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

Validity of a novel device for indoor analysis of cyclists' drag area

PURPOSE

Cyclists need to measure aerodynamic resistance accurately and reliably, as well as economically. Devices such as Notio Aerostick, an equipment device that includes one pitot tube, have appeared for this purpose. The aim of this study is, therefore, to test the reliability and degree of agreement in the evaluation of the CdA (coefficient of aerodynamic drag), assessed by means of the Notio Aerostick compared to the Virtual Elevation (VE) and Martin mathematical models.

METHOD

Seventeen professional cyclists rode in a 250-metre-long velodrome covered with a concrete surface with their own time trial bikes. Each cyclist completed three rides of 15 laps at constant speed for the evaluation of the CdA, each of them in a different position [Baseline (B), Change 1 (C1) and Change 2 (C2)].

RESULTS

The differences in CdA between methods were found for Martin in comparison with VE in all positions (p <.001) and with Notio Aerostick in B and C2 (p> .05). About differences of CdA for each method, considering between position changes, the results were the same for VE and Martin, but different for Notio Aerostick.

CONCLUSIONS

Findings suggest that, notwithstanding Notio Aerostick is valid if we compare CdA values with respect to VE, since the direction of their between-positions CdA changes differs, the results of their aerodynamic evaluation could lead us to recommend different final setups. We need studies that evaluate different units of the Notio Aerostick device as well as the reliability and precision of each sensor that includes Notio Aerostick.HighlightsThe CdA calculated by the Notio Aerostick and VE, a mathematical model previously validated, can be interchangeable, however the final position recommended by each method may be different, since the changes in the following position are given by the changes of the CdA in the previous position.None of the three methods allowed elite cyclists to measure statistically significant differences between the proposed setups.Although the CdA differences between positions were not significant, they can be decisive in the final result of a time trial competition.

Using Field Based Data to Model Sprint Track Cycling Performance

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.

Assessment of Able-Bodied and Amputee Cyclists' Aerodynamics by Computational Fluid Dynamics

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.

The Aerodynamics and Energy Cost Assessment of an Able-Bodied Cyclist and Amputated Models by Computer Fluid Dynamics

Background and Objectives: The aim of this study was to assess and compare the drag and energy cost of three cyclists assessed by computational fluid dynamics (CFD) and analytical procedures. Materials and methods: A transradial (Tr) and transtibial (Tt) were compared to a full-body cyclist at different speeds. An elite male cyclist with 65 kg of mass and 1.72 m of height volunteered for this research with his competition cloths, helmet and bicycle with 5 kg of mass. A 3D model of the bicycle and cyclist in the upright position was obtained for numerical simulations. Upon that, two more models were created, simulating elbow and knee-disarticulated athletes. Numerical simulations by computational fluid dynamics and analytical procedures were computed to assess drag and energy cost, respectively. Results: One-Way ANOVA presented no significant differences between cyclists for drag (F = 0.041; p = 0.960; η² = 0.002) and energy cost (F = 0.42; p = 0.908; η² = 0.002). Linear regression presented a very high adjustment for absolute drag values between able-bodied and Tr (R² = 1.000; Ra² = 1.000; SEE = 0.200) and Tt (R² = 1.00; Ra² = 1.000; SEE = 0.160). The linear regression for energy cost presented a very high adjustment for absolute values between able-bodied and Tr (R² = 1.000; Ra² = 1.000; SEE = 0.570) and Tt (R² = 1.00; Ra² = 1.00; SEE = 0.778). Conclusions: This study suggests that drag and energy cost was lower in the able-bodied, followed by the Tr and Tt cyclists.

Bicycling participation in people with a lower limb amputation: a scoping review

BACKGROUND

To review literature on bicycling participation, as well as facilitators and barriers for bicycling in people with a lower limb amputation (LLA).

METHODS

Peer-reviewed, primary, full text, studies about bicycling in people with a LLA from midfoot level to hemipelvectomy were searched in Pubmed, Embase, Cinahl, Cochrane library, and Sportdiscus. No language or publication date restrictions were applied. Included full-text studies were assessed for methodological quality using the Effective Public Health Practice Project tool. Data were extracted, synthesized and reported following Preferred Reporting Items for Systematic Review.

RESULTS

In total, 3144 papers were identified and 14 studies were included. The methodological quality of 13 studies was weak and 1 was moderate. Bicycling participation ranged from 4 to 48%. A shorter time span after LLA and a distal amputation were associated with a higher bicycling participation rate particularly for transportation. In people with a transtibial amputation, a correct prosthetic foot or crank length can reduce pedalling asymmetry during high-intensity bicycling. People with limitations in knee range of motion or skin abrasion can use a hinged crank arm or a low profile prosthetic socket respectively.

CONCLUSION

People with a LLA bicycled for transportation, recreation, sport and physical activity. Adaptation of prosthetic socket, pylon and foot as well as bicycle crank can affect pedalling work and force, range of motion, and aerodynamic drag. Because the suggestions from this review were drawn from evidences mostly associated to competition, prosthetists should carefully adapt the existing knowledge to clients who are recreational bicyclists.