A direct collocation framework for optimal control simulation of pedaling using OpenSim.

The direct collocation (DC) method has shown low computational costs in solving optimization problems in human movements, but it has rarely been used for solving optimal control pedaling problems. Thus, the aim of this study was to develop a DC framework for optimal control simulation of human pedaling within the OpenSim modeling environment. A planar bicycle-rider model was developed in OpenSim. The DC method was formulated in MATLAB to solve an optimal control pedaling problem using a data tracking approach. Using the developed DC framework, the optimal control pedaling problem was successfully solved in 24 minutes to ten hours with different objective function weightings and number of nodes from two different initial conditions. The optimal solutions for equal objective function weightings were successful in terms of tracking, with the model simulated pedal angles and pedal forces within ±1 standard deviation of the experimental data. With these weightings, muscle tendon unit (MTU) excitation patterns generally matched with burst timings and shapes observed in the experimental EMG data. Tracking quality and MTU excitation patterns were changed little by selection of node density above 31, and the optimal solution quality was not affected by initial guess used. The proposed DC framework could easily be turned into a predictive simulation with other objective functions such as fastest pedaling rate. This flexible and computationally efficient framework should facilitate the use of optimal control methods to study the biomechanics, energetics, and control of human pedaling.

Provisional COVID-19 infrastructure induces large, rapid increases in cycling.

The bicycle is a low-cost means of transport linked to low risk of transmission of infectious disease. During the COVID-19 crisis, governments have therefore incentivized cycling by provisionally redistributing street space. We evaluate the impact of this new bicycle infrastructure on cycling traffic using a generalized difference in differences design. We scrape daily bicycle counts from 736 bicycle counters in 106 European cities. We combine these with data on announced and completed pop-up bike lane road work projects. Within 4 mo, an average of 11.5 km of provisional pop-up bike lanes have been built per city and the policy has increased cycling between 11 and 48% on average. We calculate that the new infrastructure will generate between $1 and $7 billion in health benefits per year if cycling habits are sticky.

A Scoping Review of Bikeability Assessment Methods.

Bicycling holds promise as a healthy and sustainable means of transportation and physical activity. Despite the growing interest in community-based environmental approaches to promoting physical activity, bikeability has received relatively little attention. This paper provides a scoping review of the instruments developed to measure bikeability along with practice-based analyses of the tools related to user expertise, estimated cost, and required time to implement. The review summarizes the literature, identifies research gaps, and informs stakeholders with articles from EBSCO and transportation databases published after 2003 when the previous bikeability instrument review paper was published. Data extraction included the tool name, data collection method, study location, data collection scale, type of measure, and description. Two reviewers independently reviewed articles included in the full text review, and the inter-rater agreement exceeded 90%. The database search yielded 388 unique articles, and 17 met the inclusion/exclusion criteria. Most of the studies, 11 of 17, were applied to settings outside of the U.S. Five studies employed a self-report survey, and five studies examined bikeability using geospatial data, like GIS. Seven studies used a direct observation audit tool-one specifically using a mobile app and another using virtual observation techniques with Google Street View. Bikeability tools are useful for assessing communities and their supports for bicycling. Our primary finding is that advances in technology over the past two decades have driven innovative and useful methodologies, in a variety of disciplines, for assessing the environment, but more consensus is needed to provide a universal definition of bikeability.

The Canadian Bikeway Comfort and Safety (Can-BICS) Classification System: A common naming convention for cycling infrastructure. / Système de classification du confort et de la sécurité des voies cyclables canadiennes (Can-BICS) : convention d'appellation commune des aménagements cyclables.

There is no standard naming convention for cycling infrastructure across cities. Our aim was to develop a common nomenclature for cycling infrastructure in Canada, relevant to the context of public health practice. We drew on transportation engineering design guides and public health guidance to develop a bicycle facility classification system: the Canadian Bikeway Comfort and Safety (Can-BICS) classification system, a three-tiered classification scheme that groups five bicycle facilities based on safety performance and user comfort. Adopting consistent nomenclature as per the Can-BICS system will support regional and national surveillance efforts in public health, planning and sustainability.

A common nomenclature for cycling infrastructure in Canada is needed to further public health surveillance efforts on activetransportation environments. The Can-BICS system is a threetiered cycling infrastructure classification system that reflects the safety performance and user comfort of five bicycle facility types. High-comfort bikeways are lowstress routes. These bikeways include cycle tracks on major streets, local street bikeways and cycle-only off-street paths. Medium-comfort bikeways are low-to-medium stress routes. These bikeways include multi-use paths sited next to a roadway or along independent corridors. Low-comfort bikeways are highstress routes. These bikeways include painted bike lanes along busy roadways.

Il est nécessaire d'établir une nomenclature commune pour les aménagements cyclables au Canada afin d'améliorer les mesures de surveillance en santé publique en matière de milieux de transport actif. Le système Can-BICS est un système de classification des amé- nagements cyclables à trois niveaux qui définit le degré de sécurité et le confort pour les usagers de cinq types d'aménagement cyclable. Les voies cyclables très confortables sont peu stressantes : ce sont principalement les pistes cyclables sur chaussée longeant les rues principales, les voies cyclables dans les rues secondaires (« vélorues ¼) et les pistes en site propre. Les voies cyclables moyennement confortables sont peu ou moyennement stressantes : ce sont principalement les sentiers polyvalents longeant une chaussée ou formant un corridor indépendant. Les voies cyclables peu confortables sont très stressantes : ce sont principalement les bandes cyclables peintes au sol sur des routes achalandées.

Cycling Without Age Program: The Impact for Residents in Long-Term Care.

Long-term care facilities seek ways to enhance the quality of life for residents. Cycling Without Age (CWA), a new international cycling program, is gaining momentum for older adults. This study explored resident riders' and trishaw pilots' lived experience of their participation in the CWA program using a qualitative approach at a long-term care facility in the United States. Researchers conducted 27 face-to-face, semi-structured interviews with riders and pilots. For resident riders, the three themes identified included (a) breath of fresh air; (b) wave, chat, and remember; and (c) sit back and relax. Two themes were identified for the pilots: (a) change in frame of mind, and (b) mental and physical rewards. CWA can be as a new strategy for person-centered care. The CWA program provides nursing an opportunity to advocate, recommend, and obtain an order for residents to participate in the program.

A six-year review of patients admitted to hospital with injuries related to quad bike use.

AIM: To describe quad bike injury-related hospitalisations in the Midland region over a six-year period. METHOD: A retrospective review of anonymised, prospectively-collected trauma registry data from 1 July 2012 to 30 June 2018 was undertaken. Cases include patients hospitalised with quad bike-related injuries. Non-major injuries are included to provide a clearer picture of the trauma burden. RESULTS: Three hundred and forty-six injuries resulted in hospitalisation with 70.2% of events occurring on a farm. Males outnumbered females 3.7:1. Forty-six children (<16 years) were hospitalised, of which 23 were injured on-farm and seven on a road. Over six years there was an annual average increase of 7.3% for all events occurring on a farm, 2.6% for injuries occurring during a farming activity and 4.7% for off-farm recreational injuries. CONCLUSION: Despite continued public debate and education on the safe use of quad bikes, injuries severe enough to require hospitalisation continue to occur. Children continue to be injured, both as riders and passengers. Ageing farmers are a developing area for concern. While workplace safety garners most of the safety attention, two other areas also deserve injury prevention consideration; injuries that occur on-farm but not during farming activities and those occurring off-farm to recreational riders.

Health Benefits of Indoor Cycling: A Systematic Review.

Background and Objectives: Indoor cycling is one of the most practiced activities in fitness centers for most people regardless of their physical conditioning level. Several studies have analyzed the effect of indoor cycling on several parameters related to health, such as maximal oxygen consumption, blood pressure, body composition, as well as biochemical markers such as HDL or LDL. However, no study has synthesized all health benefits associated with the indoor cycling practice in the form of a systematic review and established guidelines or recommendations. Therefore, the aim of this manuscript was to conduct a systematic review of published studies about the benefits of indoor cycling training and to establish recommendations for coaches, researchers, and practitioners. Materials and Methods: The PRISMA guidelines were followed to conduct the current systematic review. A systematic search was performed to retrieve relevant published articles until January 2019 using the following keywords: 'indoor cycling', 'indoor bicycle', and 'spinning exercise'. Information about participants, intervention, comparisons, outcomes, and study design (PICOS) was extracted. Results: A total of 300 studies were initially identified. After the revision process, 13 of them were included. The total sample size of the studies was 372 (306 women). Results revealed that indoor cycling may improve aerobic capacity, blood pressure, lipid profile, and body composition. These enhancements may be achieved as standalone intervention or combined with other physical exercises or diet. Conclusions: The combination of indoor cycling and diet is recommended to improve the lipid profile, lose weight, and reduce blood pressure. Furthermore, indoor cycling alone may also enhance aerobic capacity. Given the lack of randomized controlled trials, these conclusions should be taken with caution.

Promoting Bike Helmet Safety for Urban Children Through a Culturally Tailored Educational Video Intervention.

Bicycle-related falls are a significant cause of mortality and morbidity. Use of bicycle helmets substantially reduces risk of severe traumatic brain injury but compliance with this safety practice is particularly low in urban children. We recruited eleven 8- to 15-year-old youth to participate in focus groups to inform the creation of a video promoting helmet use. Key emerging themes included that youth were responsible for keeping themselves safe and that most youth had cell phones with cases to protect them. A video was created that linked the concept of use of cases to protect phones to use of helmets to protect heads. Soliciting information from urban youth was helpful for developing this educational video.

The team effect on doping in professional male road cycling (2005-2016).

This article questions organizations' (clubs, teams, etc) responsibility in doping use from the case of anti-doping rules violations (ADRVs) sanctioned by the Union Cycliste Internationale in professional cycling. We built a database with 271 caught riders among 10 551 professional riders employed from 2005 to 2016 in the three first world divisions. We developed a time-discrete event history model with a multilevel perspective to consider if the ADRV is related to the characteristic of a rider's career path (level 1) and/or the team by which the rider is employed (level 2). Our results confirm two hypotheses: Beginning a career before 2005 or after the age of 22 increased the risk of being caught. Each additional year in the pack increased the risk, despite the fact that a sanctioned rider's career duration average is 7.8 years (3.9 for the others). These caught riders have experienced a more tumultuous career with team changes and an interrupted path. A 2.45 Median Odds Ratio led us to assert a team effect on ADRV. By a team residual effect calculation, we identify 17 teams with a significant effect within the 129 that experienced an ADRV. Our results allow us to emphasize that to understand doping we must take into account work and employment condition, as well as team's organization. This approach completes the dominant "methodological individualism" perspective that considers athletes as analytical units and provides guidelines to the anti-doping bodies that focus their action on individuals.

Key factors for the bicycle use of visually impaired people: a Delphi study.

Purpose: This study aims to identify the most important factors that influence the independent bicycle use of visually impaired people in the Netherlands.Materials and methods: Both visually impaired people and professionals participated in a two-round online Delphi study (n = 42). In Round 1 the participants identified the factors which they ranked by relevance in Round 2.Results: The participants prioritised environmental factors related to the traffic situation, the characteristics of the infrastructure, and weather and light conditions (Kendall's W = 0.66). They indicated that the most influencing personal factors are related to personality, traffic experience, and personal background (W = 0.58). Glaucoma was ranked as the most relevant ophthalmic condition (W = 0.74), while glare was regarded as the most important factor with respect to the visual functions (W = 0.78).Conclusions: The factors provided by this study can be used to optimise the independent cycling mobility of visually impaired people. More research is needed to investigate, both, how and to what extent the mentioned factors influence the cycling behaviour.Implications for rehabilitationThe results of this study can be used to set priorities during the rehabilitation and training of visually impaired people who wish to cycle independently.Visually impaired cyclists may compensate for the consequences of their visual impairments by taking alternative routes that suit their individual abilities and limitations.Since gaining and maintaining self-confidence is important for independent cycling with a visual impairment, practitioners such as mobility trainers should not only focus on cycling-related skills and abilities, but also aim to improve the self-confidence of visually impaired people who wish to cycle.

Bike Lane Obstructions in Manhattan, New York City: Implications for Bicyclist Safety.

Over the past 5 years, the number of regular cyclists in New York City (NYC) increased by ~ 140,000 to over 800,000 regular riders. Aiming to promote safe cycling, NYC has developed over 1000 miles of planned commuting and recreational bike paths across its five boroughs. Bike lane obstructions pose a safety risk to cyclists but the extent of such obstructions is unknown. The purpose of this cross-sectional study was to document the frequency and rate of obstructions in protected bike lanes throughout Manhattan, NYC. During the fall of 2018, bicycle obstructions were observed in ten zones of Manhattan, NYC. Three kinds of obstructions within the bicycle lanes were coded: object, pedestrian, and vehicle. A total of 233 obstructions in the protected bike lanes were observed in this study. Obstructions per zone ranged from 11 to 39. The most common type of obstruction was objects, which accounted for 53.2% (n = 124) of obstructions and ranged through zones from 2 to 22. People were the second most common obstruction, which accounted for 28.3% (n = 66) of the obstructions, with a range of 1-22. Vehicles accounted for the remaining 18.5% (n = 43) of the obstructions with a range of 1-9 throughout zones. Findings of this study indicate that, even in "protected" lanes, bikers may be forced into traffic or to approach parked cars, increasing the risk of being "doored."

The Effectiveness of an On-Bicycle Curriculum on Children.

OBJECTIVE: The objective of this study was to determine whether the BikeSafe on-bicycle curriculum affects children's bicycle safety knowledge and collect cross-sectional data on cycling beliefs and attitudes. METHODS: The University of Miami's BikeSafe program collected surveys from 286 participants, aged 7-15, in 10 Miami-Dade County Parks, Recreation, and Open Spaces summer camps from June to August 2015. Pre and post knowledge assessments were analyzed for 83 intervention group and 57 control group participants. Posttesting occurred immediately following program implementation and 2-4 weeks postimplementation. RESULTS: Intervention group participants demonstrated significant differences (P < .05) in knowledge gain between testing points, whereas control group participants did not. Participants (n = 286) were more likely to be encouraged to ride a bicycle by parents/guardians (61.2%) than by friends (38.1%) or schools (19.6%). Older respondents reported lower intentions of helmet use compared to the younger age group, χ2(4) = 27.96, P < .0005. CONCLUSIONS: Children's bicycle safety knowledge increased following implementation of the BikeSafe on-bicycle curriculum. This study confirmed previous research on the decrease in helmet use as children get older and provided insight into how children view their parents' beliefs and attitudes relating to cycling. The findings of this study can be used to effectively target future educational and encouragement initiatives.

Differences in physical environmental characteristics between adolescents' actual and shortest cycling routes: a study using a Google Street View-based audit.

BACKGROUND: The objective evaluation of the physical environmental characteristics (e.g. speed limit, cycling infrastructure) along adolescents' actual cycling routes remains understudied, although it may provide important insights into why adolescents prefer one cycling route over another. The present study aims to gain insight into the physical environmental characteristics determining the route choice of adolescent cyclists by comparing differences in physical environmental characteristics between their actual cycling routes and the shortest possible cycling routes. METHODS: Adolescents (n = 204; 46.5% boys; 14.4 ± 1.2 years) recruited at secondary schools in and around Ghent (city in Flanders, northern part of Belgium) were instructed to wear a Global Positioning System device in order to identify cycling trips. For all identified cycling trips, the shortest possible route that could have been taken was calculated. Actual cycling routes that were not the shortest possible cycling routes were divided into street segments. Segments were audited with a Google Street View-based tool to assess physical environmental characteristics along actual and shortest cycling routes. RESULTS: Out of 160 actual cycling trips, 73.1% did not differ from the shortest possible cycling route. For actual cycling routes that were not the shortest cycling route, a speed limit of 30 km/h, roads having few buildings with windows on the street side and roads without cycle lane were more frequently present compared to the shortest possible cycling routes. A mixed land use, roads with commercial destinations, arterial roads, cycle lanes separated from traffic by white lines, small cycle lanes and cycle lanes covered by lighting were less frequently present along actual cycling routes compared to the shortest possible cycling routes. CONCLUSIONS: Results showed that distance mainly determines the route along which adolescents cycle. In addition, adolescents cycled more along residential streets (even if no cycle lane was present) and less along busy, arterial roads. Local authorities should provide shortcuts free from motorised traffic to meet adolescents' preference to cycle along the shortest route and to avoid cycling along arterial roads.

Doping risk and career turning points in male elite road cycling (2005-2016).

OBJECTIVES: Determine whether career paths of elite male professional riders explain the risk of being sanctioned for an Anti-Doping Rules Violation through the International Cycling Union. DESIGN, METHODS: A discrete-time logit model explored the link between career path and ADRV risk in a database of 10,551 riders engaged in the first three world divisions (2005-2016), including 271 sanctioned riders. RESULTS: Despite a longer career (7.8years), sanctioned riders have a precarious path. The odds of finding a sanctioned rider within those who experienced a career interruption is 5.80 times higher than for a non-caught one. 61% of the caught riders have experienced a team change. The odds of finding a caught rider within those who experienced such a change is 1.35 times higher. 44% of caught riders start before 23years, vs 34% for non-sanctioned ones. The odds of being sanctioned are 1.69 times higher for doped riders beginning before 23. The odds of finding a sanctioned rider are 1.94 times higher among those starting their careers before 2005 (establishment of Pro Tour), than those who started in 2008 or after. In that year, the Cycling Anti-Doping Foundation and the biologic passport were both launched. CONCLUSIONS: Caught riders could have extended their more precarious careers with doping. The post-2005 generation effect could mean that riders are cleaner or slicker at hiding doping. The higher risk of being caught for riders starting after 23 might indicate that an early professional socialization reduces the risk by teaching them to be cleaner, or better at hiding doping.

Clinical experience of a new reference material for exercise capacity in exercise stress testing in Sweden.

BACKGROUND: In 2014, the Swedish Association of Clinical Physiology recommended the use of a new reference material for exercise capacity in bicycle exercise stress testing, 'the Kalmar material'. Compared to the formerly used reference material, 'the Kristianstad material', an increase in the amount of patients being classified as having decreased exercise capacity was expected, but the extent of this in clinical practice is not known. METHODS: Results of exercise capacity from 1449 bicycle exercise tests, in patients aged ≥20 years (656 women, 793 men) performed at two departments of Clinical Physiology before and after change of reference materials, were collected. Maximal workload was related to the predicted values of both reference materials. If made, recommendations for supplemental nuclear myocardial perfusion imaging study by the attending physician were noted. RESULTS: Using the new reference material, 31% of all patients were classified as having a decreased exercise capacity, compared to 17% using the formerly used reference material. The difference between the two reference materials was largest in the older age groups. In one of the departments, an increase in recommendations of supplemental myocardial perfusion studies was seen after introduction of the new reference material, whereas the opposite was seen at the other department. CONCLUSION: A large amount of patients are being classified as having decreased exercise capacity and very few as having good exercise capacity using the new reference material for exercise capacity.

Relation of oxygen uptake to work rate in prepubertal healthy children - reference for VO2 /W-slope and effect on cardiorespiratory fitness assessment.

PURPOSE: Exercise testing by cycle ergometer allows to observe the interaction between oxygen uptake (VO2 ) and workload (W), and VO2 /W-slope can be used as a diagnostic tool. Respectively, peak oxygen uptake (VO2PEAK ) can be estimated by maximal workload. We aim to determine reference for VO2 /W-slope among prepubertal children and define agreement between estimated and measured VO2PEAK . METHODS: A total of 38 prepubertal children (20 girls) performed a maximal cycle ergometer test with respiratory gas analysis. VO2 /W-slopes were computed using linear regression. Agreement analysis by Bland and Altman for estimated and measured VO2PEAK was carried out including limits of agreement (LA). Determinants for VO2 /W-slopes and estimation bias were defined. RESULTS: VO2/W-slope was in both girls and boys ≥9·4 and did not change with exercise level, but the oxygen cost of exercise was higher among physically more active children. Estimated VO2PEAK had 6·4% coefficient of variation, and LA varied from 13% underestimation to 13% overestimation. Bias had a trend towards underestimation along lean mass proportional VO2PEAK . The primary determinant for estimation bias was VO2/W-slope (ß = -0·65; P<0·001). CONCLUSION: The reference values for VO2 /W-slope among healthy prepubertal children were similar to those published for adults and among adolescents. Estimated and measured VO2PEAK should not be considered to be interchangeable because of the variation in the relationship between VO2 and W. On other hand, variation in the relationship between VO2 and W enables that VO2 /W-slope can be used as a diagnostic tool.

Bicycle Facilities That Address Safety, Crime, and Economic Development: Perceptions from Morelia, Mexico.

México is a developing nation and, in the city of Morelia, the concept of the bicyclist as a road user appeared only recently in the Municipal Traffic Regulations. Perhaps the right bicycle infrastructure could address safety, crime, and economic development. To identify the best infrastructure, six groups in Morelia ranked and commented on pictures of bicycle environments that exist in bicycle-friendly nations. Perceptions about bike paths, but only those with impossible-to-be-driven-over solid barriers, were associated with safety from crashes, lowering crime, and contributing to economic development. Shared use paths were associated with lowering the probability of car/bike crashes but lacked the potential to deter crime and foster the local economy. Joint bus and bike lanes were associated with lower safety because of the unwillingness by Mexican bus drivers to be courteous to bicyclists. Gender differences about crash risk biking in the road with the cars (6 best/0 worst scenario) were statistically significant (1.4 for male versus 0.69 for female; p < 0.001). For crashes, crime, and economic development, perceptions about bicycle infrastructure were different in this developing nation perhaps because policy, institutional context, and policing (ticketing for unlawful parking) are not the same as in a developed nation. Countries such as Mexico should consider building cycle tracks with solid barriers to address safety, crime, and economic development.

Cycle Tracks and Parking Environments in China: Learning from College Students at Peking University.

China has a historic system of wide cycle tracks, many of which are now encroached by cars, buses and bus stops. Even with these conditions, college students still bicycle. On campuses, students park their bikes on facilities ranging from kick-stand-plazas to caged sheds with racks, pumps and an attendant. In other countries, including Canada, some of the newer cycle tracks need to be wider to accommodate an increasing number of bicyclists. Other countries will also need to improve their bike parking, which includes garage-basement cages and two-tiered racks. China could provide lessons about cycle tracks and bike parking. This study applied the Maslow Transportation Level of Service (LOS) theory, i.e., for cycle tracks and bike parking, only after the basic needs of safety and security are met for both vehicle occupants and bicyclists can the higher needs of convenience and comfort be met. With random clustering, a self-administered questionnaire was collected from 410 students in six dormitory buildings at Peking University in Beijing and an environmental scan of bicycle parking conducted in school/office and living areas. Cycle tracks (1 = very safe/5 = very unsafe) shared with moving cars were most unsafe (mean = 4.6), followed by sharing with parked cars (4.1) or bus stop users (4.1) (p < 0.001). Close to half thought campus bike parking lacked order. The most suggested parking facilities were sheds, security (guard or camera), bicycle racks and bicycle parking services (pumps, etc.). If parking were improved, three quarters indicated they would bicycle more. While caged sheds were preferred, in living areas with 1597 parked bikes, caged sheds were only 74.4% occupied. For the future of China's wide cycle tracks, perhaps a fence-separated bus lane beside a cycle track might be considered or, with China's recent increase in bike riding, shared bikes and E-bikes, perhaps cars/buses could be banned from the wide cycle tracks. In other countries, a widened cycle track entrance should deter cars. Everywhere, bike parking sheds could be built and redesigned with painted lines to offer more space and order, similar to car parking.

Qualitative Video Analysis of Track-Cycling Team Pursuit in World-Class Athletes.

CONTEXT: Track-cycling team pursuit (TP) is a highly technical effort involving 4 athletes completing 4 km from a standing start, often in less than 240 s. Transitions between athletes leading the team are obviously of utmost importance. PURPOSE: To perform qualitative video analyses of transitions of world-class athletes in TP competitions. METHODS: Videos captured at 100 Hz were recorded for 77 races (including 96 different athletes) in 5 international track-cycling competitions (eg, UCI World Cups and World Championships) and analyzed for the 12 best teams in the UCI Track Cycling TP Olympic ranking. During TP, 1013 transitions were evaluated individually to extract quantitative (eg, average lead time, transition number, length, duration, height in the curve) and qualitative (quality of transition start, quality of return at the back of the team, distance between third and returning rider score) variables. Determination of correlation coefficients between extracted variables and end time allowed assessment of relationships between variables and relevance of the video analyses. RESULTS: Overall quality of transitions and end time were significantly correlated (r = .35, P = .002). Similarly, transition distance (r = .26, P = .02) and duration (r = .35, P = .002) were positively correlated with end time. Conversely, no relationship was observed between transition number, average lead time, or height reached in the curve and end time. CONCLUSION: Video analysis of TP races highlights the importance of quality transitions between riders, with preferably swift and short relays rather than longer lead times for faster race times.