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Mayerhofer P, Bajić I, Maxwell Donelan J. Comparing the advantages and disadvantages of physics-based and neural network-based modelling for predicting cycling power. J Biomech 2024; 169:112121. [PMID: 38733816 DOI: 10.1016/j.jbiomech.2024.112121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 04/12/2024] [Accepted: 04/22/2024] [Indexed: 05/13/2024]
Abstract
Models of physical phenomena can be developed using two distinct approaches: using expert knowledge of the underlying physical principles or using experimental data to train a neural network. Here, our aim was to better understand the advantages and disadvantages of these two approaches. We chose to model cycling power because the physical principles are already well understood. Nine participants followed changes in cycling cadence transmitted through a metronome via earphones and we measured their cadence and power. We then developed and trained a physics-based model and a simple neural network model, where both models had cadence, derivative of cadence, and gear ratio as input, and power as output. We found no significant differences in the prediction performance between the models. Both models had good prediction accuracy despite using less input variables than traditional models and using more challenging prediction conditions by enforcing rapid speed changes during cycling. The advantages of the neural network model were that, for similar performance, it did not require an understanding of the underlying principles of cycling nor did it require measurements of fixed parameters such as system weight or wheel size. These same features also give the physics-based model the advantage of interpretability, which can be important when scientists want to better understand the process being modelled.
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Affiliation(s)
| | - Ivan Bajić
- Department of Engineering Science, Simon Fraser University, Burnaby, Canada
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2
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Polanco A, Roa S, Suárez DR, López O, Muñoz L. Influence of wind speed and road grade on the estimation of drag area in cycling. Sports Biomech 2024; 23:222-240. [PMID: 33433293 DOI: 10.1080/14763141.2020.1837925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 10/11/2020] [Indexed: 10/22/2022]
Abstract
The estimation of aerodynamic drag in cycling through road tests has the advantage of considering actual cycling conditions. The main drawback is that its accuracy depends on factors of the testing scenario as the wind speed v w and the road grade θ . For that reason, the effect of v w and θ on the estimation of drag area (C D A ) was studied. Numerical and experimental approaches were combined. The numerical approach investigated the sensitivity of C D A to v w and θ perturbations. The experimental approach analysed the effect of including or not v w and θ on the identification of C D A by comparing the changes in the prediction of power delivered. It was found that disregarding small values of v w (e.g. 0.5 m/s) and θ (e.g. gradient of 0.05%) leads to errors in the estimation of C D A of around 10%, referred to the actual value. It was also obtained that the average error of the power prediction when considering v w and θ for the identification of the parameters is about 4.4% and about 25.5% when v w and θ are neglected. It is concluded that including v w and θ data reduces the error on the identification of C D A through outdoor road experiments.
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Affiliation(s)
- Alejandra Polanco
- School of Engineering, Pontifical Javeriana University (Pontificia Universidad Javeriana), Bogota, Colombia
| | - Sergio Roa
- Department of Mechanical Engineering, University of Los Andes, Bogota, Colombia
| | - Daniel R Suárez
- School of Engineering, Pontifical Javeriana University (Pontificia Universidad Javeriana), Bogota, Colombia
| | - Omar López
- Department of Mechanical Engineering, University of Los Andes, Bogota, Colombia
| | - Luis Muñoz
- Department of Mechanical Engineering, University of Los Andes, Bogota, Colombia
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3
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Muyor JM, Antequera-Vique JA, Oliva-Lozano JM, Arrabal-Campos FM. Evaluation of Dynamic Spinal Morphology and Core Muscle Activation in Cyclists-A Comparison between Standing Posture and on the Bicycle. SENSORS (BASEL, SWITZERLAND) 2022; 22:9346. [PMID: 36502048 PMCID: PMC9738255 DOI: 10.3390/s22239346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/25/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
(1) Background: Cycling is characterized by a sustained sitting posture on the bicycle, where physiologic spinal curvatures are modified from standing to cycling. Therefore, the main objective was to evaluate and compare the morphology of the spine and the core muscle activity in standing posture and cycling at low intensity. (2) Methods: Twelve competitive cyclists participated in the study. Spinal morphology was evaluated using an infrared-camera system. Muscle activation was recorded using a surface electromyography device. (3) Conclusions: The lumbar spine changes its morphology from lordosis in standing to kyphosis (lumbar flexion) when pedaling on the bicycle. The sacral tilt significantly increases its anterior tilt when cycling compared to when standing. The spinal morphology and sacral tilt are dynamic depending on the pedal's position during the pedal stroke quadrants. The infraspinatus, latissimus dorsi, external oblique, and pectoralis major showed significantly higher activation pedaling than when standing, although with very low values.
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Affiliation(s)
- José M. Muyor
- Laboratory of Kinesiology, Biomechanics and Ergonomics (KIBIOMER Lab.), Faculty of Education Sciences, University of Almería, 04120 Almería, Spain
- Health Research Centre, Faculty of Education Sciences, University of Almería, 04120 Almería, Spain
| | - José A. Antequera-Vique
- Health Research Centre, Faculty of Education Sciences, University of Almería, 04120 Almería, Spain
| | - José M. Oliva-Lozano
- Health Research Centre, Faculty of Education Sciences, University of Almería, 04120 Almería, Spain
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4
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Knechtle B, Forte P, Weiss K, Cuk I, Nikolaidis PT, Sousa CV, Andrade MS, Thuany M. Biophysical characterization of the first ultra-cyclist in the world to break the 1,000 km barrier in 24-h non-stop road cycling: A case report. Front Cardiovasc Med 2022; 9:990382. [PMID: 36304551 PMCID: PMC9592711 DOI: 10.3389/fcvm.2022.990382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 08/09/2022] [Indexed: 11/19/2022] Open
Abstract
A plethora of factors determine elite cycling performance. Those include training characteristics, pacing strategy, aerodynamics, nutritional habits, psychological traits, physical fitness level, body mass composition, and contextual features; even the slightest changes in any of these factors can be associated with performance improvement or deterioration. The aim of the present case report is to compare the performances of the same ultra-cyclist in achieving two world records (WR) in 24 h cycling. We have analyzed and compared the distance covered and speed for each WR. The 24 h period was split into four-time intervals (0–6 h; > 6–12 h; > 12–18 h; > 18–24 h), and we compared the differences in the distance covered and speed between the two WRs. For both WRs, a strong negative correlation between distance and speed was confirmed (r = –0.85; r = –0.89, for old and new WR, respectively). Differences in speed (km/h) were shown between the two WRs, with the most significant differences in 12–18 h (Δ = 6.50 km/h). For the covered distance in each block, the most significant differences were observed in the last part of the cycling (Δ = 38.54 km). The cyclist effective surface area (ACd) was 0.25 m2 less and 20% more drag in the new WR. Additionally, the mechanical power was 8%, the power to overcome drag was 31%, and the power-weight ratio was 8% higher in the new WR. The mechanical efficiency of the cyclist was 1% higher in the new WR. Finally, the heart rate (HR) presented significant differences for the first 6 h (Old WR: 145.80 ± 5.88 bpm; New WR: 139.45 ± 5.82 bpm) and between the 12 and 18 h time interval (Old WR: 133.19 ± 3.53 bpm; New WR: 137.63 ± 2.80 bpm). The marginal gains concept can explain the performance improvement in the new WR, given that the athlete made some improvements in technical specifications after the old WR.
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Affiliation(s)
- Beat Knechtle
- Medbase St. Gallen Am Vadianplatz, St. Gallen, Switzerland,Institute of Primary Care, University of Zurich, Zurich, Switzerland,*Correspondence: Beat Knechtle,
| | - Pedro Forte
- Higher Institute of Educational Sciences of the Douro, Penafiel, Portugal,Instituto Politécnico de Bragança, Bragança, Portugal,Research Center in Sports, Health and Human Development, Covilhã, Portugal
| | - Katja Weiss
- Institute of Primary Care, University of Zurich, Zurich, Switzerland
| | - Ivan Cuk
- Faculty of Sport and Physical Education, University of Belgrade, Belgrade, Serbia
| | | | - Caio Victor Sousa
- Health and Human Sciences, Loyola Marymount University, Los Angeles, CA, United States
| | - Marilia Santos Andrade
- Departamento de Fisiologia, Disciplina de Neurofisiologia e Fisiologia do Exercício, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Mabliny Thuany
- Centre of Research, Education, Innovation and Intervention in Sport (CIFI2D), Faculty of Sport, University of Porto, Porto, Portugal
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Ghasemi M, Curnier D, Caru M, Trépanier JY, Périé D. The effect of different aero handlebar positions on aerodynamic and gas exchange variables. J Biomech 2022; 139:111128. [DOI: 10.1016/j.jbiomech.2022.111128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/01/2022] [Accepted: 05/02/2022] [Indexed: 11/16/2022]
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6
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Yang SC, Lee YJ. Integrated Physiological, Biomechanical, and Subjective Responses for the Selection of Assistive Level in Pedelec Cycling. Front Physiol 2021; 12:740728. [PMID: 34955875 PMCID: PMC8694031 DOI: 10.3389/fphys.2021.740728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/09/2021] [Indexed: 11/30/2022] Open
Abstract
In recent decade, pedelec has become one of the most popular transportation modes due to its effectiveness in reducing physical effort. The effects of using pedelec as an alternative mode of exercise were explored in previous studies. However, the effects of pedelec parameters were not quantified for the self-selected gear ratio, random riding speed, and varied road slopes, which restricted its application. Hence, this study aimed to evaluate the effects of gear ratio and assistive torque and to determine the optimum riding condition regarding physiological, biomechanical, and subjective responses of the rider. The riding tests consisted of simulated slope (1.0 vs. 2.5% grade), gear ratio (light vs. heavy), and assistive levels (0.5, 1, 1.5, and 2), and the tests were conducted in a randomized order. A total of 19 non-athletes completed the riding tests to evaluate physiological [metabolic equivalent of task (MET), heart rate, and gross efficiency (GE)], biomechanical [muscle activity (expressed as reference voluntary contraction, RVC) and power output], and subjective responses [rating of perceived exertion (RPE) and sense of comfort (SC)]. The test conditions induced moderate to vigorous intensities (3.7–7.4 METs, 58.5–80.3% of maximal heart rate, 11.1–29.5% of RVC rectus femoris activity, and 9.4–14.2 RPEs). The effects of gear ratio and assistive level on the physiological responses were significant. Riding with the heavy gear ratio showed advantages in METs and GE. For the optimum assistive level selection, low GE and limited improvement in subjective responses suggested the impact of low-power output conditions. Overall, for the health pedelec commuters, riding with 0.75 W/kg power output with 50 rpm cadence is recommended to obtain the moderate intensity (4.7 METs) and the advantages in GE and subjective feelings. Moreover, the findings can be applied to exercise intensity control and save battery energy effectively in varying riding conditions.
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Affiliation(s)
- Sheng-Chieh Yang
- Cycling & Heath Tech Industry R&D Center, Taichung, Taiwan.,Department of Industrial Engineering and Engineering Management, National Tsing Hua University, Hsinchu, Taiwan
| | - Yun-Ju Lee
- Department of Industrial Engineering and Engineering Management, National Tsing Hua University, Hsinchu, Taiwan
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Ferguson HA, Harnish C, Chase JG. Using Field Based Data to Model Sprint Track Cycling Performance. SPORTS MEDICINE - OPEN 2021; 7:20. [PMID: 33725208 PMCID: PMC7966696 DOI: 10.1186/s40798-021-00310-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 02/28/2021] [Indexed: 11/21/2022]
Abstract
Cycling performance models are used to study rider and sport characteristics to better understand performance determinants and optimise competition outcomes. Performance requirements cover the demands of competition a cyclist may encounter, whilst rider attributes are physical, technical and psychological characteristics contributing to performance. Several current models of endurance-cycling enhance understanding of performance in road cycling and track endurance, relying on a supply and demand perspective. However, they have yet to be developed for sprint-cycling, with current athlete preparation, instead relying on measures of peak-power, speed and strength to assess performance and guide training. Peak-power models do not adequately explain the demands of actual competition in events over 15-60 s, let alone, in World-Championship sprint cycling events comprising several rounds to medal finals. Whilst there are no descriptive studies of track-sprint cycling events, we present data from physiological interventions using track cycling and repeated sprint exercise research in multiple sports, to elucidate the demands of performance requiring several maximal sprints over a competition. This review will show physiological and power meter data, illustrating the role of all energy pathways in sprint performance. This understanding highlights the need to focus on the capacity required for a given race and over an event, and therefore the recovery needed for each subsequent race, within and between races, and how optimal pacing can be used to enhance performance. We propose a shift in sprint-cyclist preparation away from training just for peak power, to a more comprehensive model of the actual event demands.
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Affiliation(s)
- Hamish A. Ferguson
- Centre for Bioengineering, Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8140 New Zealand
| | - Chris Harnish
- Department of Exercise Science, College of Health, Mary Baldwin University, Staunton, VA USA
| | - J. Geoffrey Chase
- Centre for Bioengineering, Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch, 8140 New Zealand
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Forte P, Morais JE, Barbosa TM, Marinho DA. Assessment of Able-Bodied and Amputee Cyclists' Aerodynamics by Computational Fluid Dynamics. Front Bioeng Biotechnol 2021; 9:644566. [PMID: 33777915 PMCID: PMC7991374 DOI: 10.3389/fbioe.2021.644566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/15/2021] [Indexed: 11/13/2022] Open
Abstract
The aim of this study was to compare the aerodynamics of able-bodied and amputee cyclists by computational fluid dynamics. The cyclists' geometry was obtained by a 3D scanner. Three CAD models were created as able-bodied, transtibial (Tt), and transradial (Tr) amputees. Numerical simulations were conducted up to 13 m/s with increments of 1 m/s to assess drag force. The drag ranged between 0.36 and 39.25 N for the able-bodied model, 0.36-43.78 for the Tr model and 0.37-41.39 N for the Tt model. The pressure drag ranged between 0.20 and 22.94 N for the normal model, 0.21-28.61 for the Tr model and 0.23-28.02 N for the Tt model. The viscous drag ranged between 0.16 and 15.31 N for the normal model, 0.15-15.17 for the Tr model and 0.14-13.38 N for the Tt model. The rolling resistance (RR) was higher on the able-bodied (2.23 N), followed by the Tr (2.20 N) and Tt (2.17 N) models. As a conclusion, the able-bodied cyclist showed less drag, followed by the Tt and Tr models, respectively. The RR presented higher values in the able-bodied, followed by the Tr and Tt models.
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Affiliation(s)
- Pedro Forte
- Department of Sports, Douro Higher Institute of Educational Sciences, Penafiel, Portugal.,Department of Sports Sciences, Instituto Politécnico de Bragança, Bragança, Portugal.,Research Centre in Sports, Health and Human Development, Covilhã, Portugal
| | - Jorge E Morais
- Department of Sports Sciences, Instituto Politécnico de Bragança, Bragança, Portugal.,Research Centre in Sports, Health and Human Development, Covilhã, Portugal
| | - Tiago M Barbosa
- Department of Sports Sciences, Instituto Politécnico de Bragança, Bragança, Portugal.,Research Centre in Sports, Health and Human Development, Covilhã, Portugal
| | - Daniel A Marinho
- Research Centre in Sports, Health and Human Development, Covilhã, Portugal.,Department of Sports Sciences, University of Beira Interior, Covilhã, Portugal
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Kordi M, Galis G, Erp TV, Terra W. Reliability and sensitivity of the Notio Konect to quantify coefficient of drag area in elite track cyclists. Eur J Sport Sci 2021; 22:774-779. [PMID: 33590804 DOI: 10.1080/17461391.2021.1891296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Elite level cycling events are performed at speeds in excess of 50 km/h. At these speeds, over 90% of the resistance forces come from aerodynamic resistance (CDA). Recently bicycle-mounted pitot tubes, such as the Notio Konect (NK) have become more commercially available making CDA easier to measure. Its reliability and sensitivity would be useful for riders and coaches to be able to understand what constitutes as a change in CDA. Accordingly, the aim of this study was to establish the intra- and inter-effort reliability and sensitivity of the CDA measures of the NK. Seven elite level track riders were used in this study which was broken into two parts: (1) Reliability and (2) Sensitivity. For both parts of the experiment, riders performed identical efforts, riding at ∼50 km/h for six laps of a 250 m indoor velodrome. For reliability, the riders performed six efforts without any changes in position or resistance. For sensitivity, they performed the efforts with a rod with discs of a known diameters attached at each end to vary the CDA by a known amount. For the reliability assessment, low coefficient of variation of intra - (0.47%) and inter-effort (0.9%) reliability were measured. With regards to sensitivity, the smallest changes in resistance (from 5 - 6 cm, i.e. 1.2% or 0.002 m2) was identified by the NK. The data in this experiment suggests that the NK is a highly reliable in measuring CDA can detect changes up to at least 1.2% in an indoor velodrome using elite level track riders. HighlightsThe Notio Konect showed high levels of inter- and intra-effort reliability.The Notio Konect could detect a change as small as 1.2% in aerodynamic drag.The findings suggest that the Notio Konect is suitable for detecting small changes in aerodynamic drag in a velodrome setting.
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Affiliation(s)
- Mehdi Kordi
- Royal Dutch Cycling Federation (KNWU), Arnhem, Netherlands.,Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle, UK
| | - Gert Galis
- Aerospace Engineering Department, Delft, Netherlands
| | - Teun van Erp
- Division of Orthopaedic Surgery, Faculty of Medicine and Health Sciences, Stellenbosch University, Tygerberg, South Africa
| | - Wouter Terra
- Aerospace Engineering Department, Delft, Netherlands
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10
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Aerodynamics of Cycling Skinsuits Focused on the Surface Shape of the Arms. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11052200] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In cycling, air resistance corresponds to 90% of the resistance on the bicycle and cyclist and 70% of this is applied to the body of the cyclist. Despite research on postures that could reduce air resistance, few studies have been conducted on full-body cycling suits. As the aerodynamics of the surface shape of clothing fabric are still unclear, the airflow around cyclists and air resistance were examined using a computational fluid dynamics (CFD) method and wind tunnel experiment. Specifically, in this study, we focused on how different surface shapes of cycling suit fabrics affect air resistance. CFD results indicate that air resistance during a race was high at the head, arms and legs of the cyclist. In the wind tunnel experiment, a cylinder model resembling the arms was used to compare the aerodynamic forces of various fabrics and the results showed that air resistance changed according to the fabric surface shape. Moreover, by changing the fabric shape of the arms of the cycling suits, reduction of air resistance by up to 8% is achievable. These results suggest that offering the most appropriate suit type to each cyclist, considering race conditions, can contribute to further improvement in their performance.
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Skovereng K, Aasvold LO, Ettema G. On the effect of changing handgrip position on joint specific power and cycling kinematics in recreational and professional cyclists. PLoS One 2020; 15:e0237768. [PMID: 32813742 PMCID: PMC7444484 DOI: 10.1371/journal.pone.0237768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 08/04/2020] [Indexed: 12/04/2022] Open
Abstract
Introduction In cycling, the utilization of the drops position (i.e. the lowest handlebar position relative to the ground) allows for reduced frontal area, likely improved aerodynamics and thus performance compared to the tops (i.e. the position producing the most upright trunk). The reduced trunk angle during seated submaximal cycling has been shown to influence cardiorespiratory factors but the effects on pedalling forces and joint specific power are unclear. The purpose of this study was to investigate the effect of changing handgrip position on joint specific power and cycling kinematics at different external work rates in recreational and professional cyclists. Method Nine professional and nine recreational cyclists performed cycling bouts using three different handgrip positions and three external work rates (i.e. 100W, 200W and external work rate corresponding to the lactate threshold (WRlt)). Joint specific power was calculated from kinematic measurements and pedal forces using 2D inverse dynamics. Results We found increased hip joint power, decreased knee joint power and increased peak crank torque for the professional cyclist compared to the recreational cyclists, but only at WRlt where the professional cyclists were working at a higher external work rate. There was no main effect of changing handgrip position on any joint, but there was a small interaction effect of external work rate and handgrip position on hip joint power contribution (Generalized eta squared (ηg2) = 0.012). At 100W, changing handgrip position from the tops to the drops decreased the hip joint contribution (-2.0 ± 3.9 percentage points (pct)) and at the WRlt, changing handgrip position increased the hip joint power (1.6 ± 3.1 pct). There was a small effect of handgrip position with the drops leading to increased peak crank torque (ηg2 = 0.02), increased mean dorsiflexion (ηg2 = 0.05) and increased hip flexion (ηg2 = 0.31) compared to the tops. Discussion The present study demonstrates that there is no main effect of changing handgrip position on joint power. Although there seems to be a small effect on hip joint power when comparing across large ranges in external work rate, any potential negative performance effect would be outweighed by the aerodynamic benefit of the drops position.
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Affiliation(s)
- Knut Skovereng
- Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, Norwegian University of Science and Technology, Trondheim, Norway
- * E-mail:
| | - Lorents Ola Aasvold
- Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, Norwegian University of Science and Technology, Trondheim, Norway
| | - Gertjan Ettema
- Department of Neuromedicine and Movement Science, Centre for Elite Sports Research, Norwegian University of Science and Technology, Trondheim, Norway
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Forte P, Morais JE, P. Neiva H, Barbosa TM, Marinho DA. The Drag Crisis Phenomenon on an Elite Road Cyclist-A Preliminary Numerical Simulations Analysis in the Aero Position at Different Speeds. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17145003. [PMID: 32664605 PMCID: PMC7399909 DOI: 10.3390/ijerph17145003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/07/2020] [Accepted: 07/09/2020] [Indexed: 11/18/2022]
Abstract
The drag crisis phenomenon is the drop of drag coefficient (Cd) with increasing Reynolds number (Re) or speed. The aim of this study was to assess the hypothetical drag crisis phenomenon in a sports setting, assessing it in a bicycle–cyclist system. A male elite-level cyclist was recruited for this research and his competition bicycle, helmet, suit, and shoes were used. A three-dimensional (3D) geometry was obtained with a 3D scan with the subject in a static aero position. A domain with 7 m of length, 2.5 m of width and 2.5 m of height was created around the cyclist. The domain was meshed with 42 million elements. Numerical simulations by computer fluid dynamics (CFD) fluent numerical code were conducted at speeds between 1 m/s and 22 m/s, with increments of 1 m/s. The drag coefficient ranged between 0.60 and 0.95 across different speeds and Re. The highest value was observed at 2 m/s (Cd = 0.95) and Re of 3.21 × 105, whereas the lower Cd was noted at 9 m/s (Cd = 0.60) and 9.63 × 105. A drag crisis was noted between 3 m/s and 9 m/s. Pressure Cd ranged from 0.35 to 0.52 and the lowest value was observed at 3 m/s and the highest at 2 m/s. The viscous drag coefficient ranged between 0.15 and 0.43 and presented a trend decreasing from 4 m/s to 22 m/s. Coaches, cyclists, researchers, and support staff must consider that Cd varies with speed and Re, and the bicycle–cyclist dimensions, shape, or form may affect drag and performance estimations. As a conclusion, this preliminary work noted a drag crisis between 3 m/s and 9 m/s in a cyclist in the aero position.
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Affiliation(s)
- Pedro Forte
- Department of Sports, Douro Higher Institute of Educational Sciences, 4560-708 Penafiel, Portugal;
- Department of Sports Sciences and Physical Education, Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal;
- Research Center in Sports, Health and Human Development, CIDESD, 6201-001 Covilhã, Portugal; (H.P.N.); (D.A.M.)
- Correspondence: ; Tel.: +351-255-318-550
| | - Jorge E. Morais
- Department of Sports, Douro Higher Institute of Educational Sciences, 4560-708 Penafiel, Portugal;
- Department of Sports Sciences and Physical Education, Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal;
- Research Center in Sports, Health and Human Development, CIDESD, 6201-001 Covilhã, Portugal; (H.P.N.); (D.A.M.)
| | - Henrique P. Neiva
- Research Center in Sports, Health and Human Development, CIDESD, 6201-001 Covilhã, Portugal; (H.P.N.); (D.A.M.)
- Department of Sports Science, Beira Interior University (UBI), 6201-001 Covilhã, Portugal
| | - Tiago M. Barbosa
- Department of Sports Sciences and Physical Education, Instituto Politécnico de Bragança, 5300-253 Bragança, Portugal;
- Research Center in Sports, Health and Human Development, CIDESD, 6201-001 Covilhã, Portugal; (H.P.N.); (D.A.M.)
| | - Daniel A. Marinho
- Research Center in Sports, Health and Human Development, CIDESD, 6201-001 Covilhã, Portugal; (H.P.N.); (D.A.M.)
- Department of Sports Science, Beira Interior University (UBI), 6201-001 Covilhã, Portugal
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Peeters T, Vleugels J, Garimella R, Truijen S, Saeys W, Verwulgen S. Vibrotactile feedback for correcting aerodynamic position of a cyclist. J Sports Sci 2020; 38:2193-2199. [PMID: 32529942 DOI: 10.1080/02640414.2020.1776814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Guidance to maintain an optimal aerodynamic position is currently unavailable during cycling. This study used real-time vibrotactile feedback to guide cyclists to a reference position with minimal projected frontal area as an indicator of aerodynamic drag, by optimizing torso, shoulder, head and elbow position without compromising comfort when sitting still on the bike. The difference in recapturing the aerodynamic reference position during cycling after predefined deviations from the reference position at different intensities was analysed for 14 participants between three interventions, consisting of 1) vibrotactile feedback with a margin of error of 1.5% above the calibrated reference projected frontal area, 2) vibrotactile feedback with a margin of 3%, and 3) no feedback. The reference position is significantly more accurately achieved using vibrotactile feedback compared to no feedback (p < 0.001), but there is no significant difference between the 1.5% and 3% margin (p = 0.11) in terms of relative projected frontal area during cycling compared to the calibrated reference position (1.5% margin -0.46 ± 1.76%, 3% margin -0.01 ± 2.01%, no feedback 2.59 ± 3.29%). The results demonstrate that vibrotactile feedback can have an added value in assisting and correcting cyclists in recapturing their aerodynamic reference position.
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Affiliation(s)
- Thomas Peeters
- Department Product Development, Faculty of Design Sciences, University of Antwerp , Antwerp, Belgium
| | - Jochen Vleugels
- Department Product Development, Faculty of Design Sciences, University of Antwerp , Antwerp, Belgium
| | - Raman Garimella
- Department Product Development, Faculty of Design Sciences, University of Antwerp , Antwerp, Belgium.,Voxdale , Wijnegem, Belgium
| | - Steven Truijen
- Department Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp , Antwerp, Belgium
| | - Wim Saeys
- Department Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp , Antwerp, Belgium
| | - Stijn Verwulgen
- Department Product Development, Faculty of Design Sciences, University of Antwerp , Antwerp, Belgium
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Forte P, Marinho DA, Barbosa TM, Morouço P, Morais JE. Estimation of an Elite Road Cyclist Performance in Different Positions Based on Numerical Simulations and Analytical Procedures. Front Bioeng Biotechnol 2020; 8:538. [PMID: 32548112 PMCID: PMC7272685 DOI: 10.3389/fbioe.2020.00538] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 05/05/2020] [Indexed: 11/17/2022] Open
Abstract
The aim of this study was to use numerical simulations and analytical procedures to compare a cyclist's performance in three different cycling positions. An elite level road cyclist competing at a national level was recruited for this research. The bicycle was 7 kg and the cyclist 55 kg. A 3D scan was taken of the subject on the competition bicycle, wearing race gear and helmet in the upright position, in the handlebar drops (dropped position) and leaning on the elbows (elbows position). Numerical simulations by computer fluid dynamics in Fluent CFD code assessed the coefficient of drag at 11.11 m/s. Following that, a set of assumptions were employed to assess cycling performance from 1 to 22 m/s. Drag values ranged between 0.16 and 99.51 N across the different speeds and positions. The cyclist mechanical power in the elbows position differed from the upright position between 0 and 23% and from the dropped position from 0 to 21%. The cyclist's energy cost in the upright position differed 2 to 16% in comparison to the elbows position and the elbows position had less 2 to 14% energy cost in comparison to the dropped position. The estimated time of arrival was computed for a 220,000 m distance and it varied between 7,715.03 s (2 h:8 min:24 s) and 220,000 s (61 h:6 min:40 s) across the different speeds and positions. In the elbows position, is expected that a cyclist may improve the winning time up to 23% in comparison to he upright and dropped position across the studied speeds.
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Affiliation(s)
- Pedro Forte
- Department of Sports Sciences, Higher Institute of Educational Sciences of the Douro, Penafiel, Portugal.,Department of Sport Sciences, Instituto Politécnico de Bragança, Bragança, Portugal.,Research Centre in Sports, Health and Human Development (CIDESD), University of Beira Interior, Covilhã, Portugal
| | - Daniel A Marinho
- Research Centre in Sports, Health and Human Development (CIDESD), University of Beira Interior, Covilhã, Portugal.,Department of Sport Sciences, University of Beira Interior, Covilhã, Portugal
| | - Tiago M Barbosa
- Department of Sport Sciences, Instituto Politécnico de Bragança, Bragança, Portugal.,Research Centre in Sports, Health and Human Development (CIDESD), University of Beira Interior, Covilhã, Portugal
| | - Pedro Morouço
- Department of Sport Sciences, University of Beira Interior, Covilhã, Portugal.,Centre for the Study of Human Performance, Universidade de Lisboa, Lisbon, Portugal.,Department of Sport Sciences, Polytechnic Institute of Leiria, Leiria, Portugal
| | - Jorge E Morais
- Department of Sport Sciences, Instituto Politécnico de Bragança, Bragança, Portugal.,Research Centre in Sports, Health and Human Development (CIDESD), University of Beira Interior, Covilhã, Portugal
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15
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Fischer G, Figueiredo P, Ardigò LP. Bioenergetics and Biomechanics of Handcycling at Submaximal Speeds in Athletes with a Spinal Cord Injury. Sports (Basel) 2020; 8:sports8020016. [PMID: 32013128 PMCID: PMC7077182 DOI: 10.3390/sports8020016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/24/2020] [Accepted: 01/27/2020] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND A study aimed at comparing bioenergetics and biomechanical parameters between athletes with tetraplegia and paraplegia riding race handbikes at submaximal speeds in ecological conditions. METHODS Five athletes with tetraplegia (C6-T1, 43 ± 6 yrs, 63 ± 14 kg) and 12 athletes with paraplegia (T4-S5, 44 ± 7 yrs, 72 ± 12 kg) rode their handbikes at submaximal speeds under metabolic measurements. A deceleration method (coasting down) was applied to calculate the rolling resistance and frontal picture of each participant was taken to calculate air resistance. The net overall Mechanical Efficiency (Eff) was calculated by dividing external mechanical work to the corresponding Metabolic Power. RESULTS Athletes with tetraplegia reached a lower aerobic speed (4.7 ± 0.6 m s-1 vs. 7.1 ± 0.9 m s-1, P = 0.001) and Mechanical Power (54 ± 15 W vs. 111 ± 25 W, P = 0.001) compared with athletes with paraplegia. The metabolic cost was around 1 J kg-1 m-1 for both groups. The Eff values (17 ± 2% vs. 19 ± 3%, P = 0.262) suggested that the handbike is an efficient assisted locomotion device. CONCLUSION Handbikers with tetraplegia showed lower aerobic performances but a similar metabolic cost compared with handbikers with paraplegia at submaximal speeds in ecological conditions.
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Affiliation(s)
- Gabriela Fischer
- School of Exercise and Sport Science, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona 37131, Italy;
- Laboratory of Biomechanics, Department of Physical Education, Federal University of Santa Catarina, Florianópolis 88040-900, Brazil
- Correspondence: ; Tel.: +55-48-3721-8558
| | - Pedro Figueiredo
- Portugal Football School, Portuguese Football Federation, Oeiras 1495-433, Portugal;
- Research Center in Sports Sciences, Health Sciences and Human Development, CIDESD, University Institute of Maia, ISMAI, Maia 4475-690, Portugal
| | - Luca Paolo Ardigò
- School of Exercise and Sport Science, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona 37131, Italy;
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Forte P, A Marinho D, M Barbosa T, E Morais J. Analysis of a normal and aero helmet on an elite cyclist in the dropped position. AIMS BIOPHYSICS 2020. [DOI: 10.3934/biophy.2020005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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17
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Valenzuela PL, Alcalde Y, Gil-Cabrera J, Talavera E, Lucia A, Barranco-Gil D. Validity of a novel device for real-time analysis of cyclists' drag area. J Sci Med Sport 2019; 23:421-425. [PMID: 31740264 DOI: 10.1016/j.jsams.2019.10.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 10/18/2019] [Accepted: 10/30/2019] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To assess the reliability, validity, and sensitivity of a novel device (Notio Konect™) which is purported to provide a real-time analysis of aerodynamic drag area (CdA) during cycling. DESIGN Observational, cross-sectional study. METHODS Fifteen trained cyclists rode in an indoor velodrome using three different positions (upright, aero [holding aero bars], and optimized aero [similar to aero, but wearing a time-trial helmet]). They completed six 1-min trials in each position. The CdA was measured with Notio and with two other systems (Track Aero System™ [TAS] and a validated mathematical model). RESULTS The CdA measured with Notio showed good reliability (intra-class correlation coefficient [ICC]=0.92, 90% confidence interval [CI]=0.89-0.95). Notio showed an almost perfect relationship with both TAS (ICC=0.99, 90% CI=0.98-0.99) and the mathematical model (ICC=0.99, 90% CI=0.98-0.99). However, the CdA values provided by the former (0.308±0.051m2) were significantly higher (albeit with a trivial effect size [ES]) compared with TAS (0.300±0.051m2, p<0.001, ES=0.15) and the mathematical model (0.303±0.051m2, p=0.005, ES=0.09). The CdA was higher in the upright than in the aero position with all systems (all p<0.001, ES=1.84-1.89), and higher in the aero than in the optimized aero position when measured with TAS (p=0.033, ES=0.22) or the mathematical model (p=0.024, ES=0.24), but not with Notio (p=0.220, ES=0.19). CONCLUSIONS Notio appears to be reliable, strongly correlated to other established systems, and discerns large (upright vs aero) but not small (aero vs optimized aero) variations in riding position. Further research is needed to confirm its validity in outdoor conditions.
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Affiliation(s)
- Pedro L Valenzuela
- Department of Systems Biology, University of Alcalá, Spain; Department of Sport and Health, Spanish Agency for Health Protection in Sport (AEPSAD), Spain.
| | | | - Jaime Gil-Cabrera
- Ciclismo y Rendimiento, Spain; Faculty of Sport Sciences, Universidad Europea de Madrid, Spain
| | - Eduardo Talavera
- Ciclismo y Rendimiento, Spain; Faculty of Sport Sciences, Universidad Europea de Madrid, Spain
| | - Alejandro Lucia
- Faculty of Sport Sciences, Universidad Europea de Madrid, Spain; Instituto de Investigación Hospital 12 de Octubre ('i+12'), Spain
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Abstract
Abstract
Aerodynamic flow around an 1/5 scale cyclist model was studied experimentally and numerically. First, measurements of drag force were performed for the model in a low-speed wind tunnel at Reynolds numbers from $$5.5 \times 10^{4}$$5.5×104 to $$1.8 \times 10^{5}$$1.8×105. Meanwhile, numerical computation using a large eddy simulation method was performed at three Reynolds numbers of $$1.1 \times 10^{4}$$1.1×104, $$6.5 \times 10^{4}$$6.5×104 and $$1.5 \times 10^{5}$$1.5×105 to obtain the drag coefficients for comparison. Second, flow visualization was made in a water channel and the wind tunnel mentioned to examine the three-dimensional flow separation pattern on the model surface, which could also be realized from the numerical results. Finally, a wake flow survey based on the hot-wire measurements in the wind tunnel showed that in the near-wake region, the flow was featured with the formation of multiple streamwise vortices. The numerical results further indicated that these vortices were evolved from the separated flows occurred on the model surface.
Graphic Abstract
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19
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Dyer B, Disley BX. The aerodynamic impact of a range of prostheses designs when cycling with a trans-tibial amputation. Disabil Rehabil Assist Technol 2019; 15:577-581. [PMID: 31012750 DOI: 10.1080/17483107.2019.1594409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Previous studies have proposed that an aerodynamically optimized prosthetic limb could provide performance enhancement for competitive paracyclists. Four different designs of prosthetic limbs were assessed for their impact upon the aerodynamic drag of an elite cyclist with a lower-limb amputation. The pylon area acted as the controlled location for the differences in design between the test prostheses. A validated field test method was used to derive the participant's total aerodynamic drag when using the prostheses designs. The field test method produced a repeatable experimental process and demonstrated that small changes in form made to the pylon region resulted in measurable differences to the participant's cycling performance. In addition, statistical significance was obtained between a baseline design and the prostheses prototype with the greatest aspect ratio (p= <.05). The magnitude of improvements recorded in this study could potentially influence a rider's finishing time at international sporting events like the Paralympic Games.Implications for RehabilitationSmall changes in form made to a cycling prostheses design can potentially deliver worthwhile performance enhancement.Prosthetists may obtain greater end-user satisfaction by taking a broader approach to sports prostheses design than just fit and biomechanical function alone.This study indicates that other regions of the cycling prosthesis could now benefit from aerodynamic optimization with the aim to further improve paracycling performance.
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Affiliation(s)
- Bryce Dyer
- Faculty of Science & Technology, Bournemouth University, Poole, UK
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20
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Mannion P, Toparlar Y, Clifford E, Hajdukiewicz M, Andrianne T, Blocken B. The impact of arm-crank position on the drag of a paralympic hand-cyclist. Comput Methods Biomech Biomed Engin 2019; 22:386-395. [DOI: 10.1080/10255842.2018.1558217] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Paul Mannion
- Department of Civil Engineering, College of Engineering and Informatics, National University of Ireland Galway, University Road, Galway, Ireland
- Department of the Built Environment, Eindhoven University of Technology, Eindhoven, The Netherlands
- Informatics Research Unit for Sustainable Engineering (IRUSE), Galway, Ireland
| | - Yasin Toparlar
- Department of the Built Environment, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Eoghan Clifford
- Department of Civil Engineering, College of Engineering and Informatics, National University of Ireland Galway, University Road, Galway, Ireland
- Informatics Research Unit for Sustainable Engineering (IRUSE), Galway, Ireland
| | - Magdalena Hajdukiewicz
- Department of Civil Engineering, College of Engineering and Informatics, National University of Ireland Galway, University Road, Galway, Ireland
- Informatics Research Unit for Sustainable Engineering (IRUSE), Galway, Ireland
| | - Thomas Andrianne
- Department of Aerospace and Mechanical engineering, University of Liège, Allée de la Découverte, 9 Quartier Polytech 1, Liège, Belgium
| | - Bert Blocken
- Department of the Built Environment, Eindhoven University of Technology, Eindhoven, The Netherlands
- Department of Civil Engineering, Leuven University, Kasteelpark Arenberg 40, Leuven, Belgium
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21
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Sousa CV, Barbosa LP, Sales MM, Santos PA, Tiozzo E, Simões HG, Nikolaidis PT, Knechtle B. Cycling as the Best Sub-8-Hour Performance Predictor in Full Distance Triathlon. Sports (Basel) 2019; 7:E24. [PMID: 30669265 PMCID: PMC6359305 DOI: 10.3390/sports7010024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 01/15/2019] [Accepted: 01/16/2019] [Indexed: 01/06/2023] Open
Abstract
For any triathlon distance (short, Olympic, half-distance and full-distance), competitors spend more time cycling than swimming or running, but running has emerged as the discipline with the greatest influence on overall performance at the Olympic distance. However, there is a lack of evidence on which discipline has the greatest influence on performance in the overall full-distance triathlon (3.8 km swimming/180 km cycling/42.195 km running), especially for the fastest performing athletes of all time. The total race times of 51 fastest triathletes (sub-8-hour) were studied, while for the split times, a sample of 44 participants was considered. The discipline that seemed to better predict total race time was cycling (coefficient = 0.828; p < 0.001), followed by running (coefficient = 0.726; p < 0.001) and swimming (coefficient = 0.476; p < 0.001). Furthermore, cycling was the discipline with the highest performance improvement over the years, whereas running had a slightly decrease. In conclusion, cycling seems to be the discipline with greater influence in final result for the full-distance triathlon.
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Affiliation(s)
- Caio Victor Sousa
- Graduate Program in Physical Education, Catholic University of Brasília, Brasília 71966-700, DF, Brazil.
- Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
| | - Lucas Pinheiro Barbosa
- Graduate Program in Physical Education, Catholic University of Brasília, Brasília 71966-700, DF, Brazil.
| | - Marcelo Magalhães Sales
- Department of Physical Education, Goiás State University, Quirinopolis 75860-000, GO, Brazil.
| | - Patrick Anderson Santos
- Graduate Program in Physical Education, Catholic University of Brasília, Brasília 71966-700, DF, Brazil.
| | - Eduard Tiozzo
- Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
| | - Herbert Gustavo Simões
- Graduate Program in Physical Education, Catholic University of Brasília, Brasília 71966-700, DF, Brazil.
| | | | - Beat Knechtle
- Institute of Primary Care, University of Zurich, CH-8006 Zurich, Switzerland.
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23
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Tengattini S, Bigazzi AY. Physical characteristics and resistance parameters of typical urban cyclists. J Sports Sci 2018; 36:2383-2391. [PMID: 29598811 DOI: 10.1080/02640414.2018.1458587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
This study investigates the rolling and drag resistance parameters and bicycle and cargo masses of typical urban cyclists. These factors are important for modelling of cyclist speed, power and energy expenditure, with applications including exercise performance, health and safety assessments and transportation network analysis. However, representative values for diverse urban travellers have not been established. Resistance parameters were measured utilizing a field coast-down test for 557 intercepted cyclists in Vancouver, Canada. Masses were also measured, along with other bicycle attributes such as tire pressure and size. The average (standard deviation) of coefficient of rolling resistance, effective frontal area, bicycle plus cargo mass, and bicycle-only mass were 0.0077 (0.0036), 0.559 (0.170) m2, 18.3 (4.1) kg, and 13.7 (3.3) kg, respectively. The range of measured values is wider and higher than suggested in existing literature, which focusses on sport cyclists. Significant correlations are identified between resistance parameters and rider and bicycle attributes, indicating higher resistance parameters for less sport-oriented cyclists. The findings of this study are important for appropriately characterising the full range of urban cyclists, including commuters and casual riders.
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Affiliation(s)
- Simone Tengattini
- a Department of Civil Engineering , The University of British Columbia , Vancouver , Canada
| | - Alexander York Bigazzi
- b Department of Civil Engineering and School of Community and Regional Planning , The University of British Columbia , Vancouver , Canada
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24
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The variations on the aerodynamics of a world-ranked wheelchair sprinter in the key-moments of the stroke cycle: A numerical simulation analysis. PLoS One 2018; 13:e0193658. [PMID: 29489904 PMCID: PMC5831413 DOI: 10.1371/journal.pone.0193658] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 02/15/2018] [Indexed: 11/19/2022] Open
Abstract
Biomechanics plays an important role helping Paralympic sprinters to excel, having the aerodynamic drag a significant impact on the athlete’s performance. The aim of this study was to assess the aerodynamics in different key-moments of the stroke cycle by Computational Fluid Dynamics. A world-ranked wheelchair sprinter was scanned on the racing wheelchair wearing his competition gear and helmet. The sprinter was scanned in three different positions: (i) catch (hands in the 12h position on the hand-rim); (ii) the release (hands in the 18h position on the hand-rim) and; (iii) recovery phase (hands do not touch the hand-rim and are hyperextended backwards). The simulations were performed at 2.0, 3.5, 5.0 and 6.5 m/s. The mean viscous and pressure drag components, total drag force and effective area were retrieved after running the numerical simulations. The viscous drag ranged from 3.35 N to 2.94 N, pressure drag from 0.38 N to 5.51 N, total drag force from 0.72 N to 8.45 N and effective area from 0.24 to 0.41 m2. The results pointed out that the sprinter was submitted to less drag in the recovery phase, and higher drag in the catch. These findings suggest the importance of keeping an adequate body alignment to avoid an increase in the drag force.
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Optimizing the Team for Required Power During Track-Cycling Team Pursuit. Int J Sports Physiol Perform 2017; 12:1385-1391. [DOI: 10.1123/ijspp.2016-0451] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Purpose: Since the aim of the men’s team pursuit in time-trial track cycling is to accomplish a distance of 4000 m as fast as possible, optimizing aerodynamic drag can contribute to achieving this goal. The aim of this study was to determine the drafting effect in second, third, and fourth position during the team pursuit in track cycling as a function of the team members’ individual frontal areas in order to minimize the required power. Method: Eight experienced track cyclists of the Dutch national selection performed 39 trials of 3 km in different teams of 4 cyclists at a constant velocity of 15.75 m/s. Frontal projected areas were determined, and together with field-derived drag coefficients for all 4 positions, the relationships between frontal areas of team members and drag fractions were estimated using generalized estimating equations. Results: The frontal area of both the cyclist directly in front of the drafter and the drafter himself turned out to be significant determinants of the drag fraction at the drafter’s position (P < .05) for all 3 drafting positions. Predicted required power for individuals in drafting positions differed up to 35 W depending on team composition. For a team, a maximal difference in team efficiency (1.2%) exists by selecting cyclists in a specific sequence. Conclusion: Estimating required power for a specific team composition gives insight into differences in team efficiency for the team pursuit. Furthermore, required power for individual team members ranges substantially depending on team composition.
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Dyer B, Disley BX. Validation of the virtual elevation field test method when assessing the aerodynamics of para-cyclists with a uni-lateral trans-tibial amputation. Disabil Rehabil Assist Technol 2017; 13:107-111. [PMID: 28287007 DOI: 10.1080/17483107.2017.1297857] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
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 m2 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.
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Affiliation(s)
- Bryce Dyer
- a Faculty of Science & Technology , Bournemouth University , Poole , UK
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Priego Quesada JI, Pérez-Soriano P, Lucas-Cuevas AG, Salvador Palmer R, Cibrián Ortiz de Anda RM. Effect of bike-fit in the perception of comfort, fatigue and pain. J Sports Sci 2016; 35:1459-1465. [PMID: 27490817 DOI: 10.1080/02640414.2016.1215496] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The aim of this study was to assess the influence of different bike positions on the perception of fatigue, pain and comfort. Twenty cyclists underwent three tests that involved cycling for 45 min at their individual 50% peak aerobic power output while adopting different positions on the bike. Participants performed the cycling tests adopting three positions defined by two parameters (knee flexion angle [20°, 30°, 40°] and trunk flexion angle [35°, 45°, 55°]) in random order. Angles were measured using a 2D motion analysis system during cycling and applying Fonda's correction factor. Perceptions of comfort, fatigue and pain were reported before the end of each test. The combination of 40° knee flexion and 35° trunk flexion was perceived as the most uncomfortable position. Moreover, greater knee flexion had a negative effect on trunk comfort, accompanied by greater levels of fatigue and pain perception in the anterior part of the thigh and knee. In conclusion, cyclists perceived the most comfortable position to be when the saddle height was within the recommended knee angle (30° calculated from the offset position or 40 ± 4.0° of absolute value). Upright trunk was found to be the most comfortable position for recreational cyclists, where aerodynamics is not so important. Cyclists' bike perceptions should be taken into account when it comes to choosing the most beneficial position, since this can play a role in injury prevention and enhance cycling performance.
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Affiliation(s)
- Jose Ignacio Priego Quesada
- a Biophysics and Medical Physics Group, Department of Physiology , University of Valencia , Valencia , Spain.,b Research Group in Sports Biomechanics (GIBD), Department of Physical Education and Sports , University of Valencia , Valencia , Spain
| | - Pedro Pérez-Soriano
- b Research Group in Sports Biomechanics (GIBD), Department of Physical Education and Sports , University of Valencia , Valencia , Spain
| | - Angel Gabriel Lucas-Cuevas
- b Research Group in Sports Biomechanics (GIBD), Department of Physical Education and Sports , University of Valencia , Valencia , Spain
| | - Rosario Salvador Palmer
- a Biophysics and Medical Physics Group, Department of Physiology , University of Valencia , Valencia , Spain
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Menard M, Domalain M, Decatoire A, Lacouture P. Influence of saddle setback on pedalling technique effectiveness in cycling. Sports Biomech 2016; 15:462-72. [PMID: 27239728 DOI: 10.1080/14763141.2016.1176244] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Peterman JE, Lim AC, Ignatz RI, Edwards AG, Byrnes WC. Field-measured drag area is a key correlate of level cycling time trial performance. PeerJ 2015; 3:e1144. [PMID: 26290797 PMCID: PMC4540006 DOI: 10.7717/peerj.1144] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 07/10/2015] [Indexed: 12/02/2022] Open
Abstract
Drag area (Ad ) is a primary factor determining aerodynamic resistance during level cycling and is therefore a key determinant of level time trial performance. However, Ad has traditionally been difficult to measure. Our purpose was to determine the value of adding field-measured Ad as a correlate of level cycling time trial performance. In the field, 19 male cyclists performed a level (22.1 km) time trial. Separately, field-determined Ad and rolling resistance were calculated for subjects along with projected frontal area assessed directly (AP ) and indirectly (Est AP ). Also, a graded exercise test was performed to determine [Formula: see text] peak, lactate threshold (LT), and economy. [Formula: see text] peak ([Formula: see text]) and power at LT were significantly correlated to power measured during the time trial (r = 0.83 and 0.69, respectively) but were not significantly correlated to performance time (r = - 0.42 and -0.45). The correlation with performance time improved significantly (p < 0.05) when these variables were normalized to Ad . Of note, Ad alone was better correlated to performance time (r = 0.85, p < 0.001) than any combination of non-normalized physiological measure. The best correlate with performance time was field-measured power output during the time trial normalized to Ad (r = - 0.92). AP only accounted for 54% of the variability in Ad . Accordingly, the correlation to performance time was significantly lower using power normalized to AP (r = - 0.75) or Est AP (r = - 0.71). In conclusion, unless normalized to Ad , level time trial performance in the field was not highly correlated to common laboratory measures. Furthermore, our field-measured Ad is easy to determine and was the single best predictor of level time trial performance.
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Affiliation(s)
- James E. Peterman
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Allen C. Lim
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Ryan I. Ignatz
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Andrew G. Edwards
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - William C. Byrnes
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
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Costes A, Turpin NA, Villeger D, Moretto P, Watier B. A reduction of the saddle vertical force triggers the sit-stand transition in cycling. J Biomech 2015; 48:2998-3003. [PMID: 26298490 DOI: 10.1016/j.jbiomech.2015.07.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 07/24/2015] [Accepted: 07/30/2015] [Indexed: 10/23/2022]
Abstract
The purpose of the study was to establish the link between the saddle vertical force and its determinants in order to establish the strategies that could trigger the sit-stand transition. We hypothesized that the minimum saddle vertical force would be a critical parameter influencing the sit-stand transition during cycling. Twenty-five non-cyclists were asked to pedal at six different power outputs from 20% (1.6 ± 0.3 W kg(-1)) to 120% (9.6 ± 1.6 W kg(-1)) of their spontaneous sit-stand transition power obtained at 90 rpm. Five 6-component sensors (saddle tube, pedals and handlebars) and a full-body kinematic reconstruction were used to provide the saddle vertical force and other force components (trunk inertial force, hips and shoulders reaction forces, and trunk weight) linked to the saddle vertical force. Minimum saddle vertical force linearly decreased with power output by 87% from a static position on the bicycle (5.30 ± 0.50 N kg(-1)) to power output=120% of the sit-stand transition power (0.68 ± 0.49 N kg(-1)). This decrease was mainly explained by the increase in instantaneous pedal forces from 2.84 ± 0.58 N kg(-1) to 6.57 ± 1.02 N kg(-1) from 20% to 120% of the power output corresponding to the sit-stand transition, causing an increase in hip vertical forces from -0.17 N kg(-1) to 3.29 N kg(-1). The emergence of strategies aiming at counteracting the elevation of the trunk (handlebars and pedals pulling) coincided with the spontaneous sit-stand transition power. The present data suggest that the large decrease in minimum saddle vertical force observed at high pedal reaction forces might trigger the sit-stand transition in cycling.
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Affiliation(s)
- Antony Costes
- University of Toulouse, UPS, PRISSMH, 118 Route de Narbonne, 31062 Toulouse Cedex 9, France.
| | - Nicolas A Turpin
- University of Toulouse, UPS, PRISSMH, 118 Route de Narbonne, 31062 Toulouse Cedex 9, France; Center for Interdisciplinary Research in Rehabilitation (CRIR), Institut de Réadaptation Gingras-Lindsay de Montréal and Jewish Rehabilitation Hospital, Laval, Quebec, Canada
| | - David Villeger
- University of Toulouse, UPS, PRISSMH, 118 Route de Narbonne, 31062 Toulouse Cedex 9, France
| | - Pierre Moretto
- University of Toulouse, UPS, CRCA, 118 route de Narbonne, F-31062 Toulouse Cedex 9, France; CNRS, CRCA, 118 route de Narbonne, F-31062 Toulouse Cedex 9, France
| | - Bruno Watier
- CNRS, LAAS, 7 Avenue du Colonel Roche, F-31400 Toulouse, France; University of Toulouse, UPS, LAAS, F-31400 Toulouse, France
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Dyer B. The importance of aerodynamics for prosthetic limb design used by competitive cyclists with an amputation: An introduction. Prosthet Orthot Int 2015; 39:232-7. [PMID: 24692061 DOI: 10.1177/0309364614527121] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 02/11/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND/OBJECTIVES This study introduces the importance of the aerodynamics to prosthetic limb design for athletes with either a lower-limb or upper-limb amputation. STUDY DESIGN 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. METHODS 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. RESULTS 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. CONCLUSION 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. CLINICAL RELEVANCE 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.
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Affiliation(s)
- Bryce Dyer
- Faculty of Science and Technology, Bournemouth University, Poole, UK
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Fintelman DM, Sterling M, Hemida H, Li FX. Effect of different aerodynamic time trial cycling positions on muscle activation and crank torque. Scand J Med Sci Sports 2015; 26:528-34. [PMID: 25996563 DOI: 10.1111/sms.12479] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2015] [Indexed: 11/28/2022]
Abstract
To reduce air resistance, time trial cyclists and triathletes lower their torso angle. The aim of this study was to investigate the effect of lowering time trial torso angle positions on muscle activation patterns and crank torque coordination. It was hypothesized that small torso angles yield a forward shift of the muscle activation timing and crank torque. Twenty-one trained cyclists performed three exercise bouts at 70% maximal aerobic power in a time trial position at three different torso angles (0°, 8°, and 16°) at a fixed cadence of 85 rpm. Measurements included surface electromyography, crank torques and gas exchange. A significant increase in crank torque range and forward shift in peak torque timing was found at smaller torso angles. This relates closely with the later onset and duration of the muscle activation found in the gluteus maximus muscle. Torso angle effects were only observed in proximal monoarticular muscles. Moreover, all measured physiological variables (oxygen consumption, breathing frequency, minute ventilation) were significantly increased with lowering torso angle and hence decreased the gross efficiency. The findings provide support for the notion that at a cycling intensity of 70% maximal aerobic power, the aerodynamic gains outweigh the physiological/biomechanical disadvantages in trained cyclists.
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Affiliation(s)
- D M Fintelman
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - M Sterling
- School of Civil Engineering, University of Birmingham, Birmingham, UK
| | - H Hemida
- School of Civil Engineering, University of Birmingham, Birmingham, UK
| | - F-X Li
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
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Fintelman DM, Sterling M, Hemida H, Li FX. The effect of time trial cycling position on physiological and aerodynamic variables. J Sports Sci 2015; 33:1730-7. [PMID: 25658151 DOI: 10.1080/02640414.2015.1009936] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
To reduce aerodynamic resistance cyclists lower their torso angle, concurrently reducing Peak Power Output (PPO). However, realistic torso angle changes in the range used by time trial cyclists have not yet been examined. Therefore the aim of this study was to investigate the effect of torso angle on physiological parameters and frontal area in different commonly used time trial positions. Nineteen well-trained male cyclists performed incremental tests on a cycle ergometer at five different torso angles: their preferred torso angle and at 0, 8, 16 and 24°. Oxygen uptake, carbon dioxide expiration, minute ventilation, gross efficiency, PPO, heart rate, cadence and frontal area were recorded. The frontal area provides an estimate of the aerodynamic drag. Overall, results showed that lower torso angles attenuated performance. Maximal values of all variables, attained in the incremental test, decreased with lower torso angles (P < 0.001). The 0° torso angle position significantly affected the metabolic and physiological variables compared to all other investigated positions. At constant submaximal intensities of 60, 70 and 80% PPO, all variables significantly increased with increasing intensity (P < 0.0001) and decreasing torso angle (P < 0.005). This study shows that for trained cyclists there should be a trade-off between the aerodynamic drag and physiological functioning.
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Affiliation(s)
- D M Fintelman
- a School of Sport, Exercise and Rehabilitation Sciences , University of Birmingham , Birmingham , UK
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Accuracy of Indirect Estimation of Power Output From Uphill Performance in Cycling. Int J Sports Physiol Perform 2014; 9:777-82. [DOI: 10.1123/ijspp.2013-0320] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Purpose:To use measurement by cycling power meters (Pmes) to evaluate the accuracy of commonly used models for estimating uphill cycling power (Pest). Experiments were designed to explore the influence of wind speed and steepness of climb on accuracy of Pest. The authors hypothesized that the random error in Pest would be largely influenced by the windy conditions, the bias would be diminished in steeper climbs, and windy conditions would induce larger bias in Pest.Methods:Sixteen well-trained cyclists performed 15 uphill-cycling trials (range: length 1.3–6.3 km, slope 4.4–10.7%) in a random order. Trials included different riding position in a group (lead or follow) and different wind speeds. Pmes was quantified using a power meter, and Pest was calculated with a methodology used by journalists reporting on the Tour de France.Results:Overall, the difference between Pmes and Pest was –0.95% (95%CI: –10.4%, +8.5%) for all trials and 0.24% (–6.1%, +6.6%) in conditions without wind (>2 m/s). The relationship between percent slope and the error between Pest and Pmes were considered trivial.Conclusions:Aerodynamic drag (affected by wind velocity and orientation, frontal area, drafting, and speed) is the most confounding factor. The mean estimated values are close to the power-output values measured by power meters, but the random error is between ±6% and ±10%. Moreover, at the power outputs (>400 W) produced by professional riders, this error is likely to be higher. This observation calls into question the validity of releasing individual values without reporting the range of random errors.
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Padulo J, Laffaye G, Bertucci W, Chaouachi A, Viggiano D. Optimisation of starting conditions in track cycling. SPORT SCIENCES FOR HEALTH 2014. [DOI: 10.1007/s11332-014-0192-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bertucci WM, Rogier S, Reiser RF. Evaluation of aerodynamic and rolling resistances in mountain-bike field conditions. J Sports Sci 2013; 31:1606-13. [DOI: 10.1080/02640414.2013.792945] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Peveler WW. The Accuracy of Simulated Indoor Time Trials Utilizing a CompuTrainer and GPS Data. J Strength Cond Res 2013; 27:2823-7. [DOI: 10.1519/jsc.0b013e318280ce76] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bertucci W, Rogier S. Effects of different types of tyres and surfaces on the power output in the mountain bike field conditions: a preliminary study. Comput Methods Biomech Biomed Engin 2012; 15 Suppl 1:234-6. [PMID: 23009491 DOI: 10.1080/10255842.2012.713605] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- W Bertucci
- Laboratoire d'Ingénierie et Sciences des Matériaux (LISM), Université de Reims Champagne Ardenne, Campus Moulin de la Housse, 51687, Reims, France.
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