Validity of a novel device for real-time analysis of cyclists' drag area

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.

Reliability and sensitivity of the Notio Konect to quantify coefficient of drag area in elite track cyclists

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 (C_DA). Recently bicycle-mounted pitot tubes, such as the Notio Konect (NK) have become more commercially available making C_DA 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 C_DA. Accordingly, the aim of this study was to establish the intra- and inter-effort reliability and sensitivity of the C_DA 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 C_DA 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 C_DA 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.