The understanding and development of cycling aerodynamics

Steep uphill cycling using repeated transitions between seated and standing positions results in a lower blood-lactate concentration than continuous use of either seated or standing position

This study investigated whether repeated transitions between seated and standing positions has a different physiological response compared to continuous use of either seated position or standing position during steep uphill cycling among elite cyclists. Ten elite male cyclists completed three 5-min treadmill cycling tests at an inclination of 6.8° with constant individual-based speed resulting in a work intensity close to the aerobic threshold. During the first and third test, the participants used standing position (ST test) and seated position (SE test) or vice versa, whereas in the second test, they made repeated transitions between standing and seated positions every 10 s (RT test). The last 2 min of each test was used to measure the mean values of oxygen uptake (V̇O2) and respiratory exchange ratio, which were used to calculate the metabolic rate (MR) and gross efficiency (GE). Additionally, the blood-lactate concentration before and after (Lapost) each test was determined. One-way repeated measures ANOVA was used to determine the effect of cycling position on the physiological response. No significant differences between tests were observed for the variables related to aerobic energy expenditure (i.e., V̇O2, MR and GE), whereas the RT test was associated with a significantly lower Lapost compared to the ST and SE tests. Steep uphill cycling, at an intensity close to the aerobic threshold, with repeated transitions between standing and seated positions, did not have a higher oxygen consumption; instead, the blood-lactate concentration was lower during the RT test compared to that under continuous use of either seated or standing position.

Does Cycling Training Reduce Quality of Functional Movement Motor Patterns and Dynamic Postural Control in Adolescent Cyclists? A Pilot Study

The aim of this study was to assess whether cycling training may influence quality of functional movement patterns and dynamic postural control. We also sought to determine if the Functional Movement Screen and Lower Quarter Y-balance tests could be predictive of injury risk among adolescent road cyclists. Twenty-three male road cyclists, aged 15-18 years, were involved in the study. Quality of functional movement patterns was assessed using the Functional Movement Screen test (FMS). Dynamic postural control was evaluated using the Lower Quarter Y-balance test (YBT-LQ). Information on injury occurrence was collected through a retrospective survey. The results showed the highest percentage of scores equalling 0 and 1 (>30% in total) in two FMS component tests: the hurdle step and trunk stability push-up. The results also demonstrated a low injury predictive value of the Functional Movement Screen (cut-off <14/21 composite score) and the Lower Quarter Y-balance test (cut-off <94% composite score and >4 cm reach distance asymmetry) in adolescent road cyclists. The most important information obtained from this study is that youth road cyclists may have functional deficits within the lumbo-pelvic-hip complex and the trunk, while neither the FMS nor the YBT-LQ test are not recommended for injury risk screening in cyclists.

Aerodynamic analysis of uphill drafting in cycling

Some teams aiming for victory in a mountain stage in cycling take control in the uphill sections of the stage. While drafting, the team imposes a high speed at the front of the peloton defending their team leader from opponent’s attacks. Drafting is a well-known strategy on flat or descending sections and has been studied before in this context. However, there are no systematic and extensive studies in the scientific literature on the aerodynamic effect of uphill drafting. Some studies even suggested that for gradients above 7.2% the speeds drop to 17 km/h and the air resistance can be neglected. In this paper, uphill drafting is analyzed and quantified by means of drag reductions and power reductions obtained by computational fluid dynamics simulations validated with wind tunnel measurements. It is shown that even for gradients above 7.2%, drafting can yield substantial benefits. Drafting allows cyclists to save over 7% of power on a slope of 7.5% at a speed of 6 m/s. At a speed of 8 m/s, this reduction can exceed 16%. Sensitivity analyses indicate that significant power savings can be achieved, also with varying bicycle, cyclist, road and environmental characteristics.

Impact of a motorcycle on cyclist aerodynamic drag in parallel and staggered arrangements

Cycling races contain a multitude of motorcycles for various activities including television broadcasting. During parts of the race, these motorcycles can ride in close proximity of cyclists. Earlier studies focused on the impact of a nearby motorcycle on cyclist drag for in-line arrangements. It was shown that not only a motorcycle in front of a cyclist but also a motorcycle closely behind a cyclist can substantially reduce cyclist drag. However, there appears to be no information in the scientific literature about the impact of the motorcycle on cyclist drag for parallel and staggered arrangements. This paper presents wind tunnel measurements of cyclist drag for 32 different parallel and staggered cyclist-motorcycle arrangements. It is shown that the parallel arrangement leads to a drag increase for the cyclist, in the range of 5 to about 10% for a lateral distance of 2 to 1 m. The staggered arrangement can lead to either a drag increase or a drag decrease, where the latter is about 2% for most positions analyzed. For one of the parallel arrangements, computational fluid dynamics simulations were performed to provide insight into the reasons for the drag increase. A cyclist power model was used to convert the drag changes into potential time gains or losses. Compared to a lone cyclist riding at a speed of 46.8 km/h (13 m/s) on level road in calm weather, the time loss by a drag increase of 10%, 4% and − 2% was 2.16, 0.76 s and − 0.80 s per km, respectively. These time differences are large enough to influence the outcome of cycling races.

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.

Impact of Power Output on Muscle Activation and 3D Kinematics During an Incremental Test to Exhaustion in Professional Cyclists

This study aimed to quantify the influence of an increase in power output (PO) on joint kinematics and electromyographic (EMG) activity during an incremental test to exhaustion for a population of professional cyclists. The hip flexion/extension and internal/external rotation as well as knee abduction/adduction ranges of motion were significantly decreased at 100% of the maximal aerobic power (MAP). EMG analysis revealed a significant increase in the root mean square (RMS) for all muscles from 70% of the MAP. Gastrocnemius muscles [lateralis gastrocnemius (GasL) and medialis gastrocnemius (GasM)] were the less affected by the increase of PO. Cross-correlation method showed a significant increase in the lag angle values for VM in the last stage compared to the first stage, meaning that the onset of the activation started earlier during the pedaling cycle. Statistical Parametric Mapping (SPM) demonstrated that from 70% MAP, biceps femoris (BF), tibialis anterior (TA), gluteus maximus (GM), and rectus femoris (RF) yielded larger ranges of the crank cycle on which the level of recruitment was significantly increased. This study revealed specific muscular and kinematic coordination for professional cyclists in response to PO increase.

Preliminary study on crosswind aerodynamics for a group of road race cyclists

Under crosswind conditions, road cyclists experience an extra drag force and a destabilising lateral force. In these conditions a group of cyclists manages to reorganise its spatial formation to minimise these forces forming an echelon, i.e a diagonal single pace line of riders staggered across the road, a configuration which is markedly different from those adopted in wind-free conditions. To study the effect of the crosswind on drag and lateral forces on the riders we performed wind-tunnel experiments using a scale model cyclist and measuring the forces by means of a load cell. Several configurations with one, two, and four cyclists have been investigated varying yaw angles. Results show that, in a basic 4 rider configuration at a 50 $$^{\circ }$$ ∘ yaw angle, a sheltered rider within the echelon experiences less than 30% of the drag of the guttered rider behind the echelon, struggling against the crosswind. Furthermore, we show that an echelon is worth being adopted under crosswind conditions only beyond a 30 $$^{\circ }$$ ∘ yaw angle. At this critical 30 $$^{\circ }$$ ∘ yaw angle the drag on the guttered rider doubles when the gap to the front group increases from 10 cm to 1 m (in real scale). These results can be of interest in defining road cycling race strategies and they allow some significant configurations to be identified and further investigated in more complex experiments.

Aerodynamic benefits for a cyclist by drafting behind a motorcycle

Motorcycles are present in cycling races for reasons including television broadcasting. During parts of the race, these motorcycles ride in front of individual or groups of cyclists. Concerns have been expressed in the professional cycling community that these motorcycles can provide aerodynamic benefits in terms of drag reduction for the cyclists drafting behind them. However, to the best of our knowledge, no information about the extent of these benefits is present in the scientific literature. Therefore, this paper analyses the potential drag reduction for a cyclist by drafting behind a motorcycle. Wind tunnel measurements and numerical simulations with computational fluid dynamics were performed. It was shown that drafting at separation distances d = 2.64, 10, 30 and 50 m can reduce the drag of the cyclist down to 52, 77, 88 and 93% of that of an isolated cyclist, respectively. A cyclist power model is used to convert these drag reductions into potential time gains. For a non-drafting cyclist at a speed of 54 km/h on level road in calm weather, the time gains by drafting at d = 2.64, 10, 30 and 50 m are 12.7, 5.4, 2.7 and 1.6 s per km, respectively. These time differences can influence the outcome of cycling races. The current rules of the International Cycling Union do not prevent these aerodynamic benefits from occurring in races.

Vibrotactile feedback for correcting aerodynamic position of a cyclist

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.

Brachistochrone on a velodrome

The Brachistochrone problem, which describes the curve that carries a particle under gravity in a vertical plane from one height to another in the shortest time, is one of the most famous studies in classical physics. There is a similar problem in track cycling, where a cyclist aims to find the trajectory on the curved sloping surface of a velodrome that results in the minimum lap time. In this paper, we extend the classical Brachistochrone problem to find the optimum cycling trajectory in a velodrome, treating the cyclist as an active particle. Starting with two canonical cases of cycling on a sloping plane and a cone, where analytical solutions are found, we then solve the problem numerically on the reconstructed surface of the velodrome in Montigny le Bretonneux, France. Finally, we discuss the parameters of the problem and the effects of fatigue.

A Pragmatic Approach to Resolving Technological Unfairness: the Case of Nike's Vaporfly and Alphafly Running Footwear

BACKGROUND

Technology is often introduced into sport to facilitate it or to improve human performance within it. On occasion, some forms of novel technology require regulation or prevention entirely to ensure that a sport remains fair and accessible. Recently, the Nike Vaporfly and Alphafly shoes have received some concerns over their appropriateness for use in competitive distance running.

METHODS

This paper evaluates the use of these shoes against an existing framework for sports technology discourse and adopts a pragmatic approach to attempt to resolve them.

RESULTS

It is proposed that the three concerns regarding cost, access and coercion cannot be ruled out but likely remain short-term issues. As a result, it is proposed that these running shoes are acceptable forms of technology but that ongoing vigilance will be required as such technologies develop further in the future.

CONCLUSIONS

The Nike Vaporfly/Alphafly shoes do push the perceived acceptability of running shoes to the limits of the current sports regulations. However, the alleged gains have not manifested themselves to a level that could be considered excessive when reviewing historical performances or when evaluated against a set of well-cited criteria. The sport will need to adopt a stance of ongoing vigilance as such technologies continue to develop or be optimised in the future.

Design of an ergonomic gestural interface for professional road cycling

BACKGROUND

Connected bike computers can support professional cyclists in achieving better performances but interacting with them requires taking their hands off the handlebar compromising focus and safety.

OBJECTIVE

This research aims at exploring the design of an ergonomic interface based on micro-gestures that can allow cyclists to interact with a device while holding the handlebar.

METHODS

Three different studies were conducted with seven professional cyclists adopting the gesture-elicitation technique. One study aimed at eliciting free micro-gestures; a second to evaluate gestures recognizable with a smart glove; the last focused on the gestures recognized through an interactive armband.

RESULTS

The analysis of the micro-gestures elicited during these studies allowed producing a first set of guidelines to design gestural interfaces for drop-bars (a specific type of handlebar for road bikes). These guidelines suggest which fingers to use and how to design their movement in order to provide an ergonomic interface. It also introduces the principle of symmetry for the attribution of symbols to symmetric referents. Finally, it provides suggestions on the design of the interactive drop-bar.

CONCLUSIONS

The guidelines provided in this paper can support the design of gestural interfaces for professional cyclists that can enhance performance and increase safety.

On the aerodynamic flow around a cyclist model at the hoods position

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

The Rise of Elite Short-Course Triathlon Re-Emphasises the Necessity to Transition Efficiently from Cycling to Running

Transitioning efficiently between cycling and running is considered an indication of overall performance, and as a result the cycle–run (C–R) transition is one of the most researched areas of triathlon. Previous studies have thoroughly investigated the impact of prior cycling on running performance. However, with the increasing number of short-course events and the inclusion of the mixed relay at the 2020 Tokyo Olympics, efficiently transitioning from cycle–run has been re-emphasised and with it, any potential limitations to running performance among elite triathletes. This short communication provides coaches and sports scientists a review of the literature detailing the negative effects of prior variable-cycling on running performance experienced among elite, short-course and Olympic distance triathletes; as well as discussing practical methods to minimise any negative impact of cycling on running performance. The current literature suggests that variable-cycling negatively effects running ability in at least some elite triathletes and that improving swimming performance, drafting during cycling and C–R training at race intensity could improve an athlete’s triathlon running performance. It is recommended that future research clearly define the performance level, competitive format of the experimental population and use protocols that are specific to the experimental population in order to improve the training and practical application of the research findings.

Effect of the Pacing Strategies on the Open-Water 10-km World Swimming Championships Performances

PURPOSE

To (1) compare the pacing strategies of different-level open-water swimmers during the 10-km race of the FINA 2015 Swimming World Championships and (2) relate these pacing strategies to the race performance.

METHODS

Final and intermediate split times, as well as intermediate race positions, from the 10-km race participants (69 men and 51 women) were collected from the public domain and were divided into 5 groups (G1-G5) depending on their finishing positions.

RESULTS

Medalists and finalists (G1 and G2, respectively) presented an even pacing profile with swimming velocities similar to those of the less successful swimmers (G3-G5) on the initial and middle stages of the race but a 1.5-3% increase in swimming velocity in the last quarter of the race. This acceleration toward the end of the race, or "end spurt," was largely related to the race performance and was not observed in the G3 and G4 (even-paced profile) or G5 (positive pacing profile) groups. Intermediate race positions and lap rankings were negatively related to finishing position, indicating a delayed positioning of the most successful swimmers at 25%, 50%, and 75% of race distance.

CONCLUSIONS

The adoption of a conservative starting strategy by open-water swimmers with a negative pacing profile and delayed partial positioning seems to increase the chances of overall race success, as it allows a fast end spurt that is closely related to successful finishing race positions.

Aerodynamic study of time-trial helmets in cycling racing using CFD analysis

The aerodynamic drag of three different time-trial cycling helmets was analyzed numerically for two different cyclist head positions. Computational Fluid Dynamics (CFD) methods were used to investigate the detailed airflow patterns around the cyclist for a constant velocity of 15 m/s without wind. The CFD simulations have focused on the aerodynamic drag effects in terms of wall shear stress maps and pressure coefficient distributions on the cyclist/helmet system. For a given head position, the helmet shape, by itself, obtained a weak effect on a cyclist's aerodynamic performance (<1.5%). However, by varying head position, a cyclist significantly influences aerodynamic performance; the maximum difference between both positions being about 6.4%. CFD results have also shown that both helmet shape and head position significantly influence drag forces, pressure and wall shear stress distributions on the whole cyclist's body due to the change in the near-wake behavior and in location of corresponding separation and attachment areas around the cyclist.

Optimizing the Team for Required Power During Track-Cycling Team Pursuit

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.

Development of a high-performance transtibial cycling-specific prosthesis for the London 2012 Paralympic Games

BACKGROUND AND AIM

It has been reported that cycling-specific research relating to participants with an amputation is extremely limited in both volume and frequency. However, practitioners might participate in the development of cycling-specific prosthetic limbs. This technical note presents the development of a successful design of a prosthetic limb developed specifically for competitive cycling.

TECHNIQUE

This project resulted in a hollow composite construction which was low in weight and shaped to reduce a rider's aerodynamic drag.

DISCUSSION

The new prosthesis reduces the overall mass of more traditional designs by a significant amount yet provides a more aerodynamic shape over traditional approaches. These decisions have yielded a measurable increase in cycling performance. While further refinement is needed to reduce the aerodynamic drag as much as possible, this project highlights the benefits that can exist by optimising the design of sports-specific prosthetic limbs. Clinical relevance This project resulted in the creation of a cycling-specific prosthesis which was tailored to the needs of a high-performance environment. Whilst further optimisation is possible, this project provides insight into the development of sports-specific prostheses.

The analysis and forecasting of male cycling time trial records established within England and Wales

The format of cycling time trials in England, Wales and Northern Ireland, involves riders competing individually over several fixed race distances of 10-100 miles in length and using time constrained formats of 12 and 24 h in duration. Drawing on data provided by the national governing body that covers the regions of England and Wales, an analysis of six male competition record progressions was undertaken to illustrate its progression. Future forecasts are then projected through use of the Singular Spectrum Analysis technique. This method has not been applied to sport-based time series data before. All six records have seen a progressive improvement and are non-linear in nature. Five records saw their highest level of record change during the 1950-1969 period. Whilst new record frequency generally has reduced since this period, the magnitude of performance improvement has generally increased. The Singular Spectrum Analysis technique successfully provided forecasted projections in the short to medium term with a high level of fit to the time series data.

The importance of aerodynamics for prosthetic limb design used by competitive cyclists with an amputation: An introduction

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.

Effect of different aerodynamic time trial cycling positions on muscle activation and crank torque

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.

Optimal cycling time trial position models: aerodynamics versus power output and metabolic energy

The aerodynamic drag of a cyclist in time trial (TT) position is strongly influenced by the torso angle. While decreasing the torso angle reduces the drag, it limits the physiological functioning of the cyclist. Therefore the aims of this study were to predict the optimal TT cycling position as function of the cycling speed and to determine at which speed the aerodynamic power losses start to dominate. Two models were developed to determine the optimal torso angle: a 'Metabolic Energy Model' and a 'Power Output Model'. The Metabolic Energy Model minimised the required cycling energy expenditure, while the Power Output Model maximised the cyclists׳ power output. The input parameters were experimentally collected from 19 TT cyclists at different torso angle positions (0-24°). The results showed that for both models, the optimal torso angle depends strongly on the cycling speed, with decreasing torso angles at increasing speeds. The aerodynamic losses outweigh the power losses at cycling speeds above 46km/h. However, a fully horizontal torso is not optimal. For speeds below 30km/h, it is beneficial to ride in a more upright TT position. The two model outputs were not completely similar, due to the different model approaches. The Metabolic Energy Model could be applied for endurance events, while the Power Output Model is more suitable in sprinting or in variable conditions (wind, undulating course, etc.). It is suggested that despite some limitations, the models give valuable information about improving the cycling performance by optimising the TT cycling position.

The influence of seat configuration on maximal average crank power during pedaling: a simulation study

Manipulating seat configuration (i.e., seat tube angle, seat height and pelvic orientation) alters the bicycle-rider geometry, which influences lower extremity muscle kinematics and ultimately muscle force and power generation during pedaling. Previous studies have sought to identify the optimal configuration, but isolating the effects of specific variables on rider performance from the confounding effect of rider adaptation makes such studies challenging. Of particular interest is the influence of seat tube angle on rider performance, as seat tube angle varies across riding disciplines (e.g., road racers vs. triathletes). The goals of the current study were to use muscle-actuated forward dynamics simulations of pedaling to 1) identify the overall optimal seat configuration that produces maximum crank power and 2) systematically vary seat tube angle to assess how it influences maximum crank power. The simulations showed that a seat height of 0.76 m (or 102% greater than trochanter height), seat tube angle of 85.1 deg, and pelvic orientation of 20.5 deg placed the major power-producing muscles on more favorable regions of the intrinsic force-length-velocity relationships to generate a maximum average crank power of 981 W. However, seat tube angle had little influence on crank power, with maximal values varying at most by 1% across a wide range of seat tube angles (65 to 110 deg). The similar power values across the wide range of seat tube angles were the result of nearly identical joint kinematics, which occurred using a similar optimal seat height and pelvic orientation while systematically shifting the pedal angle with increasing seat tube angles.