Article

Effect on the crank torque profile when changing pedaling cadence in level ground and uphill road cycling

Authors:
  • University of Champagne-Ardenne (France)
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Despite the importance of uphill cycling performance during cycling competitions, there is very little research investigating uphill cycling, particularly concerning field studies. The lack of research is partly due to the difficulties in obtaining data in the field. The aim of this study was to analyse the crank torque in road cycling on level and uphill using different pedalling cadences in the seated position. Seven male cyclists performed four tests in the seated position (1) on level ground at 80 and 100 rpm, and (2) on uphill road cycling (9.25% grade) at 60 and 80 rpm.The cyclists exercised for 1 min at their maximal aerobic power. The bicycle was equipped with the SRM Training System (Schoberer, Germany) for the measurement of power output (W), torque (Nm), pedalling cadence (rpm), and cycling velocity (km h(-1)). The most important finding of this study indicated that at maximal aerobic power the crank torque profile (relationship between torque and crank angle) varied substantially according to the pedalling cadence and with a minor effect according to the terrain. At the same power output and pedalling cadence (80 rpm) the torque at a 45 degrees crank angle tended (p < 0.06) to be higher (+26%) during uphill cycling compared to level cycling. During uphill cycling at 60 rpm the peak torque was increased by 42% compared with level ground cycling at 100 rpm. When the pedalling cadence was modified, most of the variations in the crank torque profile were localised in the power output sector (45 degrees to 135 degrees).

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... This dynamic propulsive torque is the key factor in the mechanical efficiency of cycling (Coyle et al., 1991). The product of torque (Nm) and angular speed (rad/s) is power (W) which cyclists use to overcome the workloads and represents their end mechanical effect (Bertucci, Grappe, Girard, Betik, and Rouillon, 2005). We will focus on the following in this paper: (i) mechanical forces, (ii) joint workloads and movements, (iii) muscle activation, and (iv) mechanical efficiency. ...
... Another thing to note is that the groups did not differ significantly in their pedalling technique during the same workloads and cadence. Bertucci et al. (2005) monitored torque changes when cycling under different conditions. They discovered that torque increases by 26% when managing an 8% uphill slope at the same cadence (80 rpm). ...
... They discovered that while less experienced cyclists used more force in the second phase, the more experienced ones still had a higher mechanical efficiency, mainly due to exerting more force in the first phase. Bertucci et al. (2005) monitored torque to find the optimum cadence for flat terrain and uphill cycling. The study carried out in natural surroundings showed differences in amplitude and timing of the torque in a revolution. ...
... Nicht selten entscheiden sich Etappensiege oder die Endplatzierungen im Gesamtklassement einer Rundfahrt durch die Leistung am Berg (Bertucci, Grappe, Girard, Betik & Rouillon, 2005;Hansen & Waldeland, 2008). Laut Fonda und Sarabon (2012) (Wiggins, 2013). ...
... Kohler und Boutellier (2005) Lucia et al., 2001Lucia et al., , S. 1364 (Marsh, Martin & Sanderson, 2000;McNaughton & Thomas, 1996;Neptune & Herzog, 1999;Patterson & Moreno, 1990;Swain & Wilcox, 1992). Ein erhöhter Blutfluss plus eine verbesserte Sauerstoffversorgung der Arbeitsmuskulatur (Swain & Wilcox, 1992;Takaishi et al., 2002), eine geringere muskuläre und neuromuskuläre Erschöpfung sowie eine Reduktion des durchschnittlichen Drehmoments bei gleicher Wattleistung (Patterson & Moreno, 1990;Sanderson, 1991;Takaishi, Yamamoto, Ono, Ito & Moritani, 1998;Takaishi, Yasuda & Moritani, 1994;Takaishi, Yasuda, Ono & Moritani, 1996) (Bertucci et al., 2005;Lucia et al., 2001). Bertucci et al. (2005) (Anholm, Milne, Stark, Bourne & Friedman, 1999;Wolski, McKenzie & Wenger, 1996). ...
... Ein erhöhter Blutfluss plus eine verbesserte Sauerstoffversorgung der Arbeitsmuskulatur (Swain & Wilcox, 1992;Takaishi et al., 2002), eine geringere muskuläre und neuromuskuläre Erschöpfung sowie eine Reduktion des durchschnittlichen Drehmoments bei gleicher Wattleistung (Patterson & Moreno, 1990;Sanderson, 1991;Takaishi, Yamamoto, Ono, Ito & Moritani, 1998;Takaishi, Yasuda & Moritani, 1994;Takaishi, Yasuda, Ono & Moritani, 1996) (Bertucci et al., 2005;Lucia et al., 2001). Bertucci et al. (2005) (Anholm, Milne, Stark, Bourne & Friedman, 1999;Wolski, McKenzie & Wenger, 1996). Letzteres führt bei hoher Trittfrequenz zu einer stärkeren Beanspruchung des kardiorespiratorischen Systems (Wolski et al., 1996). ...
Thesis
Ziel der Arbeit war es, das EMG-Innervationsverhalten von vier vortriebswirksamen Muskeln der unteren Extremität beim Radfahren in der Ebene sowie bei 10 %, 20 % und 30 % Steigung zu beschreiben und mit einer Fahrt in der Ebene zu vergleichen. In einem zweiten Schritt wurde im Rahmen einer Reliabilitätsuntersuchung geklärt, wie hoch die Schwankungsbreite zwischen zwei identischen Messungen in der Ebene ausfällt. Dreizehn Radfahrer der regionalen und nationalen Leistungsklasse absolvierten einen Test mit fünf verschiedenen Belastungsbedingungen (Ebene, 10 %, 20 %, 30 %, Ebene) und elektromyografischer Messung von vier Muskeln der unteren Extremität (M. rectus femoris = RF, M. vastus lateralis = VL, M. semitendinosus = ST, M. tibialis anterior = TA). Die Untersuchungen wurden bei einer Leistung von 90 % des maximalen Laktat-steady-states sowie bei einer von den Versuchspersonen selbst gewählten über alle Belastungsstufen hinweg konstanten Trittfrequenz durchgeführt. Als wesentliche Ergebnisse zeigten sich signifikante Veränderungen des muskulären Aktivitätslevel bei 10 % Steigung im Vergleich zur Ebene für ST (+16 %) und TA (-10 %). Bei 20 % Steigung (vs. Ebene) reduzierten RF und TA ihre Intensität um 13 % (RF; p ≤ 0,05) und 18 % (TA; p ≤ 0,05). Hinsichtlich ST war ein höheres Aktivitätslevel von 18 % (p ≤ 0,05) messbar. Alle untersuchten Muskeln veränderten ihre Intensität bei 30 % Steigung im Vergleich zur Ebene (RF = -12 % (p ≤ 0,05); VL = -11 % (p ≤ 0,05); ST = +27 % (p ≤ 0,05); TA = -20 % (p ≤ 0,05)). Zusätzlich nimmt die Summenaktivität aller Muskeln mit zunehmender Steigung in der zweiten Hälfte des Tretzyklus ab (10 %: p ≤ 0,05; 20 %: p ≤ 0,05). Der Vergleich zwischen den zwei Belastungen in der Ebene brachte keine nennenswerten EMG-Veränderungen mit sich. Die Ergebnisse offenbaren, dass durch die Neuorientierung des Oberkörpers Veränderungen im EMG-Innervationsverhalten bereits bei moderater Steigung auftreten. Diese Modifikationen sind bei schwerer (20 %) und sehr schwerer Steigung (30 %) am deutlichsten, wobei neben dem M. tibialis anterior die dem Hüftgelenk entspringenden Muskeln (RF und ST) am stärksten von Veränderungen betroffen sind. Bei sehr schwerer Steigung zeigt auch der Knieextensor M. vastus lateralis Anpassungen.
... The femoral nerve also supplies articular branches to the hip and knee joints (Moore and Dalley, 1999). The femoral nerves terminal branch is the saphenous nerve that runs anteriorly and inferiorly to supply the skin and fascia on the anteromedial 9 aspects of the knee, leg, and foot (Moore and Dalley, 1999). The femoral artery is a continuation of the external iliac artery and gives rise to several branches that supply the anterior and anteromedial aspects of the thigh (Moore and Dalley, 1999). ...
... In laboratory testing situations the mean cycling velocity is imposed by the cycle ergometer (Burke, 2003). In real road cycling conditions the mean cycling velocity is less easily controlled and oscillates more, compared with the laboratory conditions (Bertucci et al., 2005). The power output and pedaling cadence primarily oscillate more in real life cycling (Bertucci et al., 2005). ...
... In real road cycling conditions the mean cycling velocity is less easily controlled and oscillates more, compared with the laboratory conditions (Bertucci et al., 2005). The power output and pedaling cadence primarily oscillate more in real life cycling (Bertucci et al., 2005). Certain factors are controllable in a laboratory setting that may 23 enhance the outcome of the results. ...
... This opens the possibility of applying and studying biomedical instrumentation related to the pedaling motion. Among these characteristics, the studies of cadence [1], forces applied to the pedal [2], and positioning of the saddle and handlebars [3] can be highlighted. Biomechanical studies of motion and applied forces are usually conducted in laboratory with the aid of training platforms such as cycle ergometers or roller trainers in order to facilitate the reproducibility of test conditions. ...
... The effectiveness index of the forces applied to each crank arm was calculated according to Equation (1). Figure 14b shows the instantaneous effectiveness index in the observed time interval for each crank arm. ...
... Through the initial bibliographic review realized in this research [24], it was possible to have a global perspective of the biomechanics studies applied to cycling [1][2][3][4][5][6][7][8][9][10][11][12][17][18][19][20][21][22][23][25][26][27], revealing new challenges. A static simulation of the crank arm under load showed the main deformation points, whereas the structure dynamic response showed a primary vibration frequency of 340.3 Hz, is above the higher crank arm loading frequency-the cadence of pedaling, with a practical maximum of 2 Hz. ...
Article
Full-text available
This report describes a new crank arm-based force platform designed to evaluate the three-dimensional force applied to the pedals by cyclists in real conditions. The force platform was designed to be fitted on a conventional competition bicycle crankset while data is transmitted wirelessly through a BluetoothTM module and also stored on a SD card. A 3D solid model is created in the SolidWorks (Dassault Systèmes SOLIDWORKS Corp.) to analyze the static and dynamic characteristics of the crank arm by using the finite elements technique. Each crankset arm is used as a load cell based on strain gauges configured as three Wheatstone bridges. The signals are conditioned on a printed circuit board attached directly to the structure. The load cell showed a maximum nonlinearity error between 0.36% and 0.61% and a maximum uncertainty of 2.3% referred to the sensitivity of each channel. A roller trainer equipped with an optical encoder was also developed, allowing the measurement of the wheel's instantaneous velocity.
... This dynamic propulsive torque is the key factor in the mechanical efficiency of cycling (Coyle et al., 1991). The product of torque (Nm) and angular speed (rad/s) is power (W) which cyclists use to overcome the workloads and represents their end mechanical effect (Bertucci, Grappe, Girard, Betik, and Rouillon, 2005). We will focus on the following in this paper: (i) mechanical forces, (ii) joint workloads and movements, (iii) muscle activation, and (iv) mechanical efficiency. ...
... Another thing to note is that the groups did not differ significantly in their pedalling technique during the same workloads and cadence. Bertucci et al. (2005) monitored torque changes when cycling under different conditions. They discovered that torque increases by 26% when managing an 8% uphill slope at the same cadence (80 rpm). ...
... They discovered that while less experienced cyclists used more force in the second phase, the more experienced ones still had a higher mechanical efficiency, mainly due to exerting more force in the first phase. Bertucci et al. (2005) monitored torque to find the optimum cadence for flat terrain and uphill cycling. The study carried out in natural surroundings showed differences in amplitude and timing of the torque in a revolution. ...
Article
Full-text available
The aim of this review paper is to outline the effects of several biomechanical factors on cycling efficiency and safety. The paper begins with a short introduction and listing of basic concepts important for understanding the biomechanics of cycling , followed by an explanation of mechanical forces and torques that are created during pedalling. Workloads and joint movement are detailed in chapter three, which is augmented by chapter four on muscle activation patterns. Throughout the text we have paid careful attention in interpreting the results of research studies into changes in bicycle geometry, feet position, terrain incline and other cycling-related factors. The paper closes with an overview of all issues and solutions as well as presenting proposals for additional research.
... Le couple moteur (T) pourrait se définir comme la cinétique des moments propulsifs créés à partir des manivelles. Il s'exprime en Newton mètre (N.m) et se calcule de la manière suivante (Bertucci et al., 2005) : ...
... avec Ft, la force effective (N) ,et m, la longueur de la manivelle (m). Le coupe moteur permet de définir les points morts haut (DPtop) et bas (DPbot) qui correspondent à des valeurs minimales du couple moteur respectivement lorsque la manivelle est en position haute et lorsque la manivelle est en position basse (Bertucci et al. , 2005) (figure 2.2). Le cycle de pédalage peut alors être décomposé en quatre phases pour chaque membre inférieur (Grappe, 2009). ...
... Généralement, le niveau d'activatité se calcule, soit par une moyenne quadratique (RMS), soit par une intégration (iEMG) (Hug & Dorel, 2009). Cependant, l'utilisation de la RMS semble préconisée (Basmajian & De Luca, 1985). C'est pourquoi la méthode RMS a été retenue pour calculer le niveau d'activation musculaire. ...
... A number of studies reported that cycling biomechanics are affected by many anthropometric parameters, remaining on a theoretical level [2][3][4][5][6][7][8]. It has been shown that pedal torque strongly depends on pedaling cadences, and that there is an important reduction in mean torque at higher cadences [8]. ...
... A number of studies reported that cycling biomechanics are affected by many anthropometric parameters, remaining on a theoretical level [2][3][4][5][6][7][8]. It has been shown that pedal torque strongly depends on pedaling cadences, and that there is an important reduction in mean torque at higher cadences [8]. In addition, at an electronically controlled and eddy current braked ergometer power settings, the forces vary over the crank angle in such a way that lower revolutions per minute (rpm) require higher accelerating pedal forces to produce the required torque. ...
... Previous studies investigated the crank torque profile [8] or the power components of a complex dynamic pedaling model, revealing the calculated net power using limb components, gravity, and velocity [7,15]. Studies calculated instantaneous peak power of muscle groups do not equal the average power over crank cycles, and many geometrical variables influence the simulated power estimation [5]. ...
Article
Full-text available
It was hypothesized that the muscle power input created by both legs would far exceed the ergometers’ constant-torque-based nominal value. It was supposed that this effect depended on the cadence and positive or negative acceleration of the eddy current brake wheel. If so, it is important to estimate the magnitude of this effect in order to protect patients who are at risk of overload. Four normally-trained subjects performed a series of tests involving ergometer pedaling with either ascending power loads in the range of 25 – 250 Watts, or a variation in cadence at intervals of 100 and 150 Watts. The ergometer’s nominal power was compared to the power calculated with the measured time series recordings of the pedal force sensors and the power calculation thereof. Highly significant discrepancies were found between the nominal power load of the ergometer and the power transferred through the pedal sensors. The pedal power was up to 88% higher than the nominal loads, and there were inter-individual differences. The measured power far exceeded the nominal value by 80-166% at a low cadence of 40, and was only approximately congruent at a cadence of 55 to 65 per minute. Confirming the hypothesis, the results suggested that the excess power requirement was mainly due to acceleration power and depended on individual muscular performance. It is important to be aware of this when patients at risk undergo ergometer testing. Power estimation using a direct pedal force measurement may provide new insight into sport-specific stationary cycling science and energy metabolism.
... Alternatively, it has been proposed that cadence selection is closely linked to the muscular demands of the task, with cyclists selecting higher cadences to minimize local muscle stress (Patterson and Moreno 1990;Takaishi et al. 1996) and to lower crank forces. Research has also shown that well-trained cyclists may select a higher cadence to reduce mean propulsive (T mean ) and peak propulsive (T peak ) torque and peripheral muscular fatigue (Bertucci et al. 2005) as measured by the crank torque profile. ...
... The crank torque profile was analyzed by dividing the crank cycle into four 90°power output sectors, as depicted in Fig. 1. Sectors 1 (between 315°and 45°) and 3 (between 135°and 225°) are associated with the top dead point (DP top ) and the bottom dead point (DP bot ) of the crank cycle, respectively (Bertucci et al. 2005). Typically, these 2 sectors are associated with the production of minimal crank torque. ...
... Typically, these 2 sectors are associated with the production of minimal crank torque. Sector 2 (between 45°and 135°) corresponds to the propulsion or pushing-down phase, and sector 4 (between 225°and 315°) to the pulling or recovery phase (Bertucci et al. 2005). ...
Article
The aim of this study was to determine the effects of high- and low-cadence interval training on the freely chosen cadence (FCC) and performance in endurance-trained cyclists. Sixteen male endurance-trained cyclists completed a series of submaximal rides at 60% maximal power (Wmax) at cadences of 50, 70, 90, and 110 r·min(-1), and their FCC to determine their preferred cadence, gross efficiency (GE), rating of perceived exertion, and crank torque profile. Performance was measured via a 15-min time trial, which was preloaded with a cycle at 60% Wmax. Following the testing, the participants were randomly assigned to a high-cadence (HC) (20% above FCC) or a low-cadence (LC) (20% below FCC) group for 18 interval-based training sessions over 6 weeks. The HC group increased their FCC from 92 to 101 r·min(-1) after the intervention (p = 0.01), whereas the LC group remained unchanged (93 r·min(-1)). GE increased from 22.7% to 23.6% in the HC group at 90 r·min(-1) (p = 0.05), from 20.0% to 20.9% at 110 r·min(-1) (p = 0.05), and from 22.8% to 23.2% at their FCC. Both groups significantly increased their total distance and average power output following training, with the LC group recording a superior performance measure. There were minimal changes to the crank torque profile in both groups following training. This study demonstrated that the FCC can be altered with HC interval training and that the determinants of the optimal cycling cadence are multifactorial and not completely understood. Furthermore, LC interval training may significantly improve time-trial results of short duration as a result of an increase in strength development or possible neuromuscular adaptations.
... Many researchers have investigated cycling performance with an inclined surface. Bertucci et al. [29] reported that the crank moment was very similar between level and uphill seated cycling. The results of Caldwell et al. [30] also showed no significant difference between level and uphill seated cycling in pedal force and crank moment. ...
... In the aspect of cycling tasks, altering postures from a seated to a standing position perhaps dramatically changed the joint moments and mechanical work due to changes in the geometry of body segments during cycling [7]. Several studies discussed the cycling posture effect during uphill by crank moment, pedal force, and cycling efficiency [29,33,34]. Only a few studies have reported joint moments and power profiles produced during uphill cycling [30,35,36]. ...
... The studies mentioned above have provided much insight into the biomechanical changes in terms of body posture or surface slope on the lower extremity. Consequently, it would help us to explain the effect of changing slope and posture on human lower extremity motion and final cycling performance by analyzing joint moments and mechanical work [29,30,[37][38][39]. However, previous research only analyzed integral, peak, or mean joint moments or mechanical work in one cycle, which would neglect some useful information. ...
Article
Full-text available
The purpose of this study was to investigate the effects of surface slope and body posture (i.e., seated and standing) on lower extremity joint kinetics during cycling. Fourteen participants cycled at 250 watts power in three cycling conditions: level seated, uphill seated and uphill standing at a 14% slope. A motion analysis system and custom instrumented pedal were used to collect the data of fifteen consecutive cycles of kinematics and pedal reaction force. One crank cycle was equally divided into four phases (90° for each phase). A two-factor repeated measures MANOVA was used to examine the effects of the slope and posture on the selected variables. Results showed that both slope and posture influenced joint moments and mechanical work in the hip, knee and ankle joints (p < 0.05). Specifically, the relative contribution of the knee joint to the total mechanical work increased when the body posture changed from a seated position to a standing position. In conclusion, both surface slope and body posture significantly influenced the lower extremity joint kinetics during cycling. Besides the hip joint, the knee joint also played the role as the power source during uphill standing cycling in the early downstroke phase. Therefore, adopting a standing posture for more power output during uphill cycling is recommended, but not for long periods, in view of the risk of knee injury.
... In other words, as long as the power output is constant, an increase in cadence leads to an increase in the crank's velocity and a decrease in the crank resistance force. Cyclists seem to prefer this smaller resistance force, since the freely chosen cadence (FCC) of about 80 rpm is higher than the most economical cadence of 55-65 rpm [12][13][14]. The FCC seems to be well chosen in sub-maximal cycling [12,13]. ...
... Rossato et al. also found that the ratio of effective force to resultant force increased with an increase in power output during sub-maximal bicycling [15]. With an increased power output, i.e. resistance, there is a need to change the muscle fiber recruitment, from solely type I fibers to type I and II fibers, so, more of the total leg muscles are used [13,14,16]. Even though the functional anatomy and the muscle fiber distribution is different from the leg muscles, the same underlying mechanism in handcycling is expected with increasing resistance; an extra activation of the arm muscle mass, resulting in a higher propulsion force and ratio of effective force to resultant force. ...
Article
Full-text available
Background: With the introduction of an add-on handcycle, a crank system that can be placed in front of a wheelchair, handcycling was made widely available for daily life. With it, people go into town more easily, e.g. to do groceries; meet up with friends, etc. They have more independency and can be socially active. Our aim is to explore some settings of the handcycle, so that it can be optimally used as a transportation device. Therefore, the effects of cadence and added resistance on gross mechanical efficiency and force application during sub-maximal synchronous handcycling were investigated. We hypothesized that a cadence of 52 rpm with a higher resistance (35 W) would lead to a higher gross mechanical efficiency and a more tangential force application than a higher cadence of 70 rpm and no extra resistance (15 W). Methods: Twelve able-bodied men rode in an instrumented add-on handcycle on a motorized level treadmill at 1.94 m/s. They performed three sessions of three four-minute blocks of steady state exercise. Gear (70, 60 and 52 rpm) was changed in-between the blocks and resistance (rolling resistance +0 W, +10 W, +20 W) was changed across sessions, both in a counterbalanced order. 3D force production, oxygen uptake and heart rate were measured continuously. Gross mechanical efficiency (ME) and fraction of effective force (FEF) were calculated as main outcomes. The effects of cadence and resistance were analyzed using a repeated measures ANOVA (P<0.05) with Bonferroni-corrected post-hoc pairwise comparisons. Results: With a decrease in cadence a slight increase in ME (70 rpm: 5.5 (0.2)%, 60 rpm: 5.7 (0.2)%, 52 rpm: 5.8 (0.2)%, P = 0.008, η2p = 0.38), while an increase in FEF (70 rpm: 58.0 (3.2)%, 60 rpm: 66.0 (2.8)%, 52 rpm: 71.3 (2.3)%, P<0.001, η2p = 0.79) is seen simultaneously. Also with an increase in resistance an increase in ME (+0 W: 4.0 (0.2)%, +10 W: 6.0 (0.3)%, +20 W: 7.0 (0.2)%, P<0.001, η2p = 0.92) and FEF (+0 W: 59.0 (2.9)%, +10 W: 66.1 (3.4)%, +20 W: 70.2 (2.4)%, P<0.001, η2p = 0.56) was found. Interpretation: A cadence of 52 rpm against a higher resistance of about 35 W leads to a more optimal direction of forces and is more mechanically efficient than propelling at a higher cadence or lower resistance. Therefore, changing gears on a handcycle is important, and it is advised to keep the linear hand velocity relatively low for locomotion purposes.
... Kautz & Hull [17] defined crank force to be muscular and non-muscular (gravitational or inertial). Bertuccia et al. [18] used horizontal and vertical components of these forces at 70 rpm to produce a force vector profile for realistic loading. The author has scaled this force vector profile to provide the desired 1800 N at 45 • to comply with the BS EN ISO 4210 testing conditions. ...
... Kautz & Hull [17] defined crank force to be muscular and non-muscular (gravitational or inertial). Bertuccia et al. [18] used horizontal and vertical components of these forces at 70 rpm to produce a force vector profile for realistic loading. The author has scaled this force vector profile to provide the desired 1800 N at 45° to comply with the BS EN ISO 4210 testing conditions. ...
Article
Full-text available
A new practical workflow for the laser Powder Bed Fusion (PBF) process, incorporating topological design, mechanical simulation, manufacture, and validation by computed tomography is presented, uniquely applied to a consumer product (crank for a high-performance racing bicycle), an approach that is tangible and adoptable by industry. The lightweight crank design was realised using topology optimisation software, developing an optimal design iteratively from a simple primitive within a design space and with the addition of load boundary conditions (obtained from prior biomechanical crank force–angle models) and constraints. Parametric design modification was necessary to meet the Design for Additive Manufacturing (DfAM) considerations for PBF to reduce build time, material usage, and post-processing labour. Static testing proved performance close to current market leaders with the PBF manufactured crank found to be stiffer than the benchmark design (static load deflection of 7.0 ± 0.5 mm c.f. 7.67 mm for a Shimano crank at a competitive mass (155 g vs. 175 g). Dynamic mechanical performance proved inadequate, with failure at 2495 ± 125 cycles; the failure mechanism was consistent in both its form and location. This research is valuable and novel as it demonstrates a complete workflow from design, manufacture, post-treatment, and validation of a highly loaded PBF manufactured consumer component, offering practitioners a validated approach to the application of PBF for components with application outside of the accepted sectors (aerospace, biomedical, autosports, space, and power generation).
... ); ratio=fe_pedal/fe_Vicon; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % smooth %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Frequency analisys % figure % Ak=abs(fft(R_force_pedal(:,1)))/length(R_force_pedal(:,1)); % calcul du spectre d'amplitude % fs=1000; % k=0:1:length(R_force_pedal(:,1))-1; % Génération de l'indice des fréqu. % f=k*fs/length(R_force_pedal(:,1)); % conversion en Hz % plot(f,Ak); % trace du spectre d'amplitude [b,a] = butter(4,30/(fe_pedal/2)); for p=1:size(R_force_pedal, 2) data_smooth= flip(filter(b,a,R_force_pedal(:,p))); R_force_pedal_smooth(:,p)= flip(filter(b,a,data_smooth)); end for p=1:size(L_force_pedal, 2) data_smooth= flip(filter(b,a,L_force_pedal(:,p))); L_force_pedal_smooth(:,p)= flip(filter(b,a,data_smooth)); end % Plot to chek % figure % hold on % plot(L_force_pedal_smooth(:,3)); % plot(L_force_pedal(:,3)) % hold off %% cut the cycle % Using the DPtop %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Right %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ...
... ); ratio=fe_pedal/fe_Vicon; %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % smooth %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Frequency analisys % figure % Ak=abs(fft(R_force_pedal(:,1)))/length(R_force_pedal(:,1)); % calcul du spectre d'amplitude % fs=1000; % k=0:1:length(R_force_pedal(:,1))-1; % Génération de l'indice des fréqu. % f=k*fs/length(R_force_pedal(:,1)); % conversion en Hz % plot(f,Ak); % trace du spectre d'amplitude [b,a] = butter(4,30/(fe_pedal/2)); for p=1:size(R_force_pedal, 2) data_smooth= flip(filter(b,a,R_force_pedal(:,p))); R_force_pedal_smooth(:,p)= flip(filter(b,a,data_smooth)); end for p=1:size(L_force_pedal, 2) data_smooth= flip(filter(b,a,L_force_pedal(:,p))); L_force_pedal_smooth(:,p)= flip(filter(b,a,data_smooth)); end % Plot to chek % figure % hold on % plot(L_force_pedal_smooth(:,3)); % plot(L_force_pedal(:,3)) % hold off %% cut the cycle % Using the DPtop %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Right %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% ...
Thesis
Full-text available
Ce mémoire se présente comme une étude exploratoire visant à investiguer les relations entre la fatigue et l’asymétrie bilatérale de pédalage en cyclisme.
... It has been shown that field derived CP estimates may be considered as valid and reliable compared with laboratory estimates, whereas the reliability (and hence validity) of field derived W´ estimates is still debated [13,14]. However, previous research has shown that road gradient may partially affect biomechanical and physiological parameters like crank kinetics (e. g. crank inertial load, crank torque profile) [15][16][17], lower limb joint kinetics (e. g. joint moments, joint mechanical work) [18,19], lower limb neuromuscular activation (e. g. intensity and timing of EMG activity) [20][21][22] and gross efficiency [15,23] during cycling in a seated position. Furthermore, it has been shown that a certain metabolic rate (e. g. ...
... Further, the 95 % LoA between flat and uphill cycling derived power output at CP of + 7.7 to −10.1 % ( + 26 to −32 W) may be too large to consider both conditions as equivalent. Road gradient partially affects biomechanical (e. g. joint moments) [15][16][17][18][19] and physiological (e. g. EMG activity) [15,[20][21][22][23] parameters during cycling exercise, indicating an effect of gradient on muscle recruitment patterns. ...
Article
The purpose of this study was to investigate the effects of flat and uphill cycling on critical power and the work available above critical power. Thirteen well-trained endurance athletes performed three prediction trials of 10-, 4- and 1-min in both flat (0.6%) and uphill (9.8%) cycling conditions on two separate days. Critical power and the work available above critical power were estimated using various mathematical models. The best individual fit was used for further statistical analyses. Paired t-tests and Bland-Altman plots with 95% limits of agreement were applied to compare power output and parameter estimates between cycling conditions. Power output during the 10- and 4-min prediction trial and power output at critical power were not significantly affected by test conditions (all at p>0.05), but the limits of agreement between flat and uphill cycling power output and critical power estimates are too large to consider both conditions as equivalent. However, power output during the 1-min prediction trial and the work available above critical power were significantly higher during uphill compared to flat cycling (p<0.05). The results of this investigation indicate that gradient affects cycling time-trial performance, power output at critical power, and the amount of work available above critical power.
... Both the cadence and the force curve have been studied extensively with regard to the effects of different influencing variables (e.g. seat position, gradient, handlebar grip) on the efficiency of the pedalling movement [4][5][6][7][8][9][10], predominantly investigated on samples of competitive cyclists. ...
... Different angular accelerations are suspected as one reason for changes in power curves. Bertucci et al. [7] found little difference between uphill and level pedalling at the same cadence (80 rpm) and power (325W) in field tests. Emanuele and Denoth [11] compared level and uphill cycling concerning the freely chosen cadence and seat position. ...
Article
Full-text available
Introduction From the perspective of dynamic systems theory, stability and variability of biological signals are both understood as a functional adaptation to variable environmental conditions. In the present study, we examined whether this theoretical perspective is applicable to the pedalling movement in cycling. Non-linear measures were applied to analyse pedalling forces with varying levels of subjective load. Materials and methods Ten subjects completed a 13-sector virtual terrain profile of 15 km total length on a roller trainer with varying degrees of virtual terrain inclination (resistance). The test was repeated two times with different instructions on how to alter the bikes gearing. During the experiment, pedalling force and heart rate were measured. Force-time curves were sequenced into single cycles, linearly interpolated in the time domain, and z-score normalised. The established time series was transferred into a two-dimensional phase space with limit cycle properties given the applied 25% phase shift. Different representations of the phase space attractor were calculated within each sector and used as non-linear measures assessing pedalling forces. Results and discussion A contrast analysis showed that changes in pedalling load were strongly associated to changes in non-linear phase space attractor variables. For the subjects investigated in this study, this association was stronger than that between heart rate and resistance level. The results indicate systematic changes of the pedalling movement as an adaptive response to an externally determined increase in workload. Future research may utilise the findings from this study to investigate possible relationships between subjective measures of exhaustion, comfort, and discomfort with biomechanic characteristics of the pedalling movement and to evaluate connections with dynamic stability measures.
... In the described environment, the generated mechanical power study and the applied force at each node are vitally important. From the force characterization, it's possible to determine parameters that can be used in biomechanical tests with different purposes, such as evaluation of symmetry among forces, postural influence, cadence effects, new components evaluation, and relationships among physiological factors [1][2][3][4][5]. Although the industry already has available capable equipment to measure the athlete's resultant produced power, some commercial models capable of delivering the normal and parallel components from the applied force are hard to be found, so their development is assigned to research laboratories [6,7]. ...
... According to Berttucci et al. [3], the absence of research in the area of racing cycling is particularly due to the difficulty of collecting the data in the field under race conditions. Nearly all of the studies about force orientation are carried out on static inclined bikes. ...
Article
Full-text available
This report describes a new crankarm dynamometer designed to evaluate the strength produced by cyclists in real conditions. The dynamometer was designed to be fitted on a conventional crankset while data were transmitted via wireless communication channels available on a Bluetooth TM module. Some 3D solid models were created in the SolidsWorks2010TM development environment to analyze the static and dynamic characteristics, by using the finite elements technique. Each crankset arm was used as a load cell based on strain gages configured as two Wheatstone bridges. The signals were conditioned on a printed circuit board attached directly to the structure. As a result, the load cell shows a maximum nonlinearity error between 2.1% and 2.8%. Some tests were performed on a cycling trainer, allowing to evaluate the system's functionality and to determine the involved forces in the crankset.
... Performance-focused studies usually target determining factors as functional threshold power (FTP, i.e. power a cyclist can sustain in 1h) or critical power (CP, i.e. power output that will result in exhaustion after 1h) and various studies use VO 2 Max to determine efficiency [47]- [49]; these tests do not target a wide population and are often invasive. Technique-focused studies mainly address four factors: cadence; torque; balance and rider's position [50]- [52]. Often these studies tend to contradict each other [53] and very little has been written on rate of power application or correlation with physiological factors. ...
... Determining, in real time, the appropriate value for the torque to be contributed by the motor requires more complex feedforward control algorithms which would have to take into account the fact that the required action would occur when the location across the pedal cycle has already changed [50]. Additional controller logic is also required to prevent unwanted input from the motor if the cyclist wishes to coast without pedalling or if the cyclist is slowing down. ...
Article
Full-text available
Air pollution and increasing traffic congestion means the current way of navigating through a city needs to be rethought. One of the possible solutions is to move away from internal combustion engines and embrace electric and hybrid vehicles. Electric Bicycles can offer an alternative to traditional modes of transport and support an environmentally friendly way to navigate an urban environment, with the benefit of encouraging physical exercise. There are still several issues that constrain a large-scale acceptance of Electric Bicycles, including the need for personalised controller strategies and the energy efficiencies. Current strategies do not include any analysis of rider's capabilities, physiological factors or pedalling techniques. The research outlined in this paper involved 30 participants that volunteered to take part in an Incremental Sub-Maximal Ramp Test with the aim of understanding and quantifying pedalling characteristics and demonstrating that a better motor controller strategy tailored towards individual requirements is possible. Gender and Cycling Experience were the most prominent factors that differentiate the capabilities of the population. Three novel controller techniques (i.e. Fixed Percentage, Torque Filling and Real-Time Power mapping) are analysed and presented as innovative methods for next generation personalised controller strategies for Electric Bicycles.
... Cadence, body position as well as topography, i.e. level ground or uphill conditions, have also been shown to influence model parameter estimates due to different biomechanical recruitment patterns (Bertucci et al. 2005;Kordi et al. 2019;Nimmerichter et al. 2012). Therefore, rider specialization (for example climber vs. time trial specialist) and race demands (uphill vs. flat, on-road vs. off-road, etc.) need to be considered in the selection of testing environments (Nimmerichter et al. 2012). ...
Article
Full-text available
Emerging trends in technological innovations, data analysis and practical applications have facilitated the measurement of cycling power output in the field, leading to improvements in training prescription, performance testing and race analysis. This review aimed to critically reflect on power profiling strategies in association with the power-duration relationship in cycling, to provide an updated view for applied researchers and practitioners. The authors elaborate on measuring power output followed by an outline of the methodological approaches to power profiling. Moreover, the deriving a power-duration relationship section presents existing concepts of power-duration models alongside exercise intensity domains. Combining laboratory and field testing discusses how traditional laboratory and field testing can be combined to inform and individualize the power profiling approach. Deriving the parameters of power-duration modelling suggests how these measures can be obtained from laboratory and field testing, including criteria for ensuring a high ecological validity (e.g. rider specialization, race demands). It is recommended that field testing should always be conducted in accordance with pre-established guidelines from the existing literature (e.g. set number of prediction trials, inter-trial recovery, road gradient and data analysis). It is also recommended to avoid single effort prediction trials, such as functional threshold power. Power-duration parameter estimates can be derived from the 2 parameter linear or non-linear critical power model: P ( t ) = W ′/ t + CP ( W ′—work capacity above CP; t —time). Structured field testing should be included to obtain an accurate fingerprint of a cyclist’s power profile.
... The fact that costly strategies to counteract the elevation of the trunk emerged at the power at which the participants spontaneously switched to the STAND position suggests that this position could have been chosen in order to avoid these strategies. It is worth mentioning that several other factors may influence the choice of the cycling position in the field such as aerodynamics (Debraux et al., 2011;Millet et al., 2014), or slope gradient (Bertucci et al., 2005;Duc et al., 2008). However, the difficulty to keep force on the saddle during high pedal reaction force production observed in this study is making the SEAT position less attractive in these conditions, giving a mechanical reason to trigger the sitstand transition. ...
... There have been several studies that have measured the variability of muscle activity at different cadences ( Lepers et al., 2001, Foss and Hallén, 2004, Bertucci et al., 2005b, Bini et al., 2010b ...
Thesis
Full-text available
Considering that Patello-Femoral Pain (PFP) is responsible for over 25% of all road cycling related injury and over 65% of injuries in the lower limb, alongside trauma related pain it remains the main injury affecting experienced and elite cyclists and is commonly treated using taping. Taping can broadly be categorised into ̳McConnell‘ and ̳Kinesiology type tape‘ (KTT) as these are seen as recognised clinical approaches in dealing with patella tracking and pain issues. The aim was to collect specific data to inform and develop a study into current taping techniques used in cycling related knee pain. An online questionnaire determined the techniques used by clinicians treating elite and experienced cyclists. Recruitment was through professional networking and the social network TwitterTM. The questionnaire indicated a clear preference for the use of KTT. A specific taping technique was identified for use in a laboratory-based study. Respondents indicated their rationale for using tape, which included pain reduction, neuro-muscular adaptation, placebo and altered biomechanics. A subsequent study then investigated the interventions, KTT, neutral tape and no taping, alongside comparing asymptomatic (n=12) and symptomatic (n=8) cyclists. Each cyclist conducted three separate and randomised intervention tests at three powers (100W,200W,300W) on a static trainer. Kinematic data were collected using a 10-camera Oqus 3 motion analysis system. Reflective markers were placed on the foot, shank, thigh and pelvis using the CAST technique. This study showed significant differences in the knee, ankle and hip kinematics between cyclists with and without knee pain. The knee had increased ROM (coronal) in those with knee pain (p=0.005 or 18% change) whereas in the hip, those with knee pain had less movement (p=0.001 or 26% change). The ankle however had an increase in movement (transverse) in those with knee pain (p=0.034 or 14% change). Significant differences in hip, knee and ankle kinematics on the application of KTT were found, however these had no identifiable pattern that suggested any clinical indication. Interestingly, similar levels of differences were also found with the neutral taping application, which indicated that a specific technique might not be critical. It was also noted that 3 200 watts of power produced the most pain response during testing (33% change) which may have a practical application to future taping related clinical testing. If we are looking to establish a biomechanical change using KTT, ROM may indeed be reduced, however individuals had different patterns of movement, which did not appear to indicate a consistent or predictable effect. This may mean that pain reduction is more likely through a mechanism of neuromuscular adaptation or proprioception. It appears unclear whether a specific technique of application is fundamental to outcome. The hip, knee and ankle variants may aid clinical application when treating cycling related knee pain through screening and testing. This variation in movement may be linked to increased patello-femoral (PF)/tibio-femoral contact areas and PF stress when significant power is applied during cycling. The findings indicated a proximal to distal relationship, which is in line with current evidence and has implications to rehabilitation. Taping reduced pain, however it is likely that this effect is not what the anecdotal rhetoric presumes. If the intent is to use the tape to elicit specific biomechanical changes then this is difficult to substantiate and measure. If the expectations are purely around pain then it is likely that pain will be decreased using KTT, albeit short term. Further work is clearly required in the area of PFP and cycling.
... This study provided torque-angle curves for upper limb arm grinding for America's Cup sailors, along with kinematic and muscle activation data characterizing the movement. Cycling literature [26][27][28] has consistently reported that torque or applied force for a single limb occurs almost entirely in the down stroke (0˝-180˝, with 0˝crank position again vertically upward) with virtually no positive force, and in many cases a negative force applied during the following up stroke [27][28][29]. In contrast torque during grinding was never negative, with the mean curve remaining above 20 Nm throughout the entire 360˝cycle. ...
Article
Grinding is a key physical element in America’s Cup sailing. This study aimed to describe kinematics and muscle activation patterns in relation to torque applied in forward and backward grinding. Ten male America’s Cup sailors (33.6 ± 5.7 years, 97.9 ± 13.4 kg, 186.6 ± 7.4 cm) completed forward and backward grinding on a customised grinding ergometer. In forward grinding peak torque (77 Nm) occurred at 95° (0° = crank vertically up) on the downward section of the rotation at the end of shoulder flexion and elbow extension. Backward grinding torque peaked at 35° (69 Nm) following the pull action (shoulder extension, elbow flexion) across the top of the rotation. During forward grinding, relatively high levels of torque (>50 Nm) were maintained through the majority (72%) of the cycle, compared to 47% for backward grinding, with sections of low torque corresponding with low numbers of active muscles. Variation in torque was negatively associated with forward grinding performance (r = −0.60; 90% CI −0.88 to −0.02), but positively associated with backward performance (r = 0.48; CI = −0.15 to 0.83). Magnitude and distribution of torque generation differed according to grinding direction and presents an argument for divergent training methods to improve forward and backward grinding performance.
... Fig. 7a shows that the crank torque profile for these two situations are only slightly different. These experimental findings are in accordance with earlier work done by Bertucci et al. (2005b). They stated that for a given power output at a certain pedaling cadence, the cycling terrain has a minor effect on crank torque profile. ...
Article
This paper introduces the inverse-inverse dynamics method for prediction of human movement and applies it to prediction of cycling motions. Inverse-inverse dynamics optimizes a performance criterion by variation of a parameterized movement. First, a musculoskeletal model of cycling is built in the AnyBody Modeling System (AMS). The movement is then parameterized by means of time functions controlling selected degrees-of-freedom (DOF) of the model. Subsequently, the parameters of these functions are optimized to produce an optimum posture or movement according to a user-defined cost function and constraints. The cost function and the constraints typically express performance, comfort, injury risk, fatigue, muscle load, joint forces and other physiological properties derived from the detailed musculoskeletal analysis. A physiology-based cost function that expresses the integral effort over a cycle to predict the motion pattern and crank torque was used. An experiment was conducted on a group of eight highly trained male cyclists to compare experimental observations to the simulation results. The proposed performance criterion predicts realistic crank torque profiles and ankle movement patterns.
... As propostas de ajuste do ciclo ergômetro em protocolos de reabilitação apresentam pouca fundamentação científica. Além disso, os estudos que analisam a interferência da altura do selim, da cadência e da potência de pedalada são, em sua maioria, relacionados somente com o rendimento esportivo no ciclismo [9] [10] [11]. ...
Conference Paper
Full-text available
Resumo: O objetivo deste estudo foi comparar os componentes de compressão e cisalhamento anterior da força tibiofemoral durante pedalada em diferentes alturas do selim, diferentes cadências e cargas. Participaram deste estudo nove sujeitos saudáveis do sexo masculino. No protocolo foram avaliadas de três alturas do selim (altura do trocânter, 3 cm abaixo e 3 cm acima desta), duas cadências (40 e 70 rpm) e três cargas de trabalho (0, 5 e 10 N). Foi utilizado um modelo biomecânico bidimensional e analisadas as médias do pico de compressão e de cisalhamento anterior da força na articulação tibiofemoral durante oito ciclos de pedalada. Os resultados indicam aumento do pico de compressão e de cisalhamento anterior da força tibiofemoral com o aumento da carga de trabalho. Palavras Chave: Força intersegmentar, articulação tibiofemoral, ciclo ergômetro, reabilitação, dinâmica inversa. Abstract: The aim of the present study was to compare shear and compressive tibiofemoral forces during cycling at different saddle height, cadences and workloads. Nine healthy subjects were volunteered for this study. In the protocol three saddle height (trochanter height, 3 cm upward and 3 cm downward), two cadences (40 and 70 rpm), and three workloads (0, 5 and 10 N) were evaluated. It was used a bi-dimensional biomechanical model and analyzed the average of peaks of anterior shear and compressive tibiofemoral forces for eight pedaling cycles. The results indicate an increase of the anterior shear and compressive tibiofemoral forces increasing the workload.
... 17 higher levels in hcT and hb were found after 2 to decrease as cadence increases at a constant workload. 62 heart rate and torque peak in the rSN decreases in post-could be caused by this pedaling cadence decrease. participants went all out; they were encouraged for that. ...
Article
Full-text available
Background: This pilot study had the aim to determine the effects of a new dose of maximal-intensity interval training in hypoxia in active adults. Methods: Twenty-four university student volunteers were randomly assigned to three groups: hypoxia group, normoxia group or control group. The eight training sessions consisted of 2 sets of 5 repeated sprints of 10 seconds with a recovery of 20 seconds between sprints and a recovery period of 10 minutes between sets. Body composition was measured following standard procedures. A blood sample was taken for an immediate haematocrit and haemoglobin concentration assessment. An all-out 3-ute test was performed to evaluate ventilation parameters and power. Results: Haemoglobin and haematocrit were significantly higher for the hypoxia group in Post- and Det- (p=0.01; p=0.03). Fat mass percentage was significantly lower for the hypoxia group in both assessments (p=0.05; p=0.05). The hypoxia group underwent a significant increase in mean power after the recovery period. Conclusions: A new dose of 8 sessions of maximal-intensity interval training in hypoxia is enough to decrease the percentage of fat mass and to improve haemoglobin and haematocrit parameters and mean muscle power in healthy and active adults.
... Pedaling cadence has a nonlinear effect on physiological states due to changes in mechanical and metabolic efficiency (Faria et al., 1982; Umberger, Gerritsen, & Martin, 2006; Woolford et al., 1999). Studies have shown that cycling at 50 to 60 r/min produces higher muscle tension, electromyographic activity, and torque than cycling at 90 to 100 r/min, with effect sizes ranging from 1.1 to 3.1 (Bertucci, Grappe, Girard, Betik, & Rouillon, 2005; Loïlgen, Graham, & Sjogaard, 1980; Lucia et al., 2004). On the other hand, higher cycling cadence leads to higher oxygen uptake (VO 2 ), ventilation, and heart rate (HR) with effect sizes ranging from 0.5 to 4.0 (Ahlquist, Bassett, Sufit, Nagle, & Thomas, 1992; Belli & Hintzy, 2002; Faria et al., 1982; Jameson & Ring, 2000; Sidossis, Horowitz, & Coyle, 1992 ). Contrasting results have been found for the ratings of perceived exertion (RPE) when cycling at different cadences. ...
Article
Full-text available
Pleasure plays a key role in exercise behavior. However, the influence of cycling cadence needs to be elucidated. Here, we verified the effects of cycling cadence on affect, perceived exertion (ratings of perceived exertion), and physiological responses. In three sessions, 15 men performed a maximal cycling incremental test followed by two 30-min constant workload (50% of peak power) bouts at 60 and 100 r/min. The pleasure was higher when participants cycled at 60 r/min, whereas ratings of perceived exertion, heart rate, and oxygen uptake were lower (p < .05). Additionally, the rate of decrease in pleasure and increase in ratings of perceived exertion was less steep at 60 r/min (p < .01). Cycling at 60 r/min is more pleasant, and the perceived effort and physiological demand are lower than at 100 r/min.
... The majority of studies investigating the effects of training in cycling cadence have focused on adaptations from strength training instead of the effects of HIIT. Indeed, when cyclists pedal at low cadences the muscle force applied to the cranks increase (Bertucci et al. 2005). Rønnestad et al. (2012a) reported that freely chosen cadence during a constant 5-min cycling at 125 W reduced by 11 ± 2 rpm from pre strength training intervention to 4 weeks into the intervention period in noncyclists. ...
Article
Full-text available
The aim of this study was to determine the effects of block training (BL) on pacing during a 20-km hilly cycling time trial (TT) in trained cyclists. Twenty male cyclists were separated into two groups: control and BL. The training of each cyclist was monitored during a period of 3 weeks. In the first week cyclists performed an overload period of seven consecutive days of high intensity interval training followed by two weeks of normal training. Cyclists performed one TT before intervention and two TT after seven and fourteen days at the end of training. Each training session consisted of 10 sets of 3 repeated maximal-effort sprints (15, 30, and 45s) with an effort/recovery duration ratio of 1:5. The main finding of this study was that the power output displayed a significantly higher start from the start until the halfway point of the TT (p<0.05). Additionally, power output was characterized by a significant higher end spurt in the final 2 km in the BL after two weeks at the end of training (p<0.05). In addition, after two weeks at the end of the overload period the distribution of cadence was significantly lower throughout the TT (p<0.01). Therefore, a short period of consecutive days of intense training enhances cycling performance and changes the power output in the beginning and final part of the TT in trained cyclists.
... All the measurements were performed on an ergometer (Lode Excalibur 2006 with PFM, Lode B.V., Groningen, the Netherlands) equipped with a pedal force measurement system that allowed the cadence (rpm), power (W) and right/left crank torques (Nm) to be collected. Flywheel inertia value, that can alter pedalling biomechanics [5,19,49], was assumed to be 11 ± 2 kg m 2 [59]. ...
Article
Full-text available
Purpose Pure predictive dynamics aims at predicting the set of driving inputs in the absence of any a priori data and can be applied in movement science to generate biomechanical variables in many different what-if scenarios. The objective of this research was to solve the problem of the predictive dynamics of sub-maximal cycling by means of an optimal control computational algorithm that makes use of an indirect method. Methods To this, a 2D two-legged seven bodies three degrees of freedom model of the lower limbs of a cyclist has been developed and validated against the average behaviour of eight well-trained cyclists pedalling at different sub-maximal intensities (100, 220, 300 W) at constant cadence (90 rpm). Experimental data adopted in model validation consists of the hip, knee, ankle joint centre and crank kinematics and the right/left crank torques. Results It has been found that the model can replicate the major features of pedalling biomechanics and the ability of a cyclist to deliver a larger torque if a larger power output is required and the cadence is kept constant. The reported mismatches with experimental data get smaller as the power output increases. Conclusions It is suggested that: (1) an optimal control based on an indirect method approach can provide a solution to the predictive dynamics of sub-maximal cycling, (2) predictive dynamics adapts accordingly to real data for changes in power output.
... The effect of gender on commuter cyclists' intersection crossing times were investigated [3]. The crank torque in road cycling on level and uphill using different pedaling cadences in the seated position was analyzed [4] and revealed the various methods to know the human energy using Bicycle Ergometer and this information can be used as a guide for increasing fitness and building muscular endurance [5]. ...
Article
Full-text available
The normal bicycle is the one of the medium of the travelling and used for riding, sports, riding in off road purposes. In recent years many accidents occurred in off-road riding bicycle due to the lack of torque required to drive and land the bicycle in its position and continue the ride safely specially in sports bicycle. The aim of this work is to overcome these problems by introducing new mechanical transmission system with the help of internal gear technology called shaft driven system to maximize the torque of off-road bicycle using gear and shaft transmission system with normal riding condition. A shaft driven bicycle is a bicycle that uses a shaft drive instead of a chain drive which contains two set of bevel gear at both the ends to make a new kind of transmission system and transmit motion through 90 degrees angle. It replaces the traditional methods and reduces the accidents to the hill riders.
... Cadence, body position as well as topography, i.e. level ground or uphill conditions, have also been shown to influence model parameter estimates due to different biomechanical recruitment patterns (Bertucci et al. 2005;Kordi et al. 2019;Nimmerichter et al. 2012). Therefore, rider specialization (for example climber vs. time trial specialist) and race demands (uphill vs. flat, on-road vs. off-road, etc.) ...
Thesis
Monitoring and evaluating the physiological and performance characteristics of endurance athletes provides relevant information about the long-time athletic development, training process and talent identification. While there is growing evidence for the physiological and performance attributes in junior and professional cyclists, limited information is available about the U23 category. Therefore, the aim of this thesis was to examine the longitudinal physiological and performance characteristics of U23 elite cyclists, with a special focus on the application of the power profile and the power-duration relationship. Study 1 involved a critical evaluation of the current literature on power profiling methodologies and the application of the power-duration relationship. In order to improve the predictive ability of the power profile and the power-duration relationship across exercise intensity domains, it is recommended to ensure a high ecological validity (e.g. rider specialization, race demands) during standardized field testing. For this reason, single effort prediction trials outside the severe exercise intensity domain should be avoided, due to a high measurement bias and a low predictive ability regarding the power-duration relationship. Standardized field testing for power profiling should be conducted at least two times per season to obtain an accurate fingerprint of a cyclist’s performance capacity in the field. In addition, future research is required to better understand the fatigue mechanisms and downward-shift of the power profile and power-duration relationship in the moderate and heavy exercise intensity domains following prior heavy exercise. In Studies 2 and 3 the power profile and power-duration relationship were investigated throughout a competitive season in U23 elite cyclists. Study 2 examined the changes in maximal mean power output (MMP) and derived critical power (CP) and work capacity above critical power (W´) obtained during training and racing. The results revealed that the absolute power profile was not significantly different during a competitive season, except changes in the relative power profile due to a reduction in body mass. Study 3 investigated the differences in the power profile derived from training and racing, the training characteristics across a competitive season, and the relationships between the training characteristics and the power profile in U23 elite cyclists. Higher absolute and relative power profiles were recorded during racing than training. Training characteristics were lowest in pre-season followed by late-season. Changes in training characteristics correlated with changes in the power profile in early- and mid-season, but not in late-season. Practitioners should consider the influence of racing on the derived power profile and adequately balance training programs throughout a competitive season. Studies 4 and 5 analysed the power profile, workload characteristics and race performance in U23 and professional cyclists during a five-day multi-stage race. Study 4 compared the power profile, internal and external workloads, and racing performance between U23 and professional cyclists and between varying rider types, including allrounders, domestiques and general classification (GC) riders. This study demonstrated that the power profile after 1.000-3.000 kJ of total work could be used to evaluate the readiness of U23 cyclists to move into the professional ranks, as well as differentiate between rider types during racing. Study 5 specifically analysed climbing performance in a professional multistage race, and assessed the influence of climb category, prior workload, and intensity measures on climbing performance in U23 and professional cyclists. The findings indicated that climbing performance in professional road cycling is influenced by climb categorization as well as prior workload and intensity measures. Professional cyclists displayed better climbing performance than U23 cyclists, while the workload and intensity measures were higher in U23 than professional cyclists. Collectively the studies within this thesis have contributed to an improved understanding of the physiological and performance attributes of U23 elite cyclists in their maturation to the professional level. These studies have confirmed the practical application of the power profile and power-duration relationship for performance evaluation and prediction during training and racing. This thesis has enabled detailed insights about factors affecting the power profile and the power-duration relationship, and it has provided a concise applied strategy for the inclusion of power profiling in the longitudinal athletic development pathway to maximize cycling performance.
... The correlations between cadence at several lactate landmarks and FTP found in the current study could also be highlighted. This finding can be explained by the fact that PO is dependent on 2 factors: torque and angular velocity of the crank arm (3). Given that the freely chosen cadence normally increases with higher power demands, relationships between PO and cadence are to be expected (24). ...
Article
Sitko, S, Cirer-Sastre, R, Corbi, F, and López-Laval, I. Functional threshold power as an alternative to lactate thresholds in road cycling. J Strength Cond Res XX(X): 000-000, 2021-This study assessed the relationship between functional threshold power (FTP) and 7 lactate landmarks (Dmax, modified Dmax, fixed blood lactate concentrations of 2 and 4 mmol·L-1, lactate increases of 1 and 2 mmol·L-1 above baseline, and lactate increases of 1.5 mmol·L-1 above the point of minimum ratio between lactate and work rate) in a sample of 46 road cyclists with a wide range of fitness levels (age 38 ± 9 years, height 177 ± 9 cm, body mass 71.4 ± 8.6 kg, body mass index 22.7 ± 2.2 kg·m-1, fat mass 7.8 ± 4%, and V[Combining Dot Above]O2max = 61.1 ± 9.1 ml·min-1·kg-1). The cyclists performed a graded exercise test in which power outputs (POs) at the lactate landmarks were identified. Functional threshold power was established as 95% of the PO during a 20-minute test. Significance was set as p < 0.05. Statistical analyses revealed large to very large correlations between PO, relative PO (RPO), and cadence at FTP and lactate thresholds (LTs) established through Dmax, modified Dmax, and fixed lactate concentrations of 4 mmol·L-1 (r = 0.68-0.93). Significant differences (p < 0.001) were also observed for PO and RPO at FTP, fixed blood lactate concentrations of 2 mmol·L-1, and lactate increases of 1 mmol·L-1 above baseline. Therefore, although FTP estimated from a 20-minute test is strongly related to several lactate landmarks, caution is required when substituting this concept for LTs. This information will allow coaches, cyclists, and scientists to better choose assessments when attempting to estimate LT through power-based field testing.
... Most overuse injuries in cycling occur due to repetitive high loads applied to the joints. These loads normally excel when riding in low gear, long uphill riding, or with incorrect body position [4,5]. Along the entire kinetic chain, the knee is the most affected joint [6], with varus/valgus and internal/external torques as the primary mechanisms for the overuse injury occurrence [7]. ...
Article
Full-text available
The main purpose of this study was to develop and validate a 3D model for calculating knee joint loads during seated cycling. A 3D inverse dynamics approach was used to calculate knee and ankle joint loads using kinematics and kinetics data. For such a model, four kinematics clusters and three pedal markers were used, integrated with a 6-component force/torque pedal dynamometer. Seven subjects performed one five-minute trial on 75% of their maximum power at fixed cadence of 85 rpms. Data from two consecutive samples of the same cycling trial (first and last minute) were used to validate the model with the mean difference between two samples, Cronbach’s alpha, intraclass correlation coefficient (ICC), and p-value. Results showed high ICC (>0.735) and internal consistency (>0.700) with no statistically significant values (p > 0.050) except for crank angle of peak anterior force and peak axial forces at the knee and minimum normal force (p = 0.010) and minimum crank angle (p = 0.010) on the pedal. Further analyses are required to validate the model between days and to test the sensitivity to mechanical constraints.
... 1 In movement science, pedaling forces are typically examined using straightforward, linear methods. [2][3][4][5][6] There is evidence, however, that linear measures are not sensitive enough to detect changes in the variability and stability of the pedaling movement. 7 Warlop et al. 8 suggest that pedaling movement, similar to human gait, displays a non-linear temporal variability structure, and that metronome-controlled cadence leads to changes in non-linear variability in comparison to a freely chosen cadence. ...
Article
The study of biomechanical and physiological variables allows human movement scientists to investigate the characteristics of movement patterns in cyclists. While straightforward and well-investigated, linear measures may not adequately capture the underlying complexity of movements during cycling. Therefore, a non-linear phase-space measure (ML1) was applied to forces and heart rates of nine cyclists in a field test. The test was repeated two times with different instructions on how to alter the bike’s gearing while cycling a 12.5 km long level track. Pedaling forces and heart rates were measured. Future aim of the underlying study is the investigation of innovative control algorithms for e-bike propulsions. Force-time curves were sequenced into single cycles, linearly interpolated in the time domain, and z-score normalized. ML1 was calculated in a flowing window algorithm of 50 cycles. With fixed gearing, a contrast analysis showed that changes in terrain inclination were strongly associated with changes in the non-linear measure ML1. The calculation of Spearman’s cross correlation showed high coefficients of correlation between ML1 and delayed heart rate. The results indicate systematic changes of the pedaling movement as an adaptive response to changes in terrain inclination. Future research may utilize the findings from this study to investigate possible relationships between subjective measures of exhaustion, comfort, and discomfort with biomechanical characteristics of the pedaling movement.
... In 2017, Fukushimal and Fujimoto [17] presented a method for pedaling torque estimation using the recursive least square algorithm with multiple forgetting factors and they considered the condition for travelling on upward as well. In 2018, Rallo et al. [18] measured the wheel speed with a magnetic wheel encoder and showed that the pedaling cadence is correlated with the speed oscillation. ...
Article
Full-text available
In this paper, we propose an improved torque sensorless speed control method for electric assisted bicycle, this method considers the coordinate conversion. A low-pass filter is designed in disturbance observer to estimate and compensate the variable disturbance during cycling. A DC motor provides assisted power driving, the assistance method is based on the real-time wheel angular velocity and coordinate system transformation. The effect of observer is proved, and the proposed method guarantees stability under disturbances. It is also compared to the existing methods and their performances are illustrated through simulations. The proposed method improves the performance both in rapidity and stability.
... Each of these technologies was tested for reliability and have high degrees of ecological validity in cycling, and potentially in handcycling [90,103,115,116]. They can indeed reliably measure power output both in and outdoors, in training, racing or sports conditions, at both the lower and high-end of the performance spectrum and even at low levels of power output and speed [91,109,[117][118][119]. ...
Article
Full-text available
Aim: In this narrative review the potential and importance of handcycling are evaluated. Four conceptual models form the framework for this review; (1) the International Classification of Functioning, Disability and Health; (2) the Stress-Strain-Capacity model; (3) the Human-Activity-Assistive Technology model; and (4) the power balance model for cyclic exercise. Methods: Based on international handcycle experience in (scientific) research and practice, evidencebased benefits of handcycling and optimization of handcycle settings are presented and discussed for rehabilitation, daily life and recreational sports. Results: As the load can be distributed over the full 360 degrees cycle in handcycling, peak stresses in the shoulder joint and upper body muscles reduce. Moreover, by handcycling regularly, the physical capacity can be improved. The potential of handcycling as an exercise mode for a healthy lifestyle should be recognized and advocated much more widely in rehabilitation and adapted sports practice. The interface between handcycle and its user should be optimized by choosing a suitable person-specific handcycle, but mainly by optimizing the handcycle dimensions to one’s needs and desires. These dimensions can influence efficient handcycle use and potentially improve both endurance and speed of handcycling. Conclusion: To optimize performance in rehabilitation, daily life and recreational sports, continued and more systematic research is required. Full article available at: https://www.tandfonline.com/doi/full/10.1080/09638288.2020.1815872
... This new possibility for implementing field tests seems relevant, especially when considering the important setbacks associated with studying power related to cadence in a laboratory setting: it has been observed that crank torque profiles on the ergometer are significantly different and generate a higher perceived exertion compared with road cycling conditions [65]. Furthermore, the crank torque profile varies substantially according to the terrain, a conditioning factor that cannot be recreated in a laboratory setting [66]. It should also be remarked that self-selected cadence is normally higher in the laboratory setting compared with road conditions [58] and imposing a cadence can modify the amount of work that a cyclist can complete above his FTP [67]. ...
Article
Full-text available
Nowadays, the evaluation of physiological characteristics and training load quantification in road cycling is frequently performed through power meter data analyses, but the scientific evidence behind this tool is scarce and often contradictory. The aim of this paper is to review the literature related to power profiling, functional threshold testing, and performance assessment based on power meter data. A literature search was conducted following preferred reporting items for review statement (PRISMA) on the topic of {"cyclist" OR "cycling" AND "functional threshold" OR "power meter"}. The reviewed evidence provided important insights regarding power meter-based training: a) functional threshold testing is closely related to laboratory markers of steady state; b) the 20-min protocol represents the most researched option for functional threshold testing, although shorter durations may be used if verified on an individual basis; c) power profiling obtained through the recovery of recorded power outputs allows the categorization and assessment of the cyclist's fitness level; and d) power meters represent an alternative to laboratory tests for the assessment of the relationship between power output and cadence. This review elucidates the increasing amount of studies related to power profiling, functional threshold testing, and performance assessment based on power meter data, highlighting the opportunity for the expanding knowledge that power meters have brought in the road cycling field.
... Therefore, it can be assumed that pedaling at a constant cadence (CC), as a therapeutic intervention typically adopted by individuals recovering from a functional deficit, possibly is controlled by the CPG and does not require a higher level of motor control. On the other hand, athletes also train using varying pedaling cadence programs to prevent the muscles from becoming accustomed to a regular stress level [7][8][9]. The frequent changes in cadence require a higher level of motor control to accomplish the accelerations/decelerations and to adapt force output in the lower extremities. ...
Article
Full-text available
Aim: This study examined the immediate effects of a 5-min pedaling period with varying cadence (VC) on various dimensions of gait function in frail older adults. Methods: Twenty frail older adults (mean age 77.2 years) were randomly assigned to one of two groups: the VC group or the constant cadence (CC) group. Each group performed bicycle ergometry for 5 min at 20 W. The CC group pedaled continuously at a CC of 50 rpm, while the VC group pedaled continuously at cadences of 45, 55, 65, 55, and 45 rpm, in this order, changing cadence every 60 s. Immediately before and after bicycle ergometry, the following measurements were carried out: gait performance, muscle activity (electromyographic analysis), and knee motion analysis. Results: CC did not significantly affect any of the measured parameters. In contrast, the VC group showed improvement in all three parameters: an increase in normal gait speed and cadence (p < 0.01), a reduction in the activation period (p < 0.04) and CI-THIGH (antagonistic coactivation time between knee flexor and extensor muscles, p < 0.05), and an increase in maximum knee extension angular velocity (p < 0.01). Conclusion: A short period of VC bicycle ergometry with low work intensity was effective in immediately improving gait function in frail older adults.
... Rossato et al. also found that the ratio of effective force to resultant force increased with an increase in power output during sub-maximal bicycling [15]. With an increased power output, i.e. resistance, there is a need to change the muscle fiber recruitment, from solely type I fibers to type I and II fibers, so, more of the total leg muscles are used [13,14,16]. Even though the functional anatomy and the muscle fiber distribution is different from the leg muscles, the same underlying mechanism in handcycling is expected with increasing resistance; an extra activation of the arm muscle mass, resulting in a higher propulsion force and ratio of effective force to resultant force. ...
... Kautz & Hull [4] defined crank force to be muscular and non-muscular (gravitational or inertial). Horizontal and vertical components of these forces at 70 rpm were used to produce a force vector profile for realistic loading [5]. This was interpolated to provide 1800N at 45° (complying with BS EN ISO 4210), with loads corresponding with numerous studies: maximum load crank angle [6] The calculated loads were applied 65mm from the outboard crank face. ...
Preprint
Full-text available
Additive Manufacturing (AM) provides an opportunity to fundamentally redesign components previously limited by conventional manufacturing techniques. A new process for this workflow of design, manufacture by Powder Bed Fusion (PBF) and validation is presented, to which a case study of a crank for a high performance racing bicycle is applied. Topology optimisation generated conceptually ideal geometry from which a functional design was interpreted. Design for AM considerations were employed to reduce build time, material usage and post-processing labour. PBF was employed to manufacture the parts, and the build quality assessed using Computed Tomography (CT). Static and dynamic functional testing was performed and compared to a Finite Element Analysis (FEA). CT confirmed good build quality of tall, complex geometry with no significant geometrical deviation from CAD over 0.5 mm. Static testing proved performance close to current market leaders, although failure under fatigue occurred after just 2495 ± 125 cycles, the failure mechanism was consistent in both its form and location. These physical results were representative of those simulated, thus validating the FEA. This research demonstrates a complete workflow from design, manufacture, post-treatment and validation of a highly loaded PBF manufactured component, offering practitioners with a validated approach to the application of PBF.
... The torque amplitudes changed with increasing workloads, whereas the crank angles for maximal and minimal torque were constant based on the kinetic measures. However, findings in conventional cycling demonstrated a later torque maximum for conditions with higher incline [22]. With regard to the proportion of work, there were considerable differences compared to findings of studies using an attach-unit [6]. ...
Article
In Paralympic sports, biomechanical optimisation of movements and equipment seems to be promising for improving performance. In handcycling, information about the biomechanics of this sport is mainly provided by case studies. The aim of the current study was (1) to examine changes in handcycling propulsion kinematics and kinetics due to increasing workloads and (2) identify parameters that are associated with peak aerobic performance. Twelve non-disabled male competitive triathletes without handcycling experience voluntarily participated in the study. They performed an initial familiarisation protocol and incremental step test until exhaustion in a recumbent racing handcycle that was attached to an ergometer. During the incremental test, tangential crank kinetics, 3D joint kinematics, blood lactate and ratings of perceived exertion (local and global) were identified. As a performance criterion, the maximal power output during the step test (Pmax) was calculated and correlated with biomechanical parameters. For higher workloads, an increase in crank torque was observed that was even more pronounced in the pull phase than in the push phase. Furthermore, participants showed an increase in shoulder internal rotation and abduction and a decrease in elbow flexion and retroversion. These changes were negatively correlated with performance. At high workloads, it seems that power output is more limited by the transition from pull to push phase than at low workloads. It is suggested that successful athletes demonstrate small alterations of their kinematic profile due to increasing workloads. Future studies should replicate and expand the test spectrum (sprint and continuous loads) as well as use methods like surface electromyography (sEMG) with elite handcyclists.
... Mesmo não sendo investigadas em detalhes, as diferenças na largura da pélvis entre homens e mulheres são também sugeridas como um fator de influência sobre assimetrias cinéticas, especialmente por influenciarem a cinemática do quadril (WILLIAMS et al., 1987). BENTLEY et al., 2001;BROKER, 2003;BURKE, 2003;BERTUCCI et al., 2005;CARSON, 2005;ROSSATO et al., 2008). Por outro lado, um número de estudos que examinam a pedalada bilateralmente encontraram assimetria para força, torque ou trabalho no pedivela e potência produzida (CAVANAGH, 1974;DALY e CAVANAGH, 1976;SARGEANT e DAVIES, 1977;SIRIN et al., 1989;SANDERSON et al., 1991;SMAK et al., 1999;EDELINE et al., 2004;CARPES et al., 2007a;2007b (CHRISTOU et al., 2003). ...
Thesis
Full-text available
Assimetrias de desempenho, frequentemente, são relacionadas ao controle e desenvolvimento motor da extremidade superior. Por outro lado, a extremidade inferior do corpo humano está muito mais envolvida em ações bilaterais, como aquelas relacionadas à locomoção. Ainda assim, diferenças no desempenho dos membros inferiores foram descritos na literatura, como, por exemplo, em relação à força durante tarefas de andar, correr e pedalar. As razões para essas diferenças – uma vez que ambos os membros inferiores, teoricamente, tem a mesma possibilidade de movimento e a preferência lateral pode mudar de acordo com a tarefa – tem intrigado cientistas. Em estudos prévios apresentados na literatura, notamos que assimetrias na força produzida ocorrem durante a pedalada, apresentando relação, por exemplo, com a intensidade do exercício. Também sugere-se que a experiência com a tarefa influencie assimetrias. Entre os motivos para estudar esses mecanismos de assimetria está o risco aumentado de lesão inerente a assimetrias cinéticas, como constatado na corrida, assim como a importância de empregar estratégias unilaterais de treinamento e/ou reabilitação. A ativação muscular foi sugerida como sendo um fator determinante de assimetrias. A ativação muscular nos membros inferiores poderia diferir entre os membros, e tal como ocorre para a extremidade superior, levar a vantagem em favor da perna preferida. No entanto, essa hipótese não havia sido testada, considerando exercícios em diferentes configurações e sujeitos com diferentes níveis de experiência. Assim, buscamos investigar as diferenças entre o membro inferior preferido e não-preferido durante a pedalada, em testes bilaterais e unilaterais, considerando: (1) o consumo de oxigênio, (2) a eficiência muscular, (3) a magnitude da ativação muscular, (4) a variabilidade na ativação muscular, e (5) a comunicação entre os membros durante ações isoladas de um dos membros inferiores. Protocolos de ciclismo (a) incremental máximo, (b) submáximo de carga constante para pedalada bilateral, e (c) submáximo de carga constante para pedalada unilateral, com o membro inferior preferido e não-preferido, foram realizados por ciclistas e não-ciclistas. As análises estatísticas sugeriram que durante a pedalada bilateral, assimetrias de força previamente descritas não parecem estar relacionadas com diferenças na magnitude de ativação muscular (biceps femoris, gastrocnemius medialis e vastus lateralis) entre o membro inferior preferido e nãopreferido. No entanto, a variabilidade da ativação foi influenciada pela preferência em não-ciclistas. No exercício unilateral, a preferência lateral não influenciou o consumo de oxigênio e a eficiência muscular. A magnitude da ativação muscular e a sua variabilidade também não diferiram estatisticamente entre as pernas durante os protocolos unilaterais, o que não ajuda a explicar assimetrias de força dependentes em aspectos neurais. Os resultados de comunicação entre membros sugerem efeitos da preferência lateral para ciclistas na perna preferida, o que poderia influenciar a transferência interlateral de aprendizagem em sujeitos treinados. Dessa forma, a preferência lateral parece não influenciar a magnitude da ativação muscular e eficiência muscular, no entanto, ela pode apresentar diferentes efeitos frente à variabilidade da ativação muscular e da comunicação entre os membros em função da experiência com ciclismo. Assimetrias encontradas no ciclismo parecem mais frequentes para a força e podem ser relacionadas à configuração da atividade e ao efeito do ambiente de prática, sem apresentar correlatos com a ativação muscular.
... O estado da arte é o monitoramento do ciclista em tempo real através de telemetria no treino ou competição diferentemente dos sistemas anteriormente apresentados que são conectados por fios e os strain gages [6], [13] estão no pedivela [3], [14], [21] e não nos pedais, [4]. ...
... Mechanical power is the product of torque and pedal velocity and has been shown to be a key determinant of cycling performance [13]. Torque is the product of the force applied perpendicular to the crank arm and the crank arm length [14]. Although constant torque production would optimise performance, anatomical and gravitational constraints mean that torque is actually produced in a nearly sinusoidal manner with minimal torque being produced when the crank is positioned vertically [15]. ...
Technical Report
Full-text available
The aim of both studies was to assess the effects of the EasyPedal prototypes compared to conventional pedals on cycling efficiency. The main study and case study results do not indicate reduced energy expenditure when using the EasyPedal prototypes versus conventional pedals in either a typical cycling set-up or semi-recumbant position. This is based on similar levels of oxygen consumption and heart rate when using both pedal types at the same absolute cycling intensity (measured in watts. However, this does not rule out a potential benefit of the EasyPedal prototype when used at slower cycling cadences (testing in this study carried out at cadences of approximately 70 rpm) or with a novel/alternative cycling pattern. The testing detailed in this report illustrates the acute responses to using these pedal prototypes (i.e. after < 30 minutes of use). It is possible that individuals could learn to perform an altered pedalling style which could make greater use of the potential mechanical advantages of the EasyPedal prototypes. Such an altered style would take time to develop and would change the neuromuscular requirements of the task. It is still unknown how much time would be required to develop such a pattern and what possible advantages it would provide in terms of cycling efficiency
Thesis
Sébastien CORDILLET Développement d'une nouvelle méthodologie d'analyse in situ du mouvement en cyclisme-Apport des centrales inertielles pour l'estimation de la cinématique articulaire Thèse présentée et soutenue à Rennes, le 17 décembre 2019 Unité de recherche : Laboratoire Mouvement, Sport, Santé (M2S) EA 7470Résumé : L’analyse du mouvement de pédalage est un sujet largement étudié dans la littérature scientifique. Pourtant, la majorité des études est réalisée en laboratoire dans des conditions pouvant être éloignées des conditions réelles de pratique. Les centrales inertielles miniaturisées constituent une alternative prometteuse aux systèmes optoélectroniques utilisés en laboratoire, mais elles présentent aussi des verrous nécessitant des développements méthodologiques spécifiques que nous proposons d’aborder dans ce travail de thèse. Ainsi, une première étude s’est intéressée à la calibration « centrale à segment » qui permet d’apporter une signification fonctionnelle aux angles estimés à partir de centrales inertielles. Les résultats mettent en évidence une méthode de calibration dédiée au cyclisme qui permet d’estimer les angles articulaires avec justesse et précision.Le mouvement de pédalage étant par nature cyclique, il est nécessaire d’identifier certains évènements comme les points morts. La seconde étude visait donc à développer une méthodologie d’identification des points morts en ayant recours uniquement aux centrales fixées sur les segments. Enfin, une dernière étude montrait la faisabilité d’une mesure in situ en estimant les angles articulaires des membres inférieurs lors d’un contre-la-montre. Cette mesure intégrative montre que la cinématique évolue avec la distance et qu’elle est affectée par les conditions de courbures (lignes droites et virages) et la latéralité. Ce manuscrit propose des méthodes d’analyse ainsi que des recommandations en vue d’études futures sur le mouvement de pédalage en condition in situ.
Thesis
Full-text available
Introduction The sport of people with disabilities has gained increased attention, recognition and acceptance in media and society. The process of professionalisation can be seen in the development of attendance, performance, and scientific exami-nations. Because of the highly individual properties, a huge potential for the paralympic sport is lying in the field of sports biomechanics [44]. As a part of paracycling, handcycling became a very common sport for people with spinal cord injuries or amputations on recreational und international level. An optimi-sation in handcycling propulsion kinematics and kinetics could improve the performance of interational athletes. Purpose The aim of the current study was to examine the kinematics and kinetics of handcycling propulsion during an incremental test. In addition, parameters that are crucial for the sportspecific performance were identified. Methods Twelve non-disabled male triathletes (26.0±4.4 yrs., 1,83±0.06 m, 74.3±3.6 kg) without handcycling experience perfromed an initial familarization followed by a 15-s All-Out test. The tests were performed in a racing handcycle (Shark S, Sopur, Sunrisemedical, Malsch, Germany) that was attached to a ergometer (Cyclus 2, 8 Hz, RBM elektronik-automation GmbH, Leipzig, Germany). Out of this sprint test, the peak power output (POmax,AO15) and the glycolytic rate (V̇Lamax) were determined. The incremental test started with an initial load of 20 W and increased every 5 min by 20 W until subjective exhaustion. In the end of every stage, the rate of perceived exertion (RPE) on a global (cardio-pulmo-nary) and local (upper extremity) level, arterialized capillary blood lactate concentration of the ear lobe (La [mmol l-1]) and heart rate (HR [min-1]) were recorded. Performance criteria were the maximal power output during the incremental test (POmax,ST) and the calculated lactate threshold based on the fixed 4 mmol l-1 method (PO4mmol) [32; 4]. The kinematic and kinetic measure-ments occured at the end of the first and beginning of the last minute of each stage for 20 seconds. Seven high speed infrared cameras (100 Hz, MX-F40 and MX-3+, Vicon Nexus 2.3, Vicon Motion Systems Ltd., Oxford, UK) were placed aroud the handcycle. 44 spherical retro-reflective Markers were placed on the crank, the ergometer and anatomical landmarks according to the UpperLimb-Model of Vicon Nexus. The joint kinematics considered the angles and angular velocities of shoulder-flexion (SF), shourler-abduction (SA), shoulder-rotation (SR), elbow-flexion (EF), palmar-flexion (PF), radial-duction (RD) und trunk-flexion (RF). The tangential crank kinetics based on a power-meter (1000 Hz, Schobener Bike Management System, SRM, Jülich, Ger-many) installed in the crank. Out of the crank angular velocity and torque sig-nals, the acute power output (PO) was calculated. The data were averaged, filtered (4th-order low-pass Butterworth filter, cut-off frequency 10 Hz) and resampled to a length of 360 frames per cycle using MATLAB (R2016a, MathWorks®, Natick, Massachusetts, USA). Parameters of kinematics and kinetics were maximum and minimum value (MinV and MinI), range (MaxV-MinV), the crank angle of the maximum and minimum (MaxI and MinI) and the values at maximal and minimal acute PO (@MaxPO and @MinPO). Additionally, the accomplished work within one cycle during six sectors (Press-down, 330 to 30°; Pull-down, 30 to 90°; Pull-up, 90 to 150°; Lift-up, 150 to 210°; Push-up, 210 to 270°; Push-down, 270 to 330°) was calculated. Changes within the incremental test were analysed usind a one-way ANOVA with repeated measures [28]. In case of missing assumption of normal distribution (Kolmogorov-Smirnov test with Lilliefors-correction), the non-parametric Fried-man test was applied. Post-Hoc comparisons based on Bonferroni. The calculation of partial eta-squared (ηp2) was added as effect-size. To identify determinants of performance, bivariate Pearson’s correlation coefficient was calculated. For parameters with significant difference to normal distribution, the non-parametric correlation coefficient of Spearman was applied. The level of significance was set to α = 0.05 [28]. For specific comparisons of means, the effect size Cohen’s d was calculated [18]. Results The mean POmax,AO15, V̇Lamax, POmax,ST and PO4mmol were 545±70 W, 0.44±0.11 mmol l-1 s-1, 131±15 W, 87±12 W. RPElocal at exhaustion was significantly higher than RPEglobal (p = 0.003, d = 2.03). The maximal torque was found within the Pull-down or Push-up sector, whereas the lowest torque and ca-dence occured during the Lift-up. During the incremantal test, a significant decrease in retroversion (p < 0.0005, ηp2 = 0.346), adduction (p < 0.0005, ηp2 = 0.527), elbow-flexion (p < 0.0005, ηp2 = 0.572) and elbow-extension (p < 0.0005, ηp2 = 0.658) was observed. Maximal abduction (p < 0.0005, ηp2 = 0.723) and internal rotation (p = 0.031, ηp2 = 0.046) showed an increase. The MaxV-MinV of the SF (p = 0.069, ηp2 = 0.252), EF (p < 0.0005, ηp2 = 0.775) and RD (p < 0.0005, ηp2 = 0.438) rather decreased, whereas a rather increase in MaxV-MinV for SA (p = 0.003, ηp2 = 0.410), SR (p = 0.069, ηp2 = 0.035) and RF (p = 0.009, ηp2 = 0.385) was found. The maximal elbow-flexion (p = 0.002, ηp2 = 0.414), elbow-extension (p = 0.006, ηp2 = 0.310) and dorsal-flexion (p < 0.0005, ηp2 = 0.356) occured significantly later in crank cycle. At the 180° position, a signifiantly higher abduction (p < 0.0005, ηp2 = 0.405) and lower elbow-flexion (p = 0.001, ηp2 = 0.202) was measured. The angular velocity of all degrees of freedom (df) increased during the incremental test. The maximal angular velocity of anteversion (p = 0.004, ηp2 = 0.052), abduction (p = 0.009, ηp2 = 0.410), dorsal-flexion (p = 0.053, ηp2 = 0.211), ulnar-duction (p = 0.037, ηp2 = 0.169) and trunk-flexion (p = 0.006, ηp2 = 0.092) occured later in crank cycle. The Lift-up was performed with a significantly higher anteversion velocity (p < 0.0005, ηp2 = 0.348), internal-rotation velocity (p = 0.006, ηp2 = 0.092) and dorsal-flexion velocity (p = 0.024, ηp2 = 0.0284). The proportion of work showed a decrease of the Press-down from 20 W to 80 (p = 0.021, d = -1.22) and 100 W (p = 0.041, d = -1.11) and an increase of the Pull-down from 20 to 120 W (p = 0.011, d = 1.33). POmax,ST significantly correlated with Lamax,ST (p = 0.015, r = -0.680), V̇Lamax (p = 0.022, r = -0.649), and PO4mmol (p = 0.050, r = 0.577). The variability of cadence was negatively correlated with POmax,ST (p = 0.009, r = -0.711). Near the 180° position, a lower internal-rotation (p = 0.019, r = -0.662), higher elbow flexion (p = 0.005, r = 0.750), and lower dorsal-flexion (p = 0.003, r = 0.775) was beneficial for POmax,ST. An early maximal external-rotation velocity (p = 0.080, r = -0.511) and abduction velocity (p = 0.079, r = 0.525) and a late dorsal-flexion velocity (p = 0.213, p = -388) tended to result in higher POmax,ST. For PO4mmol, a significant correlation was found to the training load of the participants [h w-1] (p = 0.029, r = 0.628), and the maximal lactate concen-tration during the incremental test (p = 0.037, r = -0.605). Participants with a high MaxV-MinV in SF (p = 0.016, r = 0.676) and RD (p = 0.023, r = -0.492) and a low MaxV-MinV in EF (p = 0.087, r = -0.514) and PF (p = 0.461, r = -0.231) achieved higher PO4mmol. At 180°, a lower internal-rotation (p = 0.012, r = -0.698) and dorsal-flexion (p = 0.226, r = 0.349) and a higher abduction (p = 0.174, r = 0.420) and elbow-flexion (p = 0.214, 0.387) was beneficial for PO4mmol. The maximal anteversion velocity positively correlated with PO4mmol (p = 0.027, r = 0.349). A late occurrence of the maximal anteversion velocity (p = 0.023, r = 0.646), adduction velocity (p = 0.039, r = 0.600), dorsal-flexion velocity (p = 0.031, r = 0.623), and trunk-flexion velocity (p = 0.048, r = 0.579) and early occurrence of the maximal elbow-extension velocity (p = 0.018, r = -0.665) resulted in higher PO4mmol. At 180°, a high maximal abduction velocity (p = 0.026, r = 0.636), dorsal-flexion velocity (p = 0.003, r = -0.774), and radial-duction velocity (p = 0.025, r = 0.640) resulted in higher PO4mmol. Discussion The increase in cadence was higher than the increase in torque, which is consistent with literature, assuming that high muscle forces and concomitant limitations in local blood flow are responsible for exhaustion in arm cranking exercises [59; 66]. Another incidence for an especially local based fatigue, are the significantly higher RPE values on local level. The kinematic and kinetic results indicate that the maintenance of high PO is primaliry limited by the clean like motion near the 180° crank angle, which defines the transition between pull and push phase. For maximal PO, a reinforced pull phase could narrow the loss in crank angular velocity during the clean and thus delay fatigue. Participants who perform the clean with a higher retroversion and lower abduction and internal-rotation are advantaged. For submaximal PO, the change in direction of the force vector (especially during the clean) should be as tangential as possible to avoid unnecessary work. An active wrist motion in RD could improve the propulsion economy. Transfered to practice, a shorter crank arm and slim backrest seem to be suitible alterations of the handcycle setting. A sport specific strength training of the upper extermity is important to improve perfromance. Especially the wrist, cheast and shoulder muscles should be trained in strength and endu-rance. Limitations of the study mosty refer to the unexperienced and non-disabled participants. Therefore, future studies should replicate the current study with elite handcyclists and expand the test spectrum by sprint and continous loads considering the examination of muscle activation patterns (MAP).
Conference Paper
Full-text available
Three different starches were modified by treating with NaOCl acid. Results obtained from some of the physicochemical properties of the native starches were compared with those of the modified ones. Some of the modified starches had varying degrees of improvements in their properties. The oxidized starches of cassava and yam had increased peak viscosity (PV) as compared to the native starches. Increased peak viscosity (PV) is needed in processing conditions for products that requires improved textural properties. Some of the oxidized starches also showed appreciable improvements in their proximate compositions (PC) such as in protein content, total lipid (TL), and fibre content. Protein content of starches has significant effect in improving the protein-lipid linkages in gluten matrix which is very important in bread baking. Although the peak viscosity (PV) of cassava and yam starches was improved, the poor protein content quality may have contributed to the high setback viscosity (SV) of the starches. NaOCl oxidation of some starches, alone, may not give the optimum quality needed for industrial application. The oxidized starches showed improved colouration. The pasting properties (PP) of rice starch showed decreased peak viscosity (PV) and hold peak viscosity (HPV). The decrease in the setback viscosity (SV) of oxidized rice starch is required for industrial application, where high temperature processing is required. It is therefore recommended that biotechnological retooling of materials such as enzyme or genetic modification in cassava may be necessary to improve the processing properties of its starch.
Chapter
The SRM (Schoberer Rad Messtechnik, Welldorf, Germany) power monitoring system has been used extensively in applied field based studies to provide an accurate measurement of cycling power (Gardner et al. 2005). The SRM system consists of a PowerMeter (instrumented crank), a PowerControl (data logger and onboard data display), and a sensor cable (linking data transfer from crank to the onboard powercontrol). One limitation of the SRM system is an inability to attain power outputs until one entire crank revolution is achieved. A crucial element of track cycling time trial events is the standing start in which the athlete is generating maximum torque at low cadence. In this performance setting the cyclist accelerates the bicycle from rest and consequently initial power data is not recorded by the standard SRM system. A modification to the SRM system is described which allows for collection of instantaneous crank torque. The modification consists of an electronic de-modulator developed by SRM and a multi-channel datalogger (DL16CAN, Teller:, Germany) connected in series between the PowerMeter and the PowerControl. The pulse width modulated signal from the PowerMeter is de-modulated into a cadence voltage signal and a torque frequency signal. The signals are synchronised and recorded separately on a time base. The modification allows crank torque to be acquired at 200Hz. This equipment has opened up a new avenue of analysis in a previously under-researched and ultimately performance impacting area of track cycling.
Article
The majority of investigations in hand cycling thus far were carried out in little realistic conditions, particularly with regard to ergonomics and mechanical characteristics such as steering and stabilization mechanisms. In addition, integrated investigations studying both the physiological and biomechanical responses during realistic maximal and submaximal hand cycling have not yet been conducted. This paper illustrates the design, the working, and the possibilities of a newly developed handbike ergometer that simulates hand cycling in realistic ergonomic and mechanical conditions with a continuous control of the workload. Built-in force transducers in both crank handles allow the registration of the orthogonal force components in three dimensions along a pre-defined X, Y, and Z-axes in function of time and/or position. Consequently, the resultant force and the forces exerted in each plane of the test person can be calculated to evaluate the forward, upward, and sideward force generation during hand cycling. The tangential, radial, and transversal forces can also be calculated to analyze the movement effectiveness. As well, eight extra channels are foreseen to allow a simultaneous and synchronized electromyography registration. The handbike ergometer is therefore a useful tool to capture data that are novel and at the forefront of the field of biomechanical analyses in hand cycling, taking into consideration the physical potential of the user, the configuration of the handbike and the handbike–user interface.
Article
The wavelength of moment of active forces (driving forces) for a full cycle while pedaling with platform pedals was determined. There was defined the value of moment of passive forces, depending on drag, rolling resistance and grade of surface. Kinematic motion parameters were determined from the equation of motion of the machine, which was solved numerically. In numerical example, there were determined and compared the temporal courses of bicycle speed for possible gear ratios for the two different waveforms of the driving torque - the determined, the time-varying and the constant ones. There were compared extreme values of active and passive forces, the kinetic energy of the bike and work expended by the rider at a specified time.
Article
This work intends to investigate the effects of pedaling directions on the muscle actions during the bicycle's uphill propulsion. A test rig was developed that consists of a bicyle with a special planetary geartrain, a height-adjustable treadmill, a rear-wheel support and a magnetic brake. A three-dimensional motion analysis was performed for measuring kinematic characteristics of the forward backward pedaling and the electromygraphy(EMG) measurements were simultaneously performed for estimating the muscle actions of the leg. In this work, four muscles are considered including Gastrocnemius muscle(GM), Vastus lateralis(VL), Tibialis anterior(TA) and Soleus(SOL) while the uphill slope is varied from to . Raw EMG signals were first processed through the root-mean-square(RMS) averaging and then ensemble curves were derived by averaging the EMG RMS envelopes over 50 consecutive cycles. Results show that both the kinemactic characteristics and the muscle actions are significantly affected by the pedaling direction. The crank speed of the forward pedaling is higher but the difference in speed is reduced as the slope is increased. The ensemble curves of the :ac signals clearly exhibit some differences in their patterns, peak values and the corresponding locations with respect to the crank angle. The peak values of most EMG signals are higher for the forward pedaling regardless of the slope magnitude. However, the averages of the EMG signals are not observed to have a similar relationship with the pedaling direction, which seems to be affected by several factors such as less experience of the participants' backward pedaling. inappropriate bicycle design for the backward pedaling. These limitations will be further considered in future work.
Article
Objective: Scientific studies of specific training interventions to evoke adaptive biomechanical, aerobic and oxygen-independent cellular responses for improving cycling performance in already well-trained cyclists are limited. Consequently, related research of metabolic markers and underlying mechanisms found to be potential determinants of best competitive cycling performance are reviewed. Applicable specific training strategies which may have an impact on performance are discussed. Data sources: For this review, scientific texts, peer-reviewed journals, electronic (Web) publications and published abstracts of papers presented at conferences were identified through Highwire Press and PubMed. Study section and data extraction: The selected papers examined were from peer review established sports science and physiology journals specifically related to exercise physiology. Conclusions: Achieving the best competitive cycling performance requires the understanding and implementation of sound research in support of successful training paradigms. Knowledge of the physiological mechanisms following a training regime will allow valid training practices to be implemented. The inclusion of a combination of strategies focusing on pedalling dynamics, post-exercise recovery, hypoxia training, and sprint interval training may prove responsible for observed increases in exercise performance at sea level and at altitude.
Article
Full-text available
A pedal dynamometer recorded changes in pedaling technique (normal and tangential components of the applied force, crank orientation, and pedal orientation) of 14 elite male 40-km time trialists who rode at constant cadence as the workload increased from similar to an easy training ride to similar to a 40-km competition. There were two techniques for adapting to increased workload. Seven subjects showed no changes in pedal orientation, and predominantly increased the vertical component of the applied force during the downstroke as the workload increased. In addition to increasing the vertical component during the downstroke, the other subjects also increased the toe up rotation of the pedal throughout the downstroke and increased the horizontal component between 0° and 90°. A second finding was that negative torque about the bottom bracket during the upstroke usually became positive (propulsive) torque at the high workload. However, while torque during the upstroke did reduce the total positive work required during the downstroke, it did not contribute significantly to the external work done because 98.6% and 96.3 % of the total work done at the low and high workloads, respectively, was done during the downstroke.
Article
Full-text available
This investigation sought to determine if cycling power could be accurately modeled. A mathematical model of cycling power was derived, and values for each model parameter were determined. A bicycle-mounted power measurement system was validated by comparison with a laboratory ergometer. Power was measured during road cycling, and the measured values were compared with the values predicted by the model. The measured values for power were highly correlated (R2 = .97) with, and were not different than, the modeled values. The standard error between the modeled and measured power (2.7 W) was very small. The model was also used to estimate the effects of changes in several model parameters on cycling velocity. Over the range of parameter values evaluated, velocity varied linearly (R2 > .99). The results demonstrated that cycling power can be accurately predicted by a mathematical model.
Article
Full-text available
In cycling at race speeds, 90% of total resistance opposing motion, R T(N) T depends on aerodynamic drag of air, which is directly proportional to the effective frontal area, AC d(m2). R T was measured on a cyclist, in an open velodrome, in order to evaluate AC d in four different positions on a traditional bicycle: upright d position (UP), dropped position (DP), aero position (AP) and Obree's position (OP : the hands in support under the chest, the forearms tucked on the arms, the trunk tilted forward). R T was determined at different constant speeds, Vc(m s−1) with a special device (Max One), which allows the measurement of the external mechanical power P ext(W) in real conditions of cycling locomotion ext (R T = P extVc−1). Experiments were carried out in order to test the validity and the reproducibility of P ext provided by the measurement device. P ext was measured twice in the same experimental conditions (exercise on a treadmill against slopes varying from 1 to 14%) and no significant difference was observed between the two measurement series. A systematic measurement error was observed allowing the use of a correcting factor. As expected, in the four rider positions, R T increased linearly (p
Article
Full-text available
The purpose of this study was to estimate the differences in neuromuscular fatigue among prolonged pedalling exercises performed at different pedalling rates at a given exercise intensity. The integrated electromyogram (iEMG) slope defined by the changes in iEMG as a function of time during exercise was adopted as the measurement for estimating neuromuscular fatigue. The results of this experiment showed that the relationship between pedalling rate and the means of the iEMG slopes for eight subjects was a quadratic curve and the mean value at 70 rpm [1.56 (SD 0.65) Vmin–1] was significantly smaller (P < 0.01) than that at 50 and 60 rpm [2.25 (SD 0.54), and 2.22 (SD 0.68), respectively]. On the other hand, the mean value of oxygen consumption obtained simultaneously showed a tendency to increase linearly with the increase in pedalling rate, and the values at 70 and 80 rpm were significantly higher than those at 40 and 50 rpm. In conclusion, it was demonstrated that the degree of neuromuscular fatigue estimated by the iEMG changes for five periods of prolonged pedalling exercise at a given exercise intensity was different among the different pedalling rates, and that the pedalling rate at which minimal neuromuscular fatigue was obtained was not coincident with the rate at which the minimal oxygen consumption was obtained, but was coincident with the rate which most subjects preferred. These findings would suggest that the reason why most people prefer a relative higher pedalling rate, even though higher oxygen consumption is required, is closely related to the development of neuromuscular fatigue in the working muscles.
Article
Full-text available
The purpose of this study was to clarify the reason for the difference in the preferred cadence between cyclists and noncyclists. Male cyclists and noncyclists were evaluated in terms of pedal force, neuromuscular activity for lower extremities, and oxygen consumption among the cadence manipulation (45, 60, 75, 90, and 105 rpm) during pedaling at 150 and 200 W. Noncyclists having the same levels of aerobic and anaerobic capacity as cyclists were chosen from athletes of different sports to avoid any confounding effect from similar kinetic properties of cyclists for lower extremities (i.e., high speed contraction and high repetitions in prolonged exercise) on both pedaling performance and preferred cadence. The peak pedal force significantly decreased with increasing of cadence in both groups, and the value for noncyclists was significantly higher than that for cyclists at each cadence despite the same power output. The normalized iEMG for vastus lateralis and vastus medialis muscles increased in noncyclists with rising cadence; however, cyclists did not show such a significant increase of the normalized iEMG for the muscles. On the other hand, the normalized iEMG for biceps femoris muscle showed a significant increase in cyclists while there was no increase for noncyclists. Oxygen consumption for cyclists was significantly lower than that for noncyclists at 105 rpm for 150 W work and at 75, 90, and 105 rpm for 200 W work. We conclude that cyclists have a certain pedaling skill regarding the positive utilization for knee flexors up to the higher cadences, which would contribute to a decrease in peak pedal force and which would alleviate muscle activity for the knee extensors. We speculated that pedaling skills that decrease muscle stress influence the preferred cadence selection, contributing to recruitment of ST muscle fibers with fatigue resistance and high mechanical efficiency despite increased oxygen consumption caused by increased repetitions of leg movements.
Article
Full-text available
The intent of this study was two-fold. The first aim was to investigate how cyclists orient forces applied by the feet to the pedals in response to varying power output and cadence demands, and the second was to assess whether competitive riders responded differently from recreational riders to such variations. One group consisted of US Cycling Federation category II licensed competitive cyclists (n = 7) and the second group consisted of recreational cyclists with no competitive experience (n = 38). The subjects rode an instrumented stationary 10-speed geared bicycle mounted on a platform designed to provide rolling and inertial resistance for six pedal rate/power output conditions for a minimum of 2 min for each ride. The pedalling rates were 60, 80 and 100 rev min-1 and the power outputs 100 and 235 W. All rides were presented in random order. The forces applied to the pedals, the pedal angle with respect to the crank and the crank angle were recorded for the final 30 s of each ride. From these data, a number of variables were computed including peak normal and tangential forces, crank torque, angular impulse, proportion of resultant force perpendicular to the crank, and pedal angle. Both the competitive and recreational groups responded similarly to increases in cadence and power output. There was a decrease in the peak normal forces, whereas the tangential component remained almost constant as cadence was increased. Regardless of cadence, the riders responded to increased power output demands by increasing the amount of positive angular impulse. All the riders had a reduced index of effectiveness as cadence increased. This was found to be the result of the large effect of the forces during recovery on this calculation. There were no significant differences between the two groups in each of these variables over all conditions. It was concluded that the lack of difference between the groups was a combined consequence of the limited degrees of freedom associated with the bicycle and that the relatively low power output for the competitive riders was insufficient to discriminate or highlight superior riding technique.
Article
Full-text available
There is considerable demand for information on the effectiveness of various resistance exercises for improving physical performance, and on how exercise programs must match functional activities to produce the greatest performance gains (training specificity). Evidence supports exercise-type specificity; the greatest training effects occur when the same exercise type is used for both testing and training. Range-of-motion (ROM) specificity is supported; strength improvements are greatest at the exercised joint angles, with enough carryover to strengthen ROMs precluded from direct training due to injury. Velocity specificity is supported; strength gains are consistently greatest at the training velocity, with some carryover. Some studies have produced a training effect only for velocities at and below the training velocity while others have produced effects around the training velocity. The little, mainly isokinetic, evidence comparing different exercise velocities for improving functional performance suggests that faster exercise best improves fast athletic movements. Yet isometric exercise can improve actions like the vertical jump, which begin slowly. The rate of force application may be more important in training than actual movement speed. More research is needed into the specificity and efficacy of resistance exercise. Test populations should include both males and females of various ages and rehabilitation patients.
Article
Full-text available
This study was designed to examine the optimal pedaling rate for pedaling exercise at a given work intensity for cyclists. Six college-aged cyclists each performed six sessions of heavy pedaling exercise at individually selected work rates based on their aerobic capacity. The optimal pedaling rate was evaluated on the basis of minimal neuromuscular fatigue as evidenced by the integrated electromyogram (iEMG) slope defined by the changes in iEMG as a function of time. The means of the iEMG slope demonstrated a quadratic curve versus pedaling rate. The mean values at 80 rpm (0.53 (SD 0.20) microV.min-1) and 90 rpm (0.67 (SD 0.23) microV.min-1) were significantly smaller than those values at any other pedaling rate. On the other hand, the mean value of oxygen uptake (VO2) expressed as a percent of the subject's maximal VO2 (% VO2max) at each pedaling rate also showed a quadratic curve with minimal values at about 60 or 70 rpm. VO2 at 70 rpm (84.0 (SD 5.0) % VO2max) was significantly smaller than those values at 80 rpm (86.3 (SD 3.5) % VO2max), 90 rpm (87.4 (SD 3.8) % VO2max), and 100 rpm (90.1 (SD 3.8) % VO2max). These data strongly suggest that the optimal pedaling rate estimated from neuromuscular fatigue in working muscles is not coincident with the pedaling rate at which the smallest VO2 was obtained, but with the preferred pedaling rate of the subjects. Our findings also suggest that the reason that cyclists prefer a higher pedaling rate is closely related to the development of neuromuscular fatigue in the working muscles.
Article
Full-text available
The purpose of this study was to determine the influence of pedalling rate on cycling efficiency in road cyclists. Seven competitive road cyclists participated in the study. Four separate experimental sessions were used to determine oxygen uptake (VO2) and carbon dioxide output (VCO2) at six exercise intensities that elicited a VO2 equivalent to 54, 63, 73, 80, 87 and 93% of maximum VO2 (VO(2max)). Exercise intensities were administered in random order, separated by rest periods of 3-5 min; four pedalling frequencies (60, 80, 100 and 120 rpm) were randomly tested per intensity. The oxygen cost of cycling was always lower when the exercise was performed at 60 rpm. At each exercise intensity, VO2 showed a parabolic dependence on pedalling rate (r = 0.99-l: all P < 0.01) with a curvature that flattened as intensity increased. Likewise, the relationship between power output and gross efficiency (GE) was also best fitted to a parabola (r = 0.94-l, all P < 0.05). Regardless of pedalling rate, GE improved with increasing exercise intensity (P < 0.001). Conversely, GE worsened with pedalling rate (P < 0.001). Interestingly, the effect of pedalling cadence on GE decreased as a linear function of power output (r = 0.98, n = 6, P < 0.001). Similar delta efficiency (DE) values were obtained regardless of pedalling rate (21.5 (0.8); 22.3 (1.2), 22.6 (0.6) and 73.9 (1.0)%, for the 60; 80, 100 and 120 rpm, mean (SEM) respectively]. However, in contrast to GE, DE increased as a linear function of pedalling rate (r = 0.98, P < 0.05). The rate at which pulmonary ventilation increased was accentuated for the highest pedalling rate (P < 0.05), even after accounting for differences in exercise intensity and VO2 (P < 0.05). Pedalling rate per se did not have any influence on heart rate which, in turn, increased linearly with VO2. These results may help us to understand why competitive cyclists often pedal at cadences of 90-105 rpm to sustain a high power output during prolonged exercise.
Article
Full-text available
Bicycle pedaling has been studied from both a motor control and an equipment setup and design perspective. In both cases, although the dynamics of the bicycle drive system may have an influence on the results, a thorough understanding of the dynamics has not been developed. This study pursued three objectives related to developing such an understanding. The first was to identify the limitations of the inertial/frictional drive system model commonly used in the literature. The second was to investigate the advantages of an inertial/frictional/compliant model. The final objective was to use these models to develop a methodology for configuring a laboratory ergometer to emulate the drive system dynamics of road riding. Experimental data collected from the resulting road-riding emulator and from a standard ergometer confirmed that the inertial/frictional model is adequate for most studies of road-riding mechanics or pedaling coordination. However, the compliant model was needed to reproduce the phase shift in crank angle variations observed experimentally when emulating the high inertia of road riding. This finding may be significant for equipment setup and design studies where crank kinematic variations are important or for motor control studies where fine control issues are of interest.
Article
Full-text available
This study was undertaken to examine the effect of different pedalling cadences upon various physiological responses during endurance cycling exercise. Eight well-trained triathletes cycled three times for 30 min each at an intensity corresponding to 80% of their maximal aerobic power output. The first test was performed at a freely chosen cadence (FCC); two others at FCC–20% and FCC+20%, which corresponded approximately to the range of cadences habitually used by road racing cyclists. The mean (SD) FCC, FCC–20% and FCC+20% were equal to 86 (4), 69 (3) and 103 (5) rpm respectively. Heart rate (HR), oxygen uptake (\(\dot V{\rm O}_{\rm 2} \) ), minute ventilation (\(\dot V_{\rm E} \) ) and respiratory exchange ratio (R) were analysed during three periods: between the 4th and 5th, 14th and 15th, and 29th and 30th min. A significant effect of time (P<0.01) was found at the three cadences for HR, \(\dot V{\rm O}_{\rm 2} \) . The \(\dot V_{\rm E} \) and R were significantly (P<0.05) greater at FCC+20% compared to FCC–20% at the 5th and 15th min but not at the 30th min. Nevertheless, no significant effect of cadence was observed in HR and \(\dot V{\rm O}_{\rm 2} \) . These results suggest that, during high intensity exercise such as that encountered during a time-trial race, well-trained triathletes can easily adapt to the changes in cadence allowed by the classical gear ratios used in practice.
Article
Full-text available
This study examined circulatory and metabolic changes in a working muscle during a crank cycle in a pedaling exercise with near-infrared spectroscopy (NIRS). NIRS measurements sampled under stable metabolic and cadence conditions during incremental pedaling exercise were reordered according to the crank angles whose signals were obtained in eight male subjects. The reordered changes in muscle blood volume during a crank cycle demonstrated a pattern change that corresponded to changes in pedal force and electrical muscle activity for pedal thrust. The top and bottom peaks for muscle blood volume change at work intensities of 180 W and 220 W always preceded (88 +/- 32 and 92 +/- 23 ms, respectively) those for muscle oxygenation changes. Significant differences in the level of NIRS parameters (muscle blood volume and oxygenation level) among work intensities were noted with a common shape in curve changes related to pedal force. In addition, a temporary increase in muscle blood volume following a pedal thrust was detected at work intensities higher than moderate. This temporary increase in muscle blood volume might reflect muscle blood flow restriction caused by pedal thrusts. The results suggest that circulatory and metabolic conditions of a working muscle can be easily affected during pedaling exercise by work intensity. The present method, reordering of NIRS parameters against crank angle, serves as a useful measure in providing additional findings of circulatory dynamics and metabolic changes in a working muscle during pedaling exercise.
Article
Full-text available
This study was designed to examine the effects of cycling position (seated or standing) during level-ground and uphill cycling on gross external efficiency (GE) and economy (EC). Eight well-trained cyclists performed in a randomized order five trials of 6-min duration at 75% of peak power output either on a velodrome or during the ascent of a hill in seated or standing position. GE and EC were calculated by using the mechanical power output that was measured by crankset (SRM) and energy consumption by a portable gas analyzer (Cosmed K4b(2)). In addition, each subject performed three 30-s maximal sprints on a laboratory-based cycle ergometer or in the field either in seated or standing position. GE and EC were, respectively, 22.4 +/- 1.5% (CV = 5.6%) and 4.69 +/- 0.33 kJ x L(-1) (CV = 5.7%) and were not different between level seated, uphill seated, or uphill standing conditions. Heart rate was significantly ( < 0.05) higher in standing position. In the uphill cycling trials, minute ventilation was higher ( < 0.05) in standing than in seated position. The average 30-s power output was higher ( < 0.01) in standing (803 +/- 103 W) than in seated position (635 +/- 123 W) or on the stationary ergometer (603 +/- 81 W). Gradient or body position appears to have a negligible effect on external efficiency in field-based high-intensity cycling exercise. Greater short-term power can be produced in standing position, presumably due to a greater force developed per revolution. However, the technical features of the standing position may be one of the most determining factors affecting the metabolic responses.
Article
Full-text available
The purpose of this study into high-intensity cycling was to: (1) test the hypothesis that endurance time is longest at a freely chosen pedalling rate (FCPR), compared to pedalling rates 25% lower (FCPR-25) and higher (FCPR+25) than FCPR, and (2) investigate how physiological variables, such as muscle fibre type composition and power reserve, relate to endurance time. Twenty males underwent testing to determine their maximal oxygen uptake (VO(2max)), power output corresponding to 90% of VO(2max) at 80 rpm (W90), FCPR at W90, percentage of slow twitch muscle fibres (% MHC I), maximal leg power, and endurance time at W90 with FCPR-25, FCPR, and FCPR+25. Power reserve was calculated as the difference between applied power output at a given pedalling rate and peak crank power at this same pedalling rate. W90 was 325 (47) W. FCPR at W90 was 78 (11) rpm, resulting in FCPR-25 being 59 (8) rpm and FCPR+25 being 98 (13) rpm. Endurance time at W90(FCPR+25) [441 (188) s] was significantly shorter than at W90(FCPR) [589 (232) s] and W90(FCPR-25) [547 (170) s]. Metabolic responses such as VO(2) and blood lactate concentration were generally higher at W90(FCPR+25) than at W90(FCPR-25) and W90(FCPR). Endurance time was negatively related to VO(2max), W90 and % MHC I, while positively related to power reserve. In conclusion, at group level, endurance time was longer at FCPR and at a pedalling rate 25% lower compared to a pedalling rate 25% higher than FCPR. Further, inter-individual physiological variables were of significance for endurance time, % MHC I showing a negative and power reserve a positive relationship.
Article
Alterations in kinetic patterns of pedal force and crank torque due to changes in surface grade (level vs. 8% uphill) and postuer (seated vs. standing) were investigated during cycling on a computerized ergometer. Kinematic data from a planar cine analysis and force data from a pedal instrumented with piezoelectric crystals were recorded from multiple trials of 8 elite cyclists. These measures were used to calculate pedal force, pedal orientation, and crank torque profiles as a function of crank angle in three conditioned: seated level, seated uphill, and standing uphill. The change in surface grade from level to 8% uphill resulted in a shift in pedal angle (toe up) and a moderately higher peak crank torque, due at least in part to a reduction in the cycling cadence. However, the overall patterns of pedal and crank kinetics were similar in the two seated conditions. In contrast, the alteration in posture from sitting to standing on the hill permitted the subjects to produce different patterns of pedal and crank kinetics, characterized by significantly higher peak pedal force and crank torque that occurred much later in the downstroke. These kinetic changes were associated with modified pedal orientation (toe down) throughout the crank cycle. Further, the kinetic changes were linked to altered nonmuscular (gravitational and inertial) contributions to the applied pedal force, caused by the removal of the saddle as a base of support.
Article
Cyclists seek to maximize performance duringcompetition, and gross efficiency is an important factor affectingperformance. Gross efficiency is itself affected by pedal rate. Thus, it is important to understand factors that affect freely chosen pedal rate. Crank inertial load varies greatly during road cycling based on the selected gear ratio. Nevertheless, the possible influence of crank inertial load on freely chosen pedal rate and gross efficiency has never been investigated. This study tested the hypotheses that during cycling with sub-maximal work rates, a considerable increase in crank inertial load would cause (1) freely chosen pedal rate to increase, and as a consequence, (2) gross efficiency to decrease. Furthermore, that it would cause (3) peak crank torque to increase if a constant pedal rate was maintained. Subjects cycled on a treadmill at 150 and 250 W, with low and high crank inertial load, and with preset and freely chosen pedal rate. Freely chosen pedal rate was higher at high compared with low crank inertial load. Notably, the change in crank inertial load affected the freely chosen pedal rate as much as did the 100 W increase in work rate. Alongwith freely chosen pedal rate being higher, gross efficiency at 250 W was lower during cycling with high compared with low crank inertial load. Peak crank torque was higher during cycling at 90 rpm with high compared with low crank inertial load. Possibly, the subjects increased the pedal rate to compensate for the higher peak crank torque accompanying cycling with high compared with low crank inertial
Article
Competitive cyclists generally climb hills at a low cadence despite the recognized advantage in level cycling of high cadences. To test whether a high cadence is more economical than a low cadence during uphill cycling, nine experienced cyclists performed steady-state bicycling exercise on a treadmill under three randomized trials. Subjects bicycled at 11.3 km.h-1 up a 10% grade while 1) pedalling at 84 rpm in a sitting position-84 Sit, 2) pedalling at 41 rpm in a standing position-41 Stand, and 3) pedalling at 41 rpm in a sitting position-41 Sit. Heart rate (HR), oxygen consumption (VO2), ventilation (VE), and respiratory exchange ratio were measured continuously during 5-min trials and averaged over the last 2 min. Additionally, rating of perceived exertion was recorded during the fifth minute of each trial, and blood lactate concentration was recorded immediately before and after each trial. Significantly lower values for HR, VO2 and VE were recorded during 84 Sit (164 +/- 3 bpm, 51.8 +/- 0.8 ml.min-1 x kg-1, 94 +/- 5 l.min-1) than for either the 41 Stand (171 +/- 2 bpm, 53.1 +/- 0.7 ml.min-1 x kg-1, 105 +/- 6 l.min-1) o 41 Sit (168 +/- 2 bpm, 53.1 +/- 0.8 ml.min-1 x kg-1, 101 +/- 6 l.min-1) trials. No other differences were noted between trials for any of the measured variables. We conclude that uphill cycling is more economical at a high versus a low cadence.
Article
The purpose of this study was to calculate optimal pedaling rates based upon external work (EW) rate and mechanical work (MW) rate criteria that respectively exclude and include the internal work (IW) rate of the lower limbs. Metabolic and kinematic data were collected as 12 males pedaled an ergometer at rates of 40, 60, 80, and 98 rpm while producing external power outputs of 49, 98, and 146 W. Energy expenditure (EE) was calculated from steady rate oxygen uptake and respiratory exchange ratio values. The IW rate was determined from digitized kinematic data by modeling the thigh, shank, and foot as a three-segment linked system and calculating their changes in potential, translational kinetic, and rotational kinetic energy. The EW rate was calculated from the observed pedaling rate and the ergometer resistance. The MW rate was defined as the sum of the EW rate and IW rate. At each level of external power output, the MW rate increased linearly with pedaling rate increments while the EE displayed a curvilinear relationship. Both gross efficiency (GE = EW rate/EE) and mechanical efficiency (ME = MW rate/EE) responded quadratically to pedaling rate treatments but a repeated measures ANOVA revealed significant differences in their beta 0, beta 1, and beta 2 regression coefficients. Optimal pedaling rates calculated from ME were consistently higher (82 to 101 rpm) than those determined from GE (35 to 57 rpm). The pedaling rates that optimized ME, but not GE, are similar to the rates reported to be biomechanically optimal and preferred by trained cyclists. This study demonstrates that the choice of a work rate criterion can alter the meaning and interpretation of metabolic data.
Article
The cyclist’s ability to maintain an extremely high rate of energy expenditure for long durations at a high economy of effort is dependent upon such factors as the individual’s anaerobic threshold, muscle fibre type, muscle myoglobin concentration, muscle capillary density and certain anthropometric dimensions. Although laboratory tests have had some success predicting cycling potential, their validity has yet to be established for trained cyclists. Even in analysing the forces producing propulsive torque, cycling effectiveness cannot be based solely on the orientation of applied forces. Innovations of shoe and pedal design continue to have a positive influence on the biomechanics of pedalling. Although muscle involvement during a complete pedal revolution may be similar, economical pedalling rate appears to differ significantly between the novice and racing cyclist. This difference emanates, perhaps, from long term adaptation. Air resistance is by far the greatest retarding force affecting cycling. The aerodynamics of the rider and the bicycle and its components are major contributors to cycling economy. Correct body posture and spacing between riders can significantly enhance speed and efficiency. Acute and chronic responses to cycling and training are complex. To protect the safety and health of the cyclist there must be close monitoring and cooperation between the cyclist, coach, exercise scientist and physician.
Article
In this study we evaluated the physiological and biomechanical responses of 'elite-national class' (i.e., group 1; N = 9) and 'good-state class' (i.e., group 2; N = 6) cyclists while they simulated a 40 km time-trial in the laboratory by cycling on an ergometer for 1 h at their highest power output. Actual road racing 40 km time-trial performance was highly correlated with average absolute power during the 1 h laboratory performance test (r = -0.88; P < 0.001). In turn, 1 h power output was related to each cyclists' V̇O2 at the blood lactate threshold (r = 0.93; P < 0.001). Group 1 was not different from group 2 regarding V̇O(2max) (approximately 70 ml·kg-1·min-1 and 5.01 l·min-1) or lean body weight. However, group 1 bicycled 40 km on the road 10% faster than group 2 (P < 0.05; 54 vs 60 min). Additionally, group 1 was able to generate 11% more power during the 1 h performance test than group 2 (P < 0.05), and they averaged 90 ± 1% V̇O(2max) compared with 86 ± 2% V̇O(2max) in group 2 (P = 0.06). The higher performance power output of group 1 was produced primarily by generating higher peak torques about the center of the crank by applying larger vertical forces to the crank arm during the cycling downstroke. Compared with group 2, group 1 also produced higher peak torques and vertical forces during the downstroke even when cycling at the same absolute work rate as group 2. Factors possibly contributing to the ability of group 1 to produce higher 'downstroke power' are a greater percentage of Type I muscle fibers (P < 0.05) and a 23% greater (P < 0.05) muscle capillary density compared with group 2. We have also observed a strong relationship between years of endurance training and percent Type I muscle fibers (r = 0.75; P < 0.001). It appears that 'elite-national class' cyclists have the ability to generate higher 'downstroke power', possibly as a result of muscular adaptations stimulated by more years of endurance training.
Article
Eleven men with recreational bicycling experience rode a bicycle ergometer with instrumented force pedals to determine the effects of pedalling rate and power output on the total resultant pedal force, Fr, and the component of the force perpendicular to the crank arm. The force patterns were obtained at power outputs of 100 W and 200 W for pedalling rates of 40-120 rpm in intervals of 10 rpm. Data were not obtained at 40 rpm at the 200 W power output. The Fr averaged over a crank cycle (Far) was lowest at 90 rpm and 100 W, a value statically different (P less than 0.05) from those at 40, 50, and 120 rpm. At 200 W, the Fr was lowest at 100 rpm, a value statistically different (P less than 0.05) from those at 50, 60, and 70 rpm. The Far varied widely (range of 30% of mean for all subjects) for individuals at a given power output. The results suggest that pedalling at 90-100 rpm may minimize peripheral forces and therefore peripheral muscle fatigue even though this rate may result in higher oxygen uptake.
Employing seven male subjects, the influence of four different ergometer flywheels with the moments of inertia at the crankshaft (J') = 5.5, 10.5, 16.5, and 19.5 kg.m2 on 6-min load pulse sum (LPS), the heart rate integrated over 6-min was investigated. The J' was demonstrated to influence LPS at each of the corresponding rotational energies of the flywheels (75, 144, 226 and 276 J at 50 rev.min-1) in the four work-load steps (50, 100, 150 and 200 W). Between the values J' = 5.5 kg.m2 and 10.5 kg.m2 the LPS decreases, to rise again in the range J' = 10.5 kg.m2-19.5 kg.m2. For equal work-loads the minimum LPS was reached at a J' of 10.5 kg.m2. For the workloads of 100, 150 and 200 W it was possible to show statistically significant differences. The moment of inertia of ergometer flywheels J has a smoothing effect on the fluctuations of the rotational speed which are unavoidable during work on a cycle ergometer. The flywheel stores the leg forces acting on the pedals as rotational energy and opposes any rotational acceleration. If the J used is too small, equalization of the fluctuations of the rotational speed remains unsatisfactory. Flywheels with larger J require larger torques at the crankshaft for acceleration. For the most effective delivery of work to a cycle ergometer, an optimal rotational energy of the flywheel was found. For equal physical work, smaller or larger rotational energies require a larger expenditure of biological energy. A J' = 11 +/- 2 kg.m2 was incorporated into the draft for the German standard DIN 13,405 -- cycle-type ergometers.
Article
The physiological, subjective and biomechanical effects of altering flywheel weight and pedalling rate on a Quinton Model 870 bicycle ergometer were studied. Steel plates were added to the flywheel to increase its weight to 35·9 kg with a moment of inertia of 1·65 kg m. A 1·5 kg spoked wheel with a moment of inertia of 0·1 kg m was used as the light flywheel. Eight subjects pedalled on two separate occasions for 6 min at 40, 50, 60, 70, 80 and 90 r.p.m. with workload levels representing 30 and 60% of their [Vdot]O2max with each flywheel. Force plate pedals were used to measure the total resultant force on the pedals (FR) and the component perpendicular to the crank arm (FT). A force effectiveness index (FEI) was denned as the average of FT/FR over a crank cycle. The result showed no statistically significant change (p
Article
This investigation was undertaken to determine the effect of pedal frequency on submaximal exercise responses. Seven well-trained competitive cyclists were studied riding their road-racing bicycles on a motor-driven treadmill at 80% of maximum O2 consumption (VO2 max) using different gear ratios. Cyclists were also studied during a series of unloaded trials to assess the effects of varying rates of limb movements independent of external work load. Heart rate (HR) increased, whereas net HR (after subtracting the HR during unloaded cycling) decreased with increasing pedal frequency during loaded cycling. Expiratory flow (VE), O2 consumption (VO2), blood lactate, net VO2 (after subtracting the VO2 of unloaded cycling), and net VE (after subtracting the VE during unloaded cycling) were quadratically related to pedal frequency. The quadratic relationships evident after corrections were made for the additional work needed to move the legs more frequently may be explained at the lower pedaling rates by a less uniform pattern of blood flow caused by increasing the force requirement per pedal stroke and, at the higher pedal frequencies, by the recruitment of additional musculature to stabilize the trunk. The average of preferred frequency for the group, which was also the most economical pedaling rate judged by most of the variables was 91 rpm, although the preferred pedaling rate for each subject ranged from 72 to 102 rpm.
Article
In human locomotion the ability to generate and sustain power output is of fundamental importance. This review examines the implications for power output of having variability in the metabolic and contractile properties within the population of muscle fibres which comprise the major locomotory muscles. Reference is made to studies using an isokinetic cycle ergometer by which the global power/velocity relationship for the leg extensor muscles can be determined. The data from these studies are examined in the light of the force velocity characteristics of human type I and type II muscle fibres. The 'plasticity' of fibre properties is discussed with reference to the 'acute' changes elicited by exercise induced fatigue and changes in muscle temperature and 'chronic' changes occurring following intensive training and ageing.
Article
The purpose of this study was to compare 1) the preferred cadences and 2) the aerobic demand response to cadence manipulation of highly fit, experienced cyclists and equally fit noncyclists. Eight cyclists (C) and eight non-cyclists (NC) pedaled at 200 W under six randomly ordered cadence conditions (50, 65, 80, 95, 110 rpm and preferred cadence) on a Velodyne trainer. The VO2 responses of C and NC to cadence manipulation were similar. Both groups displayed lower VO2 values at lower cadences. VO2 differences between C and NC across cadences were not significant. Mean preferred pedaling cadence surprisingly was somewhat higher for NC (91.6 +/- 10.5 rpm) than C (85.2 +/- 9.2 rpm), but the difference was not significant. The most economical cadence was significantly lower for C (56.1 +/- 6.9 rpm) than NC (62.9 +/- 4.7 rpm). Thus, cycling experience did not substantially influence preferred cadence nor economy during moderate intensity cycling by highly fit athletes. We speculate that preferred cadence and economy similarities between C and NC are associated with similarities in the dynamic muscular training of the groups.
Article
The aim of this experiment was to investigate the effects of differing pedalling speeds on the power-duration relationship during high intensity cycle ergometry with pedal cadences of 50 (low), 90 (intermediate) and 110 (high) r.min-1. This hyperbolic power-duration relationship can be described as: (P - phiPA).t = W', where P = power output, t = time to exhaustion, and phiPA and W' are constants. Eight volunteer male subjects, aged 24 +/- 2.6 yr, with no competitive cycling training took part in this study and each undertook thirteen tests on a Lode BV Excalibur Sport V1.52 cycle ergometer over an eight week period. The first exercise bout was a 30 W.min-1 incremental cycle at 50 r.min-1 to volitional fatigue. This allowed the identification of a range of power outputs that would be used to construct and examine the power-duration relationships for each subject at 50, 90 and 110 r.min-1. At both 50 and 90 r.min-1, power outputs of 30 W above and below and 60 W above the highest work rate, as well as the maximum work rate achieved during the incremental exercise test were chosen, while at 110 r.min-1, the power outputs chosen were 25 W above and below as well as 50 W above the highest work rate achieved during the incremental exercise test and also the maximum work rate achieved during the incremental exercise test were chosen. These four work rates for each pedalling frequency were chosen because they would have exercise times to exhaustion in the range of 1-10 minutes. Each exercise bout was preceded by four minutes of unloaded cycling and then the work rate was adjusted quickly to the desired load setting by the previously programmed computerised ergometer. The results of this work indicate that for the group of subjects studied, pedalling a cycle ergometer at 50 r.min-1 allows subjects to pedal for a significantly greater time than when pedalling at either 90 or 110 r.min-1. phiPA at 50 r.min-1 was significantly greater than when pedalling at either 90 (F(1,21) = 7.47, p < 0.01) or 110 r.min-1 (F(1,21) = 10.83, p < 0.0005). There was no significant (p > 0.22) difference between phiPA at 90 and 110 r.min-1, F(1,21) = 1.36. W' however, was not significantly different when the data for 50 r.min-1, 90 r.min-1 and 110 r.min-1 were compared (F50 r.min-1 (1,21) = 0.95; p > 0.41; F90 r.min-1(1,21) = 0.79, p > 0.53; F110 r.min-1 (1,21) = 0.78, p > 0.53). Our hypothesis, that endurance performance was reduced when recreational cyclists pedal at a high cadence when compared to a low cadence was correct. Maximum sustainable power output during cycle ergometry was higher at 50 r.min-1 than at either 90 or 110 r.min-1. At the intermediate cadence endurance was better than at the high but worse than at the low cadence. In conclusion, during endurance cycling, recreaional cyclists should pedal at lower rather than higher cadences.
Article
Inertial load can affect the control of a dynamic system whenever parts of the system are accelerated or decelerated. During steady-state pedaling, because within-cycle variations in crank angular acceleration still exist, the amount of crank inertia present (which varies widely with road-riding gear ratio) may affect the within-cycle coordination of muscles. However, the effect of inertial load on steady-state pedaling coordination is almost always assumed to be negligible, since the net mechanical energy per cycle developed by muscles only depends on the constant cadence and workload. This study test the hypothesis that under steady-state conditions, the net joint torques produced by muscles at the hip, knee, and ankle are unaffected by crank inertial load. To perform the investigation, we constructed a pedaling apparatus which could emulate the low inertial load of a standard ergometer or the high inertial load of a road bicycle in high gear. Crank angle and bilateral pedal force and angle data were collected from ten subjects instructed to pedal steadily (i.e., constant speed across cycles) and smoothly (i.e., constant speed within a cycle) against both inertias at