Article

# Crank inertial load affects freely chosen pedal rate during cycling

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

## Abstract

Cyclists seek to maximize performance during competition, and gross efficiency is an important factor affecting performance. 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 250W, 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 100W increase in work rate. Along with freely chosen pedal rate being higher, gross efficiency at 250W was lower during cycling with high compared with low crank inertial load. Peak crank torque was higher during cycling at 90rpm 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 load.

## No full-text available

... with an almost equivalent meaning. As such, it is possible to uncover results pertaining to cycling efficiency (Hansen et al., 2002;Korff et al., 2007), muscular efficiency (Neptune and Herzog., 1999;Zameziati et al., 2006;Carpes, Diefenthaeler et al., 2010), mechanical efficiency (Umberger et al., 2006; and mechanical effectiveness (Zameziati et al., 2006;Korff et al., 2007;Mornieux et al., 2010), all of which are related to alterations in cycling 'performance'. ...
... The respective load used to achieve the required mechanical power output was different between the circular and elliptical rings to account for the known alteration in drivetrain kinematics induced by having different size chainrings (i.e. 61 vs 52 teeth) (Hansen et al., 2002). ...
... Previous work into the consequences of increased crank inertial loads on freely chosen pedal speed and gross efficiency have observed increases in peak crank torque and changes in torque (Fregly et al., 2000;Hansen et al., 2002), which is thought to arise as a result of amplified stimulation of mechanoreceptors in the legs. Additionally, increased torque changes would require an enhanced rate of force development to occur within the active muscles (Hansen et al., 2002), possibly to allow torque to be produced within the appropriate portion of the pedal cycle. ...
Full-text available
Thesis
Optimisation of movement strategies during cycling is an area which has gathered a lot of attention over the past decade. Resolutions to augment performance have involved manipulations of bicycle mechanics, including chainring geometries. Elliptical chainrings are proposed to provide a greater effective diameter during the downstroke, manipulating mechanical leverage and resulting in greater power production during this period. A review of the literature indicates that there is a pervasive gap in our understanding of how the theoretical underpinnings of elliptical chainrings might be translated to practical use. Despite reasonable theory of how these chainrings might enforce a variation in crank angular velocity and consequently alter force production, performance-based analyses have struggled to present evidence of this. The purpose of this thesis was to provide a novel approach to this problem by combining experimental data with musculoskeletal modelling and evaluating how elliptical chainrings might influence crank reactive forces, joint kinematics, muscle-tendon unit behaviour and muscle activation. One main study was proposed to execute this analysis, and an anatomically constrained model was subsequently used to determine the joint kinematics and muscle-tendon unit behaviour. Bespoke elliptical chainrings were designed for this study and as such, different levels of chainring eccentricity (i.e. ratio of major to minor axis) and positioning against the crank were presented whilst controlling the influence of other variables known to affect the neuromuscular system such as cadence and load. Findings presented in this thesis makes a new and major contribution in our understanding of the neuromusculoskeletal adaptations which occur when using elliptical chainrings, showing alterations in crank reaction force, muscle-tendon unit velocities, joint kinematics and muscle excitation over a range of cadences and loads, and provides direction for where the future of this research might be best applied. Keywords: Elliptical chainrings; Cycling; Musculoskeletal modelling; Principal Component Analysis; Electromyography
... The changes in force application as a result of a change in cadence in sub-maximal daily handcycling has yet to be studied. From bicycling it is known that an increased cadence leads to a reduced effective moment of inertia of the crank (also called the crank inertial load) [12]. 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. ...
... 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]. ...
... 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]. A shift below or above the FCC is found to have a negative effect on the ratio of effective force to resultant force [15]. ...
Full-text available
Article
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.
... Accordingly, it indicates that perhaps cycling on electromagnetically braked ergometers does not fully simulate road and treadmill cycling. A reason for this might be that crank inertial load, which can be comparable between road and treadmill cycling, is lower on most cycle ergometers (Fregly et al. 2000, Hansen et al. 2002b. Crank inertial load is the effective rotational inertia about the crank axis due to the moment of inertia of the flywheel or rear wheel. ...
... In one study (Hansen et al. 2002b), freely chosen pedalling frequency was investigated in 9 healthy male individuals during horizontal treadmill cycling at low (on average 16-20 kg m À2 ) and high (on average 103-120 kg m À2 ) crank inertial load at two power outputs of approx. 150 and 250 W. Higher crank inertial load resulted in on average 3-5% higher peak crank torque (reflecting peak effective pedal force) during cycling at a constant pedalling frequency. ...
... This could require increased muscle activation, including increased common drive from supraspinal centres (De Luca & Erim 1994) to the central pattern generator (Minassian et al. 2007), and contribute to larger net excitability of the central pattern generator. A later study (Bertucci et al. 2012) supported the findings by Hansen et al. (2002b) of an increasing effect of crank inertial load on freely chosen pedalling frequency by showing a tendency (P = 0.06) for a positive correlation between crank inertial load during road cycling at consistent power output (on average approx. 245 W) and freely chosen pedalling frequency in nine male cyclists. ...
Thesis
Acta Physiol, Volume 214, Issue Supplement S702, pages 1–18 The thesis can be downloaded from the Acta Physiol homepage Summary: The overall purpose of the present dissertation was to contribute to the understanding of voluntary human rhythmic leg movement behaviour and control. This was achieved by applying pedalling as a movement model and exposing healthy and recreationally active individuals as well as trained cyclists to for example cardiopulmonary and mechanical loading, fatiguing exercise, and heavy strength training. As a part of the background, the effect of pedalling frequency on diverse relevant biomechanical, physiological, and psychophysiological variables as well as on performance was initially explored. Freely chosen pedalling frequency is considerably higher than the energetically optimal pedalling frequency. This has been shown by others and was confirmed in the present work. As a result, pedal force is relatively low while rates of VO2 and energy turnover are relatively high during freely chosen pedalling as compared to a condition where a lower and more efficient pedalling frequency is imposed. The freely chosen pedalling frequency was in the present work, and by others, found to most likely be less advantageous than the lower energetically optimal pedalling frequency with respect to performance during intensive cycling following prolonged submaximal cycling. This stimulates the motivation to understand the behaviour and control of the freely chosen pedalling frequency during cycling. Freely chosen pedalling frequency was in the present work shown to be highly individual. In addition, the pedalling frequency was shown to be steady in a longitudinal perspective across 12 weeks. Further, it was shown to be unaffected by both fatiguing hip extension exercise and hip flexion exercise as well as by increased loading on the cardiopulmonary system at constant mechanical loading, and vice versa. Based on this, the freely chosen pedalling frequency is considered to be characterised as a highly individual, steady, and robust innate voluntary motor rhythm under primary influence of central pattern generators. The last part of the characterisation is largely based on, and supported by, work of other researchers in the field. Despite the robustness of the freely chosen pedalling frequency, it may be affected by some particular factors. As an example from the present work, freely chosen pedalling frequency during treadmill cycling increased by on average 15 to 17 rpm when power output was increased from a value corresponding to 86% and up to 165% of Wmax. This phenomenon is supported by other studies. As another example from the present work, freely chosen pedalling frequency decreased by on average 9 to 14 rpm following heavy strength training that involved both hip extension and hip flexion. Further, the present work suggested that the latter phenomenon occurred within the first week of training and was caused by in particular the hip extension strength training rather than the hip flexion strength training. The fast response to the strength training indicated that neural adaptations presumably caused the observed changes in movement behaviour. The internal organisation of the central pattern generator is by some other researchers in the field considered to be functionally separated into two components, in which, one is responsible for movement frequency and another is responsible for movement pattern. For the present dissertation, the freely chosen pedalling frequency was considered to reflect the rhythmic movement frequency of the voluntary rhythmic leg movement of pedalling. The tangential pedal force profile was considered to reflect the rhythmic movement pattern. The present work showed that fatiguing hip flexion exercise in healthy and recreationally active individuals modified the tangential pedal force profile during cycling at a pre-set target pedalling frequency in a way that the minimum tangential pedal force became more negative, the maximum tangential pedal force increased, and the phase with negative tangential pedal force increased. In other words, the legs were “actively lifted” to a lesser extent in the upstroke phase. Fatiguing hip extension exercise did not have that effect. And none of the fatiguing exercises affected the freely chosen pedalling frequency. The present work furthermore showed that the primary effect of hip extension strength training was that it decreased the freely chosen pedalling frequency. An interpretation of this could be that the hip extension strength training, in particular, influenced the output from the component of the central pattern generator that may be responsible for rhythmic movement frequency.
... Il est néanmoins possible que cette stratégie soit employée pour : ● utiliser le poids du haut du corps pour appliquer une force importante sur la pédale ; ● augmenter la durée de l'application de cette force ; ● limiter le nombre d'oscillations latérales du vélo qui peut être coûteux en énergie [7] ; ● réduire le nombre de déplacements verticaux du bassin [4]. La f pp des cyclistes pour la posture « assise » (80 ± 8 tours/ min) est supérieure à celle mesurée par Hansen et al. [3], (69 à 73 tours/min), Lucia et al. [5], (71 tours/min), et Millet et al. [6] , (58,9 tours/min) mais inférieure à celle observée par Hagberg et al. [2] , (91 tours/min). Ces différences peuvent s'expliquer par : ...
... ● le contexte de l'expérimentation (laboratoire [2,3] vs terrain [5,6]) ;Fig. 1 . Effet de la posture sur la fréquence de pédalage choisie préférentiellement (f pp ). ...
... Effet de la posture sur la fréquence de pédalage choisie préférentiellement (f pp ). ● l'inclinaison du tapis ou de la route (2,7 à 10 %) ; ● le niveau d'expertise des sujets (cyclistes expérimentés [2,5, 6] et sujets non cyclistes [3]) ; ● le degré d'entraînement (sujets non entraînés [3], cyclistes amateurs [2,6] et professionnels [5]) ; ● l'intensité de l'exercice (150–400 W) ; ● les possibilités du choix du braquet. ...
Full-text available
Article
Purpose. - The aim of this work was to study the effect of the posture on the preferred pedalling frequency during uphill cycling. Methods and results. - Ten trained cyclists performed two pedalling trials of three minutes at 80% of maximal aerobic power on a treadmill with a slope of 4%. Two postures (seated and standing pedalling) were studied in a randomized order. During the first minute of each trial, the subjects had to choose their preferred pedalling frequency with adjusting their gear and then kept this rate until the end of the trial. The preferred pedalling frequency was significantly (P < 0.05) lower in standing (73 ± 7 rpm) than in seated pedalling (80 ± 9 rpm). Conclusion. - We suppose that cyclists choose a lower pedalling frequency during standing pedalling in order to generate greater peak pedal force and to decrease the number of lateral sways of bicycle and vertical elevations of pelvis, which increase energy cost. © 2006 Elsevier SAS. Tous droits réservés. Mots clés : Cyclisme ; Posture ; Fréquence de pédalage
... Caldwell, McColle, Hagberg and Li (1998) studied the crank torque profile while moving uphill (8%) and level terrain cycling and found no significant differences in the general crank torque profile when comparing at the same cadence in a seated condition. According to Bertucci et al. (2005), the reasons for this can be found in the crank inertial load, which is lower during uphill cycling because it depends on the gear ratio and the mass of the cyclist (Hansen, Jørgensen, Jensen, Fregly, & Sjøgaard, 2002). Hansen et al. (2002) observed that the crank torque profile was modified by varying the crank inertial load. ...
... in the general crank torque profile when comparing at the same cadence in a seated condition. According to Bertucci et al. (2005), the reasons for this can be found in the crank inertial load, which is lower during uphill cycling because it depends on the gear ratio and the mass of the cyclist (Hansen, Jørgensen, Jensen, Fregly, & Sjøgaard, 2002). Hansen et al. (2002) observed that the crank torque profile was modified by varying the crank inertial load. They showed that when cycling with a high crank inertial load, peak torque was significantly higher. Crank-to-torque profiles observed during laboratory conditions are probably affected by the crank inertial load and the data should thus be interpret ...
... The highest difference was observed at 45° of the crank cycle (30.7 vs. 22.8 Nm for level and uphill terrain, respectively), although no differences were observed for peak values. These results vary from those of Hansen et al. (2002) who found differences in peak torque during cycling with a high and low crank inertial load. The differences could be explained by the fact that the study of Hansen et al. (2002) was conducted on a motorized treadmill with good control over the velocity, while in the field study of Bertucci et al. (2005) the cycling velocity was more prone to oscillations. ...
Full-text available
Article
The winners of the major cycling 3-week stage races (i.e. Giro d’Italia, Tour de France, Vuelta a Espana) are usually riders who dominate in the uphill sections of the race. Amateur cyclists, however, will often avoid uphill terrain because of the discomfort involved. Therefore, understanding movement behavior during uphill cycling is needed in order to find an optimum solution that can be applied in practice. The aim of this review is to assess the quality of research performed on biomechanics and the energetics of uphill cycling. Altogether we have analyzed over 40 articles from scientific and expert periodicals that provided results on energetics, pedal and joint forces, economy and efficiency, muscular activity, as well as performance and comfort optimization during uphill cycling. During uphill cycling, cyclists need to overcome gravity and in order to achieve this, some changes in posture are necessary. The main results from this review are that changes in muscular activity are present, while on the other hand pedal forces, joint dynamics, and cycling efficiency are not substantially altered during seated uphill cycling compared to cycling on level terrain. In contrast, during standing uphill cycling, all of the previously mentioned measures are different when comparing either seated uphill cycling or level terrain cycling. Further research should focus on outdoor studies and steeper slopes.
... Several studies have shown that a difference in crank inertial load (CIL) can alter the biomechanical (crank profile torque, preferred PC, gross efficiency) or physiological measurement outcomes (Fregly et al., 1996;Hansen et al., 2002aHansen et al., , 2002bBertucci et al., 2005bBertucci et al., , 2007. Due to different gear ratios and inertia of the flywheel, the cycling ergometers used in the laboratory generate different ranges of CIL (Fregly et al., 2000). ...
... In the road cycling, the CIL (kg·m 2 ) was calculated following the methods of Hansen et al. (2002aHansen et al. ( , 2002b. In the laboratory condition, the CIL was computed from the methods previously used (Fregly et al., 2000;Duc et al., 2005;Edwards et al., 2007;Gardner et al., 2007). ...
... These results suggest that the CIL is not the major factor explaining the GE differences between the Axiom stationary ergometer and the field. These results are not in accordance with Hansen et al. (2002a) who have shown on untrained subjects that at 250 W in the laboratory the GE was higher in the condition with low CIL value (ES: 0.5). It is possible that CIL variation elicits different responses according to the level of training of the cyclists (Edwards et al., 2007). ...
Article
This study was designed to examine the biomechanical and physiological responses between cycling on the Axiom stationary ergometer (Axiom, Elite, Fontaniva, Italy) vs. field conditions for both uphill and level ground cycling. Nine cyclists performed cycling bouts in the laboratory on an Axiom stationary ergometer and on their personal road bikes in actual road cycling conditions in the field with three pedaling cadences during uphill and level cycling. Gross efficiency and cycling economy were lower (-10%) for the Axiom stationary ergometer compared with the field. The preferred pedaling cadence was higher for the Axiom stationary ergometer conditions compared with the field conditions only for uphill cycling. Our data suggests that simulated cycling using the Axiom stationary ergometer differs from actual cycling in the field. These results should be taken into account notably for improving the precision of the model of cycling performance, and when it is necessary to compare two cycling test conditions (field/laboratory, using different ergometers).
... Changes in gross efficiency have been shown to influence cycling performance (25). Both Millet et al. (22) and Hansen et al. (9) report that gross efficiency does not change when comparing level ground and uphill cycling conditions. However, both studies allowed participants to vary their cadence, a factor which is known to change gross efficiency (29). ...
... This finding suggests that gross efficiency may not increase with decreasing cadence when cycling on gradients around 10%. This potentially altered relationship between cadence and efficiency during uphill cycling could also explain the results reported by Millet et al. (22) and Hansen et al. (9). ...
... In contrast to the present study, previous studies have found no effect of gradient on gross efficiency (9,10,22). In the previous studies, cadence decreased during uphill cycling. ...
Article
Purpose: The purpose of this study was to determine the effect of gradient on cycling gross efficiency and pedaling technique. Methods: Eighteen trained cyclists were tested for efficiency, index of pedal force effectiveness (IFE), distribution of power production during the pedal revolution (dead center size [DC]), and timing and level of muscle activity of eight leg muscles. Cycling was performed on a treadmill at gradients of 0% (level), 4%, and 8%, each at three different cadences (60, 75, and 90 rev·min). Results: Efficiency was significantly decreased at a gradient of 8% compared with both 0% and 4% (P < 0.05). The relationship between cadence and efficiency was not changed by gradient (P > 0.05). At a gradient of 8%, there was a larger IFE between 45° and 225° and larger DC, compared with 0% and 4% (P < 0.05). The onset of muscle activity for vastus lateralis, vastus medialis, gastrocnemius lateralis, and gastrocnemius medialis occurred earlier with increasing gradient (all P < 0.05), whereas none of the muscles showed a change in offset (P > 0.05). Uphill cycling increased the overall muscle activity level (P < 0.05), mainly induced by increased calf muscle activity. Conclusions: These results suggest that uphill cycling decreases cycling gross efficiency and is associated with changes in pedaling technique.
... Generally, most studies find that lower cadences lead to higher efficiency than higher cadences (Sidossis et al., 1992;Chavarren & Calbet, 1999;Lucia et al., 2004;Samozino et al., 2006;Leirdal & Ettema, 2011a). High-performance level cyclists choose far higher cadences (90-105 rpm) (Lucia et al., 2001;Argentin et al., 2006;Sassi et al., 2009) than the most efficient ones, as found in laboratory studies (40-80 rpm) (Coast & Welch, 1985;Chavarren & Calbet, 1999;Belli & Hintzy, 2002;Hansen et al., 2002;Foss & Hallen, 2004Argentin et al., 2006;Samozino et al., 2006;Umberger et al., 2006). The most important factor that affects the optimal cadence is power (Ettema & Lorås, 2009). ...
... The most important factor that affects the optimal cadence is power (Ettema & Lorås, 2009). The freely chosen cadence is increasing with power (Leirdal & Ettema, 2009), and so is the most efficient cadence (Seabury et al., 1977;Coast & Welch, 1985;Hansen et al., 2002;Foss & Hallen, 2004Samozino et al., 2006). Furthermore, with increasing power, the impact of cadence on efficiency diminishes, giving higher efficiency at the same cadence on high power than at low power (Chavarren & Calbet, 1999;Samozino et al., 2006). ...
... Still, the results in the present study show a tendency that slightly lower frequency than the FCF is more efficient, similar to what is found in cycling (Sidossis et al., 1992;Chavarren & Calbet, 1999;Foss & Hallen, 2004Samozino et al., 2006). In cycling, the most efficient cadence is increasing with increasing speed (Seabury et al., 1977;Coast & Welch, 1985;MacIntosh et al., 2000;Hansen et al., 2002;Foss & Hallen, 2004. However, combining the results presented in Figs 1 and 2, it seems that in cross-country ski skating, the most efficient frequency remains about constant with increasing power. ...
Article
The purpose of the present study was to examine the effect of frequency on efficiency and performance during G3 roller ski skating. Eight well-trained male cross-country skiers performed three submaximal 5-min speeds (10, 13, and 16 km/h) and a time-to-exhaustion (TTE) performance (at 20 km/h) using the G3 skating technique using freely chosen, high, and low frequency at all four speeds. All tests were done using roller skis on a large treadmill at 5% incline. Gross efficiency (GE) was calculated as power divided by metabolic rate. Power was calculated as the sum of power against frictional forces and power against gravity. Metabolic rate was calculated from oxygen consumption and blood lactate concentration. Freely chosen frequency increased from 60 to 70 strokes/min as speed increased from 10 to 20 km/h. GE increased with power. At high power (20 km/h performance test), both efficiency and performance were significantly reduced by high frequency. In regard to choice of frequency during G3 roller ski skating, cross-country skiers seems to be self-optimized both in relation to energy saving (efficiency) and performance (TTE).
... This information might be beneficial to improve durability by placing emphasis on the maintenance of torque production capabilities for short (1 s-5 min) and long (5-60 min) duration efforts. Although more research is needed in this regard, increases in torque production capabilities might be achieved by including strength training strategies (eg, off-bike resistance training or on-bike isometric cycling) [34][35][36] or biomechanical adjustments (eg, adopting crank length and pedal speed). 6,35,36 However, given that scientific evidence for these strategies is currently not strong enough to provide clear recommendations, future research should investigate how different strategies can improve torque production capabilities. ...
... Although more research is needed in this regard, increases in torque production capabilities might be achieved by including strength training strategies (eg, off-bike resistance training or on-bike isometric cycling) [34][35][36] or biomechanical adjustments (eg, adopting crank length and pedal speed). 6,35,36 However, given that scientific evidence for these strategies is currently not strong enough to provide clear recommendations, future research should investigate how different strategies can improve torque production capabilities. ...
Purpose: No information is available on the torque/cadence relationship in road cyclists. We aimed to establish whether this relationship differs between cyclists of different performance levels or team roles. Methods: Mean maximal power (MMP) output data from 177 riders were obtained from 2012 to 2021 from training and competitions. Cyclists were categorized according to their performance level (world-tour [WT, n = 68], procontinental [PC, n = 63], or under 23 [U23, n = 46]) and team role (time trialists [n = 12], all-rounders [n = 94], climbers [n = 64], or team leaders [n = 7]). Results: A significant interaction effect was found for absolute and relative MMP (P < .001), with higher values in PC than WT for short (5-60 s) efforts and the opposite trend for longer durations. MMP was also greater in PC than in U23 for short efforts (30-60 s), with WT and PC attaining higher MMP than U23 for longer bouts (5-60 min). A significant interaction effect was found for cadence (P = .007, but with no post hoc differences) and absolute (P = .010) and relative torque (P = .002), with PC and WT showing significantly higher torque (all P < .05) than U23 for 5- to 60-minute efforts, yet with no differences between the former 2 performance levels. No interaction effect between team roles was found for cadence (P = .185) or relative torque (P = .559), but a significant interaction effect was found for absolute torque (P < .001), with all-rounders attaining significantly higher values than climbers for 5-second to 5-minute efforts. Conclusions: Differences in MMP between cycling performance levels and rider types are dependent on torque rather than cadence, which might support the role of torque development in performance.
... 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. ...
... The authors found differences in the effective direction of the force vector and the pedal angle, but with a limited focus on the upstroke movement using clipless pedals (cleats). Hansen et al. [6] describe changes in peak power and range of the force curve within the pedalling cycles at constant power and cadence depending on the terrain inclination. Different angular accelerations are suspected as one reason for changes in power curves. ...
Full-text available
Article
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.
... The changes in force application as a result of a change in cadence in sub-maximal daily handcycling has yet to be studied. From bicycling it is known that an increased cadence leads to a reduced effective moment of inertia of the crank (also called the crank inertial load) [12]. 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±14]. The FCC seems to be well chosen in sub-maximal cycling [12,13]. A shift below or above the FCC is found to have a negative effect on the ratio of effective force to resultant force [15]. ...
... Just a few studies investigated the influence of gradient on GE. Millet et al. (2002) and E. A. Hansen et al. (2002) report that GE does not change when comparing level ground and uphill cycling condition. Also Tanaka et al. (1996) measured GE during uphill cycling at different gradients (4% and 8%) at predetermined speeds. ...
... They found significant differences in GE between 0% and 8% and 4% and 8% gradient but not between 0% and 4% inclination. Contrary some previous studies found no significant differences in GE on the influence of gradient (E. A. Hansen et al., 2002;Harnish et al., 2007;Leirdal & Ettema, 2011;Millet et al., 2002). However, it should be noted that these studies used different exercise intensities and freely chosen cadence which may distort the interpretation (Arkesteijn et al., 2013). ...
Full-text available
Thesis
One of the most meaningful parameters for performance measurement in cycling are oxygen uptake kinetics and gross efficiency. A number of studies investigated efficiency and oxygen uptake during cycling in the laboratory. Therefore, the aim of this study was to analyse the effect of gradient, cadence and exercise intensity on oxygen uptake kinetics and gross efficiency (GE) in laboratory conditions and to verify previous results. Thirteen well-trained cyclists participated in this study (mean ± SD age: 23.0 ± 4.7 years; stature: 178.5 ± 5.2 cm; body mass: 69.0 ± 7.8 kg; V̇O2max: 68.2 ± 4.7 mL∙min-1∙kg-1). The study consisted of two testing sessions: one incremental graded exercise test (GXT) to exhaustion and on a separate day 8 test-trials of 6 min duration. To simulate gradient the test bike was mounted on an indoor training roller and fixed on a treadmill. The GXT was performed to determine maximum oxygen uptake (V̇O2max), maximum power output (Pmax) and gas exchange thresholds (VT and RCP). During the laboratory test the subjects performed 4 trials on level ground (1.5% inclination) and 4 uphill trials (5% inclination). The trials were performed at two intensities (90%VT and Δ70) and two cadences (60 and 90 rev.min-1). The order of the four level and uphill cycling trials was 90%VT at 60 rev.min-1, Δ70 at 60 rev.min-1, 90%VT at 90 rev.min-1, Δ70 at 90 rev.min-1. Significant differences between uphill and level ground cycling were found for the time constant (τ) (mean difference = 2.8 s; F1,12 = 5.1; p = 0.043) and end-exercise V̇O2 (mean difference = 69 mL.min-1; F1,12 = 6.3; p = 0.027) of the phase II oxygen uptake response. Cadence significantly affected the τ (mean difference = 3 s; F1,12 = 7.1; p = 0.021) and amplitude (mean difference = 176 mL.min-1; F1,12 = 14.8; p = 0.002). Significant differences between moderate and high exercise intensities were found for all measured oxygen uptake kinetics parameters (i.e. τ, amplitude, slow component, end-exercise V̇O2 gain, phase II V̇O2 gain and end-exercise V̇O2) except time delay. The GE was affected by cadence (21 ± 1.6 % at 60 rev.min-1; 18.6 ± 1.1 % at 90 rev.min-1; p < 0.001) but no significant effect of flat (19.7 ± 1.8 %) compared to uphill cycling (19.7 ± 1.8 %) was found (p = 0.81).
... La f pp des cyclistes pour la posture « assise » (80 ± 8 tours/ min) est supérieure à celle mesurée par Hansen et al. [3], (69 à 73 tours/min), Lucia et al. [5], (71 tours/min), et Millet et al. [6], (58,9 tours/min) mais inférieure à celle observée par Hagberg et al. [2], (91 tours/min). Ces différences peuvent s'expliquer par : ...
... • le contexte de l'expérimentation (laboratoire [2,3] vs terrain [5,6]) ; Fig. 1. Effet de la posture sur la fréquence de pédalage choisie préférentiellement (f pp ). ...
... Another observation was that the freely chosen pedal rate increased by 15-17 rev Á min 71 when power output increased from 86% to 165% of W max . An increase in pedal rate with increasing power output has previously been reported for submaximal treadmill cycling (Hansen, Andersen, Nielsen, & Sjøgaard, 2002a;Hansen, Jørgensen, Jensen, Fregly, & Sjøgaard, 2002b). Furthermore, it is known from road cycling that freely chosen pedal rate increases with cycling speed (Sargeant, 1994) and power output (Ebert, Martin, Stephens, & Withers, 2006). ...
... In comparison, it has been observed that the freely chosen pedal rate is unaffected by power output during cycling on electromagnetically braked ergometers (Marsh & Martin, 1998;Marsh, Martin, & Sanderson, 2000). Thus, it appears that cycling on electromagnetically braked ergometers does not fully simulate road or treadmill cycling, most likely because crank inertial load, comparable between road and treadmill cycling, is lower on most cycle ergometers (Fregly, Zajac, & Dairaghi, 2000;Hansen et al., 2002b). Davison and colleagues (Davison, Swain, Coleman, & Bird, 2000) reported a lower mean freely chosen pedal rate (61 rev Á min 71 ) at a high power output of 411 W than a lower power output of 330 W, which at first sight is in contrast to the present results. ...
... La f pp des cyclistes pour la posture « assise » (80 ± 8 tours/ min) est supérieure à celle mesurée par Hansen et al. [3], (69 à 73 tours/min), Lucia et al. [5], (71 tours/min), et Millet et al. [6], (58,9 tours/min) mais inférieure à celle observée par Hagberg et al. [2], (91 tours/min). Ces différences peuvent s'expliquer par : ...
... • le contexte de l'expérimentation (laboratoire [2,3] vs terrain [5,6]) ; Fig. 1. Effet de la posture sur la fréquence de pédalage choisie préférentiellement (f pp ). ...
Article
Purpose. – The aim of this work was to study the effect of the posture on the preferred pedalling frequency during uphill cycling. Methods and results. – Ten trained cyclists performed two pedalling trials of three minutes at 80% of maximal aerobic power on a treadmill with a slope of 4%. Two postures (seated and standing pedalling) were studied in a randomized order. During the first minute of each trial, the subjects had to choose their preferred pedalling frequency with adjusting their gear and then kept this rate until the end of the trial. The preferred pedalling frequency was significantly (P < 0.05) lower in standing (73 ± 7 rpm) than in seated pedalling (80 ± 9 rpm). Conclusion. – We suppose that cyclists choose a lower pedalling frequency during standing pedalling in order to generate greater peak pedal force and to decrease the number of lateral sways of bicycle and vertical elevations of pelvis, which increase energy cost.
... The exact mechanism behind the alteration in pedalling technique is not clear. Gear ratio was held constant throughout the study to prevent a potential eff ect of this variable on pedalling technique [ 13 ] . Consequently, the average resistance was comparable between turbo trainer and treadmill cycling due to the matched work rates in both conditions using the same gear ratio and cadence. ...
... Thus, it is anticipated that crank angular velocity profi le would also diff er, with larger variations occurring during turbo trainer cycling compared with treadmill cycling. The eff ect of varying resistance is not accounted for in the calculation of crank inertial load [ 13 ] . This provides a potential reason why varying crank inertial load on a stationary ergometer does not induce alterations in cycling technique as encountered during treadmill and turbo trainer cycling. ...
Full-text available
Article
Cycling can be performed on the road or indoors on stationary ergometers. The purpose of this study was to investigate differences in cycling efficiency, muscle activity and pedal forces during cycling on a stationary turbo trainer compared with a treadmill. 19 male cyclists cycled on a stationary turbo trainer and on a treadmill at 150, 200 and 250 W. Cycling efficiency was determined using the Douglas bags, muscle activity patterns were determined using surface electromyography and pedal forces were recorded with instrumented pedals. Treadmill cycling induced a larger muscular contribution from Gastrocnemius Lateralis, Biceps Femoris and Gluteus Maximus of respectively 14%, 19% and 10% compared with turbo trainer cycling (p<0.05). Conversely, Turbo trainer cycling induced larger muscular contribution from Vastus Lateralis, Rectus Femoris and Tibialis Anterior of respectively 7%, 17% and 14% compared with treadmill cycling (p<0.05). The alterations in muscle activity resulted in a better distribution of power during the pedal revolution, as determined by an increased Dead Centre size (p<0.05). Despite the alterations in muscle activity and pedalling technique, no difference in efficiency between treadmill (18.8±0.7%) and turbo trainer (18.5±0.6%) cycling was observed. These results suggest that cycling technique and type of ergometer can be altered without affecting cycling efficiency.
... The rotational kinetic energy and the CIL were calculated in order to simulate different conditions met in the field for cycling at speed between 10 and 50 km h -1 ( Table 3). The CIL varies with the gear ratio (m) and the mass (kg) of the cyclist [20,26,29,30] which corresponds to the inertia for each crank cycle. The CIL values for road The KE was calculated with a mass of cyclist and bike of 80 kg [26,30]: ...
... The CIL varies with the gear ratio (m) and the mass (kg) of the cyclist [20,26,29,30] which corresponds to the inertia for each crank cycle. The CIL values for road The KE was calculated with a mass of cyclist and bike of 80 kg [26,30]: ...
Article
The aim of this study was to describe and validate a new cycling ergometer with original characteristics that allow the measurement of biomechanical variables with position and crank inertial load used by the cyclist in field condition. The braking pedalling force, that permitted the simulation of the resistance to the cyclist in the field, is performed with a brushless electric motor. The validity and the reproducibility of the power output measurements were compared with the widely accepted SRM powermeter. The results indicate that taking into account a systematic error, the measurements are valid compared with the SRM, and the reproducibility of the power output measurements is similar to the SRM. In conclusion, this ergometer is the only one that allows at the same time for (1) valid and reproducible power output measurements at submaximal intensity, (2) utilisation of the personal bicycle of the cyclist, and (3) simulation of the inertial characteristics of the road cycling. KeywordsPower output–Powermeter–Reproducibility–Crank inertial load–Cycling
... It is likely that the type of ergometer plays a role in stroke rate. As an example, inertial load varies between cycle ergometers, and this variable affects the pedalling rate [30]. It thus appears that it might be difficult to compare studies which use different kayak ergometers. ...
Full-text available
Article
Moderate paddling, as in long distance kayaking, constitutes an endurance activity, which shares energetic aspects with activities such as long distance running and road cycling. The aim of the present study was to investigate whether in moderate paddling there is a U-shaped relationship between oxygen uptake and stroke rate, and also whether elite kayakers apply a freely chosen stroke rate, which is energetically optimal. Eleven young male elite kayakers performed moderate kayak ergometry at preset target stroke rates of 65, 75, and 90 strokes min-1, and at a freely chosen stroke rate, while physiological responses including oxygen uptake were measured. The results showed that considering average values calculated across all participants, there was an approximately U-shaped relationship between oxygen uptake and target stroke rate with a minimum at 75 strokes min-1. The freely chosen stroke rate was 67.0 ± 6.1 strokes min-1. Thus, the freely chosen stroke rate, for the group in total, appeared to be lower and require higher oxygen uptake as compared to the energetically optimal preset target stroke rate. Eight out of 11 participants had a higher oxygen uptake (5.1% ± 6.7%, p = 0.028, across all participants) at their freely chosen stroke rate than at the preset target stroke rate, which resulted in the lowest oxygen uptake. In conclusion, an approximately U-shaped relationship between oxygen uptake and stroke rate for young elite kayakers during moderate ergometer kayaking was found. Additionally, the freely chosen stroke rate was systematically lower and, consequently, required higher oxygen uptake than the preset stroke rate, which resulted in the lowest oxygen uptake.
... It is likely that the type of ergometer plays a role in stroke rate. As an example, inertial load varies between cycle ergometers, and this variable affects the pedalling rate [30]. It thus appears that it might be difficult to compare studies which use different kayak ergometers. ...
Article
Moderate paddling, as in long distance kayaking, constitutes an endurance activity, which shares energetic aspects with activities such as long distance running and road cycling. The aim of the present study was to investigate whether in moderate paddling there is a U-shaped relationship between oxygen uptake and stroke rate, and also whether elite kayakers apply a freely chosen stroke rate, which is energetically optimal. Eleven young male elite kayakers performed moderate kayak ergometry at preset target stroke rates of 65, 75, and 90 strokes min-1, and at a freely chosen stroke rate, while physiological responses including oxygen uptake were measured. The results showed that considering average values calculated across all participants, there was an approximately U-shaped relationship between oxygen uptake and target stroke rate with a minimum at 75 strokes min-1. The freely chosen stroke rate was 67.0 ± 6.1 strokes min-1. Thus, the freely chosen stroke rate, for the group in total, appeared to be lower and require higher oxygen uptake as compared to the energetically optimal preset target stroke rate. Eight out of 11 participants had a higher oxygen uptake (5.1% ± 6.7%, p = 0.028, across all participants) at their freely chosen stroke rate than at the preset target stroke rate, which resulted in the lowest oxygen uptake. In conclusion, an approximately U-shaped relationship between oxygen uptake and stroke rate for young elite kayakers during moderate ergometer kayaking was found. Additionally, the freely chosen stroke rate was systematically lower and, consequently, required higher oxygen uptake than the preset stroke rate, which resulted in the lowest oxygen uptake.
... A wide variety of methods have been used to study the biomechanics of pedaling. In one study, the inertial load on the crank was set to 150 W and 250 W [31], and a different range of cycling (such as 9 kg/m 2 to 36 kg/m 2 and 56 kg/m 2 to 182 kg/m 2 ) was used to study pedaling modeling. Some studies have used different saddle positions with 182 feasible pedaling places [4]. ...
Full-text available
Article
Background: Many sports and physical activities can result in lower limb injures. Pedaling is an effective exercise for lower extremity rehabilitation, but incorrect technique may cause further damage. To some extent, previous experiments have been susceptible to bias in the sample recruited for the study. Alternatively, methods used to simulation activities can enable parametric studies without the influence of noise. In addition, models can facilitate the study of all muscles in the absence of the effects of fatigue. This study investigated the effects of crank length on muscle behavior during pedaling. Methods: Six muscles (soleus, tibialis anterior, vastus medialis, vastus lateralis, gastrocnemius, and rectus femoris), divided into three groups (ankle muscle group, knee muscle group, and biarticular muscle group), were examined under three cycling crank lengths (100 mm, 125 mm, and 150 mm) in the present study. In addition, the relationship between crank length and muscle biological force was analyzed with the AnyBody Modeling System™, a human simulation modeling software based on the Hill-type model. Findings. Based on inverse kinematic analysis, the results indicate that muscle activity and muscle force decrease in varying degrees with increases in crank length. The maximum and minimum muscular forces were attained in the tibialis anterior and vastus lateralis, respectively. Interpretation. Studying the relationship between muscle and joint behavior with crank length can help rehabilitation and treating joint disorders. This study provides the pedal length distribution areas for patients in the early stages of rehabilitation.
... Of note is that increased crank inertial load during cycling also has been reported to result in a higher freely chosen pedaling rate (Hansen, Jørgensen, Jensen, Fregly, & Sjøgaard, 2002). Crank inertial load is the effective rotational inertia about the crank axis due to the moment of inertia of the flywheel or rear wheel. ...
Article
Investigations of behavior and control of voluntary stereotyped rhythmic movement contribute to the enhancement of motor function and performance of disabled, sick, injured, healthy, and exercising humans. The present article presents examples of unprompted alteration of freely chosen movement rate during voluntary stereotyped rhythmic movements. The examples, in the form of both increases and decreases of movement rate, are taken from activities of cycling, finger tapping, and locomotion. It is described that, for example, strength training, changed power output, repeated bouts, and changed locomotion speed can elicit an unprompted alteration of freely chosen movement rate. The discussion of the examples is based on a tripartite interplay between descending drive, rhythm-generating spinal neural networks, and sensory feedback, as well as terminology from dynamic systems theory.
... 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.
... Concernant la charge affective, elle était significativement plus élevée sur cycloergomètre comparé au terrain plat (+171%) et en montée (+169%). (Fregly et al., 1996 ;Hansen et al., 2002 ;Bertucci et al., 2007). Au niveau de la cadence de pédalage, les résultats obtenus sont en accord avec les précédentes études puisque la cadence sur cyclo-ergomètre était supérieure à celle sur terrain plat (+11%), toutes les deux supérieures à celle sur terrain montant (+30%) (Bertucci et al., 2012 ;Emanuele et Denoth, 2012). ...
Thesis
Ce travail de thèse s’est déroulé dans le cadre d’une convention CIFRE entre mon laboratoire de rattachement C3S (EA4660) et le département Recherche et Développement (R&D) de l’équipe cycliste professionnelle FDJ. Les différentes études que nous avons conduites se sont articulées autour de l’amélioration de la performance sportive chez le cycliste à travers une variable centrale qui est la puissance mécanique qu’il développe lors de la locomotion (Pméca) selon deux axes principaux : 1) l’évaluation et le suivi du potentiel physique avec pour but l’amélioration du processus d’entraînement et 2) l’optimisation de l’interface homme – machine à partir de l’analyse du matériel et des équipements utilisés par les cyclistes dans l’équipe FDJ.
... However, it has also been shown that an increase in the gear ratio increases the inertial load at a set cadence (Fregly, Zajac, & Dairaghi, 2000;Hansen, Jørgensen, Jensen, Fregly, & Sjøgaard, 2002). Therefore, if cadence can be increased, or maintained with an increase in inertial load (gear ratio), peak power will increase and as a result, so will the riders velocity on the track. ...
Full-text available
Article
The aim of this study was to ascertain if gear ratio selection would have an effect on peak power and time to peak power production in elite Bicycle Motocross (BMX) cyclists. Eight male elite BMX riders volunteered for the study. Each rider performed three, 10-s maximal sprints on an Olympic standard indoor BMX track. The riders' bicycles were fitted with a portable SRM power meter. Each rider performed the three sprints using gear ratios of 41/16, 43/16 and 45/16 tooth. The results from the 41/16 and 45/16 gear ratios were compared to the current standard 43/16 gear ratio. Statistically, significant differences were found between the gear ratios for peak power (F(2,14) = 6.448; p = .010) and peak torque (F(2,14) = 4.777; p = .026), but no significant difference was found for time to peak power (F(2,14) = 0.200; p = .821). When comparing gear ratios, the results showed a 45/16 gear ratio elicited the highest peak power,1658 ± 221 W, compared to 1436 ± 129 W and 1380 ± 56 W, for the 43/16 and 41/16 ratios, respectively. The time to peak power showed a 41/16 tooth gear ratio attained peak power in -0.01 s and a 45/16 in 0.22 s compared to the 43/16. The findings of this study suggest that gear ratio choice has a significant effect on peak power production, though time to peak power output is not significantly affected. Therefore, selecting a higher gear ratio results in riders attaining higher power outputs without reducing their start time.
... It is possible that the low-cadence training with the use of higher forces in the current study could be seen as a type of strength regime for the cycling muscles when compared with the lower peak forces experienced by the HC group. According to CPG theorists, the increases in performance may have an explanation similar to that of the heavy strength training studies, which were interpreted as evidence for enhanced neural efficiency (Hansen et al. 2002;Zehr 2005;Hansen and Smith 2009;Hartley and Cheung 2013;Hansen 2015). One of the limitations of this study is that the crank torque profile and the GE data were not collected in the 15-min TT; these data may have provided further support for CPG control because it would have enabled the researchers to compare the crank torque profiles at different power outputs. ...
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.
... The observed increase in cadence might be a result of the fixed rest periods between each seating position. An increase in cadence leads to lower pedal forces (Sanderson et al., 2000;Hansen et al., 2002), reflected by the more negative F min . Sanderson et al. (2000) have suggested a more negative F min concomitant to an increase in cadence reflect difficulty in maintaining the riding condition including the pulling of leg in upstroke phase. ...
Article
The aim of this study was to measure and analyse discomfort and biomechanics of cycling, i.e., muscle activation, centre of pressure of seat pressure profiles and pedal forces as a function of seat position. Twenty-one recreationally active individuals cycled for 10 min at 100Won an ergometer cycle using five different seat positions. The neutral position was considered as basic seat position and was compared with upward, downward, forward and backward seat positions. The initial bout was repeated at the end of the recording session. Discomfort increased for upward and backward condition compared with neutral (P < 0.05). Normalized surface electromyography from gastrocnemius decreased in the downward and forward position but increased in the upward and backward position. The minimum force became less negative for forward position compared with neutral seat position (P < 0.05). The degree of variability of centre of pressure increased in the upward and backward position and the entropy of the centre of pressure of sitting posture for backward position decreased compared with neutral seat position (P < 0.05). The present study revealed that consecutive changes of seat position over time lead to increase in discomfort as well as alterations of the biomechanics of cycling.
... The mechanical efficiency is usually used for the human's motorial efficiency description. The higher efficiency (economy) is being connected with better results achieved in various sport disciplines [14,23,33]. The mechanical efficiency in chosen motorial actions amounted from 2% to 80% dependently on: working limb [50], amount and time of work [51], performed exercises (eccentric, concentric, mixed) [2,3], practiced sport discipline [38], type of muscles fibres [4] or calculation methods (e.g.: running velocity counted on the basis of film [29] or as a treadmill velocity used by examined [36]). ...
Full-text available
Article
The aim of this work was to verify the hypothesis that the lowering of the pedalling rate (elicited by the increase of the exterior load) during maximal efforts performed with identical work amount causes the growth of the generated power (until the maximal values are reached) and next its fall and does not influence the gross and net mechanical efficiency changes. The above experiment was conducted with 13 untrained students who performed 5 maximal efforts with the same work amount. The first was the 30 s maximal effort (Wingate test) with the load equal 7.5% of the body weight (BW). The amount of work performed in this test was accepted as the model value for following tests to achieve. Every 3 days, each examined had next trials consisting of maximal efforts on the cycle ergometer with loads of: 2.5, 5, 10, 12.5% BW and lasting until the value of power reached in the 30 s Wingate test occurred. Changing of the external load elicited various pedalling velocity. The force-velocity (F-v) and power-velocity (P-v) dependence was calculated for every examined subject basing on the results of performed maximal efforts. The maximal power (P max) and optimal velocity (v o) were calculated basing on the P-v relationship depicted with the second order polynomial equation. The gas analyser (SensorMedics) equipped with the 2900/2900c Metabolic Measurements Cart/System software was used as for the oxygen output measuring during maximal efforts performance and in the resting phase. The ventilation and gas variable changes were monitored breath-by-breath in the open ventilation system. The POLAR-SportTester was used for the heart retraction (HR) measurement during both: efforts and resting. The capillary blood was taken from the fingertip before the test and: immediately after it, every 2 min for the first 10 min of the rest and in the 20 th min of resting. The blood was used for the acid-base balance determination with the use of the blood gas analyser – Ciba-Corning 248. The average pedalling rate decreased during effort from 151.5 rpm to 80 rpm and the power grew from 293.5 W to 761 W along with the increase of the load from 2.5% to 12.5% BW. Powers varied among specific trials with the
... The mechanical efficiency is usually used for the human's motorial efficiency description. The higher efficiency (economy) is being connected with better results achieved in various sport disciplines [14,23,33]. The mechanical efficiency in chosen motorial actions amounted from 2% to 80% dependently on: working limb [50], amount and time of work [51], performed exercises (eccentric, concentric, mixed) [2,3], practiced sport discipline [38], type of muscles fibres [4] or calculation methods (e.g.: running velocity counted on the basis of film [29] or as a treadmill velocity used by examined [36]). ...
Full-text available
Article
The aim of this work was to verify the hypothesis that the lowering of the pedalling rate (elicited by the increase of the exterior load) during maximal efforts performed with identical work amount causes the growth of the generated power (until the maximal values are reached) and next its fall and does not influence the gross and net mechanical efficiency changes. The above experiment was conducted with 13 untrained students who performed 5 maximal efforts with the same work amount. The first was the 30 s maximal effort (Wingate test) with the load equal 7.5% of the body weight (BW). The amount of work performed in this test was accepted as the model value for following tests to achieve. Every 3 days, each examined had next trials consisting of maximal efforts on the cycle ergometer with loads of: 2.5, 5, 10, 12.5% BW and lasting until the value of power reached in the 30 s Wingate test occurred. Changing of the external load elicited various pedalling velocity. The force-velocity (F-v) and power-velocity (P-v) dependence was calculated for every examined subject basing on the results of performed maximal efforts. The maximal power (P max) and optimal velocity (v o) were calculated basing on the P-v relationship depicted with the second order polynomial equation. The gas analyser (SensorMedics) equipped with the 2900/2900c Metabolic Measurements Cart/System software was used as for the oxygen output measuring during maximal efforts performance and in the resting phase. The ventilation and gas variable changes were monitored breath-by-breath in the open ventilation system. The POLAR-SportTester was used for the heart retraction (HR) measurement during both: efforts and resting. The capillary blood was taken from the fingertip before the test and: immediately after it, every 2 min for the first 10 min of the rest and in the 20 th min of resting. The blood was used for the acid-base balance determination with the use of the blood gas analyser – Ciba-Corning 248. The average pedalling rate decreased during effort from 151.5 rpm to 80 rpm and the power grew from 293.5 W to 761 W along with the increase of the load from 2.5% to 12.5% BW. Powers varied among specific trials with the
... In road cycling and racing, however, frequent accelerations and decelerations occur (however imperceptible) due to continuous changes in resistance forces resulting from environmental conditions (gradient, wind, road surface, corners), together with changes in pace by other competitors in close proximity. Since the acceleration response is greatly improved with a low crank inertial load [a function of the static and rotating mass of a bike'rider, times the square of the gear ratio (Bertucci, Grappe, Girard, Betik, & Rouillon, 2005;Hansen, Jorgensen, Jensen, Fregly, & Sjogaard, 2002b)], the gear selection that results in the adoption of a high cadence is a tactical decision (Lucia et al., 2001). Independent of inertial considerations, the gear ratios fitted to a road bike may also be an important factor in the adoption of a high preferred cadence. ...
Article
Cadence is one of the only variables cyclists can adjust to manage their performance and fatigue during an event. Not surprisingly, cadence has received a great deal of attention from the scientific community in an effort to identify the cadence that optimizes power output while minimizing the fatigue that is incurred. The literature appears to present conflicting results with little consensus as regards the optimal pedalling cadence. This is in large part due to the inconsistent definition of the term “optimal” cadence, which has been used to describe energetic cost, muscular stress, and perception of effort. The issue is further confounded by the workload-dependent nature of the “optimal” cadence – that is, at higher power outputs, the optimized cadence is different from that at lower power outputs. Although the optimal cadence is different for energetic, muscular, and perceptual definitions, the curves that describe the effect of changes in cadence on these variables consistently exhibit a J-shaped response. This suggests that there is an underlying principle that is common to each of the definitions. Indeed, it would appear that the response of both the cardio-respiratory system (energetic cost) and the muscular system (muscular stress) is determined by the types of muscle motor units that are recruited during the exercise. Furthermore, although part of the response may be due to the inherent differences in the characteristics between the different motor units, the absolute contraction velocity relative to fibre type optimum may be of greater significance. Even when the power output is increased, the shape of the response curves to changes in cadence remains constant, although the nadir of the curve does shift to the right for increasing power outputs. We propose that the point at which the energetic vs. power and the muscular stress vs. power curves intercept is defined by the cadence at which the perceived effort is minimized (i.e. the preferred cadence). However, cadence fluctuations occur under field conditions that are unrelated to physiological factors and, therefore, the ability to identify an “optimal” cadence is limited to the laboratory environment and specific field conditions.
... Proprioceptive afferents originating from Ia sensory fibers and joint mechanoreceptors are processed in the cerebellum and basal ganglia, and then subsequent extensor tone is initiated in the mescencephalic locomotor region (Whelan, 1996). Therefore, it is tenable that changes in power output (Hansen & Waldeland, 2008), road gradient (Lucia et al., 2001;Millet et al., 2002;Vogt et al., 2007), crank inertial load (Hansen, Jorgensen, et al., 2002) and muscle and joint strain (Marsh & Martin, 1998) modulate FCC because of altered proprioceptive feedback, whereas FCC remains constant in conditions of thermal loading where there is no influence of proprioception. Results from the current study conflict with previous findings that demonstrate a relationship between FCC and PO (Ebert et al., 2006;Hansen & Waldeland, 2008;Vogt et al., 2007), which suggests that FCC is not a robust voluntary motor rhythm, but rather that it is dependent on PO selection. ...
Full-text available
Article
The present study investigated relationships between changes in power output (PO) to torque (TOR) or freely chosen cadence (FCC) during thermal loading. Twenty participants cycled at a constant rating of perceived exertion while ambient temperature (Ta) was covertly manipulated at 20-min intervals of 20 °C, 35 °C, and 20 °C. The magnitude responses of PO, FCC and TOR were analyzed using repeated-measures ANOVA, while the temporal correlations were analyzed using Auto-Regressive Integrated Moving Averages (ARIMA). Increases in Ta caused significant thermal strain (p < .01), and subsequently, a decrease in PO and TOR magnitude (p < .01), whereas FCC remained unchanged (p = .51). ARIMA indicates that changes in PO were highly correlated to TOR (stationary r 2 = .954, p = .04), while FCC was moderately correlated (stationary r 2 = .717, p = .01) to PO. In conclusion, changes in PO are caused by a modulation in TOR, whereas FCC remains unchanged and therefore, unaffected by thermal stressors.
... It has been shown that at the same power output and cadence, crank inertial load is higher during level ground than during uphill cycling because crank inertia increases as a quadratic function of the gear ratio (Fregly et al. 2000). In addition, an increase in crank inertia is accompanied by an increase in peak crank torque and therefore it was suggested that cyclists prefer higher cadences during levelground cycling to reduce peak crank torque (Hansen et al. 2002). This finding was supported by Lucia et al. (2001) who reported a significantly lower mean cadence during high mountain passes (71.0 ± 1.4 rev min -1 ) than during flat mass start stages (89.3 ± 1.0 rev min -1 ) and timetrials (92.4 ± 1.3 rev min -1 ) in professional cyclists. ...
Conference Paper
Introduction The majority of interval training studies are conducted on ergometers to control external variables and exercise intensity. The differences between laboratory and outdoor cycling have been discussed recently (Jobson et al., 2007) suggesting different physiological demands. With the use of mobile power meters, exercise intensity can be monitored in the field, which improves the ecological validity of the measurements. This study tested the effects of low-cadence (60 rpm) uphill (Int60) or high-cadence (100 rpm) level-ground (Int100) interval training on power output (PO) during 20-min uphill (TTup) and flat (TTflat) time-trials as well as on performance during a laboratory graded exercise test (GXT). Methods Eighteen male cyclists (VO2max: 58.6 ± 5.4 mL/min/kg) were randomly assigned to Int60, Int100 or a control group (Con). The interval training comprised of two training sessions per week over 4 weeks, which consisted of 6x5 min at the PO corresponding to the respiratory compensation point (RCP). For the control group, no interval training was conducted. During the interval training sessions and the time-trials, PO was measured with mobile power-meters (SRM). Results A two-factor ANOVA revealed significant increases on performance measures obtained from GXT (Pmax: 2.8 ± 3.0%; p<0.01; PO and VO2 at RCP: 3.6 ± 6.3% and 4.7 ± 8.2%, respectively; p<0.05), with no significant group effects. Significant interactions between group and uphill and flat time-trial, pre vs. post-training on PO were observed (p<0.05). Int60 increased PO during both TTup (4.4 ± 5.3%) and TTflat (1.5 ± 4.5%). The changes were -1.3 ± 3.6%, 2.6 ± 6.0% for Int100 and 4.0 ± 4.6%, -3.5 ± 5.4% for Con during TTup and TTflat, respectively. PO was significantly higher during TTup than TTflat (4.4 ± 6.0%; 6.3 ± 5.6%; pre and post-training, respectively; p<0.001). Discussion The performance improvements during TTup and TTflat have shown specific adaptations in response to the interval training sessions and indicate the ecological validity of the time-trials. The application of higher pedaling forces via low cadences provides a potentially higher training stimulus with a cross-over effect to flat time-trials. When evaluating power output data or prescribing training zones, it is important to note that trained cyclists are able to produce higher power outputs during uphill compared to flat time-trial conditions.
... It has been shown that at the same power output and cadence, crank inertial load is higher during level ground than during uphill cycling because crank inertia increases as a quadratic function of the gear ratio (Fregly et al. 2000). In addition, an increase in crank inertia is accompanied by an increase in peak crank torque and therefore it was suggested that cyclists prefer higher cadences during levelground cycling to reduce peak crank torque (Hansen et al. 2002). This finding was supported by Lucia et al. (2001) who reported a significantly lower mean cadence during high mountain passes (71.0 ± 1.4 rev min -1 ) than during flat mass start stages (89.3 ± 1.0 rev min -1 ) and timetrials (92.4 ± 1.3 rev min -1 ) in professional cyclists. ...
... In road cycling and racing, however, frequent accelerations and decelerations occur (however imperceptible) due to continuous changes in resistance forces resulting from environmental conditions (gradient, wind, road surface, corners), together with changes in pace by other competitors in close proximity. Since the acceleration response is greatly improved with a low crank inertial load [a function of the static and rotating mass of a bike'rider, times the square of the gear ratio (Bertucci, Grappe, Girard, Betik, & Rouillon, 2005;Hansen, Jorgensen, Jensen, Fregly, & Sjogaard, 2002b)], the gear selection that results in the adoption of a high cadence is a tactical decision (Lucia et al., 2001). Independent of inertial considerations, the gear ratios fitted to a road bike may also be an important factor in the adoption of a high preferred cadence. ...
... Namely, no bicycle motion (backward and forward displacements) was present in our study as would have been observed in real-life conditions. Moreover, exercising on a cycle ergometer does not allow real changes of the crank inertial load (Bertucci et al. 2007;Hansen et al. 2002). For example, Bertucci et al. (2007) showed that at maximal aerobic power, the crank torque profiles during cycling on the ergometer were significantly different (especially on dead points of the crank cycle) and generate a higher perceived exertion compared to road cycling conditions. ...
Article
In the present study, we quantitatively described and compared lower extremity neuromuscular patterns during level cycling (LC), 10 and 20% uphill cycling (UC). We hypothesized that both the timing and intensity of activity of selected lower extremity muscles will differ between steep (but not moderate slope) UC condition and LC. Twelve trained mountain bikers performed an experimental test with three different cycling conditions (level, 10% slope and 20% slope) with EMG monitoring of eight lower extremity muscles. Significant changes (p < 0.05) in muscle activation timing during 20% UC compared to LC (15° later onset and 39° earlier offset) were observed in m. rectus femoris (RF). Range of activity during 20% UC compared to LC was also significantly (p < 0.05) modified in m. vastus medialis, m. vastus lateralis (8° and 5° shorter) and m. biceps femoris (BF; 17° longer). Furthermore, a reduction of EMG activity level was observed for RF and m. tibialis anterior (TA) during 20% UC compared to LC (25 and 19%; p < 0.05), while the opposite effect was observed for m. gluteus maximus (GM; 12%; p < 0.05). Peak cross-correlation coefficients in all cycling conditions for all muscles were high (all coefficients ≥ 0.83). We have shown that altered body orientation during steep, but not moderate, slope UC significantly modified the timing and intensity of several lower extremity muscles, the most affected being those that cross the hip joint and TA. The observed modifications in neuromuscular patterns during 20% UC could have a significant effect on lower extremity joint kinetics and cycling efficiency.
Full-text available
Article
This paper presents the development of the experimental data based mathematical models for cutting the slivers from bamboo by means of human powered flywheel motor. There were various dependent and independent variables involved in the process of cutting the bamboo sliver by human powered flywheel motor. Therefore, apart from formulation and development of the model, the optimization was done to find the best sets of the independent variable to achieve the responses as an output. The bamboo sliver cutting machine was designed, fabricated and based on the theory of experimentation, the experiment was performed and total 108 sets of readings were recorded. In this work, the responses of three response variables such as number of slivers, processing time and resistive torque were experimentally studied and the experimental data based models for these three response variables are optimized to get the best set of independent variables involved in the bamboo sliver cutting process.
Full-text available
Article
The slope simulation method of the spiral mechanism, the rubbing transmission, the resistance simulation method of magnetic particle brake loading on the rear wheel is proposed by anglicizing the road sports conditions and resistance of the actual cycling. the structure design, loading design and control design of the road sports condition simulator is designed. the structure of putting the motor forward and forcing the big sprocket rotation through the chain transmission, and the method of the frequency converter regulates the rotational speed of the motor within the range of certain frequency, PLC programming the rotation rules is adopted. The complete device is applied to athletes sports training of the national bicycle team at ordinary times after debugging successfully.
Full-text available
Book
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.
Full-text available
Article
Whilst a number of studies investigated gross efficiency (GE) in laboratory conditions, few studies have analyzed GE in field conditions. Therefore, the aim of this study was to analyze the effect of gradient and cadence on GE in field conditions. Thirteen trained cyclists (mean ± SD age: 23.3 ± 4.1 years; stature: 177.0 ± 5.5 cm; body mass: 69.0 ± 7.2 kg; VO2max 68.4 ± 5.1 mL·min-1·kg-1) completed an incremental graded exercise test to determine the ventilatory threshold (VT) and 4 field trials of 6 min duration at 90% of VT on flat (1.1%) and uphill terrain (5.1%) with two different cadences (60 and 90 rev·min-1). Oxygen uptake was measured with a portable gas analyzer and power output was controlled with a mobile power crank, which was mounted on a 26-inch mountain bike. GE was significantly affected by cadence (20.6 ± 1.7% vs. 18.1 ± 1.3% at 60 and 90 rev·min-1, respectively; P<0.001) and terrain (20.0 ± 1.5% vs. 18.7 ± 1.7% at flat and uphill cycling, respectively; P=0.029). The end-exercise oxygen uptake was 2536 ± 352 mL·min-1 and 2594 ± 329 mL·min-1 for flat and uphill cycling, respectively (P=0.489). There was a significant difference in end-exercise oxygen uptake between the 60 (2352 ± 193 mL·min-1) and the 90 rev·min-1 (2778 ± 431 mL·min-1) (P<0.001). This findings support previous laboratory based studies demonstrating reductions in GE with increasing cadence and gradient that might be attributed to changes in muscle activity pattern.
Article
To establish the level of agreement between test performance of young elite cyclists in a laboratory and a track field-based trial. Fourteen adolescent cyclists (age: 14.8±1.1 years; V[Combining Dot Above] O2max: 63.5±5.6 mLminkg) performed three tests of 10 s, 1 min and 3 min on an air-braked ergometer (Wattbike) and on a 250-m track using their own bikes mounted with mobile power-meters (SRM). The agreement between maximum and mean power output (Pmax and Pmean) measured on the Wattbike and SRM was assessed with the 95% limits of agreement (LoA). Power output was strongly correlated between Wattbike and SRM for all tests (r=0.94-0.96; P<0.001). However, power output was significantly higher on the Wattbike compared to track cycling during all tests. The bias and 95% LoA were 76±78 W (8.8±9.5%; P=0.003, dηp=0.38) for Pmax10s and 82±55 W (10.9±7.9%; P<0.001, dηp=0.46) for Pmean10s. During the 1-min and 3-min test the bias and 95% LoA was 72±30 W (17.9±7.1%; P<0.001, dηp=0.84) and 28±20 W (9.6±6.1%; P<0.001, dηp=0.51), respectively. Laboratory tests, as assessed using a stationary ergometer, resulted in maximal and mean power output scores that were consistently higher than a track field-based test using a mobile ergometer. These results might be attributed to the technical ability of the riders and their experience to optimize gearing and cadence to maximize performance. Prediction of field-based testing on the track from laboratory tests should be used with caution.
Article
Exergame controllers are intended to add fun to monotonous exercise. However, studies on exergame controllers mostly focus on designing new controllers and exploring specific application domains without analyzing human factors, such as performance, comfort, and effort. In this paper, we examine the characteristics of a speed-based exergame controller that bear on human factors related to body movement and exercise. Users performed tasks such as changing and maintaining exercise speed for avatar control while their performance was measured. The exergame controller follows Fitts' law, but requires longer movement time than a gamepad and Wiimote. As well, resistance force and target speed affect performance. User experience data confirm that the comfort and mental effort are adequate as practical game controllers. The paper concludes with discussion on applying our findings to practical exergame design.
Article
The main aim of this study was to compare the freely chosen cadence (FCC) and the cadence at which the blood lactate concentration at constant power output is minimized (optimal cadence [Copt]). The second aim was to examine the effect of a concomitant change of road incline and body position on FCC, the maximal external power output (Pmax), and the corresponding Copt. FCC, Copt, and Pmax were analyzed under 2 conditions: cycling on level ground in a dropped position (LGDP) and cycling uphill in an upright position (UHUP). Seven experienced cyclists participated in this study. They cycled on a treadmill to test the 2 main hypotheses: Experienced cyclists would choose an adequate cadence close to Copt independent of the cycling condition, and FCC and Copt would be lower and Pmax higher for UHUP than with LGDP. Most but not all experienced cyclists chose an adequate cadence close to Copt. Independent of the cycling condition, FCC and Copt were not statistically different. FCC (82.1 ± 11.1 and 89.3 ± 10.6 rpm, respectively) and Copt (81.5 ± 9.8 and 87.7 ± 10.9 rpm, respectively) were significantly lower and Pmax was significantly higher (2.0 ± 2.1%) for UHUP than for LGDP. Most experienced cyclists choose a cadence near Copt to minimize peripheral fatigue at a given power output independent of the cycling condition. Furthermore, it is advantageous to use a lower cadence and a more upright body position during uphill cycling.
Full-text available
Article
In the sport of rowing, increasing the impulse applied to the oar handle during the stroke can result in greater boat velocities; this may be facilitated by increasing the surface area of the oar blade and/or increasing the length of the oars. The purpose of this study was to compare the effects of different rowing resistances on the physiological response to rowing. 5 male and 7 female club rowers completed progressive, incremental exercise tests on an air-braked rowing ergometer, using either low (LO; 100) or high (HI; 150) resistance (values are according to the adjustable "drag factor" setting on the ergometer). Expired air, blood lactate concentration, heart rate, rowing cadence, and ergometer power output were monitored during the tests. LO rowing elicited significantly greater cadences (P<0.01) and heart rates (P<0.05), whereas rowing economy (J · L O2 equivalents - 1) was significantly greater during HI rowing (P<0.05). These results suggest that economically, rowing with a greater resistance may be advantageous for performance. Moreover, biomechanical analysis of ergometer rowing support the notion that the impulse generated during the stroke increases positively as a function of rowing resistance. We conclude that an aerobic advantage associated with greater resistance parallels the empirical trend toward larger oar blades in competitive rowing. This may be explained by a greater stroke impulse at the higher resistance.
Full-text available
Article
Cycling is scientifically an interesting activity because it is par-ticularly suitable for muscle-mechanical and physiological re-search. Numerous publications on cycling document this interest. A practical focus of this research is the examination of cadence and pedaling technique from different points of view. Focusing on competition the optimal cadence and pedaling technique to gene-rate maximal power for an endurance activity are of great interest. With one question cycling research has not argued enough yet: why do professional cyclists adopt a lower cadence when they are cycling uphill compared to cycling on level ground? Currently no scientific evidence is available to explain this choice of a lower cadence. This review article shows the current research state in the field of optimal cadence and pedaling technique and lists some potential factors that could affect the optimal cadence and give an answer to the mentioned question. Conclusion: A general optimal cadence does not exist. With a holistic mechano-physiological model the variations of optimal cadence could be explained. Übersichtsartikel Schweizerische Zeitschrift für «Sportmedizin und Sporttraumatologie» 56 (2), 71–76, 2008 Zusammenfassung Radrennfahren ist eine wissenschaftlich interessante Sportart, weil sie sich sehr gut für muskelmechanische und leistungsphysio-logische Untersuchungen eignet. Die zahlreichen Publikationen zum Thema Radfahren dokumentieren dieses Interesse. Ein pra-xisnaher Schwerpunkt ist die Auseinandersetzung mit der Tritt-frequenz und der Tritttechnik aus verschiedenen Betrachtungs-weisen. Im wettkampforientierten Rahmen stehen dabei die op-timale Trittfrequenz und die Tritttechnik im Mittelpunkt, um im Ausdauerbereich eine maximale Leistung erbringen zu können. Mit einer Frage hat sich die Wissenschaft aber noch ungenügend auseinandergesetzt: Wieso wird im Profi-Radsport am Berg im Vergleich zur Ebene eine tiefere Trittfrequenz gefahren? Keine wissenschaftliche Arbeit vermag bislang die Wahl einer tieferen Trittfrequenz zu erklären. Dieser Übersichtsartikel zeigt den mo-mentanen Stand der Forschung im Bereich der optimalen Tritt-frequenz und der Tritttechnik und führt mögliche Faktoren auf, welche die optimale Trittfrequenz beeinflussen und die erwähnte Frage beantworten könnten. Schlussfolgerung: Eine allgemeingül-tige optimale Trittfrequenz gibt es nicht. Mit einem ganzheitlichen mechano-physiologischen Modell könnten die Variationen der op-timalen Trittfrequenz aufgezeigt werden.
Article
In race cycling, the external power–cadence relationship at the performance level, that is sustainable for the given race distance, plays a key role. The two variables of interest from this relationship are the maximal external power output (P max) and the corresponding optimal cadence (C opt). Experimental studies and field observations of cyclists have revealed that when cycling uphill is compared to cycling on level ground, the freely chosen cadence is lower and a more upright body position seems to be advantageous. To date, no study has addressed whether P max or C opt is influenced by road incline or body position. Thus, the main aim of this study was to examine the effect of road incline (0 vs. 7%) and racing position (upright posture vs. dropped posture) on P max and C opt. Eighteen experienced cyclists participated in this study. Experiment I tested the hypothesis that road incline influenced P max and C opt at the second ventilatory threshold ($$P_{ \max }^{{{\text{VT}}_{ 2} }}$$ and $$C_{\text{opt}}^{{{\text{VT}}_{ 2} }}$$). Experiment II tested the hypothesis that the racing position influenced $$P_{ \max }^{{{\text{VT}}_{ 2} }}$$, but not $$C_{\text{opt}}^{{{\text{VT}}_{ 2} }}$$. The results of experiment I showed that $$C_{\text{opt}}^{{{\text{VT}}_{ 2} }}$$ and $$P_{ \max }^{{{\text{VT}}_{ 2} }}$$ were significantly lower when cycling uphill compared to cycling on level ground (P < 0.01). Experiment II revealed that $$P_{ \max }^{{{\text{VT}}_{ 2} }}$$ was significantly greater for the upright posture than for the dropped posture (P < 0.01) and that the racing position did not affect $$C_{\text{opt}}^{{{\text{VT}}_{ 2} }}$$. The main conclusions of this study were that when cycling uphill, it is reasonable to choose (1) a lower cadence and (2) a more upright body position.
Article
In maximal sprint cycling, the power-cadence relationship to assess the maximal power output (P (max)) and the corresponding optimal cadence (C (opt)) has been widely investigated in experimental studies. These studies have generally reported a quadratic power-cadence relationship passing through the origin. The aim of the present study was to evaluate an equivalent method to assess P (max) and C (opt) for endurance cycling. The two main hypotheses were: (1) in the range of cadences normally used by cyclists, the power-cadence relationship can be well fitted with a quadratic regression constrained to pass through the origin; (2) P (max) and C (opt) can be well estimated using this quadratic fit. We tested our hypothesis using a theoretical and an experimental approach. The power-cadence relationship simulated with the theoretical model was well fitted with a quadratic regression and the bias of the estimated P (max) and C (opt) was negligible (1.0 W and 0.6 rpm). In the experimental part, eight cyclists performed an incremental cycling test at 70, 80, 90, 100, and 110 rpm to yield power-cadence relationships at fixed blood lactate concentrations of 3, 3.5, and 4 mmol L(-1). The determined power outputs were well fitted with quadratic regressions (R (2) = 0.94-0.96, residual standard deviation = 1.7%). The 95% confidence interval for assessing individual P (max) and C (opt) was ±4.4 W and ±2.9 rpm. These theoretical and experimental results suggest that P (max), C (opt), and the power-cadence relationship around C (opt) could be well estimated with the proposed method.
Full-text available
Article
This study tested the effects of low-cadence (60 rev min−1) uphill (Int60) or high-cadence (100 rev min−1) level-ground (Int100) interval training on power output (PO) during 20-min uphill (TTup) and flat (TTflat) time-trials. Eighteen male cyclists ($$\dot{V}{\text{O}}_{2\max }$$: 58.6 ± 5.4 mL min−1 kg−1) were randomly assigned to Int60, Int100 or a control group (Con). The interval training comprised two training sessions per week over 4 weeks, which consisted of six bouts of 5 min at the PO corresponding to the respiratory compensation point (RCP). For the control group, no interval training was conducted. A two-factor ANOVA revealed significant increases on performance measures obtained from a laboratory-graded exercise test (GXT) (P max: 2.8 ± 3.0%; p < 0.01; PO and $$\dot{V}{\text{O}}_{2}$$ at RCP: 3.6 ± 6.3% and 4.7 ± 8.2%, respectively; p < 0.05; and $$\dot{V}{\text{O}}_{2}$$ at ventilatory threshold: 4.9 ± 5.6%; p < 0.01), with no significant group effects. Significant interactions between group and uphill and flat time-trial, pre- versus post-training on PO were observed (p < 0.05). Int60 increased PO during both TTup (4.4 ± 5.3%) and TTflat (1.5 ± 4.5%). The changes were −1.3 ± 3.6, 2.6 ± 6.0% for Int100 and 4.0 ± 4.6%, −3.5 ± 5.4% for Con during TTup and TTflat, respectively. PO was significantly higher during TTup than TTflat (4.4 ± 6.0; 6.3 ± 5.6%; pre and post-training, respectively; p < 0.001). These findings suggest that higher forces during the low-cadence intervals are potentially beneficial to improve performance. In contrast to the GXT, the time-trials are ecologically valid to detect specific performance adaptations.
Full-text available
Article
In a comparison of traditional and theoretical exercise efficiency calculations male subjects were studied during steady-rate cycle ergometer exercises of "0," 200, 400, 600, and 800 kgm/min while pedaling at 40, 60, 80, and 100 rpm. Gross (no base-line correction), net (resting metabolism as base-line correction), work (unloading cycling as base-line correction), and delta (measurable work rate as base-line correction) efficiencies were computed. The result that gross (range 7.5-20.4%) and net (9.8-24.1%) efficiencies increased with increments in work rate was considered to be an artifact of calculation. A LINEAR OR SLIGHTLY EXPONENTIAL RELATIONSHIP BETWEEN CALORIC OUTPUT AND WORK RATE DICTATES EITHER CONSTANT OR DECREASING EFFICIENCY WITH INCREMENTS IN WORK. The delta efficiency (24.4-34.0%) definition produced this result. Due to the difficulty in obtaining 0 work equivalents, the work efficiency definition proved difficult to apply. All definitions yielded the result of decreasing efficiency with increments in speed. Since the theoretical-thermodynamic computation (assuming mitochondrial P/O = 3.0 and delta G = -11.0 kcal/mol for ATP) holds only for CHO, the traditional mode of computation (based upon VO2 and R) was judged to be superior since R less than 1.0. Assuming a constant phosphorylative-coupling efficiency of 60%, the mechanical contraction-coupling efficiency appears to vary between 41 and 57%.
Full-text available
Article
The bicycle-rider system is modeled as a planar five-bar linkage with pedal forces and pedal dynamics as input. The pedal force profile input is varied, maintaining constant average bicycle power, in order to obtain the optimal pedal force profile that minimizes two cost functions. One cost function is based on joint moments and the other is based on muscle stresses. Predicted (optimal) pedal profiles as well as joint moment time histories are compared to representative real data to examine cost function appropriateness. Both cost functions offer reasonable predictions of pedal forces. The muscle stress cost function, however, better predicts joint moments. Predicted muscle activity also correlates well with myoelectric data. The factors that lead to effective (i.e. low cost) pedalling are examined. Pedalling effectiveness is found to be a complex function of pedal force vector orientation and muscle mechanics.
Full-text available
Article
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.
Full-text available
Article
Unlabelled: This study investigated the variation in freely chosen pedal rate between subjects and its possible dependence on percentage myosin heavy chain I (%MHC I) in m. vastus lateralis, maximum leg strength and power, as well as efficiency. Additionally, the hypothesis was tested that a positive correlation exists between percentage MHC I and efficiency at pre-set pedal rates but not at freely chosen pedal rate. Twenty males performed cycling at low and high submaximal power output ( approximately 40 and 70% of the power output at which maximum oxygen uptake (VO(2max)) was attained at 80 r.p.m.) with freely chosen and pre-set pedal rates (61, 88, and 115 r.p.m.). Percentage MHC I as well as leg strength and power were determined. Freely chosen pedal rate varied considerably between subjects: 56-88 r.p.m. at low and 61-102 r.p.m. at high submaximal power output. This variation was only partly explained by percentage MHC I (21-97%) as well as by leg strength and power. Interestingly, %MHC I correlated significantly with the pedal rate at which maximum peak crank power occurred (r = -0.81). As hypothesized, %MHC I and efficiency were unrelated at freely chosen pedal rate, which was in contrast to a significant correlation found at pre-set pedal rates (r = 0.61 and r = 0.57 at low and high power output, respectively). Conclusions: Subjects with high percentage MHC I chose high pedal rates close to the pedal rates at which maximum peak crank power occurred, while subjects with low percentage MHC I tended to choose lower pedal rates, favouring high efficiency. Nevertheless, the considerable variation in freely chosen pedal rate between subjects was neither fully accounted for by percentage MHC I nor by leg strength and power. Previously recognized relationships between percentage Type I ( approximately %MHC I) and efficiency as well as between pedal rate and efficiency were confirmed for pre-set pedal rates, but for freely chosen pedal rate, these variables were unrelated.
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
This book takes a traditional approach to the development of the methods of analytical dynamics. After a review of Newtonian dynamics, the basic concepts of analytical dynamics - classification of constraints, classification of forces, virtual displacements, virtual work and variational principles - are introduced and developed. Next, Langrange's equations are derived and their integration is discussed. The Hamiltonian portion of the book covers Hamilton's canonical equations, contact transformations, and Hamilton-Jacobi theory. Also included are chapters on stability of motion, impulsive forces, and the Gibbs-Appell equation. Two types of examples are used throughout the book. The first type is intended to illustrate key results of the theoretical development, and these are deliberately kept as simple as possible. The other type is included to show the application of the theoretical results to complex, real-life problems. These examples are often quite lengthy, comprising an entire chapter in some cases. © 2005 Kluwer Academic / Plenum Publishers. All rights reserved.
Article
Nine of the best road-racing cyclists in the United States were tested to evaluate selected psychological characteristics using the Eysenck Personality Inventory (EPI) and the Profile of Mood States (POMS). Their V̇O2max and other factors possibly involved in high-level cycling performance were measured and compared to similar data on East German cyclists in an attempt to determine the performance factors affecting the success of American cyclists in international events. The cyclists were found to be more introverted than normal adults. This is in contrast to what has been found for elite marathon runners but agrees with the trait of introversion found in marathon runners at other competitive levels. The POMS profile of the cyclists was similar to those of elite marathoners, oarsmen and wrestlers. The POMS scales reveal cyclists to be less tense, confused, depressed or angry than college age normals. They also scored higher than normals on the vigor scale. The cyclists were able to average 52.8±4.9 (mean ±SE) seconds at a load in excess of 3780 kmp x min-1 on the bicycle ergometer indicating that, in addition to highly developed aerobic systems, these cyclists also possess the capacity for extremely high power outputs for short periods of time. The V̇O2max for the group averaged 70.3±2.0 ml x kg-1 x min-1 which is very similar to a number of previous reports on European cyclists; their age, height, weight and years in training were also virtually the same. Therefore, it is suggested that other factors, including tactics and technique, must contribute to the performance differences seen between American and European cyclists.
Article
After review of previous studies, it seemed desirable to investigate further the interrelationships between pedalling rate, power output, and energy expenditure, using bicycle ergometry as a model for recreational bicycling. Three young adult male subjects rode a Monark ergometer at eight pedalling rates (30-120 rev min ) and four power outputs (‘ 0 ’ 81-7. 163-4. and 1961 W) [vdot] o2 determinations were made, and using measured R, gross energy expenditure was derived. When these values were combined with the results of other researchers using similar protocol but different power outputs, it was found that: (I) a ‘ most efficient’ pedalling rate exists for each power output studied: (2) the ( most efficient ) pedalling rate increases with power output from 42 rev min at 40-8 W to 62 rev min at 326-8 W: and (3) the increase in energy expenditure observed when pedalling slower than‘ most efficient’ is more pronounced at high power outputs than at low outputs, while the increase in response to pedalling faster than “lsquo; most efficient’ is less pronounced at high power outputs than at low outputs. Thus, there is appreciable interaction between pedalling rate and power output in achieving the ‘ most efficient ’ rate in bicycle ergometry. The ‘ most efficient’ pedalling rate observed at high power outputs in the present study is considerably lower than that reported for racing cyclists by others. This discrepancy may well be related to the difference in swing weights between the ergomeler' s heavy steel flywheel and crankset, and that of the lightweight wheel and crankset used on racing bicycles.
Methodical aspects of the relationship between pedalling rate and rotating mass and perceived exertion rating (PER; Borg, 1962) were studied in trained, untrained, and ill subjects in bicycle ergometry. Pedalling rate varied between 40 and 100 rpm, work load steps were 5, 10, 15 and 20 mkp/sec in the healthy subjects, and 2.5, 5, 7.5 and 10 mkp/sec in the patients. PER decreased with increasing pedalling rate in all healthy subjects. In the patients, PER increased moderately at work load of 2.5 mkp/sec, but decreased at higher work loads up to 80 rpm, followed by a slight increase at 100 rpm. Higher mass of the flywheel, studied in 6 trained subjects, lowered the PER insignificantly. In the healthy subjects, test criteria, such as reproducibility, reliability, sensitivity, and linearity remained almost unaffected by pedalling rate. In patients, increasing pedalling speed diminished reproducibility and sensitivity. The strictness of the PER work load relationship is lowered at higher pedalling rate, especially at 100 rpm. When using the PER scale, pedalling rate has to be considered as an factor of main influence.
Article
We determined that the variability in the oxygen cost and thus the caloric expenditure of cycling at a given work rate (i.e., cycling economy) observed among highly endurance-trained cyclists (N = 19; mean +/- SE; VO2max, 4.9 +/- 0.1 l.min-1; body weight, 71 +/- 1 kg) is related to differences in their % Type I muscle fibers. The percentage of Type I and II muscle fibers was determined from biopsies of the vastus lateralis muscle that were histochemically stained for ATPase activity. When cycling a Monark ergometer at 80 RPM at work rates eliciting 52 +/- 1, 61 +/- 1, and 71 +/- 1% VO2max, efficiency was determined from the caloric expenditure responses (VO2 and RER using open circuit spirometry) to steady-state exercise. Gross efficiency (GE) was calculated as the ratio of work accomplished.min-1 to caloric expenditure.min-1, whereas delta efficiency (DE) was calculated as the slope of this relationship between approximately 50 and 70% VO2max. The % Type I fibers ranged from 32 to 76%, and DE when cycling ranged from 18.3 to 25.6% in these subjects. The % Type I fibers was positively correlated with both DE (r = 0.85; P less than 0.001; N = 19) and GE (r = 0.75; P less than 0.001; N = 19) during cycling. Additionally, % Type I fibers was positively correlated with GE (r = 0.74; P less than 0.001; N = 13) measured during the novel task of two-legged knee extension; performed at a velocity of 177 +/- 6 degrees.s-1 and intensity of 50 and 70% of peak VO2 for that activity.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
Energy expenditure during bicycling on flat terrain depends predominantly on air resistance, which is a function of total frontal area (bicycle and rider), coefficient of drag, and air speed. Body position on the bicycle may affect energy expenditure by altering either frontal area or coefficient of drag. In this study, oxygen uptake (VO2) was measured for each of four body positions in 10 cyclists (8 males, 2 females, 24 +/- 2 yr, 67.7 +/- 3.3 kg, VO2max = 65.8 +/- 1.5 ml.kg-1.min-1) while each bicycled up a 4% incline on a motor-driven treadmill (19.3 km.h-1), thereby eliminating air resistance. Positions studied included: 1) seated, hands on brake hoods, cadence 80 rev.min-1; 2) seated, hands on dropped bar (drops), 80 rev.min-1; 3) standing, hands on brake hoods, 60 rev.min-1; and 4) seated, hands on brake hoods, 60 rev.min-1. Subjects rode their own bicycles, which were equipped with a common set of racing wheels. Energy expenditure, expressed as VO2 per unit combined weight, was not significantly different between drops and hoods positioning (30.2 +/- 0.6 vs 29.9 +/- 0.9 ml.kg-1.min-1) but was significantly greater for standing compared with seated cycling (31.7 +/- 0.4 vs 28.3 +/- 0.7 ml.kg-1.min.-1, P less than 0.01). These results indicate that body posture can affect energy expenditure during uphill bicycling through factors unrelated to air resistance.
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.
This experiment was designed to estimate the optimum pedal rates at various power outputs on the cycle ergometer. Five trained bicycle racers performed five progressive maximal tests on the ergometer. Each rode at pedal rates of 40, 60, 80, 100, and 120 rev X min-1. Oxygen uptake and heart rate were determined from each test and plotted against pedal rate for power outputs of 100, 150, 200, 250, and 300 W. Both VO2 and heart rate differed significantly among pedal rates at equivalent power outputs, the variation following a parabolic curve. The low point in the curve was taken as the optimal pedal rate; i.e., the pedal rate which elicited the lowest heart rate or VO2 for a given power output. When the optimum was plotted against power output the variation was linear. These results indicate that an optimum pedal rate exists in this group of cyclists. This optimum pedal rate increases with power output, and when our study is compared to studies in which elite racers, or non-racers were used, the optimum seems to increase with the skill of the rider.
Article
1. The relation of V(O2) and speed was determined on six competition cyclists riding at speeds ranging from 12 km/hr to 41 km/hr on the runway of an airfield. Comparative measurements were made on the bicycle ergometer to determine the corresponding work rates, and from this information rolling resistance and air resistance were derived.2. V(O2) was a curvilinear function of cycling speed, and increased from 0.88 l./min at 12.5 km/hr to 5.12 l./min at 41 km/hr, mean body weight being 72.9 kg.3. On the ergometer, V(O2) was a linear function of work rate; maximum values up to 5.1 l./min (74.4 ml./kg min) and work rates up to 425 W (2600 kg m/min) were observed.4. Data are presented on the relation of pedal frequency and speed in cycling, and on the relation of mechanical efficiency and pedal frequency, as determined on the ergometer.5. The estimated rolling resistance for four subjects was 0.71 kg f. The drag coefficient was 0.79 and the drag area 0.33 m(2). The values agreed well with results obtained by other methods.6. The energy expenditure (power developed) in cycling increased approximately as the square of the speed, and not as the cube of the speed as expected. This was explained by the varying contribution of rolling resistance and air resistance to over-all resistance to motion at different speeds.
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
The aim of this investigation was to study how the known dependence of working efficiency on pedaling frequency is influenced by the work load as well as by physical fitness. Oxygen uptake, CO2 output, ventilation, heart rate, and lactate concentration in capillary blood from the ear-lobe were determined at varying combinations of work loads and pedaling rates in road-racing cyclists and medical students. Respiratory exchange ratio, consumption of energy, gross efficiency, net efficiency, and delta efficiency (Δ work rate/Δ metabolic rate) were calculated. All parameters showed a nonlinear dependence on pedaling frequency. The lowest oxygen uptake and the highest efficiency shifted to higher frequencies with increasing work load. Delta efficiency increased with rising pedaling frequency. Differences of V̇O2 and efficiencies between trained and untrained subjects were only small. Most effects can be explained by variations in leg movement frequency and recruitment of muscle fibers. There is evidence that racing cyclists chose pedaling rates yielding optimal efficiency at any load.
Article
We investigated the interrelationships between pedalling rate, power output and oxygen cost during cycling. Four highly trained racing cyclists performed two bicycle rides on a treadmill while employing three pedal speeds (60, 100, 130 rpm) at two power outputs (800 and 1800 kg-m/min). Oxygen cost progressively increased with increased pedal rate at low power outputs but decreased with increased pedal rate at high power outputs. A slow pedal rate was most efficient (18%) at the low power output while no difference in efficiency (22%) was observed at the high power output. Least efficient (14%) was a high pedal speed at a low power output. These findings indicate an appreciable interaction between pedal rate and power output in achievement of most efficient pedal frequencies. The most significant finding was that efficiency at the high power output did not change with increments in pedal speed.
Article
The purpose of this study was to identify sensitive physiological indicators for monitoring the progress in training state of elite cyclists throughout a training and competition season. Seven elite male cyclists performed maximal oxygen consumption (VO2max) tests and submaximal tests on three or four different occasions during their training and competition season. The submaximal test consisted of three successive 16-min bouts at 150, 200, and 250 W interspersed with rest periods between each load. Pedalling rate varied progressively from 50-120 rpm. Results showed that maximal heart rate (HR), ventilation (Ve), gross mechanical efficiency (MEG), and VO2max did not change during the season. Moreover, ventilation threshold (VT) did not change during the season, nor did HR, Ve, and VO2 at VT. However, changes were found in physiological variables during the submaximal test. HR decreased significantly during the season, as did VO2 (P < 0.05) for a standardized workload. On the other hand, at the higher power outputs (200 W and 250 W) MEG increased during the season. These results suggest that VO2max may not be a good indicator of enhanced capacity in elite cyclists. Rather, a standardized efficiency test during which submaximal variables such as HR, VO2, and MEG are monitored might be a more sensitive indicator of the progress in the training state of elite male cyclists during a training and competition season.
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 a constant workload. Virtually no statistically significant changes were found in the net hip and knee muscle joint torques calculated from an inverse dynamics analysis. Though the net ankle muscle joint torque, as well as the one- and two-legged crank torque, showed statistically significant increases at the higher inertia, the changes were small. In contrast, large statistically significant reductions were found in crank kinematic variability both within a cycle and between cycles (i.e., cadence), primarily because a larger inertial load means a slower crank dynamic response. Nonetheless, the reduction in cadence variability was somewhat attenuated by a large statistically significant increase in one-legged crank torque variability. We suggest, therefore, that muscle coordination during steady-state pedaling is largely unaffected, though less well regulated, when crank inertial load is increased.
Article
To determine whether an association exists between peripheral comfort level, as reflected by differentiated RPE measures, and the preferred cadences of subjects who differed in cycling experience and fitness level. Twelve experienced cyclists (C), ten runners (R), and ten less-trained noncyclists (LT), all of whom were male, pedaled at three power outputs (C, R: 100, 150, 200 W; LT: 75, 100, 150 W) and six cadences (50, 65, 80, 95, 110 rpm, and their freely chosen cadence) for 5 min per condition. Differentiated ratings of perceived exertion (RPE) were recorded during the fifth minute of the exercise. It was hypothesized that the preferred cadence selected by C, R, and LT would be the same as the cadence at which the peripheral RPE was minimized. Comparison of means failed to support this hypothesis. Irrespective of rating scale (peripheral, central, overall), the cadences at which RPE was minimized were lower than the preferred cadences, except for LT at 150 W, where there was no significant difference between the preferred cadence and the cadences at which the peripheral and overall RPE were minimized. C tended toward a more curvilinear RPE-cadence relationship compared with R and LT. Mean data for all groups showed that only the peripheral RPE decreased from 50 to 65 rpm, whereas peripheral, overall, and central RPE remained essentially unchanged from 65 to 80 rpm but increased from 80 to 110 rpm. There was a trend for the cadences at which RPE was minimized for C to be higher than the cadences that minimized RPE in either R or LT. For all groups, the cadences at which peripheral RPE was minimized were significantly higher than the cadences at which either the overall or central ratings were minimized. The small magnitudes of change in the RPE score across cadence, particularly in C and R, suggest that RPE may not be a critical variable in cadence selection during submaximal power output cycling.
Article
The purpose of the present study was to examine the neuromuscular modifications of cyclists to changes in grade and posture. Eight subjects were tested on a computerized ergometer under three conditions with the same work rate (250 W): pedaling on the level while seated, 8% uphill while seated, and 8% uphill while standing (ST). High-speed video was taken in conjunction with surface electromyography (EMG) of six lower extremity muscles. Results showed that rectus femoris, gluteus maximus (GM), and tibialis anterior had greater EMG magnitude in the ST condition. GM, rectus femoris, and the vastus lateralis demonstrated activity over a greater portion of the crank cycle in the ST condition. The muscle activities of gastrocnemius and biceps femoris did not exhibit profound differences among conditions. Overall, the change of cycling grade alone from 0 to 8% did not induce a significant change in neuromuscular coordination. However, the postural change from seated to ST pedaling at 8% uphill grade was accompanied by increased and/or prolonged muscle activity of hip and knee extensors. The observed EMG activity patterns were discussed with respect to lower extremity joint moments. Monoarticular extensor muscles (GM, vastus lateralis) demonstrated greater modifications in activity patterns with the change in posture compared with their biarticular counterparts. Furthermore, muscle coordination among antagonist pairs of mono- and biarticular muscles was altered in the ST condition; this finding provides support for the notion that muscles within these antagonist pairs have different functions.
Article
Eight experienced male cyclists (C), eight well-trained male runners (R), and eight less-trained male noncyclists (LT) were tested under multiple cadence and power output conditions to determine: (1) if the cadence at which lower extremity net joint moments are minimized (cost function cadence) was associated with preferred pedaling cadence (PC), (2) if the cost function cadence increased with increases in power output, and (3) if the association is generalizable across groups differing in cycling experience and aerobic power. Net joint moments at the hip, knee, and ankle were computed from video records and pedal reaction force data using 2-D inverse dynamics. The sum of the average absolute hip, knee, and ankle joint moments defined a cost function at each power output and cadence and provided the basis for prediction of the cadence which minimized net joint moments for each subject at each power output. The cost function cadence was not statistically different from the PC at each power output in all groups. As power output increased, however, the cost function cadence increased for all three subject groups (86 rpm at 100 W, 93 rpm at 150 W, 98 rpm at 200 W, and 96 rpm at 250 W). PC showed little change (R) or a modest decline (C, LT) with increasing power output. Based upon the similarity in the mean data but different trends in the cost function cadence and PC in response to changes in power output as well as the lack of significant correlations between these two variables, it was concluded that minimiking net joint moments is a factor modestly associated with preferred cadence selection.
Human muscle fatigue in dynamic exercise
• A J Sargeant
• A Beelen
Sargeant, A.J., Beelen, A. (1993) Human muscle fatigue in dynamic exercise. In: Sargeant, A.J., Kernell, D. (Eds.), Neuromuscular Fatigue. Amsterdam, New York, pp. 81-92.
The significance of crank load dynamics to steady-state pedalling biomechanics: an experimental and computer modeling study
• B J Fregly
Fregly, B.J., 1993. The significance of crank load dynamics to steadystate pedalling biomechanics: an experimental and computer modeling study. Ph.D. Thesis, Stanford University.
Evaluation of a new metabolic cart for exercise testing. Fifth Annual Congress of the European College of Sport Science
• K Jensen
• S Jrgensen
• L Johansen
Jensen, K., Jrgensen, S., Johansen, L., 2000. Evaluation of a new metabolic cart for exercise testing. Fifth Annual Congress of the European College of Sport Science. Jyv. askyl. a, Finland.
Bicycle drive system dynamics
• Fregly
Muscle coordination in cycling
• Li