A Demand-Centric Repositioning Strategy for Bike-Sharing Systems.

Transport-sharing systems are eco-friendly and the most promising services in smart urban environments, where the booming Internet of things (IoT) technologies play an important role in the smart infrastructure. Due to the imbalanced bike distribution, bikes and stalls in the docking stations could be unavailable when needed, leading to bad customer experiences. We develop a dynamic repositioning strategy for the management of bikes in this paper, which supports dispatchers to keep stations in service. Two open datasets are examined, and the exploratory data analysis presents that there is a significant difference of travel patterns between working and non-working days, where the former has an excess demand at rush hours and the latter is usually at a low demand. To evaluate the effect when the demand outstrips a station's capacity, we propose a non-linear scaling technique to transform demand patterns and perform the clustering analysis for each of five categories obtained from the sophisticated analysis of the dataset. Our repositioning strategy is developed according to the transformed demands. Compared with the previous work, numerical simulations reveal that our strategy has a better performance for high-demand stations, and thus can substantially reduce the repositioning cost, which brings benefit to bike-sharing operators for managing the city bike system.

A Role for Trunk Function in Elite Recumbent Handcycling Performance?

Handcycling classification considers trunk function, but there is limited scientific evidence of trunk involvement in recumbent performance. This study investigated the association between trunk function and recumbent handcycling performance of athletes without upper-limb impairments (H3-H4 sport classes). The study was divided into two parts. First, 528 time-trial results from 81 handcyclists with spinal cord injury (SCI) were obtained between 2014 and 2020. Average time-trial velocity was used as performance measure and SCI level as trunk function determinant. Multilevel regression analysis was performed to analyse differences in performance among SCI groups while correcting for lesion completeness, sex, and age. Second, in 26 handcyclists, standardised trunk flexion strength was measured with a handheld dynamometer. Peak and mean power-output from a sprint test and time-trial average velocity were used as performance measures. Spearman correlations were conducted to investigate the association between trunk strength and performance. Results showed that the different SCI groups did not exhibit significant differences in performance. Furthermore, trunk flexion strength and performance exhibited non-significant weak to moderate correlations (for time-trial speed: rs = 0.36; p = 0.07). Results of both analyses suggest that trunk flexion strength does not seem to significantly impact recumbent handcycling performance in athletes without upper-limb impairments.

Enduro World Series (EWS) Mountain Biking Injuries: A 2-year Prospective Study of 2010 Riders.

The sport of Enduro is the newest International Cycling Union sanctioned discipline in mountain biking. There are a number of studies reporting mountain biking injury to date however there are none detailing injuries in Enduro. The aim of the present study was to determine the rate, severity and nature of rider injury during the Enduro World Series. Rider injury, and race and practice exposure data were recorded prospectively during 10 events across the 2017 and 2018 seasons. Incorporating 2010 riders (males 90%; females 10%) from 46 countries. 8.9% of riders were injured with mean 12.3 days time-loss per injury. Racing injury incidence was 38.3/1000 hours and practice injury incidence 3.6/1000 hours (p=0.01). The shoulder/clavicle (12.8% of all injuries), hand (9.0%) and head (9.0%) were the most injured locations. Concussion injury was the most frequent diagnosis (7.4%), and shoulder/clavicle fractures caused the greatest burden (442 total days lost). Of those with concussion 28.6% continued racing, and 42.9% reported no time-loss (i. e. time off) post-race. In conclusion, the rate of injury during EWS race events was comparable to Downhill racing. Targeted injury prevention strategies around rider concussion education and rider qualification criteria may help to reduce the risk of injury in Enduro.

Demands of professional cycling races: Influence of race category and result.

This study analyses the influence of race category and result on the demands of professional cycling races. In total, 2920 race files were collected from 20 male professional cyclists, within a variety of race categories: Single-day (1.WT) and multi-day (2.WT) World Tour races, single-day (1.HC) and multi-day (2.HC) Hors Catégorie races and single-day (1.1) and multi-day (2.1) category 1 races. Additionally, the five cycling "monuments" were analysed separately. Maximal mean power outputs (MMP) were measured across a broad range of durations. Volume and load were large to very largely (d = 1.30-4.80) higher in monuments compared to other single-day race categories. Trivial to small differences were observed for most intensity measures between different single-day race categories, with only RPE and sRPE·km-1 being moderately (d = 0.70-1.50) higher in the monuments. Distance and duration were small to moderately (d = 0.20-0.80) higher in 2.WT races compared to 2.HC and 2.1 multi-day race categories with only small differences in terms of load and intensity. Generally, higher ranked races (i.e. Monuments, 2.WT and GT) tend to present with lower shorter-duration MMPs (e.g. 5-120 sec) compared to races of "lower rank" (with less differences and/or mixed results being present over longer durations), potentially caused by a "blunting" effect of the higher race duration and load of higher ranked races on short duration MMPs. MMP were small to largely higher over shorter durations (<5 min) for a top-10 result compared to no top-10, within the same category.

Muscle Typology of World-Class Cyclists across Various Disciplines and Events.

PURPOSE: Classic track-and-field studies demonstrated that elite endurance athletes exhibit a slow muscle typology, whereas elite sprint athletes have a predominant fast muscle typology. In elite cycling, conclusive data on muscle typology are scarce, which may be due to the invasive nature of muscle biopsies. The noninvasive estimation of muscle typology through the measurement of muscle carnosine enabled to explore the muscle typology of 80 world-class cyclists of different disciplines. METHODS: The muscle carnosine content of 80 cyclists (4 bicycle motor cross racing [BMX], 33 track, 8 cyclo-cross, 24 road, and 11 mountain bike) was measured in the soleus and gastrocnemius by proton magnetic resonance spectroscopy and expressed as a z-score relative to a reference population. Track cyclists were divided into track sprint and endurance cyclists based on their Union Cycliste Internationale (UCI) ranking. Moreover, road cyclists were further characterized based on the percentage of UCI points earned during either single and multistage races. RESULTS: BMX cyclists (carnosine aggregate z-score of 1.33) are characterized by a faster muscle typology than track, cyclo-cross, road, and mountain bike cyclists (carnosine aggregate z-score of -0.08, -0.76, -0.96, and -1.02, respectively; P < 0.05). Track cyclists also possess a faster muscle typology compared with mountain bikers (P = 0.033) and road cyclists (P = 0.005). Moreover, track sprinters show a significant faster muscle typology (carnosine aggregate z-score of 0.87) compared with track endurance cyclists (carnosine aggregate z-score of -0.44) (P < 0.001). In road cyclists, the higher the carnosine aggregate z-score, the higher the percentage of UCI points gained during single-stage races (r = 0.517, P = 0.010). CONCLUSIONS: Prominent differences in the noninvasively determined muscle typology exist between elite cyclists of various disciplines, which opens opportunities for application in talent orientation and transfer.

Do Handcycling Time-Trial Velocities Achieved by Para-Cycling Athletes Vary Across Handcycling Classes?

The classification system for handcycling groups athletes into five hierarchical classes, based on how much their impairment affects performance. Athletes in class H5, with the least impairments, compete in a kneeling position, while athletes in classes H1 to H4 compete in a recumbent position. This study investigated the average time-trial velocity of athletes in different classes. A total of 1,807 results from 353 athletes who competed at 20 international competitions (2014-2018) were analyzed. Multilevel regression was performed to analyze differences in average velocities between adjacent pairs of classes, while correcting for gender, age, and event distance. The average velocity of adjacent classes was significantly different (p < .01), with higher classes being faster, except for H4 and H5. However, the effect size of the differences between H3 and H4 was smaller (d = 0.12). Hence, results indicated a need for research in evaluating and developing evidence-based classification in handcycling, yielding a class structure with meaningful performance differences between adjacent classes.

Automatic Identification of Physical Activity Type and Duration by Wearable Activity Trackers: A Validation Study.

BACKGROUND: Activity trackers are now ubiquitous in certain populations, with potential applications for health promotion and monitoring and chronic disease management. Understanding the accuracy of this technology is critical to the appropriate and productive use of wearables in health research. Although other peer-reviewed validations have examined other features (eg, steps and heart rate), no published studies to date have addressed the accuracy of automatic activity type detection and duration accuracy in wearable trackers. OBJECTIVE: The aim of this study was to examine the ability of 4 commercially available wearable activity trackers (Fitbits Flex 2, Fitbit Alta HR, Fitbit Charge 2, and Garmin Vívosmart HR), in a controlled setting, to correctly and automatically identify the type and duration of the physical activity being performed. METHODS: A total of 8 activity types, including walking and running (on both a treadmill and outdoors), a run embedded in walking bouts, elliptical use, outdoor biking, and pool lap swimming, were tested by 28 to 34 healthy adult participants (69 total participants who participated in some to all activity types). Actual activity type and duration were recorded by study personnel and compared with tracker data using descriptive statistics and mean absolute percent error (MAPE). RESULTS: The proportion of trials in which the activity type was correctly identified was 93% to 97% (depending on the tracker) for treadmill walking, 93% to 100% for treadmill running, 36% to 62% for treadmill running when preceded and followed by a walk, 97% to 100% for outdoor walking, 100% for outdoor running, 3% to 97% for using an elliptical, 44% to 97% for biking, and 87.5% for swimming. When activities were correctly identified, the MAPE of the detected duration versus the actual activity duration was between 7% and 7.9% for treadmill walking, 8.7% and 144.8% for treadmill running, 23.6% and 28.9% for treadmill running when preceded and followed by a walk, 4.9% and 11.8% for outdoor walking, 5.6% and 9.6% for outdoor running, 9.7% and 13% for using an elliptical, 9.5% and 17.7% for biking, and was 26.9% for swimming. CONCLUSIONS: In a controlled setting, wearable activity trackers provide accurate recognition of the type of some common physical activities, especially outdoor walking and running and walking on a treadmill. The accuracy of measurement of activity duration varied considerably by activity type and tracker model and was poor for complex sets of activity, such as a run embedded within 2 walking segments.

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

BACKGROUND: 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 riders (N.=21), hill riders (N.=35), or sprinters (N.=20) and obtain the multivariate model for further cyclists classification by specialties, based on selected variables. METHODS: Seventeen variables were measured at submaximal and maximum load on the cycle ergometer Cosmed E 400HK (Cosmed, Rome, Italy) (initial 100 W with 25-W 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. RESULTS: 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. CONCLUSIONS: Respiratory indicators mostly contribute to the discriminant power of the model, which may significantly contribute to training practice and laboratory tests in future.

Bioimpedance patterns and bioelectrical impedance vector analysis (BIVA) of road cyclists.

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

The categorization of amateur cyclists as research participants: findings from an observational study.

Sampling bias is an issue for research involving cyclists. The heterogeneity of cyclist populations, on the basis of skill level and riding purpose, can generate incorrect inferences about one specific segment of the population of interest. In addition, a more accurate categorization would be helpful when physiological parameters are not available. This study proposes using self-reported data to categorize amateur cyclist types by varying skill levels and riding purposes, therefore improving sample selection in experimental studies. A total of 986 cyclists completed an online questionnaire between February and October 2016. Two-step cluster analyses were performed to generate distinct groups, and dependent variables of these groups were compared (demographics and characteristics of cycling practice). The cluster analysis relied on 4 descriptors (cycling weekly volume, average cycling speed, riding purpose, and cycling discipline) and yielded five distinct groups: competitive road, recreational road, competitive mountain bike (MTB), recreational MTB and competitive triathlon. Among these groups, averages and distributions for age, height, body mass, body mass index, training volume and intensity, and years of experience varied. This categorization can potentially help researchers recruit specific groups of cyclists based upon self-reported data and therefore better align the sample characteristic with the research aims.

Improvements in Cycling but Not Handcycling 10 km Time Trial Performance in Habitual Caffeine Users.

Caffeine supplementation during whole-/lower-body exercise is well-researched, yet evidence of its effect during upper-body exercise is equivocal. The current study explored the effects of caffeine on cycling/handcycling 10 km time trial (TT) performance in habitual caffeine users. Eleven recreationally trained males (mean (SD) age 24 (4) years, body mass 85.1 (14.6) kg, cycling/handcycling peak oxygen uptake ( V · peak) 42.9 (7.3)/27.6 (5.1) mL∙kg∙min(-1), 160 (168) mg/day caffeine consumption) completed two maximal incremental tests and two familiarization sessions. During four subsequent visits, participants cycled/handcycled for 30 min at 65% mode-specific V · peak (preload) followed by a 10 km TT following the ingestion of 4 mg∙kg(-1) caffeine (CAF) or placebo (PLA). Caffeine significantly improved cycling (2.0 (2.0)%; 16:35 vs. 16:56 min; p = 0.033) but not handcycling (1.8 (3.0)%; 24:10 vs. 24:36 min; p = 0.153) TT performance compared to PLA. The improvement during cycling can be attributed to the increased power output during the first and last 2 km during CAF. Higher blood lactate concentration (Bla) was reported during CAF compared to PLA (p < 0.007) and was evident 5 min post-TT during cycling (11.2 ± 2.6 and 8.8 ± 3.2 mmol/L; p = 0.001) and handcycling (10.6 ± 2.5 and 9.2 ± 2.9 mmol/L; p = 0.006). Lower overall ratings of perceived exertion (RPE) were seen following CAF during the preload (p < 0.05) but not post-TT. Lower peripheral RPE were reported at 20 min during cycling and at 30 min during handcycling, and lower central RPE was seen at 30 min during cycling (p < 0.05). Caffeine improved cycling but not handcycling TT performance. The lack of improvement during handcycling may be due to the smaller active muscle mass, elevated (Bla) and/or participants' training status.

Percepción subjetiva del esfuerzo como herramienta en el control de la intensidad en la actividad de ciclismo indoor / Rating of perceived exertion as a tool to control intensity in indoor cycling activity / Percepção subjectiva do esforço como ferramenta de controlo da intensisdade da actividade de ciclismo indoor

One hundred and thirty-three subjects between 22 and 64 years old (38 males and 95 females) from a private sport centre participated in this study. Mean percentage heart rate intensity (%HRR) and overall ratings of perceived exertion (RPE) were measured during an indoor cycling session. Mean %HRR and RPE shown during the main phase were considered as high intensity in male and females. The correlation value between %HHR and overall RPE was low but significant. In conclusion, indoor cycling is a high-intensity activity. Borg’s RPE is not a valid instrument for controlling the intensity of effort during indoor cycling activity

A un total de 133 sujetos entre 22 y 64 años (38 hombres y 95 mujeres) pertenecientes a un centro deportivo privado, se les evaluó el porcentaje de la intensidad de la frecuencia cardiaca de reserva (%FCR) alcanzada y la percepción subjetiva del esfuerzo (RPE) durante una sesión real de ciclismo indoor. La intensidad media alcanzada y la RPE manifestada en la fase principal fue alta, tanto en hombres como en mujeres. Se encontró una significativa y baja correlación entre la RPE y la FC media de reserva obtenida en la fase principal de la sesión. En conclusión, el ciclismo indoor es unaactividad de alta intensidad. La RPE de Borg no es un instrumento válido para el control de la intensidad en esta actividad

um total de 133 sujeitos entre 22 e 64 anos (38 homens e 95 mulheres) pertencentes a um centro desportivo privado, foi avaliada a percen-tagem da intensidade da frequência cardíaca de reserva (%FCR) alcançada e a percepção subjectiva do esforço (RPE) durante uma sessão real de ciclismoindoor. A intensidade média alcançada e a RPE manifestada na fase principal foi alta, tanto em homens como em mulheres. Foi verificada uma significativae baixa correlação entre a RPE e a FC medida de reserva obtida na fase principal da sessão. Em conclusão, o ciclismo indooré uma actividade de altaintensidade. A RPE de Borg não é um instrumento válido para o controlo da intensidade nesta actividade

Consumo de oxigênio durante ciclismo na máxima fase estável de lactato sanguíneo até a exaustão: modelo contínuo vs. intermitente / Consumo de oxígeno durante ciclismo en la máxima fase estable de lactato sanguíneo hasta el agotamiento: modelo continuo vs. intermitente / Oxygen uptake during cycling at maximal lactate steady state to exhaustion: continuous vs. intermittent model

Objetivo. Analisar o consumo de oxigênio (VO2) acumulado e o tempo em que o VO2 é mantido (TMcg) em elevados valores durante o exercício realizado na máxima fase estável de lactato (MLSS) determinada de forma contínua (MLSScon) e intermitente (MLSSint) até à exaustão. Método. Catorze ciclistas treinados realizaram um teste incremental máximo no cicloergômetro; 2‐5 testes contínuos e 2‐4 testes intermitentes, para determinação da MLSScon e MLSSint, respectivamente; por fim mais 2 testes até a exaustão (TTE) (contínuo e intermitente), conduzidos nas respectivas cargas de MLSS. Resultados. O TTE contínuo foi significativamente menor do que o TTE intermitente (54,7 ± 10,9 vs. 67,8 ± 14,3, respectivamente; p = 0,001). O VO2 da carga (VO2cg) foi significantemente maior na condição intermitente (p < 0,05), em ambas as situações (MLSS e TTE). Por outro lado, o TMcg e o VO2 acumulado na carga (VO2ACcg) foram maiores na condição contínua (p < 0,0001), em ambas as situações. O total de VO2 acumulado (VO2ACt) foi similar entre as condições contínuas e intermitentes (104,7 ± 8,7 L vs. 103,9 ± 41,1 L para a MLSS e 193,8 ± 41,1 L vs. 226,4 ± 53,0 L para o TTE, respectivamente). Conclusão. Os exercícios contínuo e intermitente realizados com a mesma duração ou até a exaustão, e em condições metabólicas similares, apresentam valores de VO2ACt similares, embora o TMcg e o VO2ACcg sejam inferiores no exercício intermitente (AU)

Objetivo. Analizar el consumo de oxígeno (VO2) acumulado y el tiempo en que el VO2 es mantenido (TMcg) en valores elevados, durante el ejercicio realizado en la máxima fase estable de lactato (MLSS), determinada de forma continua (MLSScon) e intermitente (MLSSint) hasta el agotamiento. Método. Catorce ciclistas entrenados realizaron un test incremental máximo en el cicloergómetro; 2‐5 test continuos y 2‐4 test intermitentes, para determinación de la MLSScon y MLSSint, respectivamente; por último realizaron 2 test hasta el agotamiento (TTE) (continuo e intermitente), a las respectivas cargas de MLSS. Resultados. El TTE continuo fue significativamente menor que el TTE intermitente (54,7 ± 10,9 vs. 67,8 ± 14,3, respectivamente; p = 0,001). El VO2 de la carga (VO2cg) fue significativamente mayor en la condición intermitente (p < 0,05), en ambas situaciones (MLSS y TTE). Por otro lado, el TMcg y el VO2 acumulado en la carga (VO2ACcg) fueron mayores en la condición continua (p < 0,0001), en ambas las situaciones. El total de VO2 acumulado (VO2ACt) fue similar entre las condiciones continuas e intermitentes (104,7 ± 8,7 L vs. 103,9 ± 41,1 L para a MLSS y 193,8 ± 44,1 L vs. 226,4 ± 53,0 L para el TTE, respectivamente). Conclusión. Los ejercicios continuo e intermitente realizados con la misma duración o hasta el agotamiento, y en condiciones metabólicas similares presentan valores de VO2ACt similares, aunque el TMcg y el VO2ACcg sean inferiores en el ejercicio intermitente (AU)

Objective. The aim of this study was to analyse the accumulated oxygen uptake (VO2), as well the maintained time (TMcg) at high levels during a maximal lactate steady state (MLSS) exercise, determined in continuous (MLSScon) and intermittent (MLSSint) modes, until exhaustion. Method. Fourteen trained cyclists performed an incremental maximal testing; 2‐5 continuous and 2‐4 intermittent constant workload trials, in order to identify the MLSScon and MLSSint, respectively; two tests until exhaustion (TTE) (continuous and intermittent) were conducted using their respective MLSS workloads. Results. The continuous TTE was significantly lower than TTE at intermittent protocol (54.7 ± 10.9 vs. 67.8 ± 14.3 min; p = 0.001). The VO2 at target workload (VO2cg) was higher at intermittent exercise (p < 0.05), at both situations (MLSS and TTE). On the other hand, TMcg and the VO2 accumulated in MLSS workloads (VO2ACcg) were higher during continuous mode (p < 0.0001), at both situations. The total VO2 accumulated (VO2ACt) was similar between intermittent and continuous cycling (MLSS: 104.7 ± 8.7 L vs. 103.9 ± 41.1 L and TTE: 193.8 ± 41.1 L vs. 226.4 ± 53.0 L, respectively). Conclusion. When MLSS continuous and intermittent were performed with same duration or until exhaustion, the VO2ACt was similar, although the TMcg and VO2ACcg were smaller during intermittent exercise (AU)

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

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.

Neighborhood disadvantage and physical activity: baseline results from the HABITAT multilevel longitudinal study.

PURPOSE: To examine the association between neighborhood disadvantage and physical activity (PA). METHODS: We use data from the HABITAT multilevel longitudinal study of PA among middle-aged (40-65 years) men and women (N = 11,037, 68.5% response rate) living in 200 neighborhoods in Brisbane, Australia. PA was measured using three questions from the Active Australia Survey (general walking, moderate, and vigorous activity), one indicator of total activity, and two questions about walking and cycling for transport. The PA measures were operationalized by using multiple categories based on time and estimated energy expenditure that were interpretable with reference to the latest PA recommendations. The association between neighborhood disadvantage and PA was examined with the use of multilevel multinomial logistic regression and Markov chain Monte Carlo simulation. The contribution of neighborhood disadvantage to between-neighborhood variation in PA was assessed using the 80% interval odds ratio. RESULTS: After adjustment for sex, age, living arrangement, education, occupation, and household income, reported participation in all measures and levels of PA varied significantly across Brisbane's neighborhoods, and neighborhood disadvantage accounted for some of this variation. Residents of advantaged neighborhoods reported significantly higher levels of total activity, general walking, moderate, and vigorous activity; however, they were less likely to walk for transport. There was no statistically significant association between neighborhood disadvantage and cycling for transport. In terms of total PA, residents of advantaged neighborhoods were more likely to exceed PA recommendations. CONCLUSIONS: Neighborhoods may exert a contextual effect on the likelihood of residents participating in PA. The greater propensity of residents in advantaged neighborhoods to do high levels of total PA may contribute to lower rates of cardiovascular disease and obesity in these areas.

Physiological differences of elite and professional road cyclists related to competition level and rider specialization.

AIM: The aim of this investigation was to study the physiological response to laboratory tests in elite and professional cyclists, and to relate it to the level at which riders compete and their specialization. METHODS: A total of 71 cyclists were divided into two groups, elite and professional, and were assessed for physical measurements, a maximal graded test and a 30 s all-out test, both performed on a cycle ergometer. The sample included 24 uphill riders (UR), 32 flat terrain riders (FTR), 11 all terrain riders (ATR) and 4 sprinters (SP). RESULTS: Professional riders showed significantly higher gross mechanical efficiency (GME) than their elite counterparts (25.6+/-2.6 vs 24.4+/-2%), but otherwise no other physiological differences emerged from the comparison between these two groups. However, many differences exist as a function of rider specialization, especially between UR and FTR. Compared with FTR, UR showed a higher VO2max (78.2+/-5.5 vs 72.6+/-6.5 mL x min(-1) x kg(-1)) and a lower maximal aerobic power (438.5+/-40.8 vs 465.3+/-36.2 W). From the 30 s all-out test, SP presents the highest maximal power (P < 0.05) and maximal velocity (P < 0.05) compared with all the other groups. CONCLUSIONS: The results for GME indicate a better efficiency for professional riders and suggest the importance of technical aspects related to movement pattern in cycling. The sensitivity of the maximal graded test and the 30 s all-out test did not allowed other differentiations between elite and professional cyclists.

Cardiac responses to progressive upright exercise in adult male cyclists.

AIM: Previous investigations have indicated that maximal stroke volume is the primary factor which differentiates physiological aerobic fitness (VO2max) in endurance athletes from nonathletes. Understanding the pattern of stroke volume response to progressive exercise may provide insights into the mechanisms which are responsible for this difference. METHODS: Doppler echocardiography was used to estimate stroke volume changes with maximal upright cycle exercise in 8 highly trained adult cyclists (mean age 30.5+/-1.6 years) and 16 age-matched nontrained males. Ventricular dimensions were measured during exercise using 2-dimensional echocardiography (parastemal long axis view). Findings were compared to a group of untrained adult male subjects. RESULTS: Mean maximal oxygen uptake was 73.7+/-7.0 and 47.4+/-7.5 ml x kg(-1) x min(-1) in the 2 groups, respectively. Stroke volume rose in both the cyclists and nontrained subjects at the onset of exercise but then plateaued without significant change to exhaustion. Values for stroke index were significantly greater at rest and all levels of exercise in the cyclists (maximal 85+/-13 versus 61+/-13 ml x m(-2)). Two dimensional echocardiograms during exercise in the cyclists revealed a small initial rise in left ventricular end-diastolic dimension and then a small decline, while systolic dimension decreased progressively, resulting in a rise in shortening fraction. CONCLUSION: These findings are consistent with the concept that determinants of stroke volume at rest are most influential in defining differences in maximal stroke volume between athletes and nonathletes.

Ulnar and median nerve palsy in long-distance cyclists. A prospective study.

BACKGROUND: Although case reports have identified the presence of distal ulnar nerve sensory and motor dysfunction in long-distance cyclists, the actual incidence of this condition, referred to as "cyclist's palsy," is unknown. PURPOSE: To determine the incidence of distal ulnar nerve compression in cyclists. STUDY DESIGN: Prospective study. METHODS: Twenty-five road or mountain bike riders responded to a questionnaire and were then physically examined and interviewed before and after a 600-km bicycle ride. RESULTS: Twenty-three of the 25 cyclists experienced either motor or sensory symptoms, or both. Motor symptoms alone occurred in 36% of the hands (11 cyclists) tested; no significant difference in the incidence of motor symptoms was found among cyclists of various experience levels or based on handlebar types (mountain bike versus road bike). Sensory symptoms alone occurred in 10% of hands (four cyclists) tested, with the majority of these being in the ulnar distribution. A significantly higher proportion of mountain bike riders had sensory deficits compared with road bike riders; however, there was no significant difference in the occurrence of sensory deficits based on level of experience. A total of 24% of the hands (eight cyclists) tested experienced a combination of motor and sensory symptoms. These motor and sensory symptoms were equally distributed between road bike riders and mountain bike riders and riders of various experience levels. CONCLUSIONS: Cyclist's palsy occurs at high rates in both experienced and inexperienced cylists. Steps may be taken to decrease the incidence of cyclist's palsy; these include wearing cycling gloves, ensuring proper bicycle fit, and frequently changing hand position.