Low Cadence Research Articles

Effect of Cycling Exercise at Different Pedal Cadences on Subsequent Muscle Strength

The main purpose of this study was to compare the effects of previous high-intensity aerobic exercise at 50 and 100 rev · min −1 on subsequent strength determined through maximal repetitions (RM) and countermovement jump (CMJ). Thirteen physically active males (age, 23.0 ± 3.7 years; weight, 77.1 ± 8.8 kg; height, 179.3 ± 4.0 cm; %body fat, 14.3 ± 2.9%) performed the following procedures on different days: (1) incremental test on cycle ergometer to determine the onset of blood lactate accumulation at 50 and 100 rev · min −1 ; (2) three sets of RMs with the load corresponding to 10 RM in leg press 45° (LC); (3) three sets of 10 maximal CMJ in contact plate (JC); (4) four trials of 30 minutes at the onset of blood lactate accumulation obtained at 50 and 100 rev · min −1 , followed by three sets of RMs with 10 RM load (L50 and L100, respectively) or three sets of maximal CMJ (J50 and J100, respectively). Strength was compromised at 100 rev · min −1 (L100 = 22.6 ± 6.0 vs. LC = 30.4 ± 1.5 repetitions) in leg press, while CMJ height was reduced at 50 rev-min −1 (J50 = 29.2 ±3.0 vs. JC = 31.7 ± 2.9 cm). The reduction in number of repetitions at L100 (26%) was significantly higher than CMJ height at J50 (8%). In conclusion, the extent of strength loss after high-intensity aerobic exercise can be dependent on both pedal cadence and strength test conditions. When aerobic cycling exercise precedes strength training, it may be beneficial to use low pedal cadences to minimize strength loss.

Kinematical evidence for physically different classes of large-scale coronal EUV waves

Context. Large-scale wavelike disturbances have been observed in the solar corona in the EUV range since more than a decade. The physical nature of these so-called “EIT waves” is still being debated controversially. The two main contenders are on the one hand MHD waves and/or shocks, and on the other hand magnetic reconfiguration in the framework of an expanding CME. There is a lot of observational evidence backing either one or the other scenario, and no single model has been able to reproduce all observational constraints, which are partly even contradictory. This suggests that there may actually exist different classes of coronal waves that are caused by distinct physical processes. Then, the problems in interpreting coronal waves would be mainly caused by mixing together different physical processes. Aims. We search for evidence for physically different classes of large-scale coronal EUV waves. Methods. Kinematics is the most important characteristic of any moving disturbance, hence we focus on this aspect of coronal waves. Identifying distinct event classes requires a large event sample, which is up to now only available from SOHO/EIT. We analyze the kinematics of a sample of 176 EIT waves. In order to check if the results are severely affected by the low cadence of EIT, we complement this with high-cadence data for 17 events from STEREO/EUVI. In particular, we focus on the wave speeds and their evolution. Results. Based on their kinematical behavior, we find evidence for three distinct populations of coronal EUV waves: initially fast waves (v ≥ 320 km s −1 ) that show pronounced deceleration (class 1 events), waves with moderate (v ≈ 170−320 km s −1 ) and nearly constant speeds (class 2), and slow waves (v ≤ 130 km s −1 ) showing a rather erratic behavior (class 3). Conclusions. The kinematical behavior of the fast decelerating disturbances is consistent with nonlinear large-amplitude waves or shocks that propagate faster than the ambient fast-mode speed and subsequently slow down due to decreasing amplitude. The waves with moderate speeds are consistent with linear waves moving at the local fast-mode speed. Thus both populations can be explained in terms of the wave/shock model. The slow perturbations with erratic behavior, on the other hand, are not consistent with this scenario. These disturbances could well be due to magnetic reconfiguration.

DIRECT IMAGING OF QUASI-PERIODIC FAST PROPAGATING WAVES OF ∼2000 km s –1 IN THE LOW SOLAR CORONA BY THE SOLAR DYNAMICS OBSERVATORY ATMOSPHERIC IMAGING ASSEMBLY

Quasi-periodic, propagating fast mode magnetosonic waves in the corona were difficult to observe in the past due to relatively low instrument cadences. We report here evidence of such waves directly imaged in EUV by the new SDO AIA instrument. In the 2010 August 1 C3.2 flare/CME event, we find arc-shaped wave trains of 1-5% intensity variations (lifetime ~200 s) that emanate near the flare kernel and propagate outward up to ~400 Mm along a funnel of coronal loops. Sinusoidal fits to a typical wave train indicate a phase velocity of 2200 +/- 130 km/s. Similar waves propagating in opposite directions are observed in closed loops between two flare ribbons. In the k-$\omega$ diagram of the Fourier wave power, we find a bright ridge that represents the dispersion relation and can be well fitted with a straight line passing through the origin. This k-$\omega$ ridge shows a broad frequency distribution with indicative power at 5.5, 14.5, and 25.1 mHz. The strongest signal at 5.5 mHz (period 181 s) temporally coincides with quasi-periodic pulsations of the flare, suggesting a common origin. The instantaneous wave energy flux of $(0.1-2.6) \times 10^7 ergs/cm^2/s$ estimated at the coronal base is comparable to the steady-state heating requirement of active region loops.

Deceleration and dispersion of large-scale coronal bright fronts

One of the most dramatic manifestations of solar activity are large-scale coronal bright fronts (CBFs) observed in extreme ultraviolet (EUV) images of the solar atmosphere. To date, the energetics and kinematics of CBFs remain poorly understood, due to the low image cadence and sensitivity of previous EUV imagers and the limited methods used to extract the features. In this paper, the trajectory and morphology of CBFs was determined in order to investigate the varying properties of a sample of CBFs, including their kinematics and pulse shape, dispersion, and dissipation. We have developed a semi-automatic intensity profiling technique to extract the morphology and accurate positions of CBFs in 2.5-10 min cadence images from STEREO/EUVI. The technique was applied to sequences of 171A and 195A images from STEREO/EUVI in order to measure the wave properties of four separate CBF events. Following launch at velocities of ~240-450kms^{-1} each of the four events studied showed significant negative acceleration ranging from ~ -290 to -60ms^{-2}. The CBF spatial and temporal widths were found to increase from ~50 Mm to ~200 Mm and ~100 s to ~1500 s respectively, suggesting that they are dispersive in nature. The variation in position-angle averaged pulse-integrated intensity with propagation shows no clear trend across the four events studied. These results are most consistent with CBFs being dispersive magnetoacoustic waves.

Concurrent Training: A Comparison of High and Low Cadence Cycle Ergometry on Lower-body Strength in Young Moderately Trained Males

Concurrent Training: A Comparison of High and Low Cadence Cycle Ergometry on Lower-body Strength in Young Moderately Trained Males

Effects of low and high cadence interval training on power output in flat and uphill cycling time-trials

This study tested the effects of low-cadence (60 rev min(-1)) uphill (Int(60)) or high-cadence (100 rev min(-1)) level-ground (Int(100)) interval training on power output (PO) during 20-min uphill (TT(up)) and flat (TT(flat)) time-trials. Eighteen male cyclists ([Formula: see text]: 58.6 ± 5.4 mL min(-1) kg(-1)) were randomly assigned to Int(60), Int(100) 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 [Formula: see text] at RCP: 3.6 ± 6.3% and 4.7 ± 8.2%, respectively; p < 0.05; and [Formula: see text] 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). Int(60) increased PO during both TT(up) (4.4 ± 5.3%) and TT(flat) (1.5 ± 4.5%). The changes were -1.3 ± 3.6, 2.6 ± 6.0% for Int(100) and 4.0 ± 4.6%, -3.5 ± 5.4% for Con during TT(up) and TT(flat), respectively. PO was significantly higher during TT(up) than TT(flat) (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.

Step activity monitoring to assess ambulation before and after total ankle arthroplasty

The study objective was to compare walking activity before and after total ankle arthroplasty (TAA). Nineteen patients who underwent TAA were prospectively reviewed with a dedicated ambulatory activity-monitoring device. Patients were tested 1 month prior to surgery, and at least 18 months post-operative. Ambulatory parameters included number of steps at different cadences and time spent walking at different paces. The American Orthopaedic Foot and Ankle (AOFAS) hindfoot scale was assessed at similar intervals. Following TAA, there was significant improvement in the number of steps walked at normal cadence, while importantly the number of steps walked at low and medium cadence decreased. There was no significant difference between the time actually spent walking at any cadence after arthroplasty. The mean AOFAS hindfoot scale significantly improved. Following TAA, patients show an improved walking pace and AOFAS hindfoot scale, but no difference in the amount of time spent walking.

Comparing Low vs. High Cadence during Sustained Power on the Cycle Ergometer

In cycling performance, concerns remain pertaining to proper cadence vs. power output. Metabolic measurements through gas analysis and blood lactate have addressed some of these concerns. However, cardiovascular measures, specifically work of the heart (WH) have not been addressed. PURPOSE: the aim of this study was to compare cardiovascular parameters between differing cadence and tension settings during equal sustained power output. METHODS: Nine (n=9) subjects participated. After signing a University approved IRB, medical-health and PAR-Q fitness readiness questionnaire, they were randomly assigned to one of two protocols. Pre-test measures included heart rate (HR, b*min.-1), blood pressure (SBP, DBP, mmHg), height (cm), weight (kg) and age (y). Bicycle ergometer (MonarkTM) adjustments were consistent across subjects and maintained for the second test. Protocol 1(low cadence, LC) consisted of a five (5) minute warm-up followed by sustaining a power output of 150 watts at 50 RPM cadence at 900 kgm for 20 minutes. Protocol 2 (high cadence, HC) followed the same warm-up procedure and sustained power (150 watts) utilizing a cadence of 100 RPM at 450 kgm for 20 minutes. Measures taken minute-by-minute during the sustained 20 minute period were the following: HR (Polar TM), SBP/DBP (sphygmomanometer, stethoscope), and rate pressure product (WH) from the calculation; (HR*SBP)*100-1. Statistical procedures included means (SD) of group measures. Comparison between protocols was determined with a dependent samples T-test. Significance was set at p < 0.05. RESULTS: Subject demographics were the following: age, 36 (13.6) y; height, 157.8 (10) cm; weight, 80.9 (13.9). Between test differences were statistically significant between average HR for 20 minutes of sustained work, LC HR=131.5 (3.2) vs. HC HR=149.3 (7.3). SBP was not different between protocols. However, WH was significantly greater in the HC group vs. the LC group at, 244.1 (23.7) vs. 208.1 (11.5) respectively. CONCLUSION: LC allowed for lower HR and WH when compared to HC with both groups sustaining the same power (150 watts) over a 20 minute time period. SBP was not different between protocols. This indicates similar vascular response between groups and a greater myocardial stress associated with high cadence work.

Effect of isokinetic cycling versus weight training on maximal power output and endurance performance in cycling

The aim of this study was to compare the effects of a weight training program for the leg extensors with isokinetic cycling training (80 rpm) on maximal power output and endurance performance. Both strength training interventions were incorporated twice a week in a similar endurance training program of 12 weeks. Eighteen trained male cyclists (VO(2peak) 60 +/- 1 ml kg(-1) min(-1)) were grouped into the weight training (WT n = 9) or the isokinetic training group (IT n = 9) matched for training background and sprint power (P (max)), assessed from five maximal sprints (5 s) on an isokinetic bicycle ergometer at cadences between 40 and 120 rpm. Crank torque was measured (1 kHz) to determine the torque distribution during pedaling. Endurance performance was evaluated by measuring power, heart rate and lactate during a graded exercise test to exhaustion and a 30-min performance test. All tests were performed on subjects' individual race bicycle. Knee extension torque was evaluated isometrically at 115 degrees knee angle and dynamically at 200 degrees s(-1) using an isokinetic dynamometer. P (max) at 40 rpm increased in both the groups (~15%; P < 0.05). At 120 rpm, no improvement of P (max) was found in the IT training group, which was possibly related to an observed change in crank torque at high cadences (P < 0.05). Both groups improved their power output in the 30-min performance test (P < 0.05). Isometric knee extension torque increased only in WT (P < 0.05). In conclusion, at low cadences, P (max) improved in both training groups. However, in the IT training group, a disturbed pedaling technique compromises an improvement of P (max) at high cadences.

Influence of crank length on cycle ergometry performance of well-trained female cross-country mountain bike athletes

The aim of this study was to determine the differential effects of three commonly used crank lengths (170, 172.5 and 175 mm) on performance measures relevant to female cross-country mountain bike athletes (n = 7) of similar stature. All trials were performed in a single blind and balanced order with a 5- to 7-day period between trials. Both saddle height and fore-aft position to pedal axle distance at a crank angle of 90 degrees was controlled across all trials. The laboratory tests comprised a supra-maximal (peak power-cadence); an isokinetic (50 rpm) test; and a maximal test of aerobic capacity. The time to reach supra-maximal peak power was significantly (P < 0.05) shorter in the 170 mm (2.57 +/- 0.79 s) condition compared to 175 mm (3.29 +/- 0.76 s). This effect represented a mean performance advantage of 27.8% for 170 mm compared to 175 mm. There was no further inter-condition differences between performance outcome measurements derived for the isokinetic (50 rpm) maximum power output, isokinetic (50 rpm) mean power output or indices of endurance performance. The decreased time to peak power with the greater rate of power development in the 170 mm condition suggests a race advantage may be achieved using a shorter crank length than commonly observed. Additionally, there was no impediment to either power output produced at low cadences or indices of endurance performance using the shorter crank length and the advantage of being able to respond quickly to a change in terrain could be of strategic importance to elite athletes.

Effects of Low- vs. High-Cadence Interval Training on Cycling Performance

High-resistance interval training produces substantial gains in sprint and endurance performance of cyclists in the competitive phase of a season. Here, we report the effect of changing the cadence of the intervals. We randomized 18 road cyclists to 2 groups for 4 weeks of training. Both groups replaced part of their usual training with 8 30-minute sessions consisting of sets of explosive single-leg jumps alternating with sets of high-intensity cycling sprints performed at either low cadence (60-70 min(-1)) or high cadence (110-120 min(-1)) on a training ergometer. Testosterone concentration was assayed in saliva samples collected before and after each session. Cycle ergometry before and after the intervention provided measures of performance (mean power in a 60-s time trial, incremental peak power, 4-mM lactate power) and physiologic indices of endurance performance (maximum oxygen uptake, exercise economy, fractional utilization of maximum oxygen uptake). Testosterone concentration in each session increased by 97% +/- 39% (mean +/- between-subject SD) in the low-cadence group but by only 62% +/- 23% in the high-cadence group. Performance in the low-cadence group improved more than in the high-cadence group, with mean differences of 2.5% (90% confidence limits, +/-4.8%) for 60-second mean power, 3.6% (+/-3.7%) for peak power, and 7.0% (+/-5.9%) for 4-mM lactate power. Maximum oxygen uptake showed a corresponding mean difference of 3.2% (+/-4.2%), but differences for other physiologic indices were unclear. Correlations between changes in performance and physiology were also unclear. Low-cadence interval training is probably more effective than high-cadence training in improving performance of well-trained competitive cyclists. The effects on performance may be related to training-associated effects on testosterone and to effects on maximum oxygen uptake.

“EXTREME ULTRAVIOLET WAVES” ARE WAVES: FIRST QUADRATURE OBSERVATIONS OF AN EXTREME ULTRAVIOLET WAVE FROM STEREO

The nature of CME-associated low corona propagating disturbances, 'EUV waves', has been controversial since their discovery by EIT on \textit{SOHO}. The low cadence, single viewpoint EUV images and the lack of simultaneous inner corona white light observations has hindered the resolution of the debate on whether they are true waves or just projections of the expanding CME. The operation of the twin EUV imagers and inner corona coronagraphs aboard \textsl{STEREO} has improved the situation dramatically. During early 2009, the \textsl{STEREO} Ahead (STA) and Behind (STB) spacecraft observed the Sun in quadrature having an $\approx 90^\circ$ angular separation. An EUV wave and CME erupted from active region 11012, on February 13, when the region was exactly at the limb for STA and hence at disk center for STB. The \textit{STEREO} observations capture the development of a CME and its accompanying EUV wave not only with high cadence but also in quadrature. The resulting unprecentented dataset allowed us to separate the CME structures from the EUV wave signatures and to determine without doubt the true nature of the wave. It is a fast-mode MHD wave after all!

Robustness of a 3 min all‐out cycling test to manipulations of power profile and cadence in humans

The purpose of this study was to assess whether end-test power output (EP, synonymous with 'critical power') and the work done above EP (WEP) during a 3 min all-out cycling test against a fixed resistance were affected by the manipulation of cadence or pacing. Nine subjects performed a ramp test followed, in random order, by three cadence trials (in which flywheel resistance was manipulated to achieve end-test cadences which varied by approximately 20 r.p.m.) and two pacing trials (30 s at 100 or 130% of maximal ramp test power, followed by 2.5 min all-out effort against standard resistance). End-test power output was calculated as the mean power output over the final 30 s and the WEP as the power-time integral over 180 s for each trial. End-test power output was unaffected by reducing cadence below that of the 'standard test' but was reduced by approximately 10 W on the adoption of a higher cadence [244 +/- 41 W for high cadence (at an end-test cadence of 95 +/- 7 r.p.m.), 254 +/- 40 W for the standard test (at 88 +/- 6 r.p.m.) and 251 +/- 38 W for low cadence (at 77 +/- 5 r.p.m.)]. Pacing over the initial 30 s of the test had no effect on the EP or WEP estimates in comparison with the standard trial. The WEP was significantly higher in the low cadence trial (16.2 +/- 4.4 kJ) and lower in the high cadence trial (12.9 +/- 3.6 kJ) than in the standard test (14.2 +/- 3.7 kJ). Thus, EP is robust to the manipulation of power profile but is reduced by adopting cadences higher than 'standard'. While the WEP is robust to initial pacing applied, it is sensitive to even relatively minor changes in cadence.

Cadência de pedalada no ciclismo: uma revisão de literatura

After decades of studies and innumerable quarrels, there is not still a consensus on the optimal pedaling rate in the cycling. The present study aimed to review systematically the scientific studies that investigated the mechanical efficiency through the pedaling rates in cycling. Such experiments have demonstrated that diverse factors could be capable to modify the optimal pedaling preferred rate and pedaling efficiency as well. The conclusive point of literature defines the low pedaling cadences as more economic and efficient that the high ones. The ideal cadence for the majority of the practitioners is generally lower than the cadence preferred by the trained cyclists.

The Force–Velocity Relationship of Paralyzed Quadriceps Muscles During Functional Electrical Stimulation Cycling

Objectives. To investigate the nature of the force-velocity relationship on muscle forces and power outputs during functional electrical stimulation (FES)-evoked cycling at different pedaling cadences. Materials and Methods. Ten patients with T4-T9 spinal cord injuries (ASIA A) performed FES-evoked cycling at 50 rev/min using a motorized isokinetic ergometer for 20min, after which quadriceps crank torque and power were measured at 10, 30, and 50 rev/min. Results. Pedal cadence affected both the shape and the magnitudes of the quadriceps torque and power curves. Significantly greater average torque (T) and peak crank torques (PTi) were elicited at lower pedal cadences (T(10) >T(50) , p<0.001; PTi(10) >PTi(50) , p=0.007). Instantaneous peak power (PPi) and average power output (PO) increased significantly with pedal cadence, such that PPi(50) and PPi(30) >PPi(10) (p<0.001) and PO(50) or PO(30) >PO(10) (p<0.001). At the higher cadences, peak torque and peak power were developed at significantly later angles (p<0.001). Conclusions. The force-velocity relationship of muscle has a significant effect upon the muscle forces produced during FES-evoked cycling. However, muscle force rise times and fatigue within FES-evoked contractions, especially at a low cadence, should be considered when making comparisons between different FES-cycling cadences.

Effect of cycling position on oxygen uptake and preferred cadence in trained cyclists during hill climbing at various power outputs

Numerous researchers have studied the physiological responses to seated and standing cycling, but actual field data are sparse. One open issue is the preferred cadence of trained cyclists while hill climbing. The purpose of this study, therefore, was to examine the affect of cycling position on economy and preferred cadence in trained cyclists while they climbed a moderate grade hill at various power outputs. Eight trained cyclists (25.8 +/- 7.2 years, [Formula: see text] 68.8 +/- 5.0 ml kg(-1) min(-1), peak power 407.6 +/- 69.0 W) completed a seated and standing hill climb at approximately 50, 65 and 75% of peak power output (PPO) in the order shown, although cycling position was randomized, i.e., half the cyclists stood or remained seat on their first trial at each power output. Cyclists also performed a maximal trial unrestricted by position. Heart rate, power output, and cadence were measured continuously with a power tap; ventilation [Formula: see text], BF and cadence were significantly higher with seated climbing at all intensities; there were no other physiological differences between the climbing positions. These data support the premise that trained cyclists are equally economical using high or low cadences, but may face a limit to benefits gained with increasing cadence.

Muscle activation during cycling at different cadences: Effect of maximal strength capacity

The purpose of this study was to examine the influence of maximal strength capacity on muscle activation, during cycling, at three selected cadences: a low cadence (50 rpm), a high cadence (110 rpm) and the freely chosen cadence (FCC). Two groups of trained cyclists were selected on the basis of the different maximal isokinetic voluntary contraction values (MVCi) of their lower extremity muscles as follow: F min (lower MVCi group) and F max (higher MVCi group). All subjects performed three 4-min cycling exercises at a power output corresponding to 80% of the ventilatory threshold under the three cadences. Neuromuscular activity of vastus lateralis (VL), rectus femoris (RF) and biceps femoris (BF) was studied quantitatively (integrated electromyography, IEMG) and qualitatively (timing of muscle bursts during crank cycle). Cadence effects were observed on the EMG activity of VL muscle and on the burst onset of the BF, VL and RF muscles. A greater normalized EMG activity of VL muscle was observed for the F min group than the F max group at all cadences (respectively F min vs. F max at 50 rpm: 17 ± 5% vs. 38 ± 6%, FCC: 22 ± 7% vs. 44 ± 5% and 110 rpm: 21 ± 6% vs. 45 ± 6%). At FCC and 110 rpm, the burst onset of BF and RF muscles of the F max group started earlier in the crank cycle than the F min group These results indicate that in addition to the cadence, the maximal strength capacity influences the lower extremity muscular activity during cycling.

Power Output in Professional Cyclists during the Tour de France

Until present, workload in cycling competitions was mostly described through heart rate measurements and indirect estimation of exercise intensity. However, the most accurate variable to describe workload in cycling is to measure directly the power applied by the rider to propel his bicycle. PURPOSE: To illustrate direct power output of professional cyclist during a three-week stage race (Tour de France). METHODS: 143 Stage recordings of 15 riders of the 2005 Tour de France were monitored using a mobile power measurement device (SRM Trainingssystem, Julich, Germany), which recorded Power (W) and cadence (rpm). The studied riders were not contending for a high overall ranking but represented a broad range of skills from mountain specialists to team helpers. According to their topographic characteristics, stages were categorized into flat (7 stages/54 recordings), hilly (5/43) and mountain stages (6/46). Data was electronically processed, overall averages for power in different stage types, time in different power- and cadence bands and maximal mean power (MMP) for various durations were calculated. RESULTS: Power output averaged 218 +/− 21 W (3.1 +/− 0.3 W/kg) for flat, 234 +/−13 W (3.3 +/− 0.2W/kg) for mountain-, and 228 +/− 22 W (3.3 +/− 0.3 W/kg) for hilly stages. Mean cadence was 74 +/− 6.3 rpm for flat, 69 +/− 3.2 rpm for mountain-, and 70 +/− 5.2 rpm for hilly stages. Riders spent significantly more race time at medium- and high power output (76 % vs. 66 %) and lower cadence (56 % vs. 36 %) in mountain and hilly stages compared to flat stages. Mountain stages showed higher MMP (426 W vs. 385 W) for longer durations (1800 sec) and lower MMP (1046 W vs. 1179 W) for shorter durations (15 sec) compared to flat stages. CONCLUSION: Measurements of power output allow a direct description of the workload sustained by an athlete during cycling competition. Our data shows that different topographical characteristics of a race require distinct power output capacities with long, medium- to high intensity efforts at low cadence during mountain stages and short, high intensity power bursts during flat stages. As the presented data was obtained from riders without ambitions for a high overall ranking in the three week race, it can be speculated that riders aiming for a top overall finish display even higher average power outputs during decisive stages.

Interactions between cadence and power output effects on mechanical efficiency during sub maximal cycling exercises

The purpose of this study was to investigate the interactions between cadence and power output effects on cycling efficiency. Fourteen healthy subjects performed four constant power output-tests (40, 80, 120 and 160 W) in which the cadence varied in five bouts from 40 to 120 rpm. Gross efficiency (GE) was determined over the last ten respiratory cycles of each bout and was calculated as the ratio of mechanical energy to energy expenditure. Results showed that (1) GE-cadence relationships reached a maximum at each power output corresponding to the cadence maximising efficiency (CAeff) and (2) GE increased with power output whatever the cadence until a maximal theoretical value. Moreover, interactions were found between these two factors: the cadence effect decreased linearly with power output and the power output effect increased exponentially with cadence. Consequently, cycling efficiency decreased more when cadence differed from CAeff at low than at high power output, and increased more with power output at high cadence than at low cadence. These interactions between cadence and power output effects on GE were mainly due to cadence and power output effects on the energy expenditure shares not contributing to power production.

Effects of Altering Pedal Cadence on Cycling Time-Trial Performance

Our purpose was to examine the effects of altering cadence on 5- mile (8.045 km) time-trial (TT) performance in well-trained amateur male cyclists. Twelve cyclists (mean (SD) age: 24 (4) y; body mass: 70.9 (5.9) kg; and VO2max: 4.56 (0.52) L · min -1 ) rode three 5-mile TT. The first was at their freely chosen or preferred cadence (PC); the other two, high cadence (HC; PC + 10.8 %) and low cadence (LC; PC - 9.2%), were randomly assigned and com- pleted in a counterbalanced crossover design. Subjects rode their own bicycles, fitted with a power meter, and attached to a wind- load simulator. Practice sessions were completed 2d prior to each TT. Cadences for PC, LC, and HC were 92(2 ), 83 (6), 101 (6) rpm, respectively; they were also significantly different from each other (p < 0.05). LC was 2.5 % faster than HC and more eco- nomical than HC and PC (66 (3), 69 (2), 71 (4 W · L -1 O2 ·m in -1 , re- spectively) (p ≤ 0.05). LC heart rate and ventilatory efficiency (VE/ VO2-ratio) were lower than PC counterparts, while LC and HC mi- nute ventilation (VE) were less than PC VE (p < 0.05). LC may be the optimal cadence for 5 mile TT in well-trained amateur male cyclists because LC was the most economical, was faster than HC, resulted in the greatest proportion of fastest times (58 % vs. 25 % and 17 % for PC and HC, respectively), and elicited less cardiore- spiratory strain than PC.