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1.
The pre-event warm-up or “priming” routine for optimising cycling performance is not well-defined or uniform to a specific event. We aimed to determine the effects of varying the intensity of priming on 3 km cycling performance. Ten endurance-trained male cyclists completed four 3 km time-trials (TT) on four separate occasions, each preceded by a different priming strategy including “self-selected” priming and three intermittent priming strategies incorporating 10 min of constant-load cycling followed by 5 × 10 s bouts of varying relative intensity (100% and 150% of peak aerobic power, Wpeak, and all-out priming). The self-selected priming trial (379 ± 44 W) resulted in similar mean power during the 3 km TT to intermittent priming at 100% (376 ± 45 W; ?0.7%; unclear) and 150% (374 ± 48 W; ?1.5%, unclear) of Wpeak, but significantly greater than all-out priming (357 ± 45 W; ?5.8%, almost certainly harmful). Differences between intermittent and self-selected priming existed with regards to heart rate (6.2% to 11.5%), blood lactate (?22.9% to 125%) and VO2 kinetics (?22.9% to 8.2%), but these were not related to performance outcomes. In conclusion, prescribed intermittent priming strategies varying in intensity did not substantially improve 3 km TT performance compared to self-selected priming.  相似文献   

2.
This study tested the hypothesis that ischemic preconditioning (IPC) would increase critical power (CP) during a 3 minute all-out cycling test. Twelve males completed two 3 minute all-out cycling tests, in a crossover design, separated by 7 days. These tests were preceded by IPC (4 x 5 minute intervals at 220 mmHg bilateral leg occlusion) or SHAM treatment (4 x 5 minute intervals at 20 mmHg bilateral leg occlusion). CP was calculated as the mean power output during the final 30 s of the 3 minute test with W′ taken as the total work done above CP. Muscle oxygenation was measured throughout the exercise period. There was a 15.3 ± 0.3% decrease in muscle oxygenation (TSI; [Tissue saturation index]) during the IPC stimulus, relative to SHAM. CP was significantly increased (241 ± 65 W vs. 234 ± 67 W), whereas W′ (18.4 ± 3.8 vs 17.9 ± 3.7 kJ) and total work done (TWD) were not different (61.1 ± 12.7 vs 60.8 ± 12.7 kJ), between the IPC and SHAM trials. IPC enhanced CP during a 3 minute all-out cycling test without impacting W′ or TWD. The improved CP after IPC might contribute towards the effect of IPC on endurance performance.  相似文献   

3.
Abstract

We examined the effect of one high-intensity cycling workout on aerobic capacity (VO2max), peak cycling power, and estimated change in plasma volume on subsequent days. Eight healthy males (age=29.5±5.3 years, height=1.81±0.09 m, mass=81.5±7.5 kg) visited the laboratory on three occasions. The first visit (D1) included baseline measures of cycling VO2max, haematocrit, and haemoglobin. Following a brief rest, the participants performed a high-intensity cycling workout of six 30-s cycling intervals (modelled on the Wingate cycle test) with each repetition separated by 3 min rest. The final two visits (D2 and D3) included identical measures as the first visit and occurred 48 and 96 h after the interval workout. No significant differences were found for VO2max (53.4±5.3, 53.7±6.7, and 53.7±6.2 ml · kg?1 · min?1), peak power (386±35, 384±35, and 389±35 W) or estimated change in plasma volume [?0.8±8.5% (D1–D2), 1.5±11.5% (D2–D3), and ?1.6±9.6% (D1–D3)] between any of the three test days. Our results show that one short-term high-intensity cycling workout does not alter VO2max, peak power or estimated change in plasma volume on subsequent days, and is therefore unlikely to benefit or hinder performance.  相似文献   

4.
This study investigated the effect cadence has on the estimation of critical power (CP) and the finite work capacity (W?) during the 3-minute all-out cycling test. Ten participants completed 8 tests: 1) an incremental test to calculate gas exchange threshold (GET), maximal aerobic power (MAP) and peak oxygen uptake (V?O2peak), 2–4) three time-to-exhaustion tests at 80, 100 and 105% MAP to calculate CP and W?, 5–7) four 3-minute all-out tests to calculate end power (EP) and work done above EP (WEP) using cadences ranging from preferred ?5 to preferred +10 rev·min?1 to set the fixed resistance. Significant differences were seen between CP and EP-preferred (267.5 ± 22.6 W vs. 296.6 ± 26.1 W, P < 0.001), CP and EP?5 (267.5 ± 22.6 W vs. 303.6 ± 24.0 W, P < 0.001) and between CP and EP+5 (267.5 ± 22.6 W vs. 290.0 ± 28.0 W, P = 0.002). No significant differences were seen between CP and EP+10 (267.5 ± 22.6 W vs. 278.1 ± 30.9 W, P = 0.331). Significant differences were seen between W? and WEP at all tested fixed resistances. EP is reduced when cycling at higher than preferred cadences, providing better estimates of CP.  相似文献   

5.
Abstract

There is little published data in relation to the effects of caffeine upon cycling performance, speed and power in trained cyclists, especially during cycling of ～60 s duration. To address this, eight trained cyclists performed a 1 km time-trial on an electronically braked cycle ergometer under three conditions: after ingestion of 5 mg · kg?1 caffeine, after ingestion of a placebo, or a control condition. The three time-trials were performed in a randomized order and performance time, mean speed, mean power and peak power were determined. Caffeine ingestion resulted in improved performance time (caffeine vs. placebo vs. control: 71.1 ± 2.0 vs. 73.4 ± 2.3 vs. 73.3 ± 2.7 s; P = 0.02; mean ± s). This change represented a 3.1% (95% confidence interval: 0.7–5.6) improvement compared with the placebo condition. Mean speed was also higher in the caffeine than placebo and control conditions (caffeine vs. placebo vs. control: 50.7 ± 1.4 vs. 49.1 ± 1.5 vs. 49.2 ± 1.7 km · h?1; P = 0.0005). Mean power increased after caffeine ingestion (caffeine vs. placebo vs. control: 523 ± 43 vs. 505 ± 46 vs. 504 ± 38 W; P = 0.007). Peak power also increased from 864 ± 107 W (placebo) and 830 ± 87 W (control) to 940 ± 83 W after caffeine ingestion (P = 0.027). These results provide support for previous research that found improved performance after caffeine ingestion during short-duration high-intensity exercise. The magnitude of the improvements observed in our study could be due to our use of sport-specific ergometry, a tablet form and trained participants.  相似文献   

6.
Abstract

Mechanical models of cycling time-trial performance have indicated adverse effects of variations in external power output on overall performance times. Nevertheless, the precise influences of the magnitude and number of these variations over different distances of time trial are unclear. A hypothetical cyclist (body mass 70 kg, bicycle mass 10 kg) was studied using a mathematical model of cycling, which included the effects of acceleration. Performance times were modelled over distances of 4–40 km, mean power outputs of 200–600 W, power variation amplitudes of 5–15% and variation frequencies of 2–32 per time-trial. Effects of a “fast-start” strategy were compared with those of a constant-power strategy. Varying power improved 4-km performance at all power outputs, with the greatest improvement being 0.90 s for ± 15% power variation. For distances of 16.1, 20 and 40 km, varying power by ± 15% increased times by 3.29, 4.46 and 10.43 s respectively, suggesting that in long-duration cycling in constant environmental conditions, cyclists should strive to reduce power variation to maximise performance. The novel finding of the present study is that these effects are augmented with increasing event distance, amplitude and period of variation. These two latter factors reflect a poor adherence to a constant speed.  相似文献   

7.
Abstract

The purpose of this study was to assess the agreement between two mobile cycle ergometer systems for recording high-intensity, intermittent power output. Twelve trained male cyclists (age 31.4 ± 9.8 years) performed a single 3 min intermittent cycle test consisting of 12 all-out efforts, separated by periods of passive recovery ranging from 5 to 15 s. Power output was recorded using a Polar S710 heart rate monitor and power sensor kit and an SRM Powercrank system for each test. The SRM used torque and angular velocity to calculate power, while the S710 used chain speed and vibration to calculate power. Significant differences (P < 0.05) in power were found at 8 of the 12 efforts. A significant difference (P = 0.001) was also found when power was averaged over all 12 intervals. Mean power was 556 ± 102 W and 446 ± 61 W for the SRM and S710 respectively. The S710 underestimated power by an average of 23% with random errors of ?/÷ 24% when compared with the SRM. Random errors ranged from 36% to 141% with a median of 51%. The results indicate there was little agreement between the two systems and that the Polar S710 did not provide a valid measure of power during intermittent cycling activity when compared with the SRM. Power recorded by the S710 system was influenced greatly by chain vibration and sampling rates.  相似文献   

8.
This study compared the effects of six warm-up modalities on peak power output (PPO) during the high-pull exercise. Nine resistance-trained males completed six trials using different warm-ups: high-pull specific (HPS), cycle, whole body vibration (WBV), cycle+HPS, WBV+HPS and a control. Intramuscular temperature (Tm) was increased by 2°C using WBV or cycling. PPO, Tm and electromyography (EMG) were recorded during each trial. Two high-pulls were performed prior to and 3 min after participants completed the warm-up. The greatest increase in PPO occurred with HPS (232.8 ± 89.7 W, P < 0.001); however, this was not different to combined warm-ups (cycle+HPS 158.6 ± 121.1 W; WBV+HPS 177.3 ± 93.3 W, P = 1.00). These modalities increased PPO to a greater extent than those that did not involve HPS (all P < 0.05). HPS took the shortest time to complete, compared to the other conditions (P < 0.05). EMG did not differ from pre to post warm-up or between modalities in any of the muscles investigated. No change in Tm occurred in warm-ups that did not include cycling or WBV. These results suggest that a movement-specific warm-up improves performance more than temperature-related warm-ups. Therefore, mechanisms other than increased muscle temperature and activation may be important for improving short-term PPO.  相似文献   

9.
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   

10.
ABSTRACT

We aimed to determine key biomechanical parameters explaining age-related jumping performance differences in youth elite female soccer players. Multiple biomechanical parameters from countermovement (CMJ) squat (SJ) and drop (DJ) jump testing of elite female soccer players (n = 60) within the same national training centre were analysed across ages 9-11y, 12-14y and 15-19y. Effects of age group and jump type on jump height were found, with the older jumping higher than the younger groups in all jumps (P < 0.05). For DJ, higher reactive strength index was found for older, compared to each younger group (P < 0.001). For CMJ and SJ, peak power was the most decisive characteristic, with significant differences between each group for absolute peak power (P < 0.0001) and body-weight-normalised peak power in CMJ (57 ± 7W/kg, 50 ± 7W/kg, 44.7 ± 5.5W/kg; P < 0.05) and between the older and each younger group in SJ (56.7 ± 7.1W/kg, 48.9 ± 7.1W/kg, 44.6 ± 6W/kg; P < 0.01). Age-related differences in jumping performance in youth elite female soccer players appear to be due to power production during standing jumps and by the ability to jump with shorter ground contact times during reactive jumps.  相似文献   

11.
This study investigated the effects of aerobic exercise, fluid loss and rehydration on cognitive performance in well-trained athletes. Ten endurance-trained males (25 ± 5 years; 175 ± 5 cm; 70.35 ± 5.46 kg; VO2max, 62.95 ± 7.20 ml · kg.min?1) lost ~2.5 ± 0.6% body mass via continuous cycling exercise at ~65% peak sustainable power output (60 min duration) before consuming different beverages (Water = W1 and W2, Sustagen Sport = SS, Powerade = PD) and food ad libitum on four separate occasions. Cognitive function using a four-choice reaction time task (CRT), body mass, fluid consumption volumes, urine samples and subjective ratings (alertness, concentration, energy) were obtained before and after exercise, and hourly during recovery (for 4 h). CRT latency was significantly reduced immediately after exercise compared to pre-exercise measures for all trials (W1 = ?16 ± 18 ms, W2 = ?22 ± 21 ms, PD = ?22 ± 22 ms, SS = ?19 ± 26 ms). However, this effect was short-lived with subsequent measures not different from pre-exercise values. No difference in CRT accuracy was observed at any time across all trials. Subjective ratings were not different at any time across all trials. Aerobic exercise, hypohydration or an interaction between these two may provide a small cognitive performance benefit. However, these effects are temporary and confined to the immediate post-exercise period.  相似文献   

12.
Time-to-exhaustion (TTE) trials are used in a laboratory setting to measure endurance performance. However, there is some concern with their ecological validity compared with time-trials (TT). Consequently, we aimed to compare cycling performance in TTE and TT where the duration of the trials was matched. Seventeen trained male cyclists completed three TTE trials at 80, 100 and 105% of maximal aerobic power (MAP). On a subsequent visit they performed three TT over the same duration as the TTE. Participants were blinded to elapsed time, power output, cadence and heart rate (HR). Average TTE was 865 ± 345 s, 165 ± 98 s and 117 ± 45 s for the 80, 100 and 105% trials respectively. Average power output was higher for TTE (294 ± 44 W) compared to TT (282 ± 43 W) at 80% MAP (P < 0.01), but not at 100 and 105% MAP (P > 0.05). There was no difference in cadence, HR, or RPE for any trial (P > 0.05). Critical power (CP) was also higher when derived from TTE compared to TT (P < 0.01). It is concluded that TTE results in a higher average power output compared to TT at 80% MAP. When determining CP, TTE rather than TT protocols appear superior.  相似文献   

13.
Altering torsional stiffness of cycling shoe soles may be a novel approach to reducing knee joint moments and overuse injuries during cycling. We set out to determine if the magnitude of three-dimensional knee moments were different between cycling shoe soles with different torsional stiffnesses. Eight trained male cyclists cycled at 90% lactate threshold power output in one of two cycling shoe conditions in a randomized crossover design. The shoe sole was considered torsionally flexible (FLEX) compared to a relatively stiffer (STIFF) sole. Gross efficiency (GE) and knee joint moments were quantified. No significant effect of shoe condition was seen in GE (21.4 ± 1.1% and 20.9 ± 1.6% for FLEX and STIFF, respectively, P = 0.12), nor in three-dimensional knee moments. 4 of the 8 subjects had reduced knee moments in at least 2 of the 3 moment directions. These “responders” were significantly shorter (1.73 ± 0.02 m vs 1.81 ± 0.04 m, P = 0.017) and had a higher relative maximal aerobic power (MAP) (4.6 ± 0.3 W?kg-1 vs 3.9 ± 0.3 W?kg-1, P = 0.024) compared to non-responders. These results suggest that certain shoe characteristics may influence certain individuals differently because these participants belong to different “functional groups”; certain individuals may respond positively to FLEX, while others may not. Further studies should test this proposed hypothesis.  相似文献   

14.
ABSTRACT

This study aimed to compare mechanical variables derived from torque-cadence and power-cadence profiles established from different cycle ergometer modes (isoinertial and isokinetic) and modelling procedures (second- and third-order polynomials), whilst employing a novel method to validate the theoretical maximal power output (Pmax). Nineteen well-trained cyclists (n = 12 males) completed two experimental sessions comprising six, 6-s maximal isoinertial or isokinetic cycling sprints. Maximal pedal strokes were extracted to construct power–cadence relationships using second- and third-order polynomials. A 6-s sprint at the optimal cadence (Fopt) or optimal resistance (Topt) was performed to assess construct validity of Pmax. No differences were found in the mechanical parameters when derived from isokinetic (Pmax = 1311 ± 415, Fopt = 118 ± 12) or isoinertial modes (Pmax = 1320 ± 421, Fopt = 116 ± 19). However, R2 improved (P < 0.02) when derived from isoinertial sprints. Third-order polynomial modelling improved goodness of fit values (Standard Error, adjusted R2), but derived similar mechanical parameters. Finally, peak power output during the optimised sprint did not significantly differ from the theoretical Pmax in both cycling modes, thus providing construct validity. The most accurate P-C profile can be derived from isoinertial cycling sprints, modelled using third-order polynomial equations.  相似文献   

15.
Purpose: To determine the accuracy of critical power (CP) and W? (the curvature constant of the power-duration relationship) derived from self-paced time-trial (TT) prediction trials using mobile power meters to predict 16.1-km road cycling TT performance. This study also aimed to assess the agreement between functional threshold power (FTP) and CP.

Methods: Twelve competitive male cyclists completed an incremental test to exhaustion, a FTP test and 4–5 self-paced TT bouts on a stationary bike within the lab, and a 16.1 km road TT, using mobile power meters.

Results: CP and W? derived from the power-duration relationship closely predicted TT performance. The 16.1-km road TT completion time (26.7 ± 2.2 min) was not significantly different from and was significantly correlated with the predicted time-to-completion (27.5 ± 3.3 min, r = 0.89, P < 0.01). CP and FTP were not significantly different (275 ± 40 W vs. 278 ± 42 W, P > 0.05); however, the limits of agreement between CP and FTP were 30 to -36 W.

Discussion: The findings of this study indicate that CP and W? determined using mobile power meters during maximal, self-paced TT prediction trials can be used to accurately predict 16.1-km cycling performance, supporting the application of the CP and W? for performance prediction. However, the limits of agreement were too large to consider FTP and CP interchangeable.  相似文献   


16.
ABSTRACT

Post-activation potentiation likely acutely improves power-based performance; however, few studies have demonstrated improved endurance performance. Forty collegiate female rowers performed isometric potentiating (ISO), dynamic potentiating (DYN) and control (CON) warm-up protocols on a rowing ergometer, followed by a three-minute all-out test to evaluate their total distance, peak power, mean power, critical power, anaerobic working capacity (W’) and stroke rate. Fifteen-second splits were also analysed. ISO consisted of 5 × 5-second static muscle actions with the ergometer handle rendered immovable with a nylon strap, while DYN consisted of 2 × 10-second all-out rowing bouts, separated by a 2-minute rest interval. The participants were divided into high and low experience groups by median experience level (3.75 years) for statistical analysis. Significant differences (DYN > CON; p < 0.05) were found for distance (+5.6 m), mean power (+5.9 W) and W’ (+1561.6 J) for more experienced rowers (n = 19) and no differences for less experienced rowers (n = 18). Mean power in DYN was significantly greater than CON and ISO in the 15–30, 30–45, 45–60 and 60–75 second intervals independent of experience level. These results suggest that DYN may benefit experienced female rowers and that these strategies might benefit a greater power output over shorter distances regardless of experience.  相似文献   

17.
We tested the hypothesis that work-matched supramaximal intermittent warm-up improves final-sprint power output to a greater degree than submaximal constant-intensity warm-up during the last 30?s of a 120-s supramaximal exercise simulating the final sprint during sports events lasting approximately 2?min. Ten male middle-distance runners performed a 120-s supramaximal cycling exercise consisting of 90?s of constant-workload cycling at a workload corresponding to 110% maximal oxygen uptake (VO2max) followed by 30?s of maximal-effort cycling. This exercise was preceded by 1) no warm-up (Control), 2) a constant-workload cycling warm-up at a workload of 60%VO2max for 6?min and 40?s, or 3) a supramaximal intermittent cycling warm-up for 6?min and 40?s consisting of 5 sets of 65?s of cycling at a workload of 46%VO2max?+?15?s of supramaximal cycling at a workload of 120%VO2max. By design, total work was matched between the two warm-up conditions. Supramaximal intermittent and submaximal constant-workload warm-ups similarly increased 5-s peak (590?±?191 vs. 604?±?215W, P?=?0.41) and 30-s mean (495?±?137 vs. 503?±?154W, P?=?0.48) power output during the final 30-s maximal-effort cycling as compared to the no warm-up condition (5-s peak: 471?±?165W; 30-s mean: 398?±?117W). VO2 during the 120-s supramaximal cycling was similarly increased by the two warm-ups as compared to no-warm up (P?≤?0.05). These findings show that work-matched supramaximal intermittent and submaximal constant-workload warm-ups improve final sprint (～30?s) performance to similar extents during the late stage of a 120-s supramaximal exercise bout.  相似文献   

18.
ABSTRACT

The aim of this study was to assess the influence of different bike positions on the perception of fatigue, pain and comfort. Twenty cyclists underwent three tests that involved cycling for 45 min at their individual 50% peak aerobic power output while adopting different positions on the bike. Participants performed the cycling tests adopting three positions defined by two parameters (knee flexion angle [20°, 30°, 40°] and trunk flexion angle [35°, 45°, 55°]) in random order. Angles were measured using a 2D motion analysis system during cycling and applying Fonda’s correction factor. Perceptions of comfort, fatigue and pain were reported before the end of each test. The combination of 40° knee flexion and 35° trunk flexion was perceived as the most uncomfortable position. Moreover, greater knee flexion had a negative effect on trunk comfort, accompanied by greater levels of fatigue and pain perception in the anterior part of the thigh and knee. In conclusion, cyclists perceived the most comfortable position to be when the saddle height was within the recommended knee angle (30° calculated from the offset position or 40 ± 4.0° of absolute value). Upright trunk was found to be the most comfortable position for recreational cyclists, where aerodynamics is not so important. Cyclists’ bike perceptions should be taken into account when it comes to choosing the most beneficial position, since this can play a role in injury prevention and enhance cycling performance.  相似文献   

19.
Abstract

The aim of this study was to compare optimization and correction procedures for the determination of peak power output during friction-loaded cycle ergometry. Ten male and 10 female sports students each performed five 10-s sprints from a stationary start on a Monark 864 basket-loaded ergometer. Resistive loads of 5.0, 6.5, 8.0, 9.5, and 11.0% body weight were administered in a counterbalanced order, with a recovery period of 10 min between sprints. Peak power was greater and occurred earlier, with less work having been done before the attainment of peak power, when the data were corrected to account for the inertial and frictional characteristics of the ergometer. Corrected peak power was independent of resistive load (P > 0.05), whereas uncorrected peak power varied as a quadratic function of load (P < 0.001). For males and females, optimized peak power (971 ± 122 and 668 ± 37 W) was lower (P < 0.01) than either the highest (1074 ± 111 and 754 ± 56 W respectively) or the mean (1007 ± 125 and 701 ± 45 W respectively) of the five values for corrected peak power. Optimized and mean corrected peak power were highly correlated both in males (r = 0.97, P < 0.001) and females (r = 0.96, P < 0.001). The difference between optimized and mean corrected peak power was 37 ± 30 W in males and 33 ± 14 W in females, of which approximately 15 W was due to the correction for frictional losses. We conclude that corrected peak power is independent of resistive load in males and females.  相似文献   

20.
Abstract

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 · kg?1 ± 0.4) for the flat and 235 W ± 10 (3.5 W · 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   

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