Pacing during a cross-country mountain bike mass-participation event according to race performance,experience, age and sex     

Samantha Louise Moss  Ben Francis  Giovanna Calogiuri  Jamie Highton 《European Journal of Sport Science》2019,19(6):793-801

This study describes pacing strategies adopted in an 86-km mass-participation cross-country marathon mountain bike race (the ‘Birkebeinerrittet’). Absolute (km·h^?1) and relative speed (% average race speed) and speed coefficient of variation (%CV) in five race sections (15.1, 31.4, 52.3, 74.4 and 100% of total distance) were calculated for 8182 participants. Data were grouped and analysed according to race performance, age, sex and race experience. The highest average speed was observed in males (21.8?±?3.7?km/h), 16–24?yr olds (23.0?±?4.8?km/h) and those that had previously completed >4 Birkebeinerrittet races (22.5?±?3.4?km/h). Independent of these factors, the fastest performers exhibited faster speeds across all race sections, whilst their relative speed was higher in early and late climbing sections (Cohen's d?=?0.45–1.15) and slower in the final descending race section (d?=?0.64–0.98). Similar trends were observed in the quicker age, sex and race experience groups, who tended to have a higher average speed in earlier race sections and a lower average speed during the final race section compared to slower groups. In all comparisons, faster groups also had a lower %CV for speed than slower groups (fastest %CV?=?24.02%, slowest %CV?=?32.03%), indicating a lower variation in speed across the race. Pacing in a cross-country mountain bike marathon is related to performance, age, sex and race experience. Better performance appears to be associated with higher relative speed during climbing sections, resulting in a more consistent overall race speed.  相似文献   

高温高湿环境下补液对有氧耐力的影响          下载免费PDF全文

吕志辉 《体育科研》2017,(3):84-87

目的：研究高温高湿环境下运动时补液对有氧耐力的影响。方法：随机选取吉林体育学院运动训练专业学生30名,年龄、身高、体重、肺活量、VO2max等指标均无差异,分为常温常湿组、高温高湿组、高温高湿补液组,测试实验过程中的心率（HR）、肌氧含量的变化、运动持续的时间以及恢复时间。结果：对高温高湿环境下运动进行补液干预,发现与高温高湿组相比,补液组体温、HR相对较低,肌氧饱和度下降幅度小,运动持续时间延长、恢复时间缩短。补液可以提高高温高湿环境下有氧运动的能力。  相似文献   

大强度的无氧间歇练习、有氧耐力练习及其组合练习的次序对恢复期心脏自主神经功能的影响          下载免费PDF全文

胡斐  徐盛嘉  沈铭彬  向奎金  黄强年  田东  马继政 《体育科研》2017,(6):87-92

目的：评估大强度的无氧间歇练习、有氧耐力练习及其组合练习的次序对恢复期心脏自主神经功能的影响。方法：采用随机交互设计,15名健康男性受试者分别完成4次运动：600 m间歇跑练习、30 min大强度持续跑练习、600 m间歇跑加30 min大强度持续跑练习,30 min大强度持续跑加600 m间歇跑练习,分别在运动前（0~10 min）、整个运动期间和运动后恢复期（0~20 min）记录RR间期,并进行相应HRV分析以及在运动前和运动后即刻进行血乳酸测试。结果：与安静状态相比,运动中HR、EPOC和TRIMP均显著增加,但组合练习次序间不存在显著差异;恢复期20 min内,HR随恢复时间增加逐渐降低,但同一恢复阶段不同运动方案之间无显著差异;RMSSD、SDNN、SDNN/HR、HF和LF变化相似,在整个恢复阶段均显著低于安静值,但HF和LF在恢复期（15~20 min）显著增加;而LF/HF随着恢复时间延长显著增加。结论：大强度的无氧间歇练习、持续有氧练习及其组合练习,在运动后早期恢复阶段（0~20 min）HRV变化趋于一致,提示耐力运动后心脏自主神经功能的调整可能不具有运动形式依赖性。此外,大强度无氧间歇和有氧耐力练习的组合练习次序不影响运动后恢复期心脏自主功能的调节,恢复期20 min内,交感活性仍处于较高水平。  相似文献   

Radial and tibial bone indices in athletes participating in different endurance sports: a pQCT study†     

Tanja Oosthuyse  Joanne A. McVeigh  Lisa K. Micklesfield 《European Journal of Sport Science》2017,17(2):231-240

Low magnitude bone-loading sports may benefit bone structure and strength in the exercised limbs. This study compared peripheral quantitative computed tomography measures of radial and tibial diaphyseal strength (strength–strain index, SSI), structure (total area (ToA) and cortical area (CoA), density (CoD) and thickness (CT), and circumferences), muscle cross-sectional area (MCSA) and strength (one-repetition maximum, 1-RM) in male endurance athletes taking part in (i) non-weight-bearing and non-impact sports: swimmers (SWIM, n?=?13) and road cyclists (RC, n?=?10), (ii) non-weight-bearing, impact sport: mountain bikers (MB, n?=?10), (iii) weight bearing and impact sport: runners (RUN, n?=?9). All athlete groups were also compared to sedentary controls (CON, n?=?10). Arm MCSA, 1-RM and radial bone size and strength tended to be greater in SWIM than CON and/or RC (ToA, %difference ±?95%CI, SWIM-CON: 14.6%?±?12.7%; SWIM-RC: 12.9%?±?10.7%) but not different to MB and RUN. RUN had bigger tibial CoA than CON, SWIM and RC (CoA, RUN-CON: 12.1%?±?10.7%; RUN-SWIM: 10.9%?±?9.4%; RUN-RC: 15.8%?±?9.5%) without marked changes in tibial strength indices, lower-limb MCSA or 1-RM. Both MB and RC failed to display any difference in tibial indices, lower-limb MCSA and 1-RM compared to CON. In swimmers, the bone structure and strength of the primary exercised limbs, the arms, is greater than controls and road cyclists. Conversely, although runners experience impact and weight-bearing loading, tibial structure is greater without a substantial difference in tibial strength compared to controls and non-impact sports. Failure to observe a difference in tibial indices in MB and RC compared to controls is unexpected.  相似文献   

Acute effects of Kinesio taping on muscle function and self-perceived fatigue level in healthy adults     

Nan Hee Lee  Hyun Chul Jung  Gina Ok 《European Journal of Sport Science》2017,17(6):757-764

This study investigated the acute effects of Kinesio taping (KT) on muscular power, strength, endurance, and self-perceived fatigue level. This is a randomized, partial double-blind, crossover trial. Eighteen healthy adults (7 males [23.86?±?1.68 years] and 11 females [24.82?±?3.71 years]) were enrolled in this study. All subjects underwent three different trials which included no tap (NT), placebo tap (PT), and KT. Idividuals were assessed for peak and mean power, muscular strength and endurance, and self-perceived fatigue after each condition. The results revealed no significant differences in all variables (p?>?0.05) except muscular endurance (F?=?5.775, p?=?0.007). Muscular endurance in the NT (58.28?±?12.18?reps/min) condition was significantly higher than that in the KT (52.83?±?11.76?reps/min) condition. These results suggest that KT on rectus femoris and the patella of the lower limb does not improve muscular function and self-perceived fatigue level. KT is unlikely to enhance exercise performance capacity in healthy adults.  相似文献   

Gender influence on the adaptation of atrial performance to training     

Laura Sanchis  Maria Sanz-de La Garza  Bart Bijnens  Genevieve Giraldeau  Gonzalo Grazioli  Josefa Marin 《European Journal of Sport Science》2017,17(6):720-726

Background: High-intensity training has been associated with atrial remodelling and arrhythmias in men. Our purpose was to analyse atrial performance in female endurance athletes, compared to male athletes and controls. Methods: This was a cross-sectional study. We included four groups: female athletes, females controls, male athletes and male controls. Left (LA) and right atrial (RA) volumes and function were assessed using 2D and speckle-tracking echocardiography to determine peak atrial strain-rate at atrial (SRa) and ventricular contraction (SRs), as surrogates of atrial contractile and reservoir function, respectively. ANOVA and Bonferroni’s statistical tests were used to compare variables among groups. Results: We included 82 subjects, 39 women (19 endurance athletes, 20 controls) and 43 men (22 endurance athletes, 21 controls). Mean age was similar between groups (36.6?±?5.6 years). Athletes had larger bi-atrial volumes, compared to controls (women, LA 27.1 vs. 15.8?ml/m², p?<?0.001; RA 22.31 vs. 14.2?ml/m², p?=?0.009; men, LA: 25.0 vs. 18.5?ml/m², p?=?0.003; RA 30.8 vs. 21.9?ml/m², p?<?0.001) and lower strain-rate (women, LASRa ?1.60 vs. ?2.18?s^?1, p?<?0.001; RASRa ?1.89 vs. ?2.38?s^?1, p?=?0.009; men, LASRa ?1.21 vs. ?1.44?s^?1, p?=?1; RASRa ?1.44 vs. ?1.60?s^?1, p?=?1). However, RA indexed size was lower and bi-atrial deformation greater in female athletes, compared to male athletes. Conclusions: The atria of both male and female athletes shows specific remodelling, compared to sedentary subjects, with larger size and less deformation at rest, particularly for the RA. Despite a similar extent of remodelling, the pattern in women had greater bi-atrial myocardial deformation and smaller RA size.  相似文献   

Validity of a single lactate measure to predict fixed lactate thresholds in athletes     

Ibai Garcia-Tabar  Iñaki Llodio  Luis Sánchez-Medina  Xabier Asiain  Javier Ibáñez 《Journal of sports sciences》2017,35(4):385-392

This study aimed to validate the use of a single blood lactate concentration measure taken following a 12 km h^?1 running stage (BLC₁₂) to predict and monitor fixed blood lactate concentration (FBLC) thresholds. Three complementary studies were undertaken. Study I: the relationships between BLC₁₂ and the running speeds at FBLC of 3 mmol L^?1 (S3mM) and 4 mmol L^?1 (S4mM) measured during a multistage running field test were examined in 136 elite athletes. Study II: data from 30 athletes tested one year apart were used to test the predictive capacity of the equations obtained in Study I. Study III: 80 athletes were tested before and after an intensified training period to examine whether training-induced changes in FBLC thresholds could be predicted and monitored by BLC₁₂. Study I: BLC₁₂ was significantly (P < 0.001) and inversely related to S3mM (R² = 0.89) and S4mM (R² = 0.95). Study II: prediction models yielded robust correlations between the estimated and measured FBLC thresholds (r = 0.94–0.99; P < 0.001). Study III: estimated changes predicted actual training-induced changes in FBLC thresholds (r = 0.81–0.91; P < 0.001). This study gives empirical support to use a single lactate measure during a sub-maximal running field test as a simple, low-cost and practical alternative to FBLC thresholds in athletes.  相似文献   

Short-term performance peaking in an elite cross-country mountain biker     

Bent R. Rønnestad  Joar Hansen  Geir Vegge  Iñigo Mujika 《Journal of sports sciences》2017,35(14):1392-1395

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 EMG_mean 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   

运动促进健康，从儿童青少年抓起——2016年第63届美国运动医学年会综述     

王正珍  王娟 《北京体育大学学报》2016,39(8):39-43

摘要：介绍第63届运动美国医学年会暨第7届运动是良医世界大会和能量平衡的基础科学世界大会的概况和主要热点为目的。以大会主报告和专题报告为思路,重点阐述了第63届ACSM年会主报告”青少年体质健康”和基础科学专题报告“能量平衡”。青少年体质健康的主报告指出了面对儿童青少年的静坐少动行为增加、身体活动不足的现状,研究者提出了多种干预方式,包括建立“全方位身体活动模型”,制定相关运动处方和公共政策,从学校、家庭和社区参与等多方面促进身体活动。能量平衡的基础科学专题集中在讨论能量平衡的生物和生理学机制,强调可以调节能量摄取和能量消耗的因素,以及这些因素如何与慢性疾病相关联。这些研究成果为更深入研究儿童青少年体力活动促进提供了新的思路,也为我国儿童青少年体力活动促进提供了参考。  相似文献   

“节奏策略”与极限负荷下的心理承受力训练   总被引：3，自引：0，他引：3       下载免费PDF全文

鲍政栋  章崇会 《武汉体育学院学报》2006,40(4):51-53,84

阐述了在极限负荷条件下运动员对疼痛与疲劳的忍受性作为一种心理承受力对大强度体能训练的重要性,并对疲劳与疼痛的控制方法进行了介绍与说明。以已有实证研究对“节奏策略”的支持性结论为基础,提出假设：对疲劳的认知信念的改变和通过心理技能训练改变意志努力,可以影响中枢神经系统的“疲劳管理策略”,并且会对运动表现产生积极影响。根据已有的研究结果及知识经验,提出一个四步的训练程序,来帮助提高运动员在极限负荷下的心理承受能力。  相似文献