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1.
Until recently, the physiological demands of cycling competitions were mostly reflected by the measurement of heart rate and the indirect estimation of exercise intensity. The purpose of this case study was to illustrate the varying power output of a professional cyclist during flat and mountain stages of a Grand Tour (Giro d'Italia). Nine stage recordings of a cyclist of the 2005 Giro d'Italia were monitored using a mobile power measurement device (SRM Trainingssystem, Julich, Germany), which recorded direct power output and heart rate. Stages were categorized into flat (n = 5) and mountain stages (n = 4). Data were processed electronically, and the overall mean power in flat and mountain stages and maximal mean power for various durations were calculated. Mean power output was 132 W +/- 26 (2.0 W x kg(-1) +/- 0.4) for the flat and 235 W +/- 10 (3.5 W x kg(-1) +/- 0.1) for the mountain stages. Mountain stages showed higher maximal mean power (367 W) for longer durations (1800 s) than flat stages (239 W). Flat stages are characterized by a large variability of power output with short bursts of high power and long periods with reduced intensity of exercise, whereas mountain stages mostly require submaximal, constant power output over longer periods.  相似文献   

2.
ABSTRACT

This study aimed to assess the relationship between an uphill time-trial (TT) performance and both aerobic and anaerobic parameters obtained from laboratory tests. Fifteen cyclists performed a Wingate anaerobic test, a graded exercise test (GXT) and a field-based 20-min TT with 2.7% mean gradient. After a 5-week non-supervised training period, 10 of them performed a second TT for analysis of pacing reproducibility. Stepwise multiple regressions demonstrated that 91% of TT mean power output variation (W kg?1) could be explained by peak oxygen uptake (ml kg?1.min?1) and the respiratory compensation point (W kg?1), with standardised beta coefficients of 0.64 and 0.39, respectively. The agreement between mean power output and power at respiratory compensation point showed a bias ± random error of 16.2 ± 51.8 W or 5.7 ± 19.7%. One-way repeated-measures analysis of variance revealed a significant effect of the time interval (123.1 ± 8.7; 97.8 ± 1.2 and 94.0 ± 7.2% of mean power output, for epochs 0–2, 2–18 and 18–20 min, respectively; P < 0.001), characterising a positive pacing profile. This study indicates that an uphill, 20-min TT-type performance is correlated to aerobic physiological GXT variables and that cyclists adopt reproducible pacing strategies when they are tested 5 weeks apart (coefficients of variation of 6.3; 1 and 4%, for 0–2, 2–18 and 18–20 min, respectively).  相似文献   

3.
ABSTRACT

Endurance athletes usually achieve performance peaks with 2–4 weeks of overload training followed by 1–3weeks of tapering. With a tight competition schedule, this may not be appropriate. This case investigates the effect of a 7-day overload period including daily high-intensity aerobic training followed by a 5-day step taper between two competitions in an elite cross-country mountain biker. Pre-test peak oxygen consumption was 89 ml·kg?1·min?1, peak aerobic power 6.8 W·kg?1, power output at 2 mmol·L?1 blood lactate concentration 3.9 W·kg?1, maximal isometric force 180 Nm and squat jump 21 cm. During overload, perceived leg well-being went from normal to very heavy. On day 1 after overload, vastus lateralis and vastus medialis EMGmean activity was reduced by 3% and 7%, respectively. Other baseline measurements were reduced by 3–7%. On day 4 of the taper, he felt that his legs were good and all measurements were 3–7% higher than before overload. On day 6 after the taper, his legs felt very good. This case shows that an elite mountain biker (11th in UCI World Cup one week prior to the pre-test) could achieve a rather large supercompensation by using a 12-day performance peaking protocol.  相似文献   

4.
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5.
Abstract

In this study, we examined the effects of a pre-acclimatization programme on endurance performance at moderate altitude using a resting intermittent hypoxia protocol. The time-trial performance of 11 cyclists was determined at low altitude (600 m). Athletes were randomly assigned in a double-blind fashion to the hypoxia or the control group. The pre-acclimatization programme consisted of seven sessions each lasting 1 h in normobaric hypoxia (inspired fraction of oxygen of 12.5%, equivalent to approximately 4500 m) for the hypoxia group (n = 6) and in normoxia (inspired fraction of oxygen of 20.9%) for the control group (n = 5). The time-trials were repeated at moderate altitude (1970 m). Mean power output during the time-trial at moderate altitude was decreased in the hypoxia group (?0.26 ± 0.11 W · kg?1) and in the control group (?0.13 ± 0.04 W · kg?1) compared with at low altitude but did not differ between groups (P = 0.13). Our results suggest that the applied protocol of intermittent hypoxia had no positive effect on endurance performance at moderate altitude. Whether different intermittent hypoxia protocols are advantageous remains to be determined.  相似文献   

6.
Abstract

The purpose of this study was to assess the power output of field-based downhill mountain biking. Seventeen trained male downhill cyclists (age 27.1 ± 5.1 years) competing nationally performed two timed runs of a measured downhill course. An SRM powermeter was used to simultaneously record power, cadence, and speed. Values were sampled at 1-s intervals. Heart rates were recorded at 5-s intervals using a Polar S710 heart rate monitor. Peak and mean power output were 834 ± 129 W and 75 ± 26 W respectively. Mean power accounted for only 9% of peak values. Paradoxically, mean heart rate was 168 ± 9 beats · min?1 (89% of age-predicted maximum heart rate). Mean cadence (27 ± 5 rev · min?1) was significantly related to speed (r = 0.51; P < 0.01). Analysis revealed an average of 38 pedal actions per run, with average pedalling periods of 5 s. Power and cadence were not significantly related to run time or any other variable. Our results support the intermittent nature of downhill mountain biking. The poor relationships between power and run time and between cadence and run time suggest they are not essential pre-requisites to downhill mountain biking performance and indicate the importance of riding dynamics to overall performance.  相似文献   

7.
Abstract

Maximal oxygen uptake ([Vdot]O2max) is considered the optimal method to assess aerobic fitness. The measurement of [Vdot]O2max, however, requires special equipment and training. Maximal exercise testing with determination of maximal power output offers a more simple approach. This study explores the relationship between [Vdot]O2max and maximal power output in 247 children (139 boys and 108 girls) aged 7.9–11.1 years. Maximal oxygen uptake was measured by indirect calorimetry during a maximal ergometer exercise test with an initial workload of 30 W and 15 W · min?1 increments. Maximal power output was also measured. A sample (n = 124) was used to calculate reference equations, which were then validated using another sample (n = 123). The linear reference equation for both sexes combined was: [Vdot]O2max (ml · min?1) = 96 + 10.6 · maximal power + 3.5 · body mass. Using this reference equation, estimated [Vdot]O2max per unit of body mass (ml · min?1 · kg?1) calculated from maximal power correlated closely with the direct measurement of [Vdot]O2max (r = 0.91, P <0.001). Bland-Altman analysis gave a mean limits of agreement of 0.2±2.9 (ml · min?1 · kg?1) (1 s). Our results suggest that maximal power output serves as a good surrogate measurement for [Vdot]O2max in population studies of children aged 8–11 years.  相似文献   

8.
This study compares test-retest reliability and peak exercise responses from ramp-incremented (RAMP) and maximal perceptually-regulated (PRETmax) exercise tests during arm crank exercise in individuals reliant on manual wheelchair propulsion (MWP). Ten untrained participants completed four trials over 2-weeks (two RAMP (0–40 W + 5–10 W · min?1) trials and two PRETmax. PRETmax consisted of five, 2-min stages performed at Ratings of Perceived Exertion (RPE) 11, 13, 15, 17 and 20). Participants freely changed the power output to match the required RPE. Gas exchange variables, heart rate, power output, RPE and affect were determined throughout trials. The V?O2peak from RAMP (14.8 ± 5.5 ml · kg?1 · min?1) and PRETmax (13.9 ± 5.2 ml · kg?1 · min?1) trials were not different (P = 0.08). Measurement error was 1.7 and 2.2 ml · kg?1 · min?1 and coefficient of variation 5.9% and 8.1% for measuring V?O2peak from RAMP and PRETmax, respectively. Affect was more positive at RPE 13 (P = 0.02), 15 (P = 0.01) and 17 (P = 0.01) during PRETmax. Findings suggest that PRETmax can be used to measure V?O2peak in participants reliant on MWP and leads to a more positive affective response compared to RAMP.  相似文献   

9.
Abstract

Power output and heart rate were monitored for 11 months in one female ([Vdot]O2max: 71.5 mL · kg?1 · min?1) and ten male ([Vdot]O2max: 66.5 ± 7.1 mL · kg?1 · min?1) cyclists using SRM power-meters to quantify power output and heart rate distributions in an attempt to assess exercise intensity and to relate training variables to performance. In total, 1802 data sets were divided into workout categories according to training goals, and power output and heart rate intensity zones were calculated. The ratio of mean power output to respiratory compensation point power output was calculated as an intensity factor for each training session and for each interval during the training sessions. Variability of power output was calculated as a coefficient of variation. There was no difference in the distribution of power output and heart rate for the total season (P = 0.15). Significant differences were observed during high-intensity workouts (P < 0.001). Performance improvements across the season were related to low-cadence strength workouts (P < 0.05). The intensity factor for intervals was related to performance (P < 0.01). The variability in power output was inversely associated with performance (P < 0.01). Better performance by cyclists was characterized by lower variability in power output and higher exercise intensities during intervals.  相似文献   

10.
Abstract

Seven 6 s sprints with 30 s recovery between sprints were performed against two resistive loads: 50 (L50) and 100 (L100) g · kg?1 body mass. Inertia-corrected and -uncorrected peak and mean power output were calculated. Corrected peak power output in corresponding sprints and the drop in peak power output relative to sprint 1 were not different in the two conditions, despite the fact that mean power output was 15–20% higher in L100 (P < 0.01). The effect of inertia correction on power output was more pronounced for the lighter load (L50), with uncorrected peak power output in sprint 1 being 42% lower than the corresponding corrected peak power output, while this was only 16% in L100. Fatigue assessed by the drop in uncorrected peak and mean power output in sprint 7 relative to sprint 1 was less compared with that obtained by corrected power values, especially in L50 (drop in uncorrected vs. corrected peak power output: 13.3 ± 2.2% vs. 23.1 ± 4.1%, P < 0.01). However, in L100, the difference between the drop in corrected and uncorrected mean power output in sprint 7 was much smaller (24.2 ± 3.1% and 21.2 ± 2.7%, P < 0.01), indicating that fatigue may be safely assessed even without inertia correction when a heavy load is used. In conclusion, when inertia correction is performed, fatigue during repeated sprints is unaffected by resistive load. When inertia correction is omitted, both power output and the fatigue profile are underestimated by an amount dependent on resistive load. In cases where inertia correction is not possible during a repeated sprints test, a heavy load may be preferable.  相似文献   

11.
This study examined if short-duration record power outputs can be predicted with the Anaerobic Power Reserve (APR) model in professional cyclists using a field-based approach. Additionally, we evaluated if modified model parameters could improve predictive ability of the model. Twelve professional cyclists (V?O2max 75 ± 6 ml?kg?1?min?1) participated in this investigation. Using the mean power output during the last stage of an incremental field test, sprint peak power output and an exponential constant describing the decrement in power output over time, a power-duration relationship was established for each participant. Record power outputs of different durations (5 to 180 s) were collected from training and competition data and compared to the predicted power output from the APR model. The originally proposed exponent (k = 0.026) predicted performance within an average of 43 W (Standard Error of Estimate (SEE) of 32 W) and 5.9%. Modified model parameters slightly improved predictive ability to a mean of 34–39 W (SEE of 29 – 35 W) and 4.1 – 5.3%. This study shows that a single exponent model generally fits well with the decrement in power output over time in professional cyclists. Modified model parameters may contribute to improving predictability of the model.  相似文献   

12.
ABSTRACT

The present study aimed to provide reference values for lower-limb muscle power assessed during the incremental jump squat (JS) test in elite athletes (i.e., professional athletes competing at international level). We pooled data from all JS tests performed by elite athletes of different sports in two high-performance centres between 2015 and 2019, and computed reference values (i.e., terciles) for mean power (MP), mean propulsive power (MPP), and peak power (PP). Reference values were obtained from 684 elite athletes (458 male and 226 female) of 16 different sports (boxing, judo, karate, fencing, taekwondo, wrestling, basketball, soccer, futsal, handball, rugby union, badminton, tennis, long distance running, triathlon, and sprinting). Significant differences (p < 0.001) were found between male and female athletes for MP (7.47 ± 1.93 and 6.15 ± 1.68 W·Kg?1, respectively), MPP (10.50 ± 2.75 and 8.63 ± 2.43 W·Kg?1), and PP (23.64 ± 6.12 and 19.35 ± 5.49 W·Kg?1). However, the velocity at which these power measures was attained seemed to be independent of sex (~0.95, 1.00 and 2.00 m·s?1 for mean, mean propulsive, and peak velocity, respectively) and homogeneous across different sport disciplines (coefficient of variation <10%). These data can be used to classify athletes’ power capabilities, and the optimum velocity ranges provided here could be useful for training purposes.  相似文献   

13.
This study aims to describe the intensity and load demands of different stage types within a cycling Grand Tour. Nine professional cyclists, whom are all part of the same World-Tour professional cycling team, participated in this investigation. Competition data were collected during the 2016 Giro d’Italia. Stages within the Grand Tour were classified into four categories: flat stages (FLAT), semi-mountainous stages (SMT), mountain stages (MT) and individual time trials (TT). Exercise intensity, measured with different heart rate and power output based variables, was highest in the TT compared to other stage types. During TT’s the main proportion of time was spent at the high-intensity zone, whilst the main proportion of time was spent at low intensity for the mass start stage types (FLAT, SMT, MT). Exercise load, quantified using Training Stress Score and Training Impulse, was highest in the mass start stage types with exercise load being highest in MT (329, 359?AU) followed by SMT (280, 311?AU) and FLAT (217, 298?AU). Substantial between-stage type differences were observed in maximal mean power outputs over different durations. FLAT and SMT were characterised by higher short-duration maximal power outputs (5–30?s for FLAT, 30 s–2?min for SMT) whilst TT and MT are characterised by high longer duration maximal power outputs (>10?min). The results of this study contribute to the growing body of evidence on the physical demands of stage types within a cycling Grand Tour.  相似文献   

14.
There is currently a dearth of information describing cycling performance outside of propulsive and physiological variables. The aim of the present study was to utilise a brake power meter to quantify braking during a multi-lap cross-country mountain bike time trial and to determine how braking affects performance. A significant negative association was determined between lap time and brake power (800.8 ± 216.4 W, mean ± SD; r = ?0.446; p < 0.05), while the time spent braking (28.0 ± 6.4 s) was positively associated with lap time (314.3 ± 37.9 s; r = 0.477; p < 0.05). Despite propulsive power decreasing after the first lap (p < 0.05), lap time remained unchanged (p > 0.05) which was attributed to decreased brake work (p < 0.05) and brake time (p < 0.05) in both the front and rear brakes by the final lap. A multiple regression model incorporating braking and propulsion was able to explain more of the variance in lap time (r2 = 0.935) than propulsion alone (r2 = 0.826). The present study highlights that riders’ braking contributes to mountain bike performance. As riders repeat a cross-country mountain bike track, they are able to change braking, which in turn can counterbalance a reduction in power output. Further research is required to understand braking better.  相似文献   

15.
Abstract

The goal of this study was to investigate the effects of different durations of skin temperature manipulation on pacing patterns and performance during a 15-km cycling time trial. Nineteen well-trained men completed three 15-km cycling time trials in 18°C and 50% relative humidity with 4.5-km (short-heat), 9.0-km (long-heat) or without (control) radiant heat exposure applied by infrared heaters after 1.5 km in the time trial. During the time trials, power output, mean skin temperature, rectal temperature, heart rate and rating of perceived exertion were assessed. The radiant heat exposure resulted in higher mean skin temperature during the time trial for short-heat (35.0 ± 0.6°C) and long-heat (35.3 ± 0.5°C) than for control (32.5 ± 1.0°C; P < 0.001), whereas rectal temperature was similar (P = 0.55). The mean power output was less for short-heat (273 ± 8 W; P = 0.001) and long-heat (271 ± 9 W; P = 0.02) than for control (287 ± 7 W), but pacing patterns did not differ (P = 0.55). Heart rate was greatest in control (177 ± 9 beats · min?1; P < 0.001), whereas the rating of perceived exertion remained similar. We concluded that a radiant heat exposure and associated higher skin temperature reduced overall performance, but did not modify pacing pattern during a 15-km cycling time trial, regardless of the duration of the exposure.  相似文献   

16.
Abstract

This study investigated the interaction between emotion-eliciting pictures and power output during a repetitive supra-maximal task on a cycle ergometre. Twelve male participants (mean (±SD) age, height and weight: 28.58 ± 3.23 years, 1.78 ± 0.05 m and 82.41 ± 13.29 kg) performed 5 repeated sprint tests on a cycle ergometre in front of neutral, pleasant or unpleasant pictures. For each sprint, mechanical (peak power and work), physiological (heart rate) and perceptual (affective load) indices were analysed. Affective load was calculated from the ratings of perceived exertion, which reflected the amount of pleasant and unpleasant responses experienced during exercise. The results showed that peak power, work and heart rate values were significantly lower (P < 0.05) for unpleasant pictures (9.18 ± 0.20 W ? kg?1; 47.69 ± 1.08 J ? kg?1; 152 ± 4 bpm) when compared with pleasant ones (9.50 ± 0.20 W ? kg?1; 50.11 ± 0.11 J ? kg?1; 156 ± 3 bpm). Furthermore, the affective load was found to be similar for the pleasant and unpleasant sessions. All together, these results suggested that the ability to produce maximal power output depended on whether the emotional context was pleasant or unpleasant. The fact that the power output was lower in the unpleasant versus pleasant session could reflect a regulatory process aimed at maintaining a similar level of affective load for both sessions.  相似文献   

17.
The purpose of this study was to ascertain the typical metabolic power characteristics of elite men’s hockey, and whether changes occur within matches and throughout an international tournament. National team players (n = 16), divided into 3 positional groups (strikers, midfielders, defenders), wore Global Positioning System devices in 6 matches. Energetic (metabolic power, energy expenditure) and displacement (distance, speed, acceleration) variables were determined, and intensity was classified utilising speed, acceleration and metabolic power thresholds. Midfielder’s average metabolic power (11.8 ± 1.0 W · kg?1) was similar to strikers (11.1 ± 1.3 W · kg?1) and higher than defenders (10.8 ± 1.2 W · kg?1, P = 0.001). Strikers (29.71 ± 3.39 kJ · kg?1) expended less energy than midfielders (32.18 ± 2.67 kJ · kg?1, P = 0.014) and defenders (33.23 ± 3.96 kJ · kg?1, P < 0.001). Energetic variables did not change between halves or across matches. Across all positions, over 45% of energy expenditure was at high intensity (>20 W · kg?1). International hockey matches are intense and highly intermittent; however, intensity is maintained throughout matches and over a tournament. In isolation, displacement measures underestimate the amount of high-intensity activity, whereas the integration of instantaneous speed and acceleration provides a more comprehensive assessment of the demands for variable-speed activity typically occurring in hockey matches.  相似文献   

18.
Real-world cycling performance depends not only on exercise capacities, but also on efficiently traversing the bicycle through the terrain. The aim of this study was to determine if it was possible to quantify the braking done by a cyclist in the field. One cyclist performed 408 braking trials (348 on a flat road; 60 on a flat dirt path) over 5 days on a bicycle fitted with brake torque and angular velocity sensors to measure brake power. Based on Newtonian physics, the sum of brake work, aerodynamic drag and rolling resistance was compared with the change in kinetic energy in each braking event. Strong linear relationships between the total energy removed from the bicycle-rider system through braking and the change in kinetic energy were observed on the tar-sealed road (r2 = 0.989; p < 0.0001) and the dirt path (r2 = 0.952; p < 0.0001). T-tests revealed no difference between the total energy removed and the change in kinetic energy on the road (p = 0.715) or dirt (p = 0.128). This study highlights that brake torque and angular velocity sensors are valid for calculating brake power on the disc brakes of a bicycle in field conditions. Such a device may be useful for investigating cyclists’ ability to traverse through various terrains.  相似文献   

19.
This study evaluated the changes in ratios of different intensity (rating of perceived exertion; RPE, heart rate; HR, power output; PO) and load measures (session-RPE; sRPE, individualized TRIMP; iTRIMP, Training Stress Score?; TSS) in professional cyclists. RPE, PO and HR data was collected from twelve professional cyclists (VO2max 75 ± 6 ml?min?kg?1) during a two-week baseline training period and during two cycling Grand Tours. Subjective:objective intensity (RPE:HR, RPE:PO) and load (sRPE:iTRIMP, sRPE:TSS) ratios and external:internal intensity (PO:HR) and load (TSS:iTRIMP) ratios were calculated for every session. Moderate to large increases in the RPE:HR, RPE:PO and sRPE:TSS ratios (d = 0.79–1.79) and small increases in the PO:HR and sRPE:iTRIMP ratio (d = 0.21–0.41) were observed during Grand Tours compared to baseline training data. Differences in the TSS:iTRIMP ratio were trivial to small (d = 0.03–0.27). Small to moderate week-to-week changes (d = 0.21–0.63) in the PO:HR, RPE:PO, RPE:HR, TSS:iTRIMP, sRPE:iTRIMP and sRPE:TSS were observed during the Grand Tour. Concluding, this study shows the value of using ratios of intensity and load measures in monitoring cyclists. Increases in ratios could reflect progressive fatigue that is not readily detected by changes in solitary intensity/load measures.  相似文献   

20.
The aim of this current randomised controlled trial was to evaluate the effects of a home-based physical activity (PA) intervention on cardiorespiratory fitness in breast cancer survivors. Thirty-two post-adjuvant therapy breast cancer survivors (age = 52 ± 10 years; BMI = 27.2 ± 4.4 kg?m2) were randomised to a six-month home-based PA intervention with face-to-face and telephone PA counselling or usual care. Cardiorespiratory fitness and self-reported PA were assessed at baseline and at six-months. Participants had a mean relative V?O2max of 25.3 ± 4.7 ml?kg?1?min?1, which is categorised as “poor” according to age and gender matched normative values. Magnitude-based inference analyses revealed likely at least small beneficial effects (effect sizes ≥.20) on absolute and relative V?O2 max (d = .44 and .40, respectively), and total and moderate PA (d = .73 and .59, respectively) in the intervention compared to the usual care group. We found no likely beneficial improvements in any other outcome. Our home-based PA intervention led to likely beneficial, albeit modest, increases in cardiorespiratory fitness and self-reported PA in breast cancer survivors. This intervention has the potential for widespread implementation and adoption, which could considerably impact on post-treatment recovery in this population.  相似文献   

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