Age and gender interactions in short distance triathlon performance     

Franziska Etter  Arkadiusz Bukowski  Christoph Alexander Rüst  Thomas Rosemann  Romuald Lepers 《Journal of sports sciences》2013,31(9):996-1006

Abstract

This study investigated the participation and performance trends as well as the age and gender interaction at the Olympic distance ‘Zürich Triathlon’ (1.5?km swim, 40?km cycle and 10?km run) from 2000 to 2010 in 7,939 total finishers (1,666 females and 6,273 males). Female triathletes aged from 40 to 54 years significantly (P?<?0.05) increased their participation while the participation of younger females and males remained stable. Males of 50–54 years of age and females of 45–49 years of age improved their total race time. For elite top five overall triathletes, mean gender differences in swimming, cycling, running and overall race time were 15.2?±?4.6%, 13.4?±?2.3%, 17.1?±?2.5%, and 14.8?±?1.8%, respectively. For both elite and age group athletes, the gender difference in cycling time was significantly (P?<0.001) lower than for swimming and running. The gender difference in overall Olympic distance triathlon performance increased after the age of 35 years, which appeared earlier compared to long distance triathlon as suggested by previous studies. Future investigations should compare gender difference in performance for different endurance events across age to confirm a possible effect of exercise duration on gender difference with advancing age.  相似文献   

Ground reaction forces and osteogenic index of the sport of cyclocross     

Brian Tolly  Elizabeth Chumanov 《Journal of sports sciences》2013,31(14):1365-1373

Abstract

Weight-bearing activity has been shown to increase bone mineral density. Our purpose was to measure vertical ground reaction forces (GRFs) during cyclocross-specific activities and compute their osteogenic index (OI). Twenty-five healthy cyclocross athletes participated. GRF was measured using pressure-sensitive insoles during seated and standing cycling and four cyclocross-specific activities: barrier flat, barrier uphill, uphill run-up, downhill run-up. Peak and mean GRF values, according to bodyweight, were determined for each activity. OI was computed using peak GRF and number of loading cycles. GRF and OI were compared across activities using repeated-measures ANOVA. Number of loading cycles per activity was 6(1) for barrier flat, 8(1) barrier uphill, 7(1) uphill run-up, 12(3) downhill run-up. All activities had significantly (P < 0.01) higher peak GRF, mean GRF values and OI when compared to both seated and standing cycling. The barrier flat condition (P < 0.01) had highest peak (2.9 times bodyweight) and mean GRF values (2.3 times bodyweight). Downhill run-up (P < 0.01) had the highest OI (6.5). GRF generated during the barrier flat activity is similar in magnitude to reported GRFs during running and hopping. Because cyclocross involves weight bearing components, it may be more beneficial to bone health than seated road cycling.  相似文献   

Validity and reliability of different kinematics methods used for bike fitting     

Borut Fonda  Nejc Sarabon 《Journal of sports sciences》2013,31(10):940-946

Abstract

The most common bike fitting method to set the seat height is based on the knee angle when the pedal is in its lowest position, i.e. bottom dead centre (BDC). However, there is no consensus on what method should be used to measure the knee angle. Therefore, the first aim of this study was to compare three dynamic methods to each other and against a static method. The second aim was to test the intra-session reliability of the knee angle at BDC measured by dynamic methods. Eleven cyclists performed five 3-min cycling trials; three at different seat heights (25°, 30° and 35° knee angle at BDC according to static measure) and two at preferred seat height. Thirteen infrared cameras (3D), a high-speed camera (2D), and an electrogoniometer were used to measure the knee angle during pedalling, when the pedal was at the BDC. Compared to 3D kinematics, all other methods statistically significantly underestimated the knee angle (P = 0.00; η² = 0.73). All three dynamic methods have been found to be substantially different compared to the static measure (effect sizes between 0.4 and 0.6). All dynamic methods achieved good intra-session reliability. 2D kinematics is a valid tool for knee angle assessment during bike fitting. However, for higher precision, one should use correction factor by adding 2.2° to the measured value.  相似文献   

Test–retest reliability of second lactate turnpoint using two different criteria in competitive cyclists     

《European Journal of Sport Science》2013,13(4):265-270

Abstract

The aim of this study was to determine the relative and absolute reliability of second lactate turnpoint using fixed and individual blood lactate method in competitive cyclists. Twenty-eight male, well-trained cyclists (30.2 ± 10.1 years, 72.0 ± 7.4 kg, 177.3 ± 4.7 cm) were recruited to participate in this study. Cyclists completed two incremental cycling tests to exhaustion over a period of 7 days to determine their peak power output, maximal oxygen uptake, maximal heart rate, maximal blood lactate concentration and two lactate turnpoint criteria. The fixed blood concentration criterion (3.5 mM) and an individual criterion were assessed by a lactate-power curve, considering power output, heart rate and oxygen uptake. The main finding of this study was that both lactate turnpoint criteria showed identical low within-subject variation for power output (2.8% coefficient of variation). High values for test–retest correlations ranging from r = 0.70 to r = 0.94 were found for all variables in both threshold criteria. In conclusion, the individual and fixed method to determine the second lactate turnpoint showed similar high absolute and relative reliability in competitive cyclists.  相似文献   

One session of interval work does not alter VO2max,peak power or plasma volume     

《European Journal of Sport Science》2013,13(4):285-289

Abstract

We examined the effect of one high-intensity cycling workout on aerobic capacity (VO_2max), 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 VO_2max, 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 VO_2max (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 VO_2max, peak power or estimated change in plasma volume on subsequent days, and is therefore unlikely to benefit or hinder performance.  相似文献   

Maximal lactate steady-state and anaerobic thresholds from different methods in cyclists     

《European Journal of Sport Science》2013,13(2):161-167

Abstract

The lactate anaerobic threshold (AT) determined during an incremental test has been used generally to estimate the maximal lactate steady-state intensity (MLSS_int) in several sports. Furthermore, this index could be useful to predict the time-trial cycling performance and also to prescribe training intensity to enhance aerobic capacity. The aim of this study was to compare three different AT estimations with actual MLSS_int in trained cyclists. Fourteen trained cyclists participated in this study. They had previously performed a maximal incremental cycling test (35 W increments each 3 min) in a laboratory followed by three to five visits to measure the MLSS_int (30-min tests). Blood lactate concentration ([La]), oxygen uptake ([Vdot]O₂), and heart rate (HR) were measured during all tests. Based on the incremental test, we calculated three ATs using different proposed methods: AT₁-intensity corresponds to fixed [La]; AT₂-minimum equivalent of the blood lactate-power output relationship plus 1.5 mmol·L^?1; AT₃-power output of the stage antecedent to the second lactate increase of at least 0.5 mmol·L^?1 above the previous values, where the second increase was greater than the first. The MLSS_int was determined for each participant as the highest power output that could be maintained with [La] fluctuating less than 1 mmol·L^?1 during the final 20 min of the steady-state tests. ANOVA with repeated measures was used to compare physiological variables in the different methods. The relationship between the MLSS_int and the power output of AT₁, AT₂, and AT₃ was analysed using Pearson product-moment correlation coefficients. In addition, we calculated the bias and limits of agreement between the three different methods with actual MLSS_int. The mean±s values of power output related to MLSS_int, AT₁, AT₂, and AT₃ were 247±33 W, 258±39 W, 248±35 W, and 230±36 W, respectively. The results showed that AT₃ underestimated (P <0.05) the MLSS_int for most of the participants and provided lower mean values compared with AT₁ and AT₂. Furthermore, AT₂ seems to be more accurate to estimate MLSS_int than other methods here verified when we analysed the mean values, correlation coefficient (r = 0.94), and Bland-Altman limits of agreement (± 9.5%). The AT₁ also provided good prediction values, although it presented with a trend to overestimate MLSS_int. Therefore, considering the methods analysed in the current study and the importance of this submaximal aerobic index to flat time-trials and prolonged uphill cycling performance, the AT₂ method could be used with good accuracy by coaches and athletes.  相似文献   

Vibrotactile feedback for correcting aerodynamic position of a cyclist     

Thomas Peeters  Jochen Vleugels  Raman Garimella  Steven Truijen  Wim Saeys  Stijn Verwulgen 《Journal of sports sciences》2020,38(19):2193-2199

ABSTRACT

Guidance to maintain an optimal aerodynamic position is currently unavailable during cycling. This study used real-time vibrotactile feedback to guide cyclists to a reference position with minimal projected frontal area as an indicator of aerodynamic drag, by optimizing torso, shoulder, head and elbow position without compromising comfort when sitting still on the bike. The difference in recapturing the aerodynamic reference position during cycling after predefined deviations from the reference position at different intensities was analysed for 14 participants between three interventions, consisting of 1) vibrotactile feedback with a margin of error of 1.5% above the calibrated reference projected frontal area, 2) vibrotactile feedback with a margin of 3%, and 3) no feedback. The reference position is significantly more accurately achieved using vibrotactile feedback compared to no feedback (p < 0.001), but there is no significant difference between the 1.5% and 3% margin (p = 0.11) in terms of relative projected frontal area during cycling compared to the calibrated reference position (1.5% margin ?0.46 ± 1.76%, 3% margin ?0.01 ± 2.01%, no feedback 2.59 ± 3.29%). The results demonstrate that vibrotactile feedback can have an added value in assisting and correcting cyclists in recapturing their aerodynamic reference position.  相似文献   

短距离场地自行车运动项目制胜的核心因素解析   总被引：1，自引：0，他引：1  

谢云  田麦久 《沈阳体育学院学报》2012,31(3):5-8

我国女子短距离场地自行车运动员的竞技能力水平近年来有了明显的提高,但大赛成绩却不理想。面对这一现实,运用文献资料法、专家访谈法、跟踪调查法、个案分析法、数理统计及逻辑分析法等多种研究方法,对我国女子短距离场地自行车运动项目制胜的核心因素进行解析。研究表明:对自行车专项运动成绩有决定性影响的因素称为制胜因素,制胜因素以及制胜因素之间的内在本质的联系构成了项目的制胜规律,运动员竞技能力的发展水平运用于比赛之中即为其制胜能力;场地自行车运动员是运动训练与参赛的主体,自行车比赛中对运动员竞技能力充分发挥的理想要求即是其制胜的核心要素,主要包括:全程高速能力、技术合理稳定能力、战术灵活运用能力、连续多赛能力、拼搏争胜能力。在实践中,亦可简称为"快、稳、灵、多、搏"五个要素。  相似文献   

Validity of a device designed to measure braking power in bicycle disc brakes     

Matthew C. Miller  Philip W. Fink  Paul William Macdermid  Blake G. Perry  Stephen R. Stannard 《Sports biomechanics / International Society of Biomechanics in Sports》2018,17(3):303-313

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   

Oxygen consumption,rate of perceived exertion and enjoyment in high-intensity interval eccentric cycling     

Marcin Lipski  Chris R. Abbiss  Kazunori Nosaka 《European Journal of Sport Science》2018,18(10):1390-1397

  相似文献