spread over several visits. However, more recently single-visit protocols and personal power meters have been used. This study investigated the practicality of using a 2-trial, single-visit protocol in providing reliable CP and W' estimates. Eight trained cyclists underwent 3- and 12-min maximal-exercise trials in a single session to derive (2-trial) CP and W' estimates. On a separate occasion a 5-min trial was performed, providing a 3rd trial to calculate (3-trial) CP and W'. There were no differences in CP (283 ± 66 vs 282 ± 65 W) or W' (18.72 ± 6.21 vs 18.27 ± 6.29 kJ) obtained from either the 2-trial or 3-trial method, respectively. After 2 familiarization sessions (completing a 3- and a 12-min trial on both occasions), both CP and W' remained reliable over additional separate measurements. The current study demonstrates that after 2 familiarization sessions, reliable CP and W' parameters can be obtained from trained cyclists using only 2 maximal-exercise trials. These results offer practitioners a practical, time-efficient solution for incorporating power-duration testing into applied athlete support.

Public health approaches to safer cycling for children based on developmental and physiological readiness: implications for practice

PubMed Central

Lenton, Simon; Finlay, Fiona Olwen

2018-01-01

Introduction Cyclists have a high mortality and morbidity per mile travelled compared with car occupants, a figure that is likely to increase if campaigns to increase active travel are successful. Concerns about safety is the leading factor limiting cycling for children. Objective This review brings together a paediatric perspective based on the developmental readiness of children and young people and a public health approach to reducing injuries, to produce a practical agenda for improving the safety of cycling for children. Method Selective literature review. Results While most sports realise the importance of practice and training to create mastery of the game, similar thinking has not been consistently applied to cycling proficiency, so many children do not have an opportunity to master cycling before riding on the roads. Conclusions The aim should be to minimise road traffic injuries involving children and young people in ways that create cobenefits for other members of society, increasing opportunities for active travel, reducing air pollution, creating more green space to play and reducing dependence on motor vehicles. Changes in legislation are required now to enable younger children to cycle on pavements while learning to ride and improvements in road design to separate cyclists from motor vehicles especially routes to school for older children. PMID:29637180

Controlling factors of the parental safety perception on children's travel mode choice.

PubMed

Nevelsteen, Kristof; Steenberghen, Thérèse; Van Rompaey, Anton; Uyttersprot, Liesbeth

2012-03-01

The travel mode of children changed significantly over the last 20 years, with a decrease of children travelling as pedestrians or cyclists. This study focuses on six to twelve year old children. Parents determine to a large extent the mode choice of children in this age category. Based on the analysis of an extensive survey, the research shows that traffic infrastructure has a significant impact on parental decision making concerning children's travel mode choice, by affecting both the real and the perceived traffic safety. Real traffic safety is quantified in terms of numbers of accidents and road infrastructure. For the perceived traffic safety a parental allowance probability is calculated per road type to show that infrastructure characteristics influence parental decision making on the children's mode choice. A binary logistic model shows that this allowance is determined by age, gender and traffic infrastructure near the child's home or near destinations frequently visited by children. Since both real and perceived traffic safety are influenced by infrastructure characteristics, a spatial analysis of parental perception and accident statistics can be used to indicate the locations where infrastructure improvements will be most effective to increase the number of children travelling - safely - as pedestrians or cyclists. Copyright © 2011 Elsevier Ltd. All rights reserved.

The effects of whole-body vibration on the Wingate test for anaerobic power when applying individualized frequencies.

PubMed

Surowiec, Rachel K; Wang, Henry; Nagelkirk, Paul R; Frame, Jeffrey W; Dickin, D Clark

2014-07-01

Recently, individualized frequency (I-Freq) has been introduced with the notion that athletes may elicit a greater reflex response at differing levels (Hz) of vibration. The aim of the study was to evaluate acute whole-body vibration as a feasible intervention to increase power in trained cyclists and evaluate the efficacy of using I-Freq as an alternative to 30Hz, a common frequency seen in the literature. Twelve highly trained, competitive male cyclists (age, 29.9 ± 10.0 years; body height, 175.4 ± 7.8 cm; body mass, 77.3 ± 13.9 kg) participated in the study. A Wingate test for anaerobic power was administered on 3 occasions: following a control of no vibration, 30 Hz, or I-freq. Measures of peak power, average power (AP), and the rate of fatigue were recorded and compared with the vibration conditions using separate repeated measures analysis of variance. Peak power, AP, and the rate of fatigue were not significantly impacted by either the 30 Hz or I-Freq vibration interventions (p > 0.05). Given the trained status of the individuals in this study, the ability to elicit an acute response may have been muted. Future studies should further refine the vibration parameters used and assess changes in untrained or recreationally trained populations.

Using the event analysis of systemic teamwork (EAST) to explore conflicts between different road user groups when making right hand turns at urban intersections.

PubMed

Salmon, Paul M; Lenne, Michael G; Walker, Guy H; Stanton, Neville A; Filtness, Ashleigh

2014-01-01

Collisions between different types of road users at intersections form a substantial component of the road toll. This paper presents an analysis of driver, cyclist, motorcyclist and pedestrian behaviour at intersections that involved the application of an integrated suite of ergonomics methods, the Event Analysis of Systemic Teamwork (EAST) framework, to on-road study data. EAST was used to analyse behaviour at three intersections using data derived from an on-road study of driver, cyclist, motorcyclist and pedestrian behaviour. The analysis shows the differences in behaviour and cognition across the different road user groups and pinpoints instances where this may be creating conflicts between different road users. The role of intersection design in creating these differences in behaviour and resulting conflicts is discussed. It is concluded that currently intersections are not designed in a way that supports behaviour across the four forms of road user studied. Interventions designed to improve intersection safety are discussed. Practitioner Summary: Intersection safety currently represents a key road safety issue worldwide. This paper presents a novel application of a framework of ergonomics methods for studying differences in road user behaviour at intersections. The findings support development of interventions that consider all road users as opposed to one group in isolation.

Risk factors of bicycle traffic injury among middle school students in chaoshan rural areas of china.

PubMed

Lin, Zhen-Bin; Ji, Yan-Hu; Xiao, Qing-Yu; Luo, Li-Bo; Li, Li-Ping; Choi, Bernard

2017-01-26

Bicycle injuries are a leading cause of accidental death among children in the world, and bicycle-related injuries are also very common in China, thus to find out bicycle injury risk factors is imperative. This study aims to identify the cyclist-, bicycle- and road-related risk factors of bicycle injury, to develop health education programs as an intervention and to provide a scientific basis for establishing policies against bicycle injury. We selected two middle schools randomly among seven schools in Chaoshan rural areas,where the main means of transportation for students from home to school was bicycle. The subjects were middle school students from 7th to 9th grades from Gucuo Middle School and Hefeng Middle School. Cyclists were surveyed through questionnaires about bicycle injury in the past 12 months. Multivariable logistic analysis showed that compared with a combination-type road、 motor lane and a non-intact road were both risk factors of bicycle injuries. This was followed by riding with fatigue, non-motor lane and inattentive riding. Bicycle injuries are frequent in China. Three risk factors on bicycle traffic injury among middle school students in Chaoshan rural areas of China were identified. This study provides important data to develop intervention strategies for China and other developing countries.

Road crash fatality rates in France: a comparison of road user types, taking account of travel practices.

PubMed

Bouaoun, Liacine; Haddak, Mohamed Mouloud; Amoros, Emmanuelle

2015-02-01

Travel practices are changing: bicycle and motorized two-wheeler (MTW) use are rising in some of France's large cities. These are cheaper modes of transport and therefore attractive at a time of economic crisis, but they also allow their users to avoid traffic congestion. At the same time, active transport modes such as walking and cycling are encouraged because they are beneficial to health and reduce pollution. It is therefore important to find out more about the road crash risks of the different modes of transport. To do this, we need to take account of the number of individuals who use each, and, even better, their travel levels. We estimated the exposure-based fatality rates for road traffic crashes in France, on the basis of the ratio between the number of fatalities and exposure to road accident risk. Fatality data were obtained from the French national police database of road traffic casualties in the period 2007-2008. Exposure data was estimated from the latest national household travel survey (ENTD) which was conducted from April 2007 to April 2008. Three quantities of travel were computed for each mode of transport: (1) the number of trips, (2) the distance traveled and (3) the time spent traveling. Annual fatality rates were assessed by road user type, age and sex. The overall annual fatality rates were 6.3 per 100 million trips, 5.8 per billion kilometers traveled and 0.20 per million hours spent traveling. The fatality rates differed according to road user type, age and sex. The risk of being killed was 20 to 32 times higher for motorized two-wheeler users than for car occupants. For cyclists, the risk of being killed, both on the basis of time spent traveling and the number of trips was about 1.5 times higher than for car occupants. Risk for pedestrians compared to car occupants was similar according to time spent traveling, lower according to the number of trips and higher according to the distance traveled. People from the 17-20 and 21-29 age groups and those aged 70 and over had the highest rates. Males had higher rates than females, by a factor of between 2 and 3. When exposure is taken into account, the risks for motorized two-wheeler users are extremely high compared to other types of road user. This disparity can be explained by the combination of speed and a lack of protection (except for helmets). The differential is so great that prevention measures could probably not eliminate it. The question that arises is as follows: with regard to public health, should not the use of MTW, or at least of motorcycles, be deterred? The difference between the fatality risk of cyclists and of car occupants is much smaller (1.5 times higher); besides, there is much room for improvements in cyclist safety, for instance by increasing the use of helmets and conspicuity equipment. Traffic calming could also benefit cyclists, pedestrians and perhaps moped users. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sex Difference in Draft-Legal Ultra-Distance Events - A Comparison between Ultra-Swimming and Ultra-Cycling.

PubMed

Salihu, Lejla; Rüst, Christoph Alexander; Rosemann, Thomas; Knechtle, Beat

2016-04-30

Recent studies reported that the sex difference in performance in ultra-endurance sports such as swimming and cycling changed over the years. However, the aspect of drafting in draft-legal ultra-endurance races has not yet been investigated. This study investigates the sex difference in ultra-swimming and ultra-cycling draft-legal races where drafting - swimming or cycling behind other participants to save energy and have more power at the end of the race to overtake them, is allowed. The change in performance of the annual best and the annual three best in an ultra-endurance swimming race (16-km 'Faros Swim Marathon') over 38 years and in a 24-h ultra-cycling race ('World Cycling Race') over 13 years were compared and analysed with respect to sex difference. Furthermore, performances of the fastest female and male finishers ever were compared. In the swimming event, the sex difference of the annual best male and female decreased non-significantly (P = 0.262) from 5.3% (1976) to 1.0% (2013). The sex gap of speed in the annual three fastest swimmers decreased significantly (P = 0.043) from 5.9 ± 1.6% (1979) to 4.7 ± 3.1% (2013). In the cycling event, the difference in cycling speed between the annual best male and female decreased significantly (P = 0.026) from 33.31% (1999) to 10.89% (2011). The sex gap of speed in the annual three fastest decreased significantly (P = 0.001) from 32.9 ± 0.6% (1999) to 16.4 ± 5.9% (2011). The fastest male swimmer ever (swimming speed 5.3 km/h, race time: 03:01:55 h:min:s) was 1.5% faster than the fastest female swimmer (swimming speed 5.2 km/h, race time: 03:04:09 h:min:s). The three fastest male swimmers ever (mean 5.27 ± 0.13 km/h) were 4.4% faster than the three fastest female swimmers (mean 5.05 ± 0.20 km/h) (P < 0.05). In the cycling event, the best male ever (cycling speed 45.8 km/h) was 26.4% faster than the best female (cycling speed 36.1 km/h). The three fastest male cyclists ever (45.9 km/h) (mean 45.85 ± 0.05 km/h) were 32.1% faster (P < 0.05) than the three fastest female cyclists ever (34.7 km/h) (mean 34.70 ± 1.87 km/h). In summary, in draft-legal ultra-distance events such as swimming and cycling, the sex difference in the annual top and annual top three swimmers and cyclists decreased (i.e. non-linearly in swimmers and linearly in cyclists) over the years. The sex difference of the fastest athletes ever was smaller in swimming (1.5%) than in cycling (26.4%). This finding is different from reports about races where drafting was not possible or even prohibited and where the sex difference remained stable over years.

Negotiating the Traffic: Can Cognitive Science Help Make Autonomous Vehicles a Reality?

PubMed

Chater, Nick; Misyak, Jennifer; Watson, Derrick; Griffiths, Nathan; Mouzakitis, Alex

2018-02-01

To drive safely among human drivers, cyclists and pedestrians, autonomous vehicles will need to mimic, or ideally improve upon, humanlike driving. Yet, driving presents us with difficult problems of joint action: 'negotiating' with other users over shared road space. We argue that autonomous driving provides a test case for computational theories of social interaction, with fundamental implications for the development of autonomous vehicles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Muscle Adaptations Permitting Fatigue-Resistant Exercise

DTIC Science & Technology

2014-09-15

dietary composition in which fat is the predominant calorie source, that long-distance racing sled dogs sustain exercise by high oxidation rates of free...dog is fed a diet that is approximately 33% protein, 50% fat , and 16% CHO (Eagle Ultrapack, NPAL Analysis). If we assume 10,000 kcal/day intake...the 16% CHO is below what is considered a high CHO diet , which can reach values of 64% in highly trained cyclists during competition. However, the

Advanced accident research system based on a medical and engineering data in the metropolitan area of Florence

PubMed Central

2013-01-01

Background In the metropolitan area of Florence, 62% of major traumas involve powered two wheeler rider and pillion passengers, 10% cyclists, and 7% pedestrians. The urban and extra-urban areas are the most dangerous for the vulnerable road user. In-depth investigations are needed for assessing detailed information on road accidents. This type of study has been very limited in time frame in Italy, and completely absent in the Tuscan region. Consequently a study called “In-depth Study of road Accident in FlorencE” (In-SAFE) has been initiated. Methods A network between the Department of Mechanics and Industrial Technologies (University of Florence) and the Intensive Care Unit of the Emergency Department (Careggi Teaching Hospital, Florence) was created with the aim of collecting information about the road accidents. The data collected includes: on-scene data, data coming from examination of the vehicles, kinematics and dynamic crash data, injuries, treatment, and injury mechanisms. Each injury is codified thorough the AIS score, localized by a three-dimensional human body model based on computer tomography slices, and the main scores are calculated. We then associate each injury with its cause and crash technical parameters. Finally, all the information is collected in the In-SAFE database. Results Patient mean age at the time of the accident was 34.6 years, and 80% were males. The ISS mean is 24.2 (SD 8.7) and the NISS mean is 33.6 (SD 10.5). The main road accident configurations are the “car-to-PTW” (25%) and “pedestrian run over” (17,9%). For the former, the main collision configuration is “head-on crash” (57%). Cyclists and PTW riders-and-pillions-passengers suffer serious injuries (AIS3+) mainly to the head and the thorax. The head (56.4%) and the lower extremities (12.7%) are the most frequently injured pedestrian body regions. Conclusions The aim of the project is to create an in-depth road accident study with special focus on the correlation between technical parameters and injuries. An in-depth investigation team was setup and is currently active in the metropolitan area of Florence. Twenty-eight serious road accidents involving twenty-nine ICU patients are studied. PTW users, cyclist and pedestrians are the most frequently involved in metropolitan accidents. PMID:23496830

Optimisation of sprinting performance in running, cycling and speed skating.

PubMed

van Ingen Schenau, G J; de Koning, J J; de Groot, G

1994-04-01

Sprinting performances rely strongly on a fast acceleration at the start of a sprint and on the capacity to maintain a high velocity in the phase following the start. Simulations based on a model developed in which the generation of metabolic power is related to the mechanical destinations of power showed that for short-lasting sprinting events, the best pacing strategy is an all out effort, even if this strategy causes a strong reduction of the velocity at the end of the race. Even pacing strategies should only be used in exercises lasting longer than 80 to 100 seconds. Sprint runners, speed skaters and cyclists need a large rate of breakdown of energy rich phosphates in the first 4 to 5 seconds of the race (mechanical equivalent > 20 W/kg) in order to accelerate their body, and a power output of more than 10 W/kg in the phase following the start to maintain a high velocity. Maximal speed in running is mainly limited by the necessity to rotate the legs forwards and backwards relative to the hip joint. The acceleration phase, however, relies on powerful extensions of all leg joints. Through a comparison of the hindlimb design of highly specialised animal sprinters (as can be found among predators) and of long distance animal runners (as found among hoofed animals), it is illustrated that these 2 phases of a sprint rely on conflicting requirements: improvement of maximal speed would require lower moments of inertia of the legs whereas a faster acceleration would require the involvement of more muscle mass (not only of the hip and knee extensors but also of the plantar flexors). Maximal speed in cycling and speed skating is not limited by the necessity to move leg segments but rather on air friction and rolling or ice friction. Since the drag coefficients found for speed skaters and cyclists (about 0.8) are considerably higher than those of more streamlined bodies, much progress can still be expected from the reduction of air friction. Speed skaters and especially cyclists show much smaller accelerations during the start than do sprint runners. Skaters might try to improve their very first push off by developing a start technique that allows a much more horizontally directed propulsive force. The small propulsive force at the onset of a cycling sprint is due to the gearing system.(ABSTRACT TRUNCATED AT 400 WORDS)

High Rate of Return to Cycling After Hip Arthroscopy for Femoroacetabular Impingement Syndrome.

PubMed

Frank, Rachel M; Ukwuani, Gift; Clapp, Ian; Chahla, Jorge; Nho, Shane J

Femoroacetabular impingement syndrome (FAIS) is most commonly diagnosed in athletes who sustain repetitive flexion and rotational loading to their hip. The purpose of this study was to evaluate a patient's ability to return to cycling after hip arthroscopy for FAIS. There is a high rate of return to cycling after hip arthroscopy. Retrospective analysis. Level 4. Consecutive patients who had identified themselves as cyclists and had undergone hip arthroscopy for the treatment of FAIS were reviewed. Pre- and postoperative physical examinations, imaging, and patient-reported outcomes (PROs) scores, including the modified Harris Hip Score (mHHS), Hip Outcome Score Activities of Daily Living (HOS-ADL) and Sports-Specific (HOS-SS) subscales, and visual analog scale for pain, as well as a cycling-specific questionnaire, were assessed for all patients. A total of 58 patients (62% female; mean age, 30.0 ± 7.1 years; mean body mass index, 23.2 ± 2.7 kg/m 2 ) were included. Prior to surgery, patients averaged 30 ± 42 miles per week (range, 2-300 miles). Fifty-five patients (95%) were forced to discontinue cycling at an average of 7.5 ± 6.2 months prior to surgery due to hip pain. Fifty-six patients (97%) returned to cycling at an average of 4.5 ± 2.5 months after surgery, with 33 (59%) returning to a better level of cycling and 23 (41%) to the same cycling level. Postoperatively, there was no difference in the average number of miles patients completed per week compared with preoperative values ( P = 0.08). At a mean follow-up of 31.14 ± 0.71 months (range, 24-48 months), all patients experienced significant improvements in mHHS, HOS-ADL, and HOS-SS PROs (all P < 0.0001), with an overall satisfaction rate of 91% ± 13%. Recreational and competitive cyclists return to cycling 97% of the time after hip arthroscopy for FAIS, with most of these patients returning at an average of 4.5 months after surgery. This information is helpful in counseling patients on their expectations with regard to returning to cycling after hip arthroscopy for FAIS. Cyclists return to sport 97% of the time at an average of 4.5 months after hip arthroscopy for FAIS.

Generating a city's first report on bicyclist safety: lessons from the field.

PubMed

Lopez, Dahianna S; Hemenway, David

2017-08-03

For cities aiming to create a useful surveillance system for bicycle injuries, a common challenge is that city crash reporting is scattered, faulty or non-existent. We document some of the lessons we learnt in helping the city of Boston, Massachusetts, USA, do the following: (1) Create a prototype for a comprehensive police crash data set (2) Produce the city's first cyclist safety report, (3) Make crash data available to the public and (4) Generate policy recommendations for both specific roadside improvements and for sustainable changes to the police department's crash reporting database. We provided research and technical assistance to government partners to generate the report and used participant-observation field notes to generate the list of learnt lessons. After the release of the report, the city implemented immediate activities aimed at making an effort to prevent injuries, including: (1) Furnishing over 1800 taxis with stickers to prevent 'dooring,' (2) Adding pavement markings at trolley tracks to decrease the likelihood that cyclists would fall from getting their wheels lodged in the tracks, (3) Conducting targeted enforcement of traffic laws and (4) Working directly with state and federal agencies to fund a more comprehensive surveillance system. As of January of 2017, nearly 4 years after its public release, 19 170 users have viewed the crash data set 23 247 times. Some of the lessons include finding and using committed champions, prioritising the use of existing data, creating opportunities to bridge divisions between stakeholders, partnering with local universities for assistance with advanced analytics and using deliverables, such as a cyclist safety report, to advocate for sustainability. Providing an initial report on bicycle crashes in Boston served to identify specific problems, showed the value of a data system, and provided a blueprint for an improved data system. Building a useful surveillance system depends in no small part on the wise use of advocacy, group dynamics, and politics. Our hope is that the lessons learnt from our experience in Boston can help others do even better. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Warm-up strategy and high-intensity endurance performance in trained cyclists.

PubMed

Christensen, Peter M; Bangsbo, Jens

2015-04-01

To evaluate the influence of warm-up exercise intensity and subsequent recovery on intense endurance performance, selected blood variables, and the oxygen-uptake (VO2) response. Twelve highly trained male cyclists (VO2max 72.4 ± 8.0 mL · min-1 · kg-1, incremental-test peak power output (iPPO) 432 ± 31 W; mean ± SD) performed 3 warm-up strategies lasting 20 min before a 4-min maximal-performance test (PT). Strategies consisted of moderate-intensity exercise (50%iPPO) followed by 6 min of recovery (MOD6) or progressive high-intensity exercise (10-100%iPPO and 2 × 20-s sprints) followed by recovery for 6 min (HI6) or 20 min (HI20). Before PT venous pH was lower (P < .001) in HI6 (7.27 ± 0.05) than in HI20 (7.34 ± 0.04) and MOD6 (7.35 ± 0.03). At the same time, differences (P < .001) existed for venous lactate in HI6 (8.2 ± 2.0 mmol/L), HI20 (5.1 ± 1.7 mmol/L), and MOD6 (1.4 ± 0.4 mmol/L), as well as for venous bicarbonate in HI6 (19.3 ± 2.6 mmol/L), HI20 (22.6 ± 2.3 mmol/L), and MOD6 (26.0 ± 1.4 mmol/L). Mean power in PT in HI6 (402 ± 38 W) tended to be lower (P = .11) than in HI20 (409 ± 34 W) and was lower (P = .007) than in MOD6 (416 ± 32 W). Total VO2 (15-120 s in PT) was higher in HI6 (8.18 ± 0.86 L) than in HI20 (7.85 ± 0.82 L, P = .008) and MOD6 (7.90 ± 0.74 L, P = .012). Warm-up exercise including race-pace and sprint intervals combined with short recovery can reduce subsequent performance in a 4-min maximal test in highly trained cyclists. Thus, a reduced time at high exercise intensity, a reduced intensity in the warm-up, or an extension of the recovery period after an intense warm-up is advocated.

Nutritional behavior of cyclists during a 24-hour team relay race: a field study report

PubMed Central

2012-01-01

Background Information about behavior of energy intake in ultra-endurance cyclists during a 24-hour team relay race is scarce. The nutritional strategy during such an event is an important factor which athletes should plan carefully before the race. The purpose of this study was to examine and compare the nutritional intake of ultra-endurance cyclists during a 24-hour team relay race with the current nutritional guidelines for endurance events. Additionally, we analyzed the relationship among the nutritional and performance variables. Methods Using a observational design, nutritional intake of eight males (mean ± SD: 36.7 ± 4.7 years; 71.6 ± 4.9 kg; 174.6 ± 7.3 cm; BMI 23.5 ± 0.5 kg/m2) participating in a 24-hour team relay cycling race was assessed. All food and fluid intake by athletes were weighed and recorded. Additionally, distance and speed performed by each rider were also recorded. Furthermore, before to the race, all subjects carried out an incremental exercise test to determine two heart rate-VO2 regression equations which were used to estimate the energy expenditure. Results The mean ingestion of macronutrients during the event was 943 ± 245 g (13.1 ± 4.0 g/kg) of carbohydrates, 174 ± 146 g (2.4 ± 1.9 g/kg) of proteins and 107 ± 56 g (1.5 ± 0.7 g/kg) of lipids, respectively. This amount of nutrients reported an average nutrient intake of 22.8 ± 8.9 MJ which were significantly lower compared with energy expenditure 42.9 ± 6.8 MJ (P = 0.012). Average fluid consumption corresponded to 10497 ± 2654 mL. Mean caffeine ingestion was 142 ± 76 mg. Additionally, there was no relationship between the main nutritional variables (i.e. energy intake, carbohydrates, proteins, fluids and caffeine ingestion) and the main performance variables (i.e. distance and speed). Conclusions A 24-hour hours cycling competition in a team relay format elicited high energy demands which were not compensated by energy intake of the athletes despite that dietary consumption of macronutrients did not differ to the nutritional guidelines for longer events. PMID:22309475

Metabolic clues regarding the enhanced performance of elite endurance athletes from orchiectomy-induced hormonal changes.

PubMed

Atwood, Craig S; Bowen, Richard L

2007-01-01

This article examines the metabolic performance of an elite cyclist, Lance Armstrong, before and after his diagnosis with testicular cancer. Although a champion cyclist in 1-day events prior to his diagnosis of testicular cancer at age 25, he was not a contender in multi-day endurance cycle races such as the 3-week Tour de France. His genetic makeup and physiology (high VO2max, long femur, strong heavy build) coupled with his ambition and motivation enabled him at an early age to become one of the best 1-day cyclists in the world. Following his cancer diagnosis, he underwent a unilateral orchiectomy, brain surgery and four cycles of chemotherapy. After recovering, he returned to cycling and surprisingly excelled in the Tour de France, winning this hardest of endurance events 7 years running. This dramatic transformation from a 1-day to a 3-week endurance champion has led many to query how this is possible, and under the current climate, has led to suggestions of doping as to the answer to this metamorphosis. Physiological tests following his recovery indicated that physiological parameters such as VO2max were not affected by the unilateral orchiectomy and chemotherapy. We propose that his dramatic improvement in recovery between stages, the most important factor in winning multi-day stage races, is due to his unilateral orchiectomy, a procedure that results in permanent changes in serum hormones. These hormonal changes, specifically an increase in gonadotropins (and prolactin) required to maintain serum testosterone levels, alter fuel metabolism; increasing hormone sensitive lipase expression and activity, promoting increased free fatty acid (FFA) mobilization to, and utilization by, muscles, thereby decreasing the requirement to expend limiting glycogen stores before, during and after exercise. Such hormonal changes also have been associated with ketone body production, improvements in muscle repair and haematocrit levels and may facilitate the loss of body weight, thereby increasing power to weight ratio. Taken together, these hormonal changes act to limit glycogen utilization, delay fatigue and enhance recovery thereby allowing for optimal performances on a day-to-day basis. These insights provide the foundation for future studies on the endocrinology of exercise metabolism, and suggest that Lance Armstrong's athletic advantage was not due to drug use.

Investigating the Potential of Activity Tracking App Data to Estimate Cycle Flows in Urban Areas

NASA Astrophysics Data System (ADS)

Haworth, J.

2016-06-01

Traffic congestion and its associated environmental effects pose a significant problem for large cities. Consequently, promoting and investing in green travel modes such as cycling is high on the agenda for many transport authorities. In order to target investment in cycling infrastructure and improve the experience of cyclists on the road, it is important to know where they are. Unfortunately, investment in intelligent transportation systems over the years has mainly focussed on monitoring vehicular traffic, and comparatively little is known about where cyclists are on a day to day basis. In London, for example, there are a limited number of automatic cycle counters installed on the network, which provide only part of the picture. These are supplemented by surveys that are carried out infrequently. Activity tracking apps on smart phones and GPS devices such as Strava have become very popular over recent years. Their intended use is to track physical activity and monitor training. However, many people routinely use such apps to record their daily commutes by bicycle. At the aggregate level, these data provide a potentially rich source of information about the movement and behaviour of cyclists. Before such data can be relied upon, however, it is necessary to examine their representativeness and understand their potential biases. In this study, the flows obtained from Strava Metro (SM) are compared with those obtained during the 2013 London Cycle Census (LCC). A set of linear regression models are constructed to predict LCC flows using SM flows along with a number of dummy variables including road type, hour of day, day of week and presence/absence of cycle lane. Cross-validation is used to test the fitted models on unseen LCC sites. SM flows are found to be a statistically significant (p<0.0001) predictor of total flows as measured by the LCC and the models yield R squared statistics of ~0.7 before considering spatio-temporal variation. The initial results indicate that data collected using fitness tracking apps such as Strava are a promising data source for traffic managers. Future work will incorporate the spatio-temporal structure in the data to better account for the spatial and temporal variation in the ratio of SM flows to LCC flows.

Utilizing Crowdsourced Data for Studies of Cycling and Air Pollution Exposure: A Case Study Using Strava Data.

PubMed

Sun, Yeran; Mobasheri, Amin

2017-03-08

With the development of information and communications technology, user-generated content and crowdsourced data are playing a large role in studies of transport and public health. Recently, Strava, a popular website and mobile app dedicated to tracking athletic activity (cycling and running), began offering a data service called Strava Metro, designed to help transportation researchers and urban planners to improve infrastructure for cyclists and pedestrians. Strava Metro data has the potential to promote studies of cycling and health by indicating where commuting and non-commuting cycling activities are at a large spatial scale (street level and intersection level). The assessment of spatially varying effects of air pollution during active travel (cycling or walking) might benefit from Strava Metro data, as a variation in air pollution levels within a city would be expected. In this paper, to explore the potential of Strava Metro data in research of active travel and health, we investigate spatial patterns of non-commuting cycling activities and associations between cycling purpose (commuting and non-commuting) and air pollution exposure at a large scale. Additionally, we attempt to estimate the number of non-commuting cycling trips according to environmental characteristics that may help identify cycling behavior. Researchers who are undertaking studies relating to cycling purpose could benefit from this approach in their use of cycling trip data sets that lack trip purpose. We use the Strava Metro Nodes data from Glasgow, United Kingdom in an empirical study. Empirical results reveal some findings that (1) when compared with commuting cycling activities, non-commuting cycling activities are more likely to be located in outskirts of the city; (2) spatially speaking, cyclists riding for recreation and other purposes are more likely to be exposed to relatively low levels of air pollution than cyclists riding for commuting; and (3) the method for estimating of the number of non-commuting cycling activities works well in this study. The results highlight: (1) a need for policymakers to consider how to improve cycling infrastructure and road safety in outskirts of cities; and (2) a possible way of estimating the number of non-commuting cycling activities when the trip purpose of cycling data is unknown.

Utilizing Crowdsourced Data for Studies of Cycling and Air Pollution Exposure: A Case Study Using Strava Data

PubMed Central

Sun, Yeran; Mobasheri, Amin

2017-01-01

With the development of information and communications technology, user-generated content and crowdsourced data are playing a large role in studies of transport and public health. Recently, Strava, a popular website and mobile app dedicated to tracking athletic activity (cycling and running), began offering a data service called Strava Metro, designed to help transportation researchers and urban planners to improve infrastructure for cyclists and pedestrians. Strava Metro data has the potential to promote studies of cycling and health by indicating where commuting and non-commuting cycling activities are at a large spatial scale (street level and intersection level). The assessment of spatially varying effects of air pollution during active travel (cycling or walking) might benefit from Strava Metro data, as a variation in air pollution levels within a city would be expected. In this paper, to explore the potential of Strava Metro data in research of active travel and health, we investigate spatial patterns of non-commuting cycling activities and associations between cycling purpose (commuting and non-commuting) and air pollution exposure at a large scale. Additionally, we attempt to estimate the number of non-commuting cycling trips according to environmental characteristics that may help identify cycling behavior. Researchers who are undertaking studies relating to cycling purpose could benefit from this approach in their use of cycling trip data sets that lack trip purpose. We use the Strava Metro Nodes data from Glasgow, United Kingdom in an empirical study. Empirical results reveal some findings that (1) when compared with commuting cycling activities, non-commuting cycling activities are more likely to be located in outskirts of the city; (2) spatially speaking, cyclists riding for recreation and other purposes are more likely to be exposed to relatively low levels of air pollution than cyclists riding for commuting; and (3) the method for estimating of the number of non-commuting cycling activities works well in this study. The results highlight: (1) a need for policymakers to consider how to improve cycling infrastructure and road safety in outskirts of cities; and (2) a possible way of estimating the number of non-commuting cycling activities when the trip purpose of cycling data is unknown. PMID:28282865

The usefulness of GPS bicycle tracking data for evaluating the impact of infrastructure change on cycling behaviour.

PubMed

Heesch, Kristiann C; Langdon, Michael

2016-02-01

Issue addressed A key strategy to increase active travel is the construction of bicycle infrastructure. Tools to evaluate this strategy are limited. This study assessed the usefulness of a smartphone GPS tracking system for evaluating the impact of this strategy on cycling behaviour. Methods Cycling usage data were collected from Queenslanders who used a GPS tracking app on their smartphone from 2013-2014. 'Heat' and volume maps of the data were reviewed, and GPS bicycle counts were compared with surveillance data and bicycle counts from automatic traffic-monitoring devices. Results Heat maps broadly indicated that changes in cycling occurred near infrastructure improvements. Volume maps provided changes in counts of cyclists due to these improvements although errors were noted in geographic information system (GIS) geo-coding of some GPS data. Large variations were evident in the number of cyclists using the app in different locations. These variations limited the usefulness of GPS data for assessing differences in cycling across locations. Conclusion Smartphone GPS data are useful in evaluating the impact of improved bicycle infrastructure in one location. Using GPS data to evaluate differential changes in cycling across multiple locations is problematic when there is insufficient traffic-monitoring devices available to triangulate GPS data with bicycle traffic count data. So what? The use of smartphone GPS data with other data sources is recommended for assessing how infrastructure improvements influence cycling behaviour.

Interindividual variability of electromyographic patterns and pedal force profiles in trained cyclists.

PubMed

Hug, François; Drouet, Jean Marc; Champoux, Yvan; Couturier, Antoine; Dorel, Sylvain

2008-11-01

The aim of this study was to determine whether high inter-individual variability of the electromyographic (EMG) patterns during pedaling is accompanied by variability in the pedal force application patterns. Eleven male experienced cyclists were tested at two submaximal power outputs (150 and 250 W). Pedal force components (effective and total forces) and index of mechanical effectiveness were measured continuously using instrumented pedals and were synchronized with surface electromyography signals measured in ten lower limb muscles. The intersubject variability of EMG and mechanical patterns was assessed using standard deviation, mean deviation, variance ratio and coefficient of cross-correlation (_R(0), with lag time = 0). The results demonstrated a high intersubject variability of EMG patterns at both exercise intensities for biarticular muscles as a whole (and especially for Gastrocnemius lateralis and Rectus femoris) and for one monoarticular muscle (Tibialis anterior). However, this heterogeneity of EMG patterns is not accompanied by a so high intersubject variability in pedal force application patterns. A very low variability in the three mechanical profiles (effective force, total force and index of mechanical effectiveness) was obtained in the propulsive downstroke phase, although a greater variability in these mechanical patterns was found during upstroke and around the top dead center, and at 250 W when compared to 150 W. Overall, these results provide additional evidence for redundancy in the neuromuscular system.

The impact of driver age on lost life years for other road users in France: A population based study of crash-involved road users.

PubMed

Lafont, Sylviane; Amoros, Emmanuelle; Gadegbeku, Blandine; Chiron, Mireille; Laumon, Bernard

2008-01-01

One of the concerns in road safety is the threat older drivers may pose to other road users. Using the rate of lost life years, the present study provides a public health approach to quantify this potential threat. A total of 1570686 motorised vehicle drivers or motorcycle riders and 652246 non-drivers, i.e. vehicle passengers, pedestrians and cyclists involved in injury crashes in France between 1996 and 2004, were included in a population based cross-sectional study. Fatality rates and rate of lost life years for each crash-involved driver age class were calculated for the drivers themselves and for other road users. The study has shown a significant reduction in the rate of lost life years for crash-involved other road users (whether passengers, pedestrians, cyclists or opposing drivers) as driver age increases. Other road users lost half as many years of life when involved in crashes with drivers aged over 85 than with drivers under 65 (1.26 and 2.32 per 100 expected remaining life years, respectively). Our findings suggest that among road users involved in injury crashes, older drivers are less dangerous for the other road users. By attributing other road users' lost life years to each driver age, this study represents a new contribution to the debate about ageing and road safety.

Changes in cortical activity measured with EEG during a high-intensity cycling exercise

PubMed Central

Cortese, Filomeno; Maurer, Christian; Baltich, Jennifer; Protzner, Andrea B.; Nigg, Benno M.

2015-01-01

This study investigated the effects of a high-intensity cycling exercise on changes in spectral and temporal aspects of electroencephalography (EEG) measured from 10 experienced cyclists. Cyclists performed a maximum aerobic power test on the first testing day followed by a time-to-exhaustion trial at 85% of their maximum power output on 2 subsequent days that were separated by ∼48 h. EEG was recorded using a 64-channel system at 500 Hz. Independent component (IC) analysis parsed the EEG scalp data into maximal ICs. An equivalent current dipole model was calculated for each IC, and results were clustered across subjects. A time-frequency analysis of the identified electrocortical clusters was performed to investigate the magnitude and timing of event-related spectral perturbations. Significant changes (P < 0.05) in electrocortical activity were found in frontal, supplementary motor and parietal areas of the cortex. Overall, there was a significant increase in EEG power as fatigue developed throughout the exercise. The strongest increase was found in the frontal area of the cortex. The timing of event-related desynchronization within the supplementary motor area corresponds with the onset of force production and the transition from flexion to extension in the pedaling cycle. The results indicate an involvement of the cerebral cortex during the pedaling task that most likely involves executive control function, as well as motor planning and execution. PMID:26538604

Effect of yoga on short-term heart rate variability measure as a stress index in subjunior cyclists: a pilot study.

PubMed

Patil, Satish G; Mullur, Lata M; Khodnapur, Jyoti P; Dhanakshirur, Gopal B; Aithala, Manjunatha R

2013-01-01

Subjunior athletes experience mental stress due to pressure from the coach, teachers and parents for better performance. Stress, if remains for longer period and not managed appropriately can leads to negative physical, mental and cognitive impact on children. The present study was aimed to evaluate the effect of integrated yoga module on heart rate variability (HRV) measure as a stress index in subjunior cyclists. Fast furrier transform technique of frequency domain method was used for the analysis of HRV. We have found a significant increase in high frequency (HF) component by 14.64% (P < 0.05) and decrease in the low frequency component (LF) of HRV spectrum by 5.52% (P < 0.05) and a decrease in LF/HF ratio by 19.63% (P < 0.01) in yoga group. In the control group, there was decrease in the HF component and, no significant difference in the LF component of HRV spectrum and LF/HF ratio. The results show that yoga practice decreases sympathetic activity and causes a shift in the autonomic balance towards parasympathetic dominance indicating a reduction in stress. In conclusion, yoga practice helps to reduce stress by optimizing the autonomic functions. So, it is suggested to incorporate yoga module as a regular feature to keep subjunior athletes both mentally and physically fit.

Cycling and bone health: a systematic review

PubMed Central

2012-01-01

Background Cycling is considered to be a highly beneficial sport for significantly enhancing cardiovascular fitness in individuals, yet studies show little or no corresponding improvements in bone mass. Methods A scientific literature search on studies discussing bone mass and bone metabolism in cyclists was performed to collect all relevant published material up to April 2012. Descriptive, cross-sectional, longitudinal and interventional studies were all reviewed. Inclusion criteria were met by 31 studies. Results Heterogeneous studies in terms of gender, age, data source, group of comparison, cycling level or modality practiced among others factors showed minor but important differences in results. Despite some controversial results, it has been observed that adult road cyclists participating in regular training have low bone mineral density in key regions (for example, lumbar spine). Conversely, other types of cycling (such as mountain biking), or combination with other sports could reduce this unsafe effect. These results cannot yet be explained by differences in dietary patterns or endocrine factors. Conclusions From our comprehensive survey of the current available literature it can be concluded that road cycling does not appear to confer any significant osteogenic benefit. The cause of this may be related to spending long hours in a weight-supported position on the bike in combination with the necessary enforced recovery time that involves a large amount of time sitting or lying supine, especially at the competitive level. PMID:23256921

Recovery from cycling exercise: effects of carbohydrate and protein beverages.

PubMed

Goh, Qingnian; Boop, Christopher A; Luden, Nicholas D; Smith, Alexia G; Womack, Christopher J; Saunders, Michael J

2012-07-01

The effects of different carbohydrate-protein (CHO + Pro) beverages were compared during recovery from cycling exercise. Twelve male cyclists (VO(2peak): 65 ± 7 mL/kg/min) completed ~1 h of high-intensity intervals (EX1). Immediately and 120 min following EX1, subjects consumed one of three calorically-similar beverages (285-300 kcal) in a cross-over design: carbohydrate-only (CHO; 75 g per beverage), high-carbohydrate/low-protein (HCLP; 45 g CHO, 25 g Pro, 0.5 g fat), or low-carbohydrate/high-protein (LCHP; 8 g CHO, 55 g Pro, 4 g fat). After 4 h of recovery, subjects performed subsequent exercise (EX2; 20 min at 70% VO(2peak) + 20 km time-trial). Beverages were also consumed following EX2. Blood glucose levels (30 min after beverage ingestion) differed across all treatments (CHO > HCLP > LCHP; p < 0.05), and serum insulin was higher following CHO and HCLP ingestion versus LCHP. Peak quadriceps force, serum creatine kinase, muscle soreness, and fatigue/energy ratings measured pre- and post-exercise were not different between treatments. EX2 performance was not significantly different between CHO (48.5 ± 1.5 min), HCLP (48.8 ± 2.1 min) and LCHP (50.3 ± 2.7 min). Beverages containing similar caloric content but different proportions of carbohydrate/protein provided similar effects on muscle recovery and subsequent exercise performance in well-trained cyclists.

Recovery from Cycling Exercise: Effects of Carbohydrate and Protein Beverages

PubMed Central

Goh, Qingnian; Boop, Christopher A.; Luden, Nicholas D.; Smith, Alexia G.; Womack, Christopher J.; Saunders, Michael J.

2012-01-01

The effects of different carbohydrate-protein (CHO + Pro) beverages were compared during recovery from cycling exercise. Twelve male cyclists (VO2peak: 65 ± 7 mL/kg/min) completed ~1 h of high-intensity intervals (EX1). Immediately and 120 min following EX1, subjects consumed one of three calorically-similar beverages (285–300 kcal) in a cross-over design: carbohydrate-only (CHO; 75 g per beverage), high-carbohydrate/low-protein (HCLP; 45 g CHO, 25 g Pro, 0.5 g fat), or low-carbohydrate/high-protein (LCHP; 8 g CHO, 55 g Pro, 4 g fat). After 4 h of recovery, subjects performed subsequent exercise (EX2; 20 min at 70% VO2peak + 20 km time-trial). Beverages were also consumed following EX2. Blood glucose levels (30 min after beverage ingestion) differed across all treatments (CHO > HCLP > LCHP; p < 0.05), and serum insulin was higher following CHO and HCLP ingestion versus LCHP. Peak quadriceps force, serum creatine kinase, muscle soreness, and fatigue/energy ratings measured pre- and post-exercise were not different between treatments. EX2 performance was not significantly different between CHO (48.5 ± 1.5 min), HCLP (48.8 ± 2.1 min) and LCHP (50.3 ± 2.7 min). Beverages containing similar caloric content but different proportions of carbohydrate/protein provided similar effects on muscle recovery and subsequent exercise performance in well-trained cyclists. PMID:22852050

Pyruvate ingestion for 7 days does not improve aerobic performance in well-trained individuals

NASA Technical Reports Server (NTRS)

Morrison, M. A.; Spriet, L. L.; Dyck, D. J.

2000-01-01

The purposes of the present studies were to test the hypotheses that lower dosages of oral pyruvate ingestion would increase blood pyruvate concentration and that the ingestion of a commonly recommended dosage of pyruvate (7 g) for 7 days would enhance performance during intense aerobic exercise in well-trained individuals. Nine recreationally active subjects (8 women, 1 man) consumed 7, 15, and 25 g of pyruvate and were monitored for a 4-h period to determine whether blood metabolites were altered. Pyruvate consumption failed to significantly elevate blood pyruvate, and it had no effect on indexes of carbohydrate (blood glucose, lactate) or lipid metabolism (blood glycerol, plasma free fatty acids). As a follow-up, we administered 7 g/day of either placebo or pyruvate, for a 1-wk period to seven, well-trained male cyclists (maximal oxygen consumption, 62.3 +/- 3.0 ml. kg(-1). min(-1)) in a randomized, double-blind, crossover trial. Subjects cycled at 74-80% of their maximal oxygen consumption until exhaustion. There was no difference in performance times between the two trials (placebo, 91 +/- 9 min; pyruvate, 88 +/- 8 min). Measured blood parameters (insulin, peptide C, glucose, lactate, glycerol, free fatty acids) were also unaffected. Our results indicate that oral pyruvate supplementation does not increase blood pyruvate content and does not enhance performance during intense exercise in well-trained cyclists.

Societal cost of traumatic brain injury: A comparison of cost-of-injuries related to biking with and without helmet use.

PubMed

Costa, Camille K; Dagher, Jehane H; Lamoureux, Julie; de Guise, Elaine; Feyz, Mitra

2015-01-01

The goal of this study is to determine if a difference in societal costs exists from traumatic brain injuries (TBI) in patients who wear helmets compared to non-wearers. This is a retrospective cost-of-injury study of 128 patients admitted to the Montreal General Hospital (MGH) following a TBI that occurred while cycling between 2007-2011. Information was collected from Quebec Trauma Registry. The independent variables collected were socio-demographic, helmet status, clinical and neurological patient information. The dependent variables evaluated societal costs. The median costs of hospitalization were significantly higher (p = 0.037) in the no helmet group ($7246.67 vs. $4328.17). No differences in costs were found for inpatient rehabilitation (p = 0.525), outpatient rehabilitation (p = 0.192), loss of productivity (p = 0.108) or death (p = 1.000). Overall, the differences in total societal costs between the helmet and no helmet group were not significantly different (p = 0.065). However, the median total costs for patients with isolated TBI in the non-helmet group ($22, 232.82) was significantly higher (p = 0.045) compared to the helmet group ($13, 920.15). Cyclists sustaining TBIs who did not wear helmets in this study were found to cost society nearly double that of helmeted cyclists.

Characteristics of cyclist crashes in Italy using latent class analysis and association rule mining

PubMed Central

De Angelis, Marco; Marín Puchades, Víctor; Fraboni, Federico; Pietrantoni, Luca

2017-01-01

The factors associated with severity of the bicycle crashes may differ across different bicycle crash patterns. Therefore, it is important to identify distinct bicycle crash patterns with homogeneous attributes. The current study aimed at identifying subgroups of bicycle crashes in Italy and analyzing separately the different bicycle crash types. The present study focused on bicycle crashes that occurred in Italy during the period between 2011 and 2013. We analyzed categorical indicators corresponding to the characteristics of infrastructure (road type, road signage, and location type), road user (i.e., opponent vehicle and cyclist’s maneuver, type of collision, age and gender of the cyclist), vehicle (type of opponent vehicle), and the environmental and time period variables (time of the day, day of the week, season, pavement condition, and weather). To identify homogenous subgroups of bicycle crashes, we used latent class analysis. Using latent class analysis, the bicycle crash data set was segmented into 19 classes, which represents 19 different bicycle crash types. Logistic regression analysis was used to identify the association between class membership and severity of the bicycle crashes. Finally, association rules were conducted for each of the latent classes to uncover the factors associated with an increased likelihood of severity. Association rules highlighted different crash characteristics associated with an increased likelihood of severity for each of the 19 bicycle crash types. PMID:28158296

An ultra-low power wireless sensor network for bicycle torque performance measurements.

PubMed

Gharghan, Sadik K; Nordin, Rosdiadee; Ismail, Mahamod

2015-05-21

In this paper, we propose an energy-efficient transmission technique known as the sleep/wake algorithm for a bicycle torque sensor node. This paper aims to highlight the trade-off between energy efficiency and the communication range between the cyclist and coach. Two experiments were conducted. The first experiment utilised the Zigbee protocol (XBee S2), and the second experiment used the Advanced and Adaptive Network Technology (ANT) protocol based on the Nordic nRF24L01 radio transceiver chip. The current consumption of ANT was measured, simulated and compared with a torque sensor node that uses the XBee S2 protocol. In addition, an analytical model was derived to correlate the sensor node average current consumption with a crank arm cadence. The sensor node achieved 98% power savings for ANT relative to ZigBee when they were compared alone, and the power savings amounted to 30% when all components of the sensor node are considered. The achievable communication range was 65 and 50 m for ZigBee and ANT, respectively, during measurement on an outdoor cycling track (i.e., velodrome). The conclusions indicate that the ANT protocol is more suitable for use in a torque sensor node when power consumption is a crucial demand, whereas the ZigBee protocol is more convenient in ensuring data communication between cyclist and coach.

An Ultra-Low Power Wireless Sensor Network for Bicycle Torque Performance Measurements

PubMed Central

Gharghan, Sadik K.; Nordin, Rosdiadee; Ismail, Mahamod

2015-01-01

In this paper, we propose an energy-efficient transmission technique known as the sleep/wake algorithm for a bicycle torque sensor node. This paper aims to highlight the trade-off between energy efficiency and the communication range between the cyclist and coach. Two experiments were conducted. The first experiment utilised the Zigbee protocol (XBee S2), and the second experiment used the Advanced and Adaptive Network Technology (ANT) protocol based on the Nordic nRF24L01 radio transceiver chip. The current consumption of ANT was measured, simulated and compared with a torque sensor node that uses the XBee S2 protocol. In addition, an analytical model was derived to correlate the sensor node average current consumption with a crank arm cadence. The sensor node achieved 98% power savings for ANT relative to ZigBee when they were compared alone, and the power savings amounted to 30% when all components of the sensor node are considered. The achievable communication range was 65 and 50 m for ZigBee and ANT, respectively, during measurement on an outdoor cycling track (i.e., velodrome). The conclusions indicate that the ANT protocol is more suitable for use in a torque sensor node when power consumption is a crucial demand, whereas the ZigBee protocol is more convenient in ensuring data communication between cyclist and coach. PMID:26007728

Influence of Knee Joint Extension on Submaximal Oxygen Consumption and Anaerobic Power in Cyclists

DTIC Science & Technology

1991-06-05

Cycling (pp. 91-122). Champaign, IL: Human Kinetics Books. Cavanagh, P.R. & Kram, R. (1985). Mechanical and muscular factors affecting the efficiency...M.L. (1986). Flexibility standards of the U.S. cycling team. In E.R. Burke (Ed.). Science of Cycling (pp. 47-68). Champaign, IL: Human Kinetics Books...height and pedaling cadence on power output and efficiency. In E.R. Burke (Ed.). Science of Cycling (pp. 69-907). Champaign, IL: Human Kinetics Books

Temporal Aspects of the V[o.sub.2] Response at the Power Output Associated with V[o.sub.2]peak in Well Trained Cyclists-Implications for Interval Training Prescription

ERIC Educational Resources Information Center

Laursen, Paul B.; Shing, Cecilia M.; Jenkins, David G.

2004-01-01

The power output achieved at peak oxygen consumption (V[O.sub.2]peak) and the time this power can be maintained (i.e., Tmax) have been used in prescribing high-intensity interval training. In this context, the present study examined temporal aspects of the V[O.sub.2] response to exercise at the cycling power that output well trained cyclists…

Japanese high school students' usage of mobile phones while cycling.

PubMed

Ichikawa, Masao; Nakahara, Shinji

2008-03-01

To investigate the perception and actual use of mobile phones among Japanese high school students while riding their bicycles, and their experience of bicycle crash/near-crash. A questionnaire survey was carried out at high schools that were, at the time of the survey, commissioned by the National Agency for the Advancement of Sports and Health to conduct school safety research. In the survey, we found that mobile phone use while riding a bicycle was quite common among the students during their commute, but those who have a higher perception of danger in this practice, and those who perceived that this practice is prohibited, were less likely to engage in this practice. Male students and students commuting to school by bicycle only were more likely to have used phones while riding. There was a significant relationship between phone usage while riding a bicycle and the experience of bicycle crash/near-crash, although its causality was not established. Bicycle crash/near-crash experienced while using a phone was less prevalent among the students who had a higher perception of danger in phone usage while riding, students who perceived that this practice is prohibited, and students with a shorter travel time by bicycle during the commute. Since mobile phone use while riding a bicycle potentially increases crash risk among cyclists, student bicycle commuters should be made aware of this risk. Moreover, they should be informed that cyclists' phone usage while riding is prohibited according to the road traffic law.

The effect of the Swedish bicycle helmet law for children: an interrupted time series study.

PubMed

Bonander, Carl; Nilson, Finn; Andersson, Ragnar

2014-12-01

Previous population-based research has shown that bicycle helmet laws can reduce head injury rates among cyclists. According to deterrence theory, such laws are mainly effective if there is a high likelihood of being apprehended. In this study, we investigated the effect of the Swedish helmet law for children under the age of 15, a population that cannot be fined. An interrupted time series design was used. Monthly inpatient data on injured cyclists from 1998-2012, stratified by age (0-14, 15+), sex, and injury diagnosis, was obtained from the National Patient Register. The main outcome measure was the proportion of head injury admissions per month. Intervention effect estimates were obtained using generalized autoregressive moving average (GARMA) models. Pre-legislation trend and seasonality was adjusted for, and differences-in-differences estimation was obtained using adults as a non-equivalent control group. There was a statistically significant intervention effect among male children, where the proportion of head injuries dropped by 7.8 percentage points. There was no evidence of an intervention effect on the proportion of head injuries among female children. According to hospital admission data, the bicycle helmet law appears to have had an effect only on male children. This study, while quasi-experimental and thus not strictly generalizable, can contribute to increased knowledge regarding the effects of bicycle helmet laws. Copyright © 2014 National Safety Council and Elsevier Ltd. All rights reserved.

Bicycle-Related Shoulder Injuries: Etiology and the Need for Protective Gear.

PubMed

Goldstein, Yariv; Dolkart, Oleg; Kaufman, Ehud; Amar, Eyal; Sharfman, Zachary T; Rath, Ehud; Mozes, Gavriel; Maman, Eran

2016-01-01

The popularity of bicycle riding for recreation, exercise and transportation has grown enormously in recent years, which has led to an increased incidence of bicycle-related injuries. While these injuries involve mainly the musculoskeletal system, data on shoulder-specific injuries incurred while bike riding are lacking. Classifying these shoulder injuries may provide insight and assistance in the creation and implementation of effective protective gear and measures. To investigate the types and mechanisms of shoulder injuries among cyclists. This study retrospectively examined all cyclists who incurred shoulder injuries while riding and were admitted to the emergency department and shoulder clinic between January 2008 and November 2013. The study included 157 subjects with various bicycle-related shoulder injuries treated with either conservative or surgical measures. Eighty-four percent of injuries were caused by a direct blow to the shoulder, 7% by falling on an outstretched hand, 6% were traction injuries, and 3% were due to hyperabduction. Nine different clinical types of injury were observed; the most common injuries were clavicle fractures (32%), followed by acromioclavicular joint dislocations (22%), rotator cuff tears (22%), and humeral fractures (8%). Fifty-one percent of subjects were managed with conservative care and the remaining patients required surgical interventions. Shoulder injuries incurred while riding a bicycle span the entire spectrum of shoulder injuries and often result in debilitating conditions. Although the use of helmets is increasing, there is currently no effective protective gear or measures to prevent riders from suffering shoulder injuries.

Bilateral asymmetry of skin temperature is not related to bilateral asymmetry of crank torque during an incremental cycling exercise to exhaustion

PubMed Central

Formenti, Damiano; Ludwig, Nicola; Gargano, Marco; Bosio, Andrea; Rampinini, Ermanno; Alberti, Giampietro

2018-01-01

Although moderate relationships (|r| ∼ 0.5) were reported between skin temperature and performance-related variables (e.g., kinetic), it remains unclear whether skin temperature asymmetry reflects muscle force imbalance in cycling. Therefore, the aim of this study was to assess whether a relationship exists between kinetic and thermal asymmetry during a fatiguing exercise. Ten elite cyclists were enrolled and tested on a maximal incremental cycling test. Peak crank torques of both legs were obtained at the initial and final workload. Likewise, bilateral skin temperatures were recorded before and after exercise. Asymmetric indexes were also calculated for kinetic (AIK) and skin temperature (AIT) outcomes. The bilateral peak crank torques showed a larger difference at the final compared to the initial workload (p < 0.05) of the incremental exercise. Conversely, the bilateral skin temperature did not show any differences at both initial and final workload (p > 0.05). Additionally, trivial relationships were reported between AIK and AIT (−0.3 < r < 0.2) at the initial and final workload. The obtained results showed that changes in bilateral kinetic values did not reflect concurrent changes in bilateral skin temperatures. This finding emphasizes the difficulty of associating the asymmetry of skin temperature with those of muscle effort in elite cyclists. Lastly, our study also provided further insights on thermal skin responses during exhaustive cycling exercise in very highly-trained athletes. PMID:29507831

Hormone levels of world class cyclists during the Tour of Spain stage race

PubMed Central

Lucia, A; Diaz, B; Hoyos, J; Fernandez, C; Villa, G; Bandres, F; Chicharro, J

2001-01-01

Objectives—To evaluate the hormonal response to strenuous endurance exercise performed by elite athletes. Methods—Nine professional cyclists (mean (SD) age 28 (1) years; mean (SD) VO2MAX 75.3 (2.3) ml/kg/min) who participated in a three week tour race (Vuelta a España 1999) were selected as subjects. Morning urinary levels of 6-sulphatoxymelatonin (aMT6s) and morning serum levels of testosterone, follicle stimulating (FSH), luteinising hormone (LH), and cortisol were measured in each subject at t0 (before the competition), t1 (end of first week), t2 (end of second week), and t3 (end of third week). Urine samples of aMT6s were also evaluated in the evening at t0, t1, t2, and t3. Results—Mean urinary aMT6s levels had increased significantly (p<0.01) during the day after each stage (1091 (33) v 683 (68) ng/ml at t1; 955 (19) v 473 (53) ng/ml at t2; 647 (61) v 337 (47) ng/ml at t3). Both morning and evening aMT6s levels decreased significantly during the study. A similar pattern was observed for morning serum levels of cortisol and testosterone. Conclusions—The results suggest that the basal activity of the pineal gland, adrenal glands, and testis may be decreased after consecutive days of intense, long term exercise. Key Words: melatonin; gonadotrophins; testosterone; cortisol; endurance exercise PMID:11726480

Evolution of bicycle helmet use and its determinants in France: 2000-2010.

PubMed

Richard, Jean-Baptiste; Thélot, Bertrand; Beck, François

2013-11-01

This paper aims to analyse helmet use in France, as a voluntary behaviour rather than a legal requirement, promoted by public awareness campaigns. It aims to investigate the determinants of helmet wearing and to explore its evolution from 2000 to 2010. The analysis relies on data from a series of general population surveys called "Health Barometers": 2000 (n=13,163), 2005 (n=25,651) and 2010 (n=8573). Multivariate logistic regressions were used to identify factors associated with helmet use and time trends. Nearly half of the 15-75 year olds surveyed reported that they rode a bicycle, and among these cyclists, 22.0% reported that they wore a helmet on their last ride. Further analysis by gender reveals that twice as many men than women wore helmets. Over the last decade, helmet use among cyclists has clearly increased, from 7.3% in 2000 to 22.0% in 2010, whereas the influence of social and economic factors, such as unemployment and wage disparities, appears to have decreased. Several determinants of bicycle helmet use were highlighted. To improve the effectiveness of further public information campaigns on helmet use, the key target groups should include women, under 25 year olds and people living in urban areas. Promoting the wearing of helmets among families should also be enhanced, given the higher rate of helmet use by parents as well as children. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Scintigraphic study of gastric emptying of rehydration drinks in athletes].

PubMed

Martínez Gonzálvez, A B; Nuño de la Rosa Y Pozuelo, J A; Sánchez Gascón, F; Villegas García, J A; Mulero Aniorte, F; Contreras Gutiérrez, J C

2005-01-01

This study aims to evaluate how rehydration beverage ingestion influences gastric emptying rate (in cycle ergometer) at rest and during exercise at 70 % of maximal oxygen consumption (VO2max). 26 well-trained cyclists performed a preliminary maximal test until exhaustion to evaluate their VO2max, and two submaximal exercise tests at 70 % of their mode-specific VO2max. Each test was separated by one week. During the two submaximal tests, cyclists consumed 200 ml of a 99mTc-DTPA labeled rehydration beverage (A or B) and scintigraphy determinations were performed at rest. After, exercise was initiated for 60 minutes with an intake rate of 200 ml every 15 minutes, making gastric serial scintigraphy determinations. The difference regarding chemical composition between A and B drinks resides in the fact that drink A contains a smaller load in carbohydrates (10.3 g/100 ml versus 15.2 g/100 ml of B), proteins in form of serum milk and antioxidants in form of fruit juice. Both contain ions and vitamins. at rest, gastric count number was significantly reduced (p > 0.000) from 0 to 25 minutes for both A and B beverage. At the end of exercise (60 min), there was greater gastric retention for B beverage than for A, this difference being statistically significant (p < 0.031). The A beverage, a rehydration drink on the market with protein and antioxidants with fruit juice content, has a faster gastric emptying rate than the B sport beverage.

The Association between Regional Environmental Factors and Road Trauma Rates: A Geospatial Analysis of 10 Years of Road Traffic Crashes in British Columbia, Canada

PubMed Central

Brubacher, Jeffrey R.; Chan, Herbert; Erdelyi, Shannon; Schuurman, Nadine; Amram, Ofer

2016-01-01

Background British Columbia, Canada is a geographically large jurisdiction with varied environmental and socio-cultural contexts. This cross-sectional study examined variation in motor vehicle crash rates across 100 police patrols to investigate the association of crashes with key explanatory factors. Methods Eleven crash outcomes (total crashes, injury crashes, fatal crashes, speed related fatal crashes, total fatalities, single-vehicle night-time crashes, rear-end collisions, and collisions involving heavy vehicles, pedestrians, cyclists, or motorcyclists) were identified from police collision reports and insurance claims and mapped to police patrols. Six potential explanatory factors (intensity of traffic law enforcement, speed limits, climate, remoteness, socio-economic factors, and alcohol consumption) were also mapped to police patrols. We then studied the association between crashes and explanatory factors using negative binomial models with crash count per patrol as the response variable and explanatory factors as covariates. Results Between 2003 and 2012 there were 1,434,239 insurance claim collisions, 386,326 police reported crashes, and 3,404 fatal crashes. Across police patrols, there was marked variation in per capita crash rate and in potential explanatory factors. Several factors were associated with crash rates. Percent roads with speed limits ≤ 60 km/hr was positively associated with total crashes, injury crashes, rear end collisions, and collisions involving pedestrians, cyclists, and heavy vehicles; and negatively associated with single vehicle night-time crashes, fatal crashes, fatal speeding crashes, and total fatalities. Higher winter temperature was associated with lower rates of overall collisions, single vehicle night-time collisions, collisions involving heavy vehicles, and total fatalities. Lower socio-economic status was associated with higher rates of injury collisions, pedestrian collisions, fatal speeding collisions, and fatal collisions. Regions with dedicated traffic officers had fewer fatal crashes and fewer fatal speed related crashes but more rear end crashes and more crashes involving cyclists or pedestrians. The number of traffic citations per 1000 drivers was positively associated with total crashes, fatal crashes, total fatalities, fatal speeding crashes, injury crashes, single vehicle night-time crashes, and heavy vehicle crashes. Possible explanations for these associations are discussed. Conclusions There is wide variation in per capita rates of motor vehicle crashes across BC police patrols. Some variation is explained by factors such as climate, road type, remoteness, socioeconomic variables, and enforcement intensity. The ability of explanatory factors to predict crash rates would be improved if considered with local traffic volume by all travel modes. PMID:27099930

Prevention, Evaluation, and Rehabilitation of Cycling-Related Injury.

PubMed

Kotler, Dana H; Babu, Ashwin N; Robidoux, Greg

2016-01-01

The unique quality of the bicycle is its ability to accommodate a wide variety of injuries and disabilities. Cycling for recreation, transportation, and competition is growing nationwide, and has proven health and societal benefits. The demands of each type of cycling dictate the necessary equipment, as well as potential for injury. Prevention of cycling-related injury in both the athlete and the recreational cyclist involves understanding the common mechanisms for both traumatic and overuse injury, and early correction of strength and flexibility imbalances, technique errors, and bicycle fit.

Injuries and helmet use related to non-motorized wheeled activities among pediatric patients.

PubMed

Lindsay, H; Brussoni, M

2014-07-01

Patients presenting to emergency departments (ED) for injuries resulting from recreational activities represent a unique source of information on important directions for injury prevention efforts. We describe the epidemiology of non-motorized wheeled activity-related injury in pediatric patients presenting to Canadian EDs as well as patients' helmet use. Data for the years 2004 to 2009 were abstracted from the Canadian Hospitals Injury Reporting and Prevention Program (CHIRPP), a national ED injury surveillance program in fifteen hospitals. Most of the 28 618 children aged 1 to 16 years injured during non-motorized wheeled activities were injured while cycling, followed by skateboarding. Most injuries occurred among boys. Children injured on scooters tended to be younger whereas skateboarders were the oldest. On average, the number of all injuries decreased by 6% over the time period. Falls were the most common mechanism of injury; 8.3% of patients had head injuries, which were seen more often among cyclists than other wheeled-activity users. Helmet use was greatest among cyclists (62.2%) and lowest among skateboarders (32.9%). Injured patients presenting to EDs in jurisdictions with legislation mandating helmet use had 2.12 greater odds of helmet use and 0.86 lesser odds of head injury compared with those presenting in jurisdictions without helmet laws. These results provide further evidence that legislation mandating helmet use may be an effective way of reducing injury among all wheeled-activity users. The small number of patients who presented with helmet use and protective gear (59.4% overall) suggests that this remains an area for intervention.

The Effect of Inspiratory Muscle Training on Respiratory and Limb Locomotor Muscle Deoxygenation During Exercise with Resistive Inspiratory Loading.

PubMed

Turner, L A; Tecklenburg-Lund, S L; Chapman, R; Shei, R-J; Wilhite, D P; Mickleborough, T

2016-07-01

We investigated how inspiratory muscle training impacted respiratory and locomotor muscle deoxygenation during submaximal exercise with resistive inspiratory loading. 16 male cyclists completed 6 weeks of either true (n=8) or sham (n=8) inspiratory muscle training. Pre- and post-training, subjects completed 3, 6-min experimental trials performed at ~80%  ˙VO2peak with interventions of either moderate inspiratory loading, heavy inspiratory loading, or maximal exercise imposed in the final 3 min. Locomotor and respiratory muscle oxy-, deoxy-, and total-haemoglobin and myoglobin concentration was continuously monitored using near-infrared spectroscopy. Locomotor muscle deoxygenation changes from 80%  ˙VO2peak to heavy inspiratory loading were significantly reduced pre- to post-training from 4.3±5.6 µM to 2.7±4.7 µM. Respiratory muscle deoxygenation was also significantly reduced during the heavy inspiratory loading trial (4.6±3.5 µM to 1.9±1.5 µM) post-training. There was no significant difference in oxy-, deoxy-, or total-haemoglobin and myoglobin during any of the other loading trials, from pre- to post-training, in either group. After inspiratory muscle training, highly-trained cyclists exhibited decreased locomotor and respiratory muscle deoxygenation during exercise with heavy inspiratory loading. These data suggest that inspiratory muscle training reduces oxygen extraction by the active respiratory and limb muscles, which may reflect changes in respiratory and locomotor muscle oxygen delivery. © Georg Thieme Verlag KG Stuttgart · New York.

How does a modal shift from short car trips to cycling affect road safety?

PubMed

Schepers, J P; Heinen, E

2013-01-01

Governments aim to promote a shift from car to bicycle, but concerns about road safety seem to represent an important argument against this encouragement. This study examines the road safety impact of a modal shift from short car trips to cycling in Dutch municipalities. The road safety effect is estimated using Accident Prediction Models (APMs) that account for the non-linearity of risk. APMs are developed utilizing Negative Binomial regression. This study is the first to develop APMs using crash and mobility data from municipalities, and utilizing these models to estimate the effects of changing modal splits of current car and bicycle use to modal splits that actually exist in these municipalities. The results suggest that, under conditions such as in Dutch municipalities, transferring short trips made by cars to bicycles does not change the number of fatalities, but increases the number of serious road injuries. The neutral effect on fatalities, despite the high fatality risk for cyclists, can be explained by there being fewer cars on the road to pose a risk to others, the shorter length of bicycle trips compared to the car trips they replace, and the "safety in numbers" phenomenon. The rise in the number of serious road injuries is due wholly to the high number of cycling crashes with no other vehicle involved. The effect of a modal shift is dependent on the age of the population in which the shift is concentrated, and can be influenced by measures affecting cyclists' injury risk. Copyright © 2012 Elsevier Ltd. All rights reserved.

Risk factors associated with the severity of injury outcome for paediatric road trauma.

PubMed

Mitchell, R J; Bambach, M R; Foster, K; Curtis, K

2015-05-01

Road trauma is one of the most common causes of injury for children. Yet risk factors associated with different levels of injury severity for childhood road trauma have not been examined in-depth. This study identifies crash and injury risk factors associated with the severity of non-fatal injury outcome for paediatric road trauma. A retrospective analysis was conducted of paediatric road trauma identified in linked police-reported and hospitalisation records during 1 January 2001 to 31 December 2011 in New South Wales (NSW), Australia. The linkage rate was 54%. Injury severity was calculated from diagnosis classifications in hospital records using the International Classification of Disease Injury Severity Score. Univariate and multi-variable logistic regression was conducted. There were 2412 car occupants, 1701 pedestrians and 612 pedal cyclists hospitalised where their hospital record linked to a police report. For car occupants, unauthorised vehicle drivers had twice the odds (OR: 2.21, 95%CI 1.47-3.34) and learner/provisional drivers had one and a half times higher odds (OR: 1.54, 95%CI 1.15-2.07) of a child car occupant sustaining a serious injury compared to a minor injury. For pedal cyclists and pedestrians, there were lower odds of a crash occurring during school commuting time and higher odds of a crash occurring during the weekend or on a dry road for children who sustained a serious versus a minor injury. Injury prevention initiatives, such as restraint and helmet use, that should reduce injury and/or crash severity are advocated. Copyright © 2015 Elsevier Ltd. All rights reserved.

Road traffic accidents in children: the ‘what’, ‘how’ and ‘why’

PubMed Central

Lee, Yue Yen; Fang, Eric; Weng, Yanyi; Ganapathy, Sashikumar

2018-01-01

INTRODUCTION Road traffic accidents (RTAs) in Singapore involving children were evaluated, with particular focus on the epidemiology, surrounding circumstances and outcomes of these accidents. Key factors associated with worse prognosis were identified. We proposed some measures that may be implemented to reduce the frequency and severity of such accidents. METHODS This was a retrospective study of RTAs involving children aged 0–16 years who presented to the Children’s Emergency at KK Women’s and Children’s Hospital, Singapore, from January 2011 to June 2014. Data was obtained from the National Trauma Registry and analysed in tiers based on the Injury Severity Score (ISS). RESULTS A total of 1,243 accidents were reviewed. RTA victims included motor vehicle passengers (60.4%), pedestrians (28.5%), cyclists (9.9%) and motorcycle pillion riders (1.2%). The disposition of emergency department (ED) patients was consistent with RTA severity. For serious RTAs, pedestrians accounted for 63.6% and 57.7% of Tier 1 (ISS > 15) and Tier 2 (ISS 9–15) presentations, respectively. Overall use of restraints was worryingly low (36.7%). Not restraining increased the risk of serious RTAs by 8.4 times. Young age, high ISS and low Glasgow Coma Scale score predicted a longer duration of intensive care unit stay. CONCLUSION The importance of restraints for motor vehicle passengers or helmets for motorcycle pillion riders and cyclists in reducing morbidity requires emphasis. Suggestions for future prevention and intervention include road safety education, regulation of protective restraints, use of speed enforcement devices and creation of transport policies that minimise kerbside parking. PMID:29214322

Predominance of Intrinsic Mechanism of Resting Heart Rate Control and Preserved Baroreflex Sensitivity in Professional Cyclists after Competitive Training.

PubMed

Azevedo, Luciene Ferreira; Perlingeiro, Patricia; Hachul, Denise Tessariol; Gomes-Santos, Igor Lucas; Tsutsui, Jeane Mike; Negrao, Carlos Eduardo; De Matos, Luciana D N J

2016-01-01

Different season trainings may influence autonomic and non-autonomic cardiac control of heart rate and provokes specific adaptations on heart's structure in athletes. We investigated the influence of transition training (TT) and competitive training (CT) on resting heart rate, its mechanisms of control, spontaneous baroreflex sensitivity (BRS) and relationships between heart rate mechanisms and cardiac structure in professional cyclists (N = 10). Heart rate (ECG) and arterial blood pressure (Pulse Tonometry) were recorded continuously. Autonomic blockade was performed (atropine-0.04 mg.kg-1; esmolol-500 μg.kg-1 = 0.5 mg). Vagal effect, intrinsic heart rate, parasympathetic (n) and sympathetic (m) modulations, autonomic influence, autonomic balance and BRS were calculated. Plasma norepinephrine (high-pressure liquid chromatography) and cardiac structure (echocardiography) were evaluated. Resting heart rate was similar in TT and CT. However, vagal effect, intrinsic heart rate, autonomic influence and parasympathetic modulation (higher n value) decreased in CT (P≤0.05). Sympathetic modulation was similar in both trainings. The autonomic balance increased in CT but still showed parasympathetic predominance. Cardiac diameter, septum and posterior wall thickness and left ventricular mass also increased in CT (P<0.05) as well as diastolic function. We observed an inverse correlation between left ventricular diastolic diameter, septum and posterior wall thickness and left ventricular mass with intrinsic heart rate. Blood pressure and BRS were similar in both trainings. Intrinsic heart rate mechanism is predominant over vagal effect during CT, despite similar resting heart rate. Preserved blood pressure levels and BRS during CT are probably due to similar sympathetic modulation in both trainings.

HIT maintains performance during the transition period and improves next season performance in well-trained cyclists.

PubMed

Rønnestad, Bent R; Askestad, Arild; Hansen, Joar

2014-09-01

To investigate the effects of combining low-intensity endurance training (LIT) with one high-intensity endurance training (HIT) session every 7-10 days (EXP, n = 7) vs. traditional approach focusing on LIT (TRAD, n = 6) during the transition period. The effects of different training strategies during the transition period were investigated after the transition period and at the beginning of the subsequent competition season. Well-trained cyclists were tested after the competition season, after an 8-week transition period, and after a 16-week preparatory period, before the subsequent competition season. The only difference between groups was a larger time with HIT during the transition phase in EXP. It was very likely that EXP had a larger impact on power output at 4 mmol L(-1) [la(-)] after both the transition period and after the preparatory period than TRAD [between-group change (90% CI): 10.6% (8.2%) and 12.9% (11.9%), respectively]. It was very likely that EXP had a larger impact on mean power output in the 40-min all-out trial after the transition period than TRAD [between-group change 12.4% (7.6%)]. EXP was also likely to have a larger improvement in the 40-min trial performance from pre-test to after the preparatory period than TRAD [between-group change 6.0% (6.6%)]. The present findings suggest that HIT sessions should be incorporated during the transition phase to avoid reduction in fitness and performance level and thereby increase the likelihood of improved performance from the end of one season to the beginning of the subsequent season.

Impact of upper body precooling during warm-up on subsequent time trial paced cycling in the heat.

PubMed

Katica, Charles P; Wingo, Jonathan E; Herron, Robert L; Ryan, Greg A; Bishop, Stacy H; Richardson, Mark

2018-06-01

The purpose of this study was to test the hypothesis that cooling the upper body during a warm-up enhances performance during a subsequent 16.1-km simulated cycling time trial in a hot environment. Counterbalanced, repeated measures design. Eight trained, male cyclists (peak oxygen uptake=57.8±5.0mLkg -1 min -1 ) completed two simulated 16.1-km time trials in a hot environment (35.0±0.5°C, 43.8±2.0% relative humidity) each separated by 72h. Treatments were counterbalanced; participants warmed up for 20min while either wearing head and neck ice wraps and an ice vest (COOLING) or no cooling apparatus (CONTROL). Following the warm-up mean skin temperature (T¯ sk ), mean body temperature (T¯ b ) and rating of thermal comfort were significantly lower than baseline following the COOLING trial (all P<0.05); however, rectal temperature was unaffected (P=0.35). Because the effects of precooling on T¯ sk and T¯ b were not sustained during exercise, values for COOLING and CONTROL were not different throughout the time trial (P=0.38). Nonetheless, time to completion was significantly faster following the COOLING intervention when compared to the CONTROL (29.3±3.6min, vs. 30.3±3.1min; P=0.04). These data suggest that in short distance time trials in hot conditions cyclists may benefit from utilizing a cooling modality during the warm-up. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Considerations on the Assessment and Use of Cycling Performance Metrics and their Integration in the Athlete's Biological Passport.

PubMed

Menaspà, Paolo; Abbiss, Chris R

2017-01-01

Over the past few decades the possibility to capture real-time data from road cyclists has drastically improved. Given the increasing pressure for improved transparency and openness, there has been an increase in publication of cyclists' physiological and performance data. Recently, it has been suggested that the use of such performance biometrics may be used to strengthen the sensitivity and applicability of the Athlete Biological Passport (ABP) and aid in the fight against doping. This is an interesting concept which has merit, although there are several important factors that need to be considered. These factors include accuracy of the data collected and validity (and reliability) of the subsequent performance modeling. In order to guarantee high quality standards, the implementation of well-structured Quality-Systems within sporting organizations should be considered, and external certifications may be required. Various modeling techniques have been developed, many of which are based on fundamental intensity/time relationships. These models have increased our understanding of performance but are currently limited in their application, for example due to the largely unaccounted effects of environmental factors such as, heat and altitude. In conclusion, in order to use power data as a performance biometric to be integrated in the biological passport, a number of actions must be taken to ensure accuracy of the data and better understand road cycling performance in the field. This article aims to outline considerations in the quantification of cycling performance, also presenting an alternative method (i.e., monitoring race results) to allow for determination of unusual performance improvements.

Considerations on the Assessment and Use of Cycling Performance Metrics and their Integration in the Athlete's Biological Passport

PubMed Central

Menaspà, Paolo; Abbiss, Chris R.

2017-01-01

Over the past few decades the possibility to capture real-time data from road cyclists has drastically improved. Given the increasing pressure for improved transparency and openness, there has been an increase in publication of cyclists' physiological and performance data. Recently, it has been suggested that the use of such performance biometrics may be used to strengthen the sensitivity and applicability of the Athlete Biological Passport (ABP) and aid in the fight against doping. This is an interesting concept which has merit, although there are several important factors that need to be considered. These factors include accuracy of the data collected and validity (and reliability) of the subsequent performance modeling. In order to guarantee high quality standards, the implementation of well-structured Quality-Systems within sporting organizations should be considered, and external certifications may be required. Various modeling techniques have been developed, many of which are based on fundamental intensity/time relationships. These models have increased our understanding of performance but are currently limited in their application, for example due to the largely unaccounted effects of environmental factors such as, heat and altitude. In conclusion, in order to use power data as a performance biometric to be integrated in the biological passport, a number of actions must be taken to ensure accuracy of the data and better understand road cycling performance in the field. This article aims to outline considerations in the quantification of cycling performance, also presenting an alternative method (i.e., monitoring race results) to allow for determination of unusual performance improvements. PMID:29163232

No improvement in race performance by naps in male ultra-endurance cyclists in a 600-km ultra-cycling race.

PubMed

Knechtle, Beat; Wirth, Andrea; Knechtle, Patrizia; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

2012-04-30

Ultra-endurance performance is of increasing popularity. We investigated the associations between anthropometry, training and support during racing, with race performance in 67 male recreational ultra-endurance cyclists participating in the 'Swiss Cycling Marathon' over 600 kilometres, an official qualifier for the cycling ultra-marathon 'Paris-Brest-Paris'. The 54 finishers showed no differences in anthropometry and did not train differently compared to the 13 non-finishers. During the race, the finishers were significantly more frequently racing alone than being followed by a support crew. After bivariate analysis, percent body fat (r = 0.43), the cycling distance per training unit (r = -0.36), the duration per training unit (r = -0.31) and the sleep time during the race (r = 0.50) were related to overall race time. The 23 non-sleepers in the finisher group completed the race within (mean and IQR) 1,567 (1,453-1,606) min, highly significantly faster than the 31 sleepers with 1,934 (1,615-2,033) min (P = 0.0003). No variable of support during the race was associated with race time. After multivariate analysis, percent body fat (P = 0.026) and duration per training unit (P = 0.005) remained predictor variables for race time. To summarize, for a successful finish in a cycling ultra-marathon over 600 kilometres such as the 'Swiss Cycling Marathon', percent body fat and duration per training unit were related to race time whereas equipment and support during the race showed no association. Athletes with naps were highly significantly slower than athletes without naps.

On the effect of networks of cycle-tracks on the risk of cycling. The case of Seville.

PubMed

Marqués, R; Hernández-Herrador, V

2017-05-01

We analyze the evolution of the risk of cycling in Seville before and after the implementation of a network of segregated cycle tracks in the city. Specifically, we study the evolution of the risk for cyclists of being involved in a collision with a motor vehicle, using data reported by the traffic police along the period 2000-2013, i.e. seven years before and after the network was built. A sudden drop of such risk was observed after the implementation of the network of bikeways. We study, through a multilinear regression analysis, the evolution of the risk by means of explanatory variables representing changes in the built environment, specifically the length of the bikeways and a stepwise jump variable taking the values 0/1 before/after the network was implemented. We found that this last variable has a high value as explanatory variable, even higher than the length of the network, thus suggesting that networking the bikeways has a substantial effect on cycling safety by itself and beyond the mere increase in the length of the bikeways. We also analyze safety in numbers through a non-linear regression analysis. Our results fully agree qualitatively and quantitatively with the results previously reported by Jacobsen (2003), thus providing an independent confirmation of Jacobsen's results. Finally, the mutual causal relationships between the increase in safety, the increase in the number of cyclists and the presence of the network of bikeways are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Use of a syndromic surveillance system to describe the trend in cycling-related presentations to emergency departments in Sydney.

PubMed

Dinh, Michael M; Kastelein, Christopher; Bein, Kendall J; Green, Timothy C; Bautovich, Tanya; Ivers, Rebecca

2015-08-01

To describe population-based trends in cycling-related presentations to EDs over the past decade. A retrospective cohort of road trauma patients (motor vehicle, motor cyclist, cyclist and pedestrian) presenting to EDs in the Sydney Greater Metropolitan Area between 2004 and 2013 was obtained using the Public Health Real-time Emergency Department Surveillance System. The outcomes of interest were the cycling-related ED presentation rate per 1000 population, as well as the proportion of cycling-related presentations that died in ED or were admitted to a critical care ward. Trends in ED presentation rates based on presentation counts and Sydney population data were plotted and described. There were 68,438 cycling-related presentations identified, representing 30% of all road trauma patients presenting to EDs in Sydney. There was a 91% increase in cycling-related presentations for the 35 to 64-year-old age group and a 123% increase in cycling-related presentations in the 65-year-old and over age group. All other age groups were associated with a stable or decrease in cycling-related ED presentation rates. The proportion of presentations requiring critical care ward admission or death in ED has decreased by 20%. Using an ED syndromic surveillance system, cycling-related ED presentation rates in Sydney Australia have increased in those aged 35 years and over the past 10 years, with a relative decrease in the proportion of deaths in ED or those requiring critical care admission. © 2015 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

The importance of aerodynamics for prosthetic limb design used by competitive cyclists with an amputation: An introduction.

PubMed

Dyer, Bryce

2015-06-01

This study introduces the importance of the aerodynamics to prosthetic limb design for athletes with either a lower-limb or upper-limb amputation. The study comprises two elements: 1) An initial experiment investigating the stability of outdoor velodrome-based field tests, and 2) An experiment evaluating the application of outdoor velodrome aerodynamic field tests to detect small-scale changes in aerodynamic drag respective of prosthetic limb componentry changes. An outdoor field-testing method is used to detect small and repeatable changes in the aerodynamic drag of an able-bodied cyclist. These changes were made at levels typical of alterations in prosthetic componentry. The field-based test method of assessment is used at a smaller level of resolution than previously reported. With a carefully applied protocol, the field test method proved to be statistically stable. The results of the field test experiments demonstrate a noticeable change in overall athlete performance. Aerodynamic refinement of artificial limbs is worthwhile for athletes looking to maximise their competitive performance. A field-testing method illustrates the importance of the aerodynamic optimisation of prosthetic limb components. The field-testing protocol undertaken in this study gives an accessible and affordable means of doing so by prosthetists and sports engineers. Using simple and accessible field-testing methods, this exploratory experiment demonstrates how small changes to riders' equipment, consummate of the scale of a small change in prosthetics componentry, can affect the performance of an athlete. Prosthetists should consider such opportunities for performance enhancement when possible. © The International Society for Prosthetics and Orthotics 2014.

Personal and trip characteristics associated with safety equipment use by injured adult bicyclists: a cross-sectional study

PubMed Central

2012-01-01

Background The aim of this study was to estimate use of helmets, lights, and visible clothing among cyclists and to examine trip and personal characteristics associated with their use. Methods Using data from a study of transportation infrastructure and injuries to 690 adult cyclists in Toronto and Vancouver, Canada, we examined the proportion who used bike lights, conspicuous clothing on the torso, and helmets on their injury trip. Multiple logistic regression was used to examine associations between personal and trip characteristics and each type of safety equipment. Results Bike lights were the least frequently used (20% of all trips) although they were used on 77% of trips at night. Conspicuous clothing (white, yellow, orange, red) was worn on 33% of trips. Helmets were used on 69% of trips, 76% in Vancouver where adult helmet use is required by law and 59% in Toronto where it is not. Factors positively associated with bike light use included night, dawn and dusk trips, poor weather conditions, weekday trips, male sex, and helmet use. Factors positively associated with conspicuous clothing use included good weather conditions, older age, and more frequent cycling. Factors positively associated with helmet use included bike light use, longer trip distances, hybrid bike type, not using alcohol in the 6 hours prior to the trip, female sex, older age, higher income, and higher education. Conclusions In two of Canada’s largest cities, helmets were the most widely used safety equipment. Measures to increase use of visibility aids on both daytime and night-time cycling trips may help prevent crashes. PMID:22966752

The physiology of mountain biking.

PubMed

Impellizzeri, Franco M; Marcora, Samuele M

2007-01-01

Mountain biking is a popular outdoor recreational activity and an Olympic sport. Cross-country circuit races have a winning time of approximately equal 120 minutes and are performed at an average heart rate close to 90% of the maximum, corresponding to 84% of maximum oxygen uptake (VO2max). More than 80% of race time is spent above the lactate threshold. This very high exercise intensity is related to the fast starting phase of the race; the several climbs, forcing off-road cyclists to expend most of their effort going against gravity; greater rolling resistance; and the isometric contractions of arm and leg muscles necessary for bike handling and stabilisation. Because of the high power output (up to 500W) required during steep climbing and at the start of the race, anaerobic energy metabolism is also likely to be a factor of off-road cycling and deserves further investigation. Mountain bikers' physiological characteristics indicate that aerobic power (VO2max >70 mL/kg/min) and the ability to sustain high work rates for prolonged periods of time are prerequisites for competing at a high level in off-road cycling events. The anthropometric characteristics of mountain bikers are similar to climbers and all-terrain road cyclists. Various parameters of aerobic fitness are correlated to cross-country performance, suggesting that these tests are valid for the physiological assessment of competitive mountain bikers, especially when normalised to body mass. Factors other than aerobic power and capacity might influence off-road cycling performance and require further investigation. These include off-road cycling economy, anaerobic power and capacity, technical ability and pre-exercise nutritional strategies.

Self-paced cycling performance and recovery under a hot and highly humid environment after cooling.

PubMed

Gonzales, B R; Hagin, V; Guillot, R; Placet, V; Monnier-Benoit, P; Groslambert, A

2014-02-01

This study investigated the effects of pre- and post-cooling on self-paced time-trial cycling performance and recovery of cyclists exercising under a hot and highly humid environment (29.92 °C-78.52% RH). Ten male cyclists performed a self-paced 20-min time trial test (TT20) on a cyclo-ergometer while being cooled by a cooling vest and a refrigerating headband during the warm-up and the recovery period. Heart rate, power output, perceived exertion, thermal comfort, skin and rectal temperatures were recorded. Compared to control condition (222.78 ± 47 W), a significant increase (P<0.05) in the mean power output during the TT20 (239.07 ± 45 W; +7.31%) was recorded with a significant (P<0.05) decrease in skin temperature without affecting perceived exertion, heart rate, or rectal temperature at the end of the TT20. However, pace changes occurred independently of skin or rectal temperatures variations but a significant difference (P<0.05) in the body's heat storage was observed between both conditions. This result suggests that a central programmer using body's heat storage as an input may influence self-paced time-trial performance. During the recovery period, post-cooling significantly decreased heart rate, skin and rectal temperatures, and improved significantly (P<0.05) thermal comfort. Therefore, in hot and humid environments, wearing a cooling vest and a refrigerating headband during warm-up improves self-paced performance, and appears to be an effective mean of reaching skin rest temperatures more rapidly during recovery.

Occurrence rates and predictors of lower urinary tract symptoms and incontinence in female athletes.

PubMed

Simeone, C; Moroni, A; Pettenò, A; Antonelli, A; Zani, D; Orizio, C; Cosciani Cunico, S

2010-01-01

To assess the prevalence of lower urinary tract symptoms (LUTS) and incontinence in female athletes and to determine the etiological factors. An anonymous self-questionnaire was collected from 623 casual female athletes aged 18 to 56 years, who were involved in 12 different sports. The surveys were distributed by hand to the athletes, during their sports fitness tests, in a sports center. We investigated the relationship between urinary disorders and factors such as age, body mass index (BMI), parity, duration of physical exercise, and type of sport. The prevalence of LUTS was 54.7%, and 30% for urinary incontinence. Changes in urinary frequency were detected in 91 (14.6%) women. Prevalence of dysuria was 13.3%, urinary straining was present in 173 (27.8%) athletes, whereas urinary urgency had an estimated prevalence of 37.2% with 232 athletes suffering from this disorder. Urgency was very common in volleyball players, as was dysuria among hockey and basketball players, whereas straining mainly affected aerobic participants and cyclists. Long training hours and competitive practices were correlated with the onset of LUTS. High-impact sports were more frequently associated with incontinence, while low-impact sports with LUTS. The sport with the main number of incontinent people was football. Urge incontinence affected a lot of athletes, mainly cyclists and football players. Stress incontinence was more frequent in hockey and volleyball players. LUTS and incontinence are prevalent in female athletes. In many cases, the disorders were present only during sports activities. In this sample, the presence of urinary disorders did not seem to be a barrier during sports or exercise.

Road traffic accidents in children: the 'what', 'how' and 'why'.

PubMed

Lee, Yue Yen; Fang, Eric; Weng, Yanyi; Ganapathy, Sashikumar

2018-04-01

Road traffic accidents (RTAs) in Singapore involving children were evaluated, with particular focus on the epidemiology, surrounding circumstances and outcomes of these accidents. Key factors associated with worse prognosis were identified. We proposed some measures that may be implemented to reduce the frequency and severity of such accidents. This was a retrospective study of RTAs involving children aged 0-16 years who presented to the Children's Emergency at KK Women's and Children's Hospital, Singapore, from January 2011 to June 2014. Data was obtained from the National Trauma Registry and analysed in tiers based on the Injury Severity Score (ISS). A total of 1,243 accidents were reviewed. RTA victims included motor vehicle passengers (60.4%), pedestrians (28.5%), cyclists (9.9%) and motorcycle pillion riders (1.2%). The disposition of emergency department (ED) patients was consistent with RTA severity. For serious RTAs, pedestrians accounted for 63.6% and 57.7% of Tier 1 (ISS > 15) and Tier 2 (ISS 9-15) presentations, respectively. Overall use of restraints was worryingly low (36.7%). Not restraining increased the risk of serious RTAs by 8.4 times. Young age, high ISS and low Glasgow Coma Scale score predicted a longer duration of intensive care unit stay. The importance of restraints for motor vehicle passengers or helmets for motorcycle pillion riders and cyclists in reducing morbidity requires emphasis. Suggestions for future prevention and intervention include road safety education, regulation of protective restraints, use of speed enforcement devices and creation of transport policies that minimise kerbside parking. Copyright: © Singapore Medical Association.

[Medical coverage of a road bicycle race].

PubMed

Reifferscheid, Florian; Stuhr, Markus; Harding, Ulf; Schüler, Christine; Thoms, Jürgen; Püschel, Klaus; Kappus, Stefan

2010-07-01

Major sport events require adequate expertise and experience concerning medical coverage and support. Medical and ambulance services need to cover both participants and spectators. Likewise, residents at the venue need to be provided for. Concepts have to include the possibility of major incidents related to the event. Using the example of the Hamburg Cyclassics, a road bicycle race and major event for professional and amateur cyclists, this article describes the medical coverage, number of patients, types of injuries and emergencies. Objectives regarding the planning of future events and essential medical coverage are consequently discussed. (c) Georg Thieme Verlag Stuttgart-New York.

Stitch in the side: causes, workup, and solutions.

PubMed

Eichner, E Randy

2006-12-01

Side stitch is an acute, localized, sharp, transient pain that occurs during exercise, most often in runners or swimmers, but also in those participating in team sports, and less often in cyclists. The pain is vexing and performance-limiting, but fleeting and benign. Three theories compete to explain it: diaphragmatic ischemia, stress on peritoneal ligaments, and irritation of the parietal peritoneum. The differential diagnosis seems broad, but the classic side stitch is so unique in its features and setting that a reasonable working diagnosis can be made from a careful history and physical examination. Practical tips, although anecdotal, offer lasting solutions.

Active and safe transportation of elementary-school students: comparative analysis of the risks of injury associated with children travelling by car, walking and cycling between home and school.

PubMed

Lavoie, M; Burigusa, G; Maurice, P; Hamel, D; Turmel, E

2014-11-01

Elementary school active transportation programs aim to address physical inactivity in children by prompting a modal shift from travel by car to walking or cycling among children living a distance from school conducive to walking or cycling. The objectives of this study are to evaluate the risk of injury related to walking, cycling and travelling by car between home and school among elementary-school students in the Montréal area and to evaluate the impact on number of injuries of a modal shift from travel by car to walking or cycling. The risk of injury was estimated for the 2003-2007 period by calculating the average annual rate of injury in children aged 5 to 12 years walking, cycling or being driven in a car, per 100 million kms travelled during the normal hours of travel between home and school. The impact of a modal shift from travel by car was evaluated for children living a distance from school conducive to walking and cycling (under 1.6 km), that is, the targets of active transportation programs. This evaluation was done using the regional rate of injury calculated for each travel mode. Between 2003 and 2007, an average of 168 children aged 5 to 12 years were injured each year while walking (n = 64), cycling (n = 28) and being driven in a car (n = 76) during the normal hours of travel between home and school in the Montréal area. The rate of injury was 69 children injured per 100 million kms for travel by car (reference group), 314 pedestrians (relative risk [RR] = 4.6; 95% confidence interval [CI]: 4.3-5.1) and 1519 cyclists (RR = 22.2; 95% CI: 14.3-30.0). A shift of 20% in the distance travelled by car to walking by children living less than 1.6 km from their school is estimated to result in an increase of 2.2% (n = 3.7) in the number of children injured each year in the area. In the case of a shift to cycling, the number of resulting injuries is estimated to be 24.4, an increase of 14.5%. The risk of injury among elementary-school students during the normal hours of travel between home and school is higher for walking and cycling than for travel by car, and cyclists are at greater risk of injury than pedestrians. A modal shift from travel by car would increase the number of children injured in the area (minor injuries, for the most part) if no action were taken to reduce the risk of injury to pedestrians and cyclists.

The acute effects of L-arginine on hormonal and metabolic responses during submaximal exercise in trained cyclists.

PubMed

Forbes, Scott C; Harber, Vicki; Bell, Gordon J

2013-08-01

L-arginine may enhance endurance performance mediated by two primary mechanisms including enhanced secretion of endogenous growth hormone (GH) and as a precursor of nitric oxide (NO); however, research in trained participants has been equivocal. The purpose was to investigate the effect of acute L-arginine ingestion on the hormonal and metabolic response during submaximal exercise in trained cyclists. Fifteen aerobically trained men (age: 28 ± 5 y; body mass: 77.4 ± 9.5 kg; height: 180.9 ± 7.9 cm; VO2max: 59.6 ± 5.9 ml·kg- 1·min-1) participated in a randomized, double-blind, crossover study. Subjects consumed L-arginine (ARG; 0. 075 g·kg-1 body mass) or a placebo (PLA) before performing an acute bout of submaximal exercise (60 min at 80% of power output achieved at ventilatory threshold). The ARG condition significantly increased plasma L-arginine concentrations (~146%), while no change was detected in the PLA condition. There were no differences between conditions for GH, nonesterified fatty acids (NEFA), lactate, glucose, VO2, VCO2, RER, CHO oxidation, and NOx. There was reduced fat oxidation at the start of exercise (ARG: 0.36 ± 0.25 vs. PLA: 0.42 ± 0.23 g·min-1, p < .05) and an elevated plasma glycerol concentrations at the 45-min time point (ARG: 340.3 vs. PLA: 288.5 μmol·L-1, p < .05) after L-arginine consumption. In conclusion, the acute ingestion of L-arginine did not alter any hormonal, metabolic, or cardio-respiratory responses during submaximal exercise except for a small but significant increase in glycerol at the 45-min time point and a reduction in fat oxidation at the start of exercise.

Body temperature and its effect on leukocyte mobilization, cytokines and markers of neutrophil activation during and after exercise.

PubMed

Peake, Jonathan; Peiffer, Jeremiah J; Abbiss, Chris R; Nosaka, Kazunori; Okutsu, Mitsuharu; Laursen, Paul B; Suzuki, Katsuhiko

2008-03-01

We investigated the influence of rectal temperature on the immune system during and after exercise. Ten well-trained male cyclists completed exercise trials (90 min cycling at 60% VO(2max) + 16.1 - km time trial) on three separate occasions: once in 18 degrees C and twice in 32 degrees C. Twenty minutes after the trials in 32 degrees C, the cyclists sat for approximately 20 min in cold water (14 degrees C) on one occasion, whereas on another occasion they sat at room temperature. Rectal temperature increased significantly during cycling in both conditions, and was significantly higher after cycling in 32 degrees C than in 18 degrees C (P < 0.05). Leukocyte counts increased significantly during cycling but did not differ between the conditions. The concentrations of serum interleukin (IL)-6, IL-8 and IL-10, plasma catecholamines, granulocyte-colony stimulating factor, myeloperoxidase and calprotectin increased significantly following cycling in both conditions. The concentrations of serum IL-8 (25%), IL-10 (120%), IL-1 receptor antagonist (70%), tumour necrosis factor-alpha (17%), plasma myeloperoxidase (26%) and norepinephrine (130%) were significantly higher after cycling in 32 degrees C than in 18 degrees C. During recovery from exercise in 32 degrees C, rectal temperature was significantly lower in response to sitting in cold water than at room temperature. However, immune changes during 90 min of recovery did not differ significantly between sitting in cold water and at room temperature. The greater rise in rectal temperature during exercise in 32 degrees C increased the concentrations of serum IL-8, IL-10, IL-1ra, TNF-alpha and plasma myeloperoxidase, whereas the greater decline in rectal temperature during cold water immersion after exercise did not affect immune responses.

Effect of Seat Tube Angle and Exercise Intensity on Muscle Activity Patterns in Cyclists

PubMed Central

DUGGAN, WILL; DONNE, BERNARD; FLEMING, NEIL

2017-01-01

Previous studies have reported improved efficiency at steeper seat tube angle (STA) during ergometer cycling; however, neuromuscular mechanisms have yet to be fully determined. The current study investigated effects of STA on lower limb EMG activity at varying exercise intensities. Cyclists (n=11) were tested at 2 workloads; 160W and an individualised workload (IWL) equivalent to lactate threshold (TLac) minus 10%δ (derived from maximal incremental data), using 3 STA (70, 75 and 80°). Electromyographic data from Vastus Medialis (VM), Rectus Femoris (RF), Vastus Lateralis (VL) and Biceps Femoris (BF) were assessed. The timing and magnitude of activation were quantified and analysed using a two-way ANOVA. STA had significant (P < 0.05) effects on timing of onset and offset of VM, timing of offset of VL, and angle at peak for RF, all occurring later at 80 vs. 70° STA at IWL. In RF, increased activity occurred during the first 108° of the crank cycle at 80 vs. 70° at IWL (P < 0.01). As most of the power in the pedal stroke is generated during the mid-section of the down-stroke, movement of the activation range of knee extensors into the predominantly power phase of the pedal stroke would potentially account for increased efficiency and decreased cardio-respiratory costs. Greater activity of bi-articular RF, in the first 108º of the crank cycle at IWL (80 vs. 70º) may more closely resemble the pelvic stabilising activity of RF in running biomechanics; and potentially explain the more effective transition from cycling to running reported in triathletes using steeper STA. PMID:29399245

The effects of acute carbohydrate and caffeine feeding strategies on cycling efficiency.

PubMed

Cole, Matthew; Hopker, James G; Wiles, Jonathan D; Coleman, Damian A

2018-04-01

To assess the effect of carbohydrate and caffeine on gross efficiency (GE), 14 cyclists (V̇O 2max 57.6 ± 6.3 ml.kg -1. min -1 ) completed 4 × 2-hour tests at a submaximal exercise intensity (60% Maximal Minute Power). Using a randomized, counter-balanced crossover design, participants consumed a standardised diet in the 3-days preceding each test and subsequently ingested either caffeine (CAF), carbohydrate (CHO), caffeine+carbohydrate (CAF+CHO) or water (W) during exercise whilst GE and plasma glucose were assessed at regular intervals (~30 mins). GE progressively decreased in the W condition but, whilst caffeine had no effect, this was significantly attenuated in both trials that involved carbohydrate feedings (W = -1.78 ± 0.31%; CHO = -0.70 ± 0.25%, p = 0.008; CAF+CHO = -0.63 ± 0.27%, p = 0.023; CAF = -1.12 ± 0.24%, p = 0.077). Blood glucose levels were significantly higher in carbohydrate ingestion conditions (CHO = 4.79 ± 0.67 mmol·L -1, p < 0.001; CAF+CHO = 5.05 ± 0.81 mmol·L -1 , p < 0.001; CAF = 4.46 ± 0.75 mmol·L -1 ; W = 4.20 ± 0.53 mmol·L -1 ). Carbohydrate ingestion has a small but significant effect on exercise-induced reductions in GE, indicating that cyclists' feeding strategy should be carefully monitored prior to and during assessment.

Predictors of the frequency and subjective experience of cycling near misses: Findings from the first two years of the UK Near Miss Project.

PubMed

Aldred, Rachel; Goodman, Anna

2018-01-01

Using 2014 and 2015 data from the UK Near Miss Project, this paper examines the stability of self-report incident rates for cycling near misses across these two years. It further examines the stability of the individual-level predictors of experiencing a near miss, including what influences the scariness of an incident. The paper uses three questions asked for only in 2015, which allow further exploration of factors shaping near miss rates and impacts of incidents. Firstly, a respondent's level of cycling experience; secondly, whether an incident was perceived as deliberate; and finally, whether the respondent themselves described the incident as a 'near miss' (as opposed to only a frightening and/or annoying non-injury incident). Using this data, we find a decline of almost a third in incident rates in 2015 compared to 2014, which we believe is likely to be largely an artefact due to differences in reporting rates. This suggests caution about interpreting small fluctuations in subjectively reported near miss rates. However, in both years near miss rates are many times more frequent than injury collisions. In both years of data collection our findings are very similar in terms of the patterning of incident types, and how frightening different incident categories are, which increases confidence in these findings. We find that new cyclists experience very high incident rates compared to other cyclists, and test a conceptual model explaining how perceived deliberateness, near-miss status, and scariness are connected. For example, incidents that are perceived to be deliberate are more likely to be experienced as very frightening, independent of their 'near miss' status. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improving Training Condition Assessment in Endurance Cyclists: Effects of Ganoderma lucidum and Ophiocordyceps sinensis Dietary Supplementation

PubMed Central

Rossi, Paola; Buonocore, Daniela; Altobelli, Elisa; Brandalise, Federico; Cesaroni, Valentina; Iozzi, Davide; Savino, Elena; Marzatico, Fulvio

2014-01-01

The main reasons for taking daily dietary supplements are to maintain good health, to improve homeostasis, and to create conditions for reducing the risk of disease. Due to growing market demand, the search for effective, nontoxic, natural compounds with antioxidant and ergogenic properties has increasingly become a matter of interest. This paper describes how a specific combination of fungal supplements can help improve the performance of endurance athletes. We report the effects of a brief 3-month trial of two fungal supplements, Ganoderma lucidum and Cordyceps sinensis (3 capsules of O. sinensis and 2 capsules of G. lucidum per day), in 7 healthy male volunteers, aged between 30 and 40 years, who are all amateur cyclists that participate in “Gran Fondo” cycling races. This trial investigated the effects of fungal supplements on the level of physical fitness of the athletes by monitoring and comparing the following biomarkers just before and after physical exertion: the testosterone/cortisol ratio in the saliva and oxidative stress (DPPH free radical scavenging activity). A decrease of more than 30% in the testosterone/cortisol ratio after race compared to before race was considered as a risk factor for nonfunctional overreaching (NFO) or the overtraining syndrome (OTS). The results show that, after 3 months of supplementation, the testosterone/cortisol ratio changed in a statistically significant manner, thereby protecting the athletes from NFO and OTS. Antioxidant activity was measured by quantifying the scavenging ability of the human serum on the synthetic free radical DPPH. After 3 months of fungal supplementation, the data demonstrate an increased scavenger capacity of free radicals in the athletes' serum after the race, thereby protecting the athletes from oxidative stress. PMID:24799948

The Effects of Bicycle Frame Geometry on Muscle Activation and Power During a Wingate Anaerobic Test

PubMed Central

Ricard, Mark D.; Hills-Meyer, Patrick; Miller, Michael G.; Michael, Timothy J.

2006-01-01

The purpose of this study was to compare the effects of bicycle seat tube angles (STA) of (72° and 82°) on power production and EMG of the vastus laeralis (VL), vastus medialis (VM), semimembranous (SM), biceps femoris (BF) during a Wingate test (WAT). Twelve experienced cyclists performed a WAT at each STA. Repeated measures ANOVA was used to identify differences in muscular activation by STA. EMG variables were normalized to isometric maximum voluntary contraction (MVC). Paired t-tests were used to test the effects of STA on: peak power, average power, minimum power and percent power drop. Results indicated BF activation was significantly lower at STA 82° (482.9 ± 166.6 %MVC·s) compared to STA 72° (712.6 ± 265.6 %MVC·s). There were no differences in the power variables between STAs. The primary finding was that increasing the STA from 72° to 82° enabled triathletes’ to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle. Key Points Road cyclists claim that bicycle seat tube angles between 72° and 76° are most effective for optimal performance in racing. Triathletes typically use seat tube angles greater than 76°. It is thought that a seat tube angle greater than 76° facilitates a smoother bike to run transition in the triathlon. Increasing the seat tube angle from 72 to 82 enabled triathletes’ to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle. Reduced hamstring muscular activation in the triathlon frame (82 seat tube angle) may serve to reduce hamstring tightness following the bike phase of the triathlon, allowing the runner to use a longer stride length. PMID:24198678

Effect of gear ratio on peak power and time to peak power in BMX cyclists.

PubMed

Rylands, Lee P; Roberts, Simon J; Hurst, Howard T

2017-03-01

The aim of this study was to ascertain if gear ratio selection would have an effect on peak power and time to peak power production in elite Bicycle Motocross (BMX) cyclists. Eight male elite BMX riders volunteered for the study. Each rider performed three, 10-s maximal sprints on an Olympic standard indoor BMX track. The riders' bicycles were fitted with a portable SRM power meter. Each rider performed the three sprints using gear ratios of 41/16, 43/16 and 45/16 tooth. The results from the 41/16 and 45/16 gear ratios were compared to the current standard 43/16 gear ratio. Statistically, significant differences were found between the gear ratios for peak power (F(2,14) = 6.448; p = .010) and peak torque (F(2,14) = 4.777; p = .026), but no significant difference was found for time to peak power (F(2,14) = 0.200; p = .821). When comparing gear ratios, the results showed a 45/16 gear ratio elicited the highest peak power,1658 ± 221 W, compared to 1436 ± 129 W and 1380 ± 56 W, for the 43/16 and 41/16 ratios, respectively. The time to peak power showed a 41/16 tooth gear ratio attained peak power in -0.01 s and a 45/16 in 0.22 s compared to the 43/16. The findings of this study suggest that gear ratio choice has a significant effect on peak power production, though time to peak power output is not significantly affected. Therefore, selecting a higher gear ratio results in riders attaining higher power outputs without reducing their start time.

Increased hepatic gluconeogenesis: the secret of Lance Armstrong's success.

PubMed

Bongaerts, Ger P A; Wagener, D J Theo

2007-01-01

Enormous amounts of lactic acid are produced during endurance sport by muscle cells. This metabolite is thought responsible for the muscle pain and the fatigue during sport. Its internal removal from the body by enzymatic conversion depends mainly on the capacity of the hepatic gluconeogenesis that converts lactic acid to glucose. The extraordinary sportive results of the racing cyclist Lance Armstrong did us realize that a high capacity of hepatic gluconeogenesis was the basis of his success, because it might have provided him with less pain complaints caused by lactic acid and with an extra source of energy from lactic acid. This enhanced gluconeogenesis can be due to his heavy training program. At the age of 12-13 years he daily swam 10,000m and cycled 32km. In later years as cyclist his training labour was also more than normal. A constitutional increased gluconeogenesis cannot be excluded, because as a boy of 12 years he became already fourth in 1500m free style swimming in a contest for swimmers from whole Texas. The last argument for an increased gluconeogenesis is that Armstrong in October 1996 suffered from an extensively disseminated testicular tumour. This large tumour load caused that in the tumour the oxidative (=aerobic) energy generation changed into a fermentative (=anaerobic) one. This resulted in a high increase of lactic acid that putted up the gluconeogenesis in the liver. We think that this stimulated, high level gluconeogenesis remained high in the following years, when Armstrong restarted cycling, that it provided him with extra energy from lactic acid and with fewer complaints due to the exercise, and that thus this was the basis of his success.

Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body.

PubMed

van der Zwaard, Stephan; van der Laarse, Willem J; Weide, Guido; Bloemers, Frank W; Hofmijster, Mathijs J; Levels, Koen; Noordhof, Dionne A; de Koning, Jos J; de Ruiter, Cornelis J; Jaspers, Richard T

2018-04-01

Optimizing physical performance is a major goal in current physiology. However, basic understanding of combining high sprint and endurance performance is currently lacking. This study identifies critical determinants of combined sprint and endurance performance using multiple regression analyses of physiologic determinants at different biologic levels. Cyclists, including 6 international sprint, 8 team pursuit, and 14 road cyclists, completed a Wingate test and 15-km time trial to obtain sprint and endurance performance results, respectively. Performance was normalized to lean body mass 2/3 to eliminate the influence of body size. Performance determinants were obtained from whole-body oxygen consumption, blood sampling, knee-extensor maximal force, muscle oxygenation, whole-muscle morphology, and muscle fiber histochemistry of musculus vastus lateralis. Normalized sprint performance was explained by percentage of fast-type fibers and muscle volume ( R 2 = 0.65; P < 0.001) and normalized endurance performance by performance oxygen consumption ( V̇o 2 ), mean corpuscular hemoglobin concentration, and muscle oxygenation ( R 2 = 0.92; P < 0.001). Combined sprint and endurance performance was explained by gross efficiency, performance V̇o 2 , and likely by muscle volume and fascicle length ( P = 0.056; P = 0.059). High performance V̇o 2 related to a high oxidative capacity, high capillarization × myoglobin, and small physiologic cross-sectional area ( R 2 = 0.67; P < 0.001). Results suggest that fascicle length and capillarization are important targets for training to optimize sprint and endurance performance simultaneously.-Van der Zwaard, S., van der Laarse, W. J., Weide, G., Bloemers, F. W., Hofmijster, M. J., Levels, K., Noordhof, D. A., de Koning, J. J., de Ruiter, C. J., Jaspers, R. T. Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body.

Sprinting for the Win; Distribution of Power Output in Women's Professional Cycling.

PubMed

Peiffer, Jeremiah J; Abbiss, Chris R; Haakonssen, Eric C; Menaspà, Paolo

2018-04-24

This study examined the power output distribution and sprint characteristics of professional female road cyclists. 31 race files, representing top-five finishes, were collected from seven professional female cyclists. Files were analysed for sprint characteristics including; mean and peak power output, velocity and duration. The final 20 min before the sprint was analysed to determine the mean maximal power output (MMP) consistent with 5, 15, 30, 60, 240 and 600s durations. Throughout the race, the number of efforts for each duration exceeding 80% of its corresponding final 20-min MMP (MMP 80 ) were determined. The number of 15s efforts exceeding 80% of the mean final sprint power output (MSP 80 ) were determined. Sprint finishes lasted 21.8 ± 6.7s with a mean and peak power output of 679 ± 101W and 886 ± 91W, respectively. Throughout the race, more 5, 15, and 30s efforts above MMP 80 were completed in the 5 th compared with the 1 st - 4 th quintiles of the race. 60s efforts were greater during the 5 th compared 1 st , 2 nd , and 4 th quintiles and during the 3 rd compared with 4 th quintile. More 240s efforts were recorded during the 5 th compared with 1 st and 4 th quintiles. 82% of 15s efforts above MSP 80 were completed in the 2 nd , 3 rd and 5 th quintiles of the race. This data demonstrates the variable nature of women's professional cycling and the physical demands necessary for success; thus providing information that could enhance in-race decision-making and the development of race-specific training programs.

Effect of water-based recovery on blood lactate removal after high-intensity exercise.

PubMed

Lucertini, Francesco; Gervasi, Marco; D'Amen, Giancarlo; Sisti, Davide; Rocchi, Marco Bruno Luigi; Stocchi, Vilberto; Benelli, Piero

2017-01-01

This study assessed the effectiveness of water immersion to the shoulders in enhancing blood lactate removal during active and passive recovery after short-duration high-intensity exercise. Seventeen cyclists underwent active water- and land-based recoveries and passive water and land-based recoveries. The recovery conditions lasted 31 minutes each and started after the identification of each cyclist's blood lactate accumulation peak, induced by a 30-second all-out sprint on a cycle ergometer. Active recoveries were performed on a cycle ergometer at 70% of the oxygen consumption corresponding to the lactate threshold (the control for the intensity was oxygen consumption), while passive recoveries were performed with subjects at rest and seated on the cycle ergometer. Blood lactate concentration was measured 8 times during each recovery condition and lactate clearance was modeled over a negative exponential function using non-linear regression. Actual active recovery intensity was compared to the target intensity (one sample t-test) and passive recovery intensities were compared between environments (paired sample t-tests). Non-linear regression parameters (coefficients of the exponential decay of lactate; predicted resting lactates; predicted delta decreases in lactate) were compared between environments (linear mixed model analyses for repeated measures) separately for the active and passive recovery modes. Active recovery intensities did not differ significantly from the target oxygen consumption, whereas passive recovery resulted in a slightly lower oxygen consumption when performed while immersed in water rather than on land. The exponential decay of blood lactate was not significantly different in water- or land-based recoveries in either active or passive recovery conditions. In conclusion, water immersion at 29°C would not appear to be an effective practice for improving post-exercise lactate removal in either the active or passive recovery modes.

How bicycle level of traffic stress correlate with reported cyclist accidents injury severities: A geospatial and mixed logit analysis.

PubMed

Chen, Chen; Anderson, Jason C; Wang, Haizhong; Wang, Yinhai; Vogt, Rachel; Hernandez, Salvador

2017-11-01

Transportation agencies need efficient methods to determine how to reduce bicycle accidents while promoting cycling activities and prioritizing safety improvement investments. Many studies have used standalone methods, such as level of traffic stress (LTS) and bicycle level of service (BLOS), to better understand bicycle mode share and network connectivity for a region. However, in most cases, other studies rely on crash severity models to explain what variables contribute to the severity of bicycle related crashes. This research uniquely correlates bicycle LTS with reported bicycle crash locations for four cities in New Hampshire through geospatial mapping. LTS measurements and crash locations are compared visually using a GIS framework. Next, a bicycle injury severity model, that incorporates LTS measurements, is created through a mixed logit modeling framework. Results of the visual analysis show some geospatial correlation between higher LTS roads and "Injury" type bicycle crashes. It was determined, statistically, that LTS has an effect on the severity level of bicycle crashes and high LTS can have varying effects on severity outcome. However, it is recommended that further analyses be conducted to better understand the statistical significance and effect of LTS on injury severity. As such, this research will validate the use of LTS as a proxy for safety risk regardless of the recorded bicycle crash history. This research will help identify the clustering patterns of bicycle crashes on high-risk corridors and, therefore, assist with bicycle route planning and policy making. This paper also suggests low-cost countermeasures or treatments that can be implemented to address high-risk areas. Specifically, with the goal of providing safer routes for cyclists, such countermeasures or treatments have the potential to substantially reduce the number of fatalities and severe injuries. Published by Elsevier Ltd.

The effect of mountain bike suspensions on vibrations and off-road uphill performance.

PubMed

Faiss, R; Praz, M; Meichtry, A; Gobelet, C; Deriaz, O

2007-06-01

This study evaluates the effect of front suspension (FS) and dual suspension (DS) mountain-bike on performance and vibrations during off-road uphill riding. Thirteen male cyclists (27+/-5 years, 70+/-6 kg, VO(2max)59+/-6 mL.kg(-1).min(-1), mean+/-SD) performed, in a random sequence, at their lactate threshold, an off-road uphill course (1.69 km, 212 m elevation gain) with both type of bicycles. Variable measured: a) VO(2) consumption (K4b2 analyzer, Cosmed), b) power output (SRM) c) gain in altitude and d) 3-D accelerations under the saddle and at the wheel (Physilog, EPFL, Switzerland). Power spectral analy- sis (Fourier) was performed from the vertical acceleration data. Respectively for the FS and DS mountain bike: speed amounted to 7.5+/-0.7 km.h(-1) and 7.4+/-0.8 km.h(-1), (NS), energy expenditure 1.39+/-0.16 kW and 1.38+/-0.18, (NS), gross efficiency 0.161+/-0.013 and 0.159+/-0.013, (NS), peak frequency of vibration under the saddle 4.78+/-2.85 Hz and 2.27+/-0.2 Hz (P<0.01) and median-frequency of vertical displacements of the saddle 9.41+/-1.47 Hz and 5.78+/-2.27 Hz (P<0.01). Vibrations at the saddle level of the DS bike are of low frequencies whereas those of the FS bike are mostly of high frequencies. In the DS bike, the torque produced by the cyclist at the pedal level may generate low frequency vibrations. We conclude that the DS bike absorbs more high frequency vibrations, is more comfortable and performs as well as the FS bicycle.

Properties of the vastus lateralis muscle in relation to age and physiological function in master cyclists aged 55-79 years.

PubMed

Pollock, Ross D; O'Brien, Katie A; Daniels, Lorna J; Nielsen, Kathrine B; Rowlerson, Anthea; Duggal, Niharika A; Lazarus, Norman R; Lord, Janet M; Philp, Andrew; Harridge, Stephen D R

2018-04-01

In this study, results are reported from the analyses of vastus lateralis muscle biopsy samples obtained from a subset (n = 90) of 125 previously phenotyped, highly active male and female cyclists aged 55-79 years in regard to age. We then subsequently attempted to uncover associations between the findings in muscle and in vivo physiological functions. Muscle fibre type and composition (ATPase histochemistry), size (morphometry), capillary density (immunohistochemistry) and mitochondrial protein content (Western blot) in relation to age were determined in the biopsy specimens. Aside from an age-related change in capillary density in males (r = -.299; p = .02), no other parameter measured in the muscle samples showed an association with age. However, in males type I fibres and capillarity (p < .05) were significantly associated with training volume, maximal oxygen uptake, oxygen uptake kinetics and ventilatory threshold. In females, the only association observed was between capillarity and training volume (p < .05). In males, both type II fibre proportion and area (p < .05) were associated with peak power during sprint cycling and with maximal rate of torque development during a maximal voluntary isometric contraction. Mitochondrial protein content was not associated with any cardiorespiratory parameter in either males or females (p > .05). We conclude in this highly active cohort, selected to mitigate most of the effects of inactivity, that there is little evidence of age-related changes in the properties of VL muscle across the age range studied. By contrast, some of these muscle characteristics were correlated with in vivo physiological indices. © 2018 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Concentrically trained cyclists are not more susceptible to eccentric exercise-induced muscle damage than are stretch-shortening exercise-trained runners.

PubMed

Snieckus, Audrius; Kamandulis, Sigitas; Venckūnas, Tomas; Brazaitis, Marius; Volungevičius, Gintautas; Skurvydas, Albertas

2013-03-01

Here, we test the hypothesis that continuous concentric exercise training renders skeletal muscles more susceptible to damage in response to eccentric exercise. Elite road cyclists (CYC; n = 10, training experience 8.1 ± 2.0 years, age 22.9 ± 3.7 years), long-distance runners (LDR; n = 10, 9.9 ± 2.3 years, 24.4 ± 2.5 years), and healthy untrained (UT) men (n = 10; 22.4 ± 1.7 years) performed 100 submaximal eccentric contractions at constant angular velocity of 60° s(-1). Concentric isokinetic peak torque, isometric maximal voluntary contraction (MVC), and electrically induced knee extension torque were measured at baseline and immediately and 48 h after an eccentric exercise bout. Muscle soreness was assessed and plasma creatine kinase (CK) activity was measured at baseline and 48 h after exercise. Voluntary and electrically stimulated knee extension torque reduction were significantly greater (p < 0.05) in UT than in LDR and CYC. Immediately and 48 h after exercise, MVC decreased by 32 % and 20 % in UT, 20 % and 5 % in LDR, and 25 % and 6 % in CYC. Electrically induced 20 Hz torque decreased at the same times by 61 and 29 % in UT, 40 and 17 % in LDR, and 26 and 14 % in CYC. Muscle soreness and plasma CK activity 48 h after exercise did not differ significantly between athletes and UT subjects. In conclusion, even though elite endurance athletes are more resistant to eccentric exercise-induced muscle damage than are UT people, stretch-shortening exercise-trained LDR have no advantage over concentrically trained CYC.

Effect of evening postexercise cold water immersion on subsequent sleep.

PubMed

Robey, Elisa; Dawson, Brian; Halson, Shona; Gregson, Warren; King, Stuart; Goodman, Carmel; Eastwood, Peter

2013-07-01

This study investigated the effect of cold water immersion after evening exercise on subsequent sleep quality and quantity in trained cyclists. In the evenings (~1900 h) on three separate occasions, male cyclists (n = 11) underwent either no exercise (control, CON), exercise only (EX), or exercise followed by cold water immersion (CWI). EX comprised cycling for 15 min at 75% peak power, then a 15-min maximal time trial. After each condition, a full laboratory-based sleep study (polysomnography) was performed. Core and skin temperature, heart rate, salivary melatonin, ratings of perceived fatigue, and recovery were measured in each trial. No differences were observed between conditions for any whole night sleep measures, including total sleep time, sleep efficiency, sleep onset latency, rapid eye movement onset latency, wake after sleep onset, or proportion of the night spent in different sleep stages. Core temperature in EX and CWI trials was higher than CON, until it decreased below that of EX and CON until bedtime in CWI. After bedtime, core temperature was similar for all conditions throughout the night, except for a 90-min period where it was lower for CWI than EX and CON (3.5-4.5 h postexercise). Heart rates for EX and CWI were both significantly higher than CON postexercise until bedtime, whereas skin temperature after CWI was significantly lower than EX and CON, remaining lower than EX until 3 h postexercise. Melatonin levels and recovery ratings were similar between conditions. Fatigue ratings were significantly elevated after exercise in both CWI and EX conditions, with EX still being elevated compared with CON at bedtime. Whole night sleep architecture is not affected by evening exercise alone or when followed by CWI.

Reproductive function in male endurance athletes: sperm analysis and hormonal profile.

PubMed

Lucía, A; Chicharro, J L; Pérez, M; Serratosa, L; Bandrés, F; Legido, J C

1996-12-01

The purpose of this investigation was to study the effects of endurance exercise on male reproductive function (sex hormones and seminograms). Professional cyclists [n = 12; mean age 24 +/- 2 (SD) yr], elite triathletes (n = 9; 26 +/- 3 yr), recreational marathon runners (n = 10; 32 +/- 6 yr), and sedentary subjects (control group; n = 9; 30 +/- 4 yr) were selected as subjects. for each group, the following parameters were measured three times during the sports season (training period: winter; competition period: spring; resting period: fall): percentage of body fat, hormonal profile (resting levels of follicle-stimulating hormone, luteinizing hormone, total and free testosterone, and cortisol), and seminograms (quantitative parameters sperm volume and sperm count; qualitative parameters: sperm motality and morphology). The following comparisons were made in the measured parameters: 1) within groups (longitudinal design) and 2) between groups in each of the three periods (cross-sectional design) and over time (mixed design). In addition, both the volume and the intensity of training of each subject during the season (except for the control group) were quantified. Despite significant differences in training characteristics and in body fat percent, in general no significant differences (P > 0.05) were found in hormonal profiles or in semen characteristics between or within groups. A lower sperm motility (46.2 +/- 19.5%), however, was observed in the cyclists during the competition period when compared either with the other groups during this same period (P < 0.05) or with themselves during the other two periods of study (P < 0.01). In any case, the later phenomenon was attributed to physical factors associated with cycling, such as mechanical trauma to the testis and/or increased gonadal temperature. In conclusion, our findings suggest that endurance exercise does not adversely affect the hypothalamic-pituitary-testis axis.

A scientific nutrition strategy improves time trial performance by ≈6% when compared with a self-chosen nutrition strategy in trained cyclists: a randomized cross-over study.

PubMed

Hottenrott, Kuno; Hass, Erik; Kraus, Manon; Neumann, Georg; Steiner, Martin; Knechtle, Beat

2012-08-01

We investigated whether an athlete's self-chosen nutrition strategy (A), compared with a scientifically determined one (S), led to an improved endurance performance in a laboratory time trial after an endurance exercise. S consisted of about 1000 mL·h(-1) fluid, in portions of 250 mL every 15 min, 0.5 g sodium·L(-1), 60 g glucose·h(-1), 30 g fructose·h(-1), and 5 mg caffeine·kg body mass(-1). Eighteen endurance-trained cyclists (16 male; 2 female) were tested using a randomized crossover-design at intervals of 2 weeks, following either A or S. After a warm-up, a maximal oxygen uptake test was performed. Following a 30-min break, a 2.5-h endurance exercise on a bicycle ergometer was carried out at 70% maximal oxygen uptake. After 5 min of rest, a time trial of 64.37 km (40 miles) was completed. The ingested nutrition was recorded every 15 min. In S, the athletes completed the time trial faster (128 vs. 136 min; p ≤ 0.001) and with a significantly higher power output (212 vs. 184 W; p ≤ 0.001). The intake of fluid, energy (carbohydrate-, mono-, and disaccharide), and sodium was significantly higher in S compared with A (p ≤ 0.001) during the endurance exercise. In the time trial, only sodium intake was significantly higher in S (p ≤ 0.001). We concluded that a time trial performance after a 2.5-h endurance exercise in a laboratory setting was significantly improved following a scientific nutrition strategy.

Predicting Critical Power in Elite Cyclists: Questioning the Validity of the 3-Minute All-Out Test.

PubMed

Bartram, Jason C; Thewlis, Dominic; Martin, David T; Norton, Kevin I

2017-07-01

New applications of the critical-power concept, such as the modeling of intermittent-work capabilities, are exciting prospects for elite cycling. However, accurate calculation of the required parameters is traditionally time invasive and somewhat impractical. An alternative single-test protocol (3-min all-out) has recently been proposed, but validation in an elite population is lacking. The traditional approach for parameter establishment, but with fewer tests, could also prove an acceptable compromise. Six senior Australian endurance track-cycling representatives completed 6 efforts to exhaustion on 2 separate days over a 3-wk period. These included 1-, 4-, 6-, 8-, and 10-min self-paced efforts, plus the 3-min all-out protocol. Traditional work-vs-time calculations of CP and anaerobic energy contribution (W') using the 5 self-paced efforts were compared with calculations from the 3-min all-out protocol. The impact of using just 2 or 3 self-paced efforts for traditional CP and W' estimation was also explored using thresholds of agreement (8 W, 2.0 kJ, respectively). CP estimated from the 3-min all-out approach was significantly higher than from the traditional approach (402 ± 33, 351 ± 27 W, P < .001), while W' was lower (15.5 ± 3.0, 24.3 ± 4.0 kJ, P = .02). Five different combinations of 2 or 3 self-paced efforts led to CP estimates within the threshold of agreement, with only 1 combination deemed accurate for W'. In elite cyclists the 3-min all-out approach is not suitable to estimate CP when compared with the traditional method. However, reducing the number of tests used in the traditional method lessens testing burden while maintaining appropriate parameter accuracy.

Alcohol intoxication in non-motorised road trauma.

PubMed

Mitra, Biswadev; Charters, Kate E; Spencer, John C; Fitzgerald, Mark C; Cameron, Peter A

2017-02-01

To determine the proportion of non-motorised road users involved in road traffic crashes that presents to hospital intoxicated. We undertook a retrospective cohort study using data collected from the Alfred Trauma Registry. All patients presenting to an adult major trauma centre in Victoria, Australia from July 2009 to June 2014 who were involved in a road traffic crash as a non-motorised road user - pedestrians, pedal-cyclists, non-motorised scooter users, horse riders - were included. Patients who had a blood alcohol measurement were included, and intoxication was defined as a blood alcohol concentration ≥0.05 g/100 mL. There were 1323 patients included for analysis with data on presenting blood alcohol concentration. Alcohol was detected in 248 (18.7%; 95% CI: 16.7-20.9) patients, whereas 211 (15.9%; 95% CI: 14.1-18.0) were intoxicated. Among all included pedestrians, 161 (24.7%) were intoxicated; among all included pedal-cyclists, 47 (7.3%) were intoxicated. Intoxicated patients were significantly younger, and a higher proportion were males and more likely to present after hours and on public holidays (P < 0.01). Survival to hospital discharge and inpatient rehabilitation requirements were similar among intoxicated and non-intoxicated patients. Intoxication was common among non-motorised road users, and the proportion of intoxicated patients in this subgroup appears unchanged over time despite public awareness programmes. The true burden of intoxication in non-motorised road users remains unknown because of a lack of routine testing. Legislation directed at testing for intoxication of non-motorised users and introduction of penalties should be considered to improve safety of all road users. © 2016 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

Effect of Preexercise Ingestion of Modified Amylomaize Starch on Glycemic Response While Cycling.

PubMed

Parks, Rachel B; Angus, Hector F; King, Douglas S; Sharp, Rick L

2018-01-01

Amylomaize-7 is classified as a resistant corn starch and is 68% digestible. When modified by partial hydrolysis in ethanol and hydrochloric acid its digestibility is 92%, yet retains its low glycemic and insulinemic properties. The purpose of this study was to characterize the metabolic response when modified amylomaize-7 or dextrose is consumed in the hour before exercise, and to compare the effect on performance of a brief high-intensity cycling trial. Ten male, trained cyclists were given 1 g/kg body mass of dextrose (DEX) or modified amylomaize-7 (AMY-7) or a flavored water placebo (PL) 45 min prior to exercise on a cycle ergometer. A 15-min ride at 60% W max was immediately followed by a self-paced time trial (TT) equivalent to 15 min at 80% W max . When cyclists consumed DEX, mean serum glucose concentration increased by 3.3 ± 2.1 mmol/L before exercise, compared to stable serum glucose observed for AMY-7 or PL. Glucose concentrations returned to baseline by pre-TT in all treatments. However, the mean post-TT glucose concentration of the DEX group was significantly lower than baseline, AMY-7, or PL. Serum insulin concentration increased nine-fold from baseline to preexercise in the DEX trial, whereas PL or AMY-7 remained unchanged. Time required to complete the performance trial was not significantly different between DEX, AMY-7 or PL. Preexercise ingestion of modified amylomaize-7 compared to dextrose resulted in a more stable serum glucose concentration, but did not offer a performance advantage in this high-intensity cycling trial.

Applying the health action process approach to bicycle helmet use and evaluating a social marketing campaign.

PubMed

Karl, Florian M; Smith, Jennifer; Piedt, Shannon; Turcotte, Kate; Pike, Ian

2017-08-05

Bicycle injuries are of concern in Canada. Since helmet use was mandated in 1996 in the province of British Columbia, Canada, use has increased and head injuries have decreased. Despite the law, many cyclists do not wear a helmet. Health action process approach (HAPA) model explains intention and behaviour with self-efficacy, risk perception, outcome expectancies and planning constructs. The present study examines the impact of a social marketing campaign on HAPA constructs in the context of bicycle helmet use. A questionnaire was administered to identify factors determining helmet use. Intention to obey the law, and perceived risk of being caught if not obeying the law were included as additional constructs. Path analysis was used to extract the strongest influences on intention and behaviour. The social marketing campaign was evaluated through t-test comparisons after propensity score matching and generalised linear modelling (GLM) were applied to adjust for the same covariates. 400 cyclists aged 25-54 years completed the questionnaire. Self-efficacy and Intention were most predictive of intention to wear a helmet, which, moderated by planning, strongly predicted behaviour. Perceived risk and outcome expectancies had no significant impact on intention. GLM showed that exposure to the campaign was significantly associated with higher values in self-efficacy, intention and bicycle helmet use. Self-efficacy and planning are important points of action for promoting helmet use. Social marketing campaigns that remind people of appropriate preventive action have an impact on behaviour. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Biking practices and preferences in a lower income, primarily minority neighborhood: Learning what residents want.

PubMed

Lusk, Anne C; Anastasio, Albert; Shaffer, Nicholas; Wu, Juan; Li, Yanping

2017-09-01

This paper examines if, in a lower-income minority neighborhood, bicycling practices and bicycle-environment preferences of Blacks and Hispanics were different from Whites. During the summer of 2014, surveys were mailed to 1537 households near a proposed cycle track on Malcolm X Boulevard in Roxbury, MA. On the Boulevard, intercept surveys were distributed to cyclists and observations noted about passing cyclist's characteristics. Data were analyzed from 252 returned-mailed surveys, 120 intercept surveys, and 709 bicyclists. White (100%), Hispanic (79%), and Black (76%) bicyclists shown pictures of 6 bicycle facility types in intercept surveys perceived the cycle track as safest. More White mailed-survey respondents thought bikes would not be stolen which may explain why more Hispanics (52%) and Blacks (47%) preferred to park their bikes inside their home compared with Whites (28%), with H/W B/W differences statistically significant ( p  < 0.05). More Hispanic (81%) and Black (54%) mailed-survey respondents thought they would bicycle more if they could bicycle with family and friends compared with Whites (40%). Bicyclists observed commuting morning and evening included Blacks (55%), Whites (36%) and Hispanics (9%). More Whites (68%) wore helmets compared with Hispanics (21%) and Blacks (17%) ( p  < 0.001). More Blacks (94%) and Hispanics (94%) rode a mountain bike compared with Whites (75%). Minority populations are biking on roads but prefer cycle tracks. They also prefer to park bikes inside their homes and bicycle with family and friends. Wide cycle tracks (bicycling with family/friends) and home bike parking should be targeted as capital investments in lower-income minority neighborhoods.

Respiratory Mechanical and Cardiorespiratory Consequences of Cycling with Aerobars.

PubMed

Charlton, Jesse M; Ramsook, Andrew H; Mitchell, Reid A; Hunt, Michael A; Puyat, Joseph H; Guenette, Jordan A

2017-12-01

Aerobars place a cyclist in a position where the trunk is flexed forward and the elbows are close to the midline of the body. This position is known to improve cycling aerodynamics and time trial race performance compared with upright cycling positions. However, the aggressive nature of this position may have important cardiorespiratory and metabolic consequences. The purpose of this investigation was to examine the respiratory mechanical, ventilatory, metabolic, and sensory consequences of cycling while using aerobars during laboratory-based cycling. Eleven endurance-trained male cyclists (age, 26 ± 9 yr; V˙O2peak, 55 ± 5 mL·kg·min) were recruited. Visit 1 consisted of an incremental cycling test to determine peak power output. Visit 2 consisted of 6-min bouts of constant load cycling at 70% of peak incremental power output in the aerobar position, drop position, and upright position while grasping the brake hoods. Metabolic and ventilatory responses were measured using a commercially available metabolic cart, and respiratory pressures were measured using an esophageal catheter. Cycling in the aerobar position significantly increased the work of breathing (Wb), power of breathing (Pb), minute ventilation, ventilatory equivalent for oxygen and carbon dioxide, and transdiaphragmatic pressure compared with the upright position. Increases in the Wb and Pb in the aerobars relative to the upright position were strongly correlated with the degree of thoracic restriction, measured as the shoulder-to-aerobar width ratio (Wb: r = 0.80, P = 0.01; Pb: r = 0.69, P = 0.04). Aerobars significantly increase the mechanical cost of breathing and leads to greater ventilatory inefficiency compared with upright cycling. Future work is needed to optimize aerobar width to minimize the respiratory mechanical consequences while optimizing aerodynamics.

The role of multilevel factors in geographic differences in bicycle crash risk: a prospective cohort study

PubMed Central

2013-01-01

Background Regular cycling plays an important role in increasing physical activity levels but raises safety concerns for many people. While cyclists bear a higher risk of injury than most other types of road users, the risk differs geographically. Auckland, New Zealand’s largest urban region, has a higher injury risk than the rest of the country. This paper identified underlying factors at individual, neighbourhood and environmental levels and assessed their relative contribution to this risk differential. Methods The Taupo Bicycle Study involved 2590 adult cyclists recruited in 2006 and followed over a median period of 4.6 years through linkage to four national databases. The Auckland participants were compared with others in terms of baseline characteristics, crash outcomes and perceptions about environmental determinants of cycling. Cox regression modelling for repeated events was performed with multivariate adjustments. Results Of the 2554 participants whose addresses could be mapped, 919 (36%) resided in Auckland. The Auckland participants were less likely to be Māori but more likely to be socioeconomically advantaged and reside in an urban area. They were less likely to cycle for commuting and off-road but more likely to cycle in the dark and in a bunch, use a road bike and use lights in the dark. They had a higher risk of on-road crashes (hazard ratio: 1.47; 95% CI: 1.22, 1.76), of which 53% (95% CI: 20%, 72%) was explained by baseline differences, particularly related to cycling off-road, in the dark and in a bunch and residing in urban areas. They were more concerned about traffic volume, speed and drivers’ behaviour. Conclusions The excess crash risk in Auckland was explained by cycling patterns, urban residence and factors associated with the region’s car-dominated transport environment. PMID:24321134

Improving Training Condition Assessment in Endurance Cyclists: Effects of Ganoderma lucidum and Ophiocordyceps sinensis Dietary Supplementation.

PubMed

Rossi, Paola; Buonocore, Daniela; Altobelli, Elisa; Brandalise, Federico; Cesaroni, Valentina; Iozzi, Davide; Savino, Elena; Marzatico, Fulvio

2014-01-01

The main reasons for taking daily dietary supplements are to maintain good health, to improve homeostasis, and to create conditions for reducing the risk of disease. Due to growing market demand, the search for effective, nontoxic, natural compounds with antioxidant and ergogenic properties has increasingly become a matter of interest. This paper describes how a specific combination of fungal supplements can help improve the performance of endurance athletes. We report the effects of a brief 3-month trial of two fungal supplements, Ganoderma lucidum and Cordyceps sinensis (3 capsules of O. sinensis and 2 capsules of G. lucidum per day), in 7 healthy male volunteers, aged between 30 and 40 years, who are all amateur cyclists that participate in "Gran Fondo" cycling races. This trial investigated the effects of fungal supplements on the level of physical fitness of the athletes by monitoring and comparing the following biomarkers just before and after physical exertion: the testosterone/cortisol ratio in the saliva and oxidative stress (DPPH free radical scavenging activity). A decrease of more than 30% in the testosterone/cortisol ratio after race compared to before race was considered as a risk factor for nonfunctional overreaching (NFO) or the overtraining syndrome (OTS). The results show that, after 3 months of supplementation, the testosterone/cortisol ratio changed in a statistically significant manner, thereby protecting the athletes from NFO and OTS. Antioxidant activity was measured by quantifying the scavenging ability of the human serum on the synthetic free radical DPPH. After 3 months of fungal supplementation, the data demonstrate an increased scavenger capacity of free radicals in the athletes' serum after the race, thereby protecting the athletes from oxidative stress.

Major genitourinary-related bicycle trauma: Results from 20 years at a level-1 trauma center.

PubMed

Osterberg, E Charles; Awad, Mohannad A; Gaither, Thomas W; Sanford, Thomas; Alwaal, Amjad; Hampson, Lindsay A; Yoo, Jennie; McAninch, Jack W; Breyer, Benjamin N

2017-01-01

Epidemiological studies have shown that bicycle trauma is associated with genitourinary (GU) injuries. Our objective is to characterize GU-related bicycle trauma admitted to a level I trauma center. We queried a prospective trauma registry for bicycle injuries over a 20-year period. Patient demographics, triage data, operative interventions and hospital details were collected. In total, 1659 patients were admitted with major bicycle trauma. Of these, 48 cases involved a GU organ, specifically the bladder (n=7), testis (n=6), urethra (n=3), adrenal (n=4) and/or kidneys (n=36). The median age of cyclists with GU injuries was 29 (range 5-70). More men were injured versus women (35 versus 13). GU-related bicycle trauma involved a motor vehicle in 52% (25/48) of injuries. The median injury severity score for GU-related bicycle trauma was 17 (range 1-50). The median number of concomitant organ injuries was 2 (range 0-6), the most common of which was the lungs (13/48, 27%) and ribs (13/48, 27%). The majority of GU injured cyclists were admitted to an ICU (15/48, 31%) or hospital floor (12/48, 25%). Operative intervention for a GU-related trauma was low (12/48, 25%). The most common GU organ injured was the kidney (36/48, 75%) however most were managed nonoperatively (33/36, 92%). Bladder injuries most often required operative intervention (6/7, 86%). Mortality following GU-related bicycle trauma was low (2/48, 4%). In a large series of bicycle trauma, GU organs were injured in 3% of cases. The majority of cases were managed non-operatively and mortality was low. Published by Elsevier Ltd.

The Efficacy of an 8-Week Concurrent Strength and Endurance Training Programme on Hand Cycling Performance.

PubMed

Nevin, Jonpaul; Waldron, Mark; Patterson, Stephen; Smith, Paul; Price, Mike; Hunt, Alex

2018-03-20

The aim of the present study was to investigate the effects of an 8-week concurrent strength and endurance training programme in comparison to endurance training only on several key determinants of hand cycling performance. Five H4 and five H3 classified hand cyclists with at least one year's hand cycling training history consented to participate in the study. Subjects underwent a battery of tests to establish body mass, body composition, VO2peak, maximum aerobic power, gross mechanical efficiency, maximal upper body strength, and 30 km time trial performance. Subjects were matched into pairs based upon 30 km time trial performance and randomly allocated to either a concurrent strength and endurance or endurance training only, intervention group. Following an 8-week training programme based upon a conjugated block periodisation model, subjects completed a second battery of tests. A mixed model, 2-way analysis of variance (ANOVA) revealed no significant changes between groups. However, the calculation of effect sizes (ES) revealed that both groups demonstrated a positive improvement in most physiological and performance measures with subjects in the concurrent group demonstrating a greater magnitude of improvement in body composition (ES -0.80 vs. -0.22) maximal aerobic power (ES 0.97 vs. 0.28), gross mechanical efficiency (ES 0.87 vs. 0.63), bench press 1 repetition maximum (ES 0.53 vs. 0.33), seated row 1 repetition maximum (ES 1.42 vs. 0.43), and 30 km time trial performance (ES -0.66 vs. -0.30). In comparison to endurance training only, an 8-week concurrent training intervention based upon a conjugated block periodisation model appears to be a more effective training regime for improving the performance capabilities of hand cyclists.

Time course of natural heat acclimatization in well-trained cyclists during a 2-week training camp in the heat.

PubMed

Karlsen, A; Nybo, L; Nørgaard, S J; Jensen, M V; Bonne, T; Racinais, S

2015-06-01

The aim of this study was to determine the time course of physiological adaptations and their relationship with performance improvements during 2 weeks of heat acclimatization. Nine trained cyclists completed 2 weeks of training in naturally hot environment (34 ± 3 °C; 18 ± 5% relative humidity). On days 1, 6, and 13, they performed standardized heat response tests (HRT-1, 2, 3), and 43.4-km time trials in the heat (TTH-1, 2, 3) were completed on days 2, 7, and 14. Within the first 5-6 days, sweat sodium concentration decreased from 75 ± 22 mmol/L to 52 ± 24 mmol/L, sweat rate increased (+20 ± 15%), and resting hematocrit decreased (-5.6 ± 5.4%), with no further changes during the remaining period. In contrast, power output during TTHs gradually improved from TTH-1 to TTH-2 (+11 ± 8%), and from TTH-2 to TTH-3 (+5 ± 4%). Individual improvements in performance from TTH-1 to TTH-2 correlated with individual changes in hematocrit (assessed after the corresponding HRT; r = -0.79, P < 0.05), however, were not related to changes in performance from TTH-2 to TTH-3. In trained athletes, sudomotor and hematological adaptations occurred within 5-6 days of training, whereas the additional improvement in performance after the entire acclimatization period did not relate to changes in these parameters. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The Effects of Intermittent Hypoxic Training on Aerobic Capacity and Endurance Performance in Cyclists

PubMed Central

Czuba, Milosz; Waskiewicz, Zbigniew; Zajac, Adam; Poprzecki, Stanislaw; Cholewa, Jaroslaw; Roczniok, Robert

2011-01-01

The aim of the present study was to evaluate the efficacy of intermittent hypoxic training (IHT) with 95 % of lactate threshold workload (WRLT) on aerobic capacity and endurance performance in well-trained cyclists. Twenty male elite cyclists, randomly divided into a hypoxia (H) group (n=10; age 22 ± 2.7years; VO2max 67.8 ± 2.5 ml·kg-1·min-1; body height (BH) 1.78 ± 0.05 m; body mass (BM) 66.7 ± 5.4kg; fat free mass (FFM) 59.3 ± 5.1kg; fat content (FAT%) 11.3 ± 2.1%), and a control (C) group (n = 10; age 23.5 ± 3. 5years; VO2max 67.7 ± 2.0 ml·kg-1·min-1; BH 1.79 ± 3.2 m; BM 69.2 ± 5.5 kg; FFM 63.6 ± 4.8 kg; FAT% 7.9 ± 1.94 %) took part in the research project. The training program used during the experiment was the same for the both groups. For three weeks, the subjects in H group performed 3 training sessions per week in normobaric hypoxia environment (IHT - O2 = 15. 2%). During the elemental core of the IHT session, the intensity was set at 95% WRLT for 30-min in 1st microcycle, 35-min in 2nd microcycle and 40-min in 3rd microcycle. The same training procedure was provided in C group, yet the intensity of the main sessions were set at 100% WRLT in the normoxia environment. The results indicate a significant (p < 0.05) increase in VO2max,VO2LT, WRmax, WRLT and change in lactate concentration (∆LA) during incremental test in H group. Also a significant (p < 0.05) decrease in time of the time trial was seen, associated with a significant increase (p < 0.05) in average generated power (Pavg) and average speed (Vavg) during the time trial. The intermittent hypoxic training (IHT) applied in this research did not significantly affect the hematological variables considered: number of erythrocytes (RBC), hemoglobin concentration (HGB) and haematocrit value (HCT). Significant blood value increases (p < 0.05) were only observed in MCV in H group. This data suggests that intermittent hypoxic training at lactate threshold intensity and medium duration (30-40min) is an effective training means for improving aerobic capacity and endurance performance at sea level. Key points The efficacy of the intermittent hypoxic training is mostly dependent on volume and intensity of exercise in the hypoxic environment. The observed results suggests that intermittent hypoxic training at lactate threshold intensity and medium duration (30-40min) is an effective training means for improving aerobic capacity and endurance performance at sea level. PMID:24149312

Exercise modality effect on oxygen uptake off-transient kinetics at maximal oxygen uptake intensity.

PubMed

Sousa, Ana; Rodríguez, Ferran A; Machado, Leandro; Vilas-Boas, J Paulo; Fernandes, Ricardo J

2015-06-01

What is the central question of this study? Do the mechanical differences between swimming, rowing, running and cycling have a potential effect on the oxygen uptake (V̇O2) off-kinetics after an exercise sustained until exhaustion at 100% of maximal oxygen uptake (V̇O2max) intensity? What is the main finding and its importance? The mechanical differences between exercise modes had a potential effect and contributed to distinct amplitude of the fast component (higher in running compared with cycling) and time constant (higher in swimming compared with rowing and cycling) in the V̇O2 off-kinetic patterns at 100% of V̇O2max intensity. This suggests that swimmers, unlike rowers and cyclists, would benefit more from a longer duration of training intervals after each set of exercise performed at V̇O2max intensity. The kinetics of oxygen uptake (V̇O2) during recovery (off-transient kinetics) for different exercise modes is largely unexplored, hampering the prescription of training and recovery to enhance performance. The purpose of this study was to compare the V̇O2 off-transient kinetics response between swimmers, rowers, runners and cyclists during their specific mode of exercise at 100% of maximal oxygen uptake (V̇O2max) intensity and to examine the on-off symmetry. Groups of swimmers, rowers, runners and cyclists (n = 8 per group) performed (i) an incremental exercise protocol to assess the velocity or power associated with V̇O2max (vV̇O2max or wV̇O2max, respectively) and (ii) a square-wave exercise transition from rest to vV̇O2max/vV̇O2maxwV̇O2maxwV̇O2max until volitional exhaustion. Pulmonary exchange parameters were measured using a telemetric portable gas analyser (K4b(2) ; Cosmed, Rome, Italy), and the on- and off-transient kinetics were analysed through a double-exponential approach. For all exercise modes, both transient periods were symmetrical in shape once they had both been adequately fitted by a double-exponential model. However, differences were found in the off-kinetic parameters between exercise modes; the amplitude of the fast component of the V̇O2 off-response was higher in running compared with cycling (48 ± 5 and 36 ± 7 ml kg(-1) min(-1) , respectively; P < 0.001), and the time constant of the same phase was higher in swimming compared with rowing and cycling (63 ± 5, 56 ± 5 and 55 ± 3 s, respectively; P < 0.001). Although both phases were well described by a double-exponential model, the differences between exercise modes had a potential effect and contributed to distinct V̇O2 off-transient kinetic patterns at 100% of V̇O2max intensity. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

[Cycling in Zagreb].

PubMed

Matos, Stipan; Krapac, Ladislav; Krapac, Josip

2007-01-01

Cycling in Zagreb, as means of urban transport inside and outside the city, has a bright past, hazy presence but a promising future. Every day, aggressive citizens who lack urban traffic culture mistreat many cyclists but also many pedestrians. Sedentary way of living, unhealthy eating habits and inadequate recreation would surely be reduced if Zagreb had a network of cycling tracks (190 cm) or lanes (80 cm). Main city roads were constructed at the beginning of the 20th century. Today, the lack of cycling tracks is particularly evident in terms of missing connections between northern and southern parts of the city. Transportation of bikes in public vehicles, parking of bikes as well as cycling along the foot of the mountains Medvednica and Zumberacko gorje is not adequately organized. Better organization is necessary not only because of the present young generation but also because of the young who will shortly become citizens of the EU, where cycling is enormously popular. Cycling tourism is not known in Zagreb, partly due to inadequate roads. The surroundings of Zagreb are more suitable for cycling tourism and attractive brochures and tourist guides offer information to tourists on bikes. Professional, acrobatic and sports cycling do not have a tradition in Zagreb and in Croatia. The same holds true for recreational cycling and indoor exercise cycling. The authors discuss the impact of popularization of cycling using print and electronic media. The role of district and local self-government in the construction and improvement of traffic roads in Zagreb is very important. It is also significant for the implementation of legal regulations that must be obeyed by all traffic participants in order to protect cyclists, the most vulnerable group of traffic participants besides passengers. Multidisciplinary action of all benevolent experts would surely increase safety and pleasure of cycling in the city and its surroundings. This would also help reduce daily stress and improve the quality of living in the capital of Croatia.

Inexperience and risky decisions of young adolescents, as pedestrians and cyclists, in interactions with lorries, and the effects of competency versus awareness education.

PubMed

Twisk, Divera; Vlakveld, Willem; Mesken, Jolieke; Shope, Jean T; Kok, Gerjo

2013-06-01

Road injuries are a prime cause of death in early adolescence. Often road safety education (RSE) is used to target risky road behaviour in this age group. These RSE programmes are frequently based on the assumption that deliberate risk taking rather than lack of competency underlies risk behaviour. This study tested the competency of 10-13 year olds, by examining their decisions - as pedestrians and cyclists - in dealing with blind spot areas around lorries. Also, the effects of an awareness programme and a competency programme on these decisions were evaluated. Table-top models were used, representing seven scenarios that differed in complexity: one basic scenario to test the identification of blind spot areas, and 6 traffic scenarios to test behaviour in traffic situations of low or high task complexity. Using a quasi-experimental design (pre-test and post-test reference group design without randomization), the programme effects were assessed by requiring participants (n=62) to show, for each table-top traffic scenario, how they would act if they were in that traffic situation. On the basic scenario, at pre-test 42% of the youngsters identified all blind spots correctly, but only 27% showed safe behaviour in simple scenarios and 5% in complex scenarios. The competency programme yielded improved performance on the basic scenario but not on the traffic scenarios, whereas the awareness programme did not result in any improvements. The correlation between improvements on the basic scenarios and the traffic scenarios was not significant. Young adolescents have not yet mastered the necessary skills for safe performance in simple and complex traffic situations, thus underlining the need for effective prevention programmes. RSE may improve the understanding of blind spot areas but this does not 'automatically' transfer to performance in traffic situations. Implications for the design of RSE are discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Influence of accurate and inaccurate 'split-time' feedback upon 10-mile time trial cycling performance.

PubMed

Wilson, Mathew G; Lane, Andy M; Beedie, Chris J; Farooq, Abdulaziz

2012-01-01

The objective of the study is to examine the impact of accurate and inaccurate 'split-time' feedback upon a 10-mile time trial (TT) performance and to quantify power output into a practically meaningful unit of variation. Seven well-trained cyclists completed four randomised bouts of a 10-mile TT on a SRM™ cycle ergometer. TTs were performed with (1) accurate performance feedback, (2) without performance feedback, (3) and (4) false negative and false positive 'split-time' feedback showing performance 5% slower or 5% faster than actual performance. There were no significant differences in completion time, average power output, heart rate or blood lactate between the four feedback conditions. There were significantly lower (p < 0.001) average [Formula: see text] (ml min(-1)) and [Formula: see text] (l min(-1)) scores in the false positive (3,485 ± 596; 119 ± 33) and accurate (3,471 ± 513; 117 ± 22) feedback conditions compared to the false negative (3,753 ± 410; 127 ± 27) and blind (3,772 ± 378; 124 ± 21) feedback conditions. Cyclists spent a greater amount of time in a '20 watt zone' 10 W either side of average power in the negative feedback condition (fastest) than the accurate feedback (slowest) condition (39.3 vs. 32.2%, p < 0.05). There were no significant differences in the 10-mile TT performance time between accurate and inaccurate feedback conditions, despite significantly lower average [Formula: see text] and [Formula: see text] scores in the false positive and accurate feedback conditions. Additionally, cycling with a small variation in power output (10 W either side of average power) produced the fastest TT. Further psycho-physiological research should examine the mechanism(s) why lower [Formula: see text] and [Formula: see text] scores are observed when cycling in a false positive or accurate feedback condition compared to a false negative or blind feedback condition.

Impact of intensified training and carbohydrate supplementation on immunity and markers of overreaching in highly trained cyclists.

PubMed

Svendsen, Ida S; Killer, Sophie C; Carter, James M; Randell, Rebecca K; Jeukendrup, Asker E; Gleeson, Michael

2016-05-01

To determine effects of intensified training (IT) and carbohydrate supplementation on overreaching and immunity. In a randomized, double-blind, crossover design, 13 male cyclists (age 25 ± 6 years, VO2max 72 ± 5 ml/kg/min) completed two 8-day periods of IT. On one occasion, participants ingested 2 % carbohydrate (L-CHO) beverages before, during and after training sessions. On the second occasion, 6 % carbohydrate (H-CHO) solutions were ingested before, during and after training, with the addition of 20 g of protein in the post-exercise beverage. Blood samples were collected before and immediately after incremental exercise to fatigue on days 1 and 9. In both trials, IT resulted in decreased peak power (375 ± 37 vs. 391 ± 37 W, P < 0.001), maximal heart rate (179 ± 8 vs. 190 ± 10 bpm, P < 0.001) and haematocrit (39 ± 2 vs. 42 ± 2 %, P < 0.001), and increased plasma volume (P < 0.001). Resting plasma cortisol increased while plasma ACTH decreased following IT (P < 0.05), with no between-trial differences. Following IT, antigen-stimulated whole blood culture production of IL-1α was higher in L-CHO than H-CHO (0.70 (95 % CI 0.52-0.95) pg/ml versus 0.33 (0.24-0.45) pg/ml, P < 0.01), as was production of IL-1β (9.3 (95 % CI 7-10.4) pg/ml versus 6.0 (5.0-7.8) pg/ml, P < 0.05). Circulating total leukocytes (P < 0.05) and neutrophils (P < 0.01) at rest increased following IT, as did neutrophil:lymphocyte ratio and percentage CD4+ lymphocytes (P < 0.05), with no between-trial differences. IT resulted in symptoms consistent with overreaching, although immunological changes were modest. Higher carbohydrate intake was not able to alleviate physiological/immunological disturbances.

Current hydration guidelines are erroneous: dehydration does not impair exercise performance in the heat.

PubMed

Wall, Bradley A; Watson, Greig; Peiffer, Jeremiah J; Abbiss, Chris R; Siegel, Rodney; Laursen, Paul B

2015-08-01

Laboratory studies that support the hydration guidelines of leading governing bodies have shown that dehydration to only -2% of body mass can lead to increase in body temperature and heart rate during exercise, and decrease in performance. These studies, however, have been conducted in relatively windless environments (ie, wind speed <12.9 km/h), without participants being blinded to their hydration status. To investigate the effect of blinded hydration status on cycling time-trial performance in the heat with ecologically valid facing wind speed conditions. During three experimental trials, 10 cyclists were dehydrated to -3% body mass by performing 2 h of submaximal exercise (walking and cycling) in the heat, before being reinfused with saline to replace 100%, 33% or 0% of fluid losses, leaving them 0%, -2% or -3% hypohydrated, respectively. Participants then completed a 25 km time trial in the heat (33°C, 40% relative humidity; wind speed 32 km/h) during which their starting hydration status was maintained by infusing saline at a rate equal to their sweat rate. The treatment was participant-blinded and the order was randomised. Completion time, power output, heart rate, rectal temperature and perceptual variables were measured. While rectal temperature was higher beyond 17 km of the time trial in the -3% vs 0% conditions (38.9±0.3°C vs 38.6±0.3°C; p<0.05), no other differences between trials were shown. When well-trained cyclists performed a 25 km cycling time trial under ecologically valid conditions and were blinded to their hydration status, performance, physiological and perceptual variables were not different between trials. These data do not support the residing basis behind many of the current hydration guidelines. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Dose effects of New Zealand blackcurrant on substrate oxidation and physiological responses during prolonged cycling.

PubMed

Cook, Matthew David; Myers, Stephen David; Gault, Mandy Lucinda; Edwards, Victoria Charlotte; Willems, Mark Elisabeth Theodorus

2017-06-01

It has been previously shown that New Zealand blackcurrant (NZBC) extract increased fat oxidation during short duration cycling. The present study examined the effect of different doses of NZBC extract on substrate oxidation and physiological responses during prolonged cycling. Using a randomized counterbalanced Latin-square design, 15 endurance-trained male cyclists (age: 38 ± 12 years, height: 187 ± 5 cm, body mass: 76 ± 10 kg, [Formula: see text]: 56 ± 8 mL kg -1  min -1 , and mean ± SD) completed four separate 120-min cycling bouts at 65% [Formula: see text] after ingesting no dose, or one of three doses (300, 600, or 900 mg day -1 ) of NZBC extract (CurraNZ™) for 7 days. A dose effect (P < 0.05) was observed for average fat oxidation (0, 300, 600, and 900 mg day -1 values of 0.63 ± 0.21, 0.70 ± 0.17, 0.73 ± 0.19, and 0.73 ± 0.14 g min -1 ) and carbohydrate oxidation (0, 300, 600, and 900 mg day -1 values of 1.78 ± 0.51, 1.65 ± 0.48, 1.57 ± 0.44, and 1.56 ± 0.50 g min -1 ). The individual percentage change of mean fat oxidation was 21.5 and 24.1% for 600 and 900 mg day -1 NZBC extract, respectively, compared to no dose. Heart rate, [Formula: see text], [Formula: see text], plasma lactate, and glucose were not affected. Seven-day intake of New Zealand blackcurrant extract demonstrated a dose-dependent effect on increasing fat oxidation during 120-min cycling at 65% [Formula: see text] in endurance-trained male cyclists.

Comparison between whole-body vibration, light-emitting diode, and cycling warm-up on high-intensity physical performance during sprint bicycle exercise.

PubMed

Teles, Maria C; Fonseca, Ivana A T; Martins, Jeanne B; de Carvalho, Marielle M; Xavier, Murilo; Costa, Sidney J; de Avelar, Núbia C P; Ribeiro, Vanessa G C; Salvador, Fabiano S; Augusto, Leonardo; Mendonça, Vanessa A; Lacerda, Ana C R

2015-06-01

The purpose of this study was to compare the effects of light-emitting diode (LED) irradiation and whole-body vibration (WBV) delivered either in isolation or combination (LED + WBV), warm-up (WU), and a control (C) treatment on performance during a sprint bicycle exercise. Ten cyclists performed a 30-second sprint cycle test under these conditions. The LED light was applied at 4 points bilaterally. Whole-body vibration consisted of 5 minutes of squats associated with WBV. LED + WBV consisted of WBV followed by LED therapy. Warm-up consisted of 17 minutes of moderate-intensity bicycle exercise. Control consisted of 10 minutes at rest. Blood lactate (BL) and ammonia (BA) levels and skin temperature (ST) were determined. Peak power (842 ± 117 vs. 800 ± 106 vs. 809 ± 128 W [p = 0.02 and p = 0.01]), relative power (12.1 ± 1.0 vs. 11.5 ± 0.9 vs. 11.6 ± 1.0 W·kg [p = 0.02 and p = 0.02]), and relative work (277 ± 23 vs. 263 ± 24 vs. 260 ± 23 J·kg [p = 0.02 and p = 0.003]) were higher in the WU group compared with the control and LED groups. In the LED + WBV group, peak (833 ± 115 vs. 800 ± 106 W [p = 0.02]) and relative (11.9 ± 0.9 vs. 11.5 ± 0.9 W·kg [p = 0.02]) power were higher than those in the control group, and relative work (272 ± 22 vs. 260 ± 23 J·kg [p = 0.02]) were improved compared with the LED group. There were no differences for BL, BA, and ST. The findings of this study confirmed the effectiveness of a warm-up as a preparatory activity and demonstrated that LED + WBV and WBV were as effective as WU in improving cyclist performance during a sprint bicycle exercise.

Genitourinary injuries after traffic accidents: Analysis of a registry of 162,690 victims.

PubMed

Terrier, Jean-Etienne; Paparel, Philippe; Gadegbeku, Blandine; Ruffion, Alain; Jenkins, Lawrence C; N'Diaye, Amina

2017-06-01

Traffic accidents are the most frequent cause of genitourinary injuries (GUI). Kidney injuries after trauma have been well described. However, there exists a paucity of data on other traumatic GUI after traffic accidents. The objective of this study was to analyze the frequency and type of all GUI, by user category, after traffic accidents. Patient cases were extracted from the trauma registry of the French department of Rhone from 1996 to 2013. We assessed the urogenital injuries presented by each of road user's categories. Severity injuries were coded with the Abbreviated Injury Scale and the Injury Severity Score. Kidney trauma was mapped with the classification of the American Association for the Surgery of Trauma. Multivariate prediction models were used for analysis of data. Of 162,690 victims, 963 presented with GUI (0.59%). 47% were motorcyclists, 22% were in a car, 18% on bicycles, and 9% were pedestrians. The most common organ injury was kidney (41%) followed by testicular (23%). Among the 208 motorists with a GUI, kidney (70%), bladder (10%), and adrenal gland (9%) were the most frequent lesions. Among the 453 motorcyclist victims with GUI, kidney (35%) and testicular (38%) traumas were the most frequent and 62% of injuries involved external genitalia. There were 175 cyclists with GUI, 70% of injuries involved external genitalia; penile traumas (23%) were the most frequent. In total, there were 395 kidney injuries, most being low grade. According to the American Association for the Surgery of Trauma kidney injuries were grade I, 59%; grade II, 11%; grade III, 16%; grade IV, 9%; grade V, 3%; and indeterminate, 2%. GUI is an infrequent trauma after traffic accidents, with kidneys being the most commonly injured. Physicians must maintain a high awareness for external genitalia injuries in motorcyclists and cyclists. Prognostic and epidemiologic study, level III.