Image dimensions of two Scandinavian endurance winter sport events

ABSTRACT

This study investigates event images of two Scandinavian endurance skiing events. It adds to the relatively limited literature on endurance sport event images and provides a better understanding of how participants perceive images of the cross country ski events Birkebeinerrennet and Vasaloppet, and to what extent the images are similar and different. A qualitative comparative case-study design was applied. The interview guide consisted of open-ended semi-structured questions, and 52 participants in Birkebeinerrennet and Vasaloppet were interviewed during March 2017. A ‘sport endurance event image’ can be composed of at least ten dimensions and associated aspects: ‘Organizational’, ‘Environmental’, ‘Emotional’, ‘Social’, ‘Historical’, ‘Physical’, ‘Competition’, ‘Cultural’, ‘Equipment’ and ‘Destination’. The findings confirm and expand earlier identified dimensions of sport event images by identifying two new dimensions (‘Equipment’ and ‘Destination’). The image of Birkebeinerrennet was more aligned with the destination than Vasaloppet, while the overall stronger and more versatile image of Vasaloppet makes it less vulnerable to loss of interest from narrow segments of participants. We offer insights about how participants perceive the race images, how two rather similar events also differ in their images, and how this can contribute to a better understanding of differences in popularity. The findings can help organisers work towards images that attract desirable visitors and participants. Future research should follow up these findings through quantitative investigations across different types of long-distance, endurance sport events taking place in different environments, seasons and regions.     

对经典竞技规范伦理学的反思

经典竞技规范伦理学中的竞技规范,仅仅是可供选择的对象,而不是无可选择的事实。因为存在着两个问题;即任一竞技规范的合理性需要被判定,竞技规范之间可能出现的冲突。“应该”不仅表现出了规劝的软弱性,更为致命的是它本身的无根性。这种无根性使得任一竞技规范系统表现为或是不相容的,或是不完备的,或是不可靠的,因而是无效的。     

体能主导类耐力性项群训练原理

耐力性项群是奥林匹克竞技运动项目中的一个大家族。近百个项目（约占３０％）的运动方式各异：分别为走、跑、骑、游、划、滑,但运动特点却都是中长时间的持续性工作,比赛特点都是中、长距离的竞速。文中从项群层次概括了所有耐力性项目选手共有的竞技能力结构特征,运动成绩的决定因素及共同的训练内容、训练方法和负荷特点     

从劳动价值论探讨运动员人力资本价值构成

将运动员作为一种资本的概念和提法一直被我国经济理论界所忽视或者回避,其价值构成更是难以度测。针对运动员人力资本的特性,试图从劳动价值论这一角度出发,探讨其价值构成,据此合理投入运动资本,优化资源分配,促进社会进步、经济发展。     

散打运动员力量耐力和速度耐力评价的实验研究

运用专项攻击能力测试与评价系统对不同运动等级散打运动员力量耐力、速度耐力进行综合测试和评价。研究结果为:1)优秀组平均击打力度大于普通组,有显著性差异;优秀组击打次数大于普通组,没有显著性差异;2)每个时间段优秀组平均击打力度、击打次数均大于普通组,但只有后10 s的平均击打力度具有显著性差异;3)普通组平均击打力度、击打次数均呈下降趋势,击打次数前10 s与中10 s、后10 s比均具有高度显著性差异;4)优秀组平均击打力度、击打次数均呈下降趋势,击打次数前10 s与中10 s有显著性差异,前10 s与后10 s有高度显著性差异。建议:应重视散打运动员速度耐力、力量耐力的训练,并应加强速度耐力、力量耐力训练方法的研究,尤其应加强散打体能训练模型的构建。     

Characterisation of baroreflex sensitivity of recreational ultra-endurance athletes

Abstract

Altered autonomic function has been identified following ultra-endurance event participation among elite world-class athletes. Despite dramatic increases in recreational athlete participation in these ultra-endurance events, the physiological effects on these athletes are less known. This investigation sought to characterise changes in surrogate measures of autonomic function: heart rate variability (HRV), blood pressure variability (BPV) and baroreceptor sensitivity (BRS) following ultra-endurance race participation. Further, we sought to compare baseline measures among ultra-endurance athletes and recreationally active controls not participating in the ultra-endurance race. Recreational ultra-endurance athletes (n = 25, 44.6 ± 8.2 years, 8 females) and recreationally active age, sex and body mass index matched controls (n = 25) were evaluated. Measurements of HRV, BPV and BRS were collected pre- and post-race for recreational ultra-endurance athletes and at baseline, for recreationally active controls. Post-race, ultra-endurance athletes demonstrated significantly greater sympathetic modulation [low frequency (LF) power HRV: 50.3 ± 21.6 normalised units (n.u.) to 65.9 ± 20.4 n.u., p = 0.01] and significantly lower parasympathetic modulation [high frequency (HF) power HRV: 45.0 ± 22.4 n.u. to 23.9 ± 13.1 n.u., p < 0.001] and BRS. Baseline measurements BRS (spectral: 13.96 ± 10.82 ms·mmHg^?1 vs. 11.39 ± 5.33 ms·mmHg^?1) were similar among recreational ultra-endurance athletes and recreationally active controls, though recreational ultra-endurance athletes demonstrated greater parasympathetic modulation of some HRV and BPV measures. Recreational ultra-endurance athletes experienced increased sympathetic tone and declines in BRS post-race, similar to previously reported elite world-class ultra-endurance athletes, though still within normal population ranges.     

浅谈400米运动员的速度耐力训练

运用文献资料法和数据统计分析法,对我国部分优秀运动员400米的速度耐力训练进行研究。研究认为,在400米跑这一径赛项目中,发展速度与发展速度耐力是提高该项目成绩的两大关键,也是训练实践中要解决的核心问题。本文以运动生理学、运动生物化学为依据,结合运动训练理论与方法,对发展速度耐力这一问题进行分析,并提出了400米跑中发展速度耐力的有效方法和手段。     

Effect of water ingestion on endurance capacity during prolonged running

This study examined the influence of water ingestion on endurance capacity during submaximal treadmill running. Four men and four women with a mean (± S.E.) age of 21.4 ± 0.7 years, height of 169 + 2 cm, body mass of 63.1 ± 2.9 kg and VO ₂ max of 51.1 ± 1.8 ml kg^?1 min^?1, performed two randomly assigned treadmill runs at 70% VO ₂ max to exhaustion. No fluid was ingested during one trial (NF‐trial), whereas a single water bolus of 3.0 ml kg^?1 body mass was ingested immediately pre‐exercise and serial feedings of 2.0 ml kg^?1 body mass were ingested every 15 min during exercise in a fluid replacement trial (FR‐trial). Run time for the NF‐trial was 77.7 ± 7.7 min, compared to 103 ± 12.4 min for the FR‐trial (P<0.01). Body mass (corrected for water ingestion) decreased by 2.0 ± 0.2% in the NF‐trial and 2.7 ± 0.2% in the FR‐trial (P<0.01), while plasma volume decreased by 1.1 ± 1.1% and 3.5 ± 1.1% in the two trials respectively (N.S.). However, these apparent differences in circulatory volume were not associated with differences in rectal temperature. Respiratory exchange ratios indicated increased carbohydrate metabolism (73% vs 64% of total energy expenditure) and suppressed fat metabolism after 75 min of exercise in the NF‐trial compared with the FR‐trial (NF‐trial, 0.90 ± 0.01; FR‐trial, 0.86 ± 0.03; P<0.01). Blood glucose concentrations were similar in both trials, while blood lactate concentrations were higher in the NF‐trial at the end of exercise (4.83 ± 0.34 vs 4.18 ± 0.38 mM; P<0.05). In summary, water ingestion during prolonged running improved endurance capacity.     

青少年竞走运动员的心理诊断

采用"福莱斯特心理负荷症状调查表 "对影响竞走运动员的竞赛心理因素进行测试和研究.结果说明:不同因素使不同性别、组别、年龄的竞走运动员参赛时的心理表现不同.各种不利因素的出现使运动员主要产生"这是我经常失败的原因"和"成绩总是不好"的心理.生理因素的影响是造成运动员经常失败的原因之一.认知因素和刺激因素的出现使运动员的心理表现主要为"这一情况对我无所谓",其次是"激励我去夺取优异成绩".影响成绩的因素主要为"失眠"、"情绪过于紧张"和"出师不利"、"自我感觉身体不适,竞技状态不佳".     

Effect of 6 weeks of endurance training on the lactate minimum speed

The aim of this study was to assess the sensitivity of the lactate minimum speed test to changes in endurance fitness resulting from a 6 week training intervention. Sixteen participants (mean +/- s :age 23 +/- 4 years;body mass 69.7 +/- 9.1 kg) completed 6 weeks of endurance training. Another eight participants (age 23 +/- 4 years; body mass 72.7 +/-12.5 kg) acted as non-training controls. Before and after the training intervention, all participants completed: (1) a standard multi-stage treadmill test for the assessment of VO 2max , running speed at the lactate threshold and running speed at a reference blood lactate concentration of 3 mmol.l -1 ; and (2) the lactate minimum speed test, which involved two supramaximal exercise bouts and an 8 min walking recovery period to increase blood lactate concentration before the completion of an incremental treadmill test. Additionally, a subgroup of eight participants from the training intervention completed a series of constant-speed runs for determination of running speed at the maximal lactate steady state. The test protocols were identical before and after the 6 week intervention. The control group showed no significant changes in VO 2max , running speed at the lactate threshold, running speed at a blood lactate concentration of 3 mmol.l -1 or the lactate minimum speed.In the training group, there was a significant increase in VO 2max (from 47.9 +/- 8.4 to 52.2 +/- 2.7 ml.kg -1 .min -1 ), running speed at the maximal lactate steady state (from 13.3 +/- 1.7 to 13.9 +/- 1.6 km.h -1 ), running speed at the lactate threshold (from 11.2 +/- 1.8 to 11.9 +/- 1.8 km.h -1 ) and running speed at a blood lactate concentration of 3 mmol.l -1 (from 12.5 +/- 2.2 to 13.2 +/- 2.1 km.h -1 ) (all P ? 0.05). Despite these clear improvements in aerobic fitness, there was no significant difference in lactate minimum speed after the training intervention (from 11.0 +/- 0.7 to 10.9 +/- 1.7 km.h -1 ). The results demonstrate that the lactate minimum speed,when assessed using the same exercise protocol before and after 6 weeks of aerobic exercise training, is not sensitive to changes in endurance capacity.     

Post-activation potentiation (PAP) in endurance sports: A review

While there is strong support of the usefulness of post-activation potentiation (PAP) phenomenon in power demanding sports, the role that PAP could play in endurance sports has received less attention. The aim of this review is to present evidence for a better understanding of PAP in endurance athletes; and to discuss the physiological basis and methodological aspects necessary for better practices and designing further studies. A search for relevant articles on PAP and endurance trained athletes was carried out using Medline and ISI Web of Knowledge databases. Twenty-two studies were included in the review. The current evidence suggests the possible influence of PAP for performance enhancement after appropriate conditioning activities during warm up. Evaluation of PAP responses during testing, training and competition may be also important for athletes monitoring. There are many unresolved questions about the optimum load parameters for benefiting from PAP in both training and competition; and the role that PAP may exert for optimal performance while interacting with central and peripheral factors associated with muscle fatigue. Further studies should elucidate the association between PAP responses and long-term adaptations in endurance athletes.     

Changes in leg strength 8 and 32 h after endurance exercise

The aim of this study was to determine the effects of a single bout of endurance exercise on subsequent strength performance. Eight males with a long history of resistance training performed isokinetic, isometric and isotonic leg extension strength tests 8 and 32 h after 50 min of cycle ergometry at 70-110% of critical power. The participants also completed a control condition in which no cycling was performed. Plasma lactate and ammonia were measured before and immediately after each strength test. Isokinetic, isometric and isotonic leg extension torques were not significantly different 8 or 32 h after endurance exercise compared with the control condition ( P > 0.05). A large (50.3%), but not statistically significant, increase in plasma ammonia was evident during the strength tests performed 8 h after endurance exercise, while a significant ( P ? 0.05) increase in ammonia was also seen 32 h after endurance exercise. No significant changes in plasma ammonia were evident in the control condition. Our results suggest that leg extension strength was not compromised by an earlier bout of endurance cycling. However, metabolic activity during the strength tests might have been altered by the preceding bout of endurance exercise.     

优秀运动员"运动寿命"解析

界定了运动寿命的概念，分析了运动寿命与年龄、竞赛成绩的关系以及影响运动寿命的因素。     

Eating disorder prevention initiatives for athletes: A review

A substantial amount of evidence suggests that collegiate and elite athletes involved in weight-sensitive sports are at greater risk of developing eating disorders (EDs) than the general population. With the limited effectiveness of treatment for EDs, prevention of EDs has been broadly considered in the literature. The present paper reviewed the existing literature on ED prevention programmes for athletes in order to determine the current status of prevention programmes and recommend future directions. The available literature suggests that selective, primary interventions with multiple targets and an interactive multimodal approach appear most effective. Current challenges in the field, including lack of longitudinal research, hesitation by the sport community to be involved in ED research and poor cross-field communication and collaboration, are also explored. The lack of dissemination of evidence-based prevention programmes and the simultaneous promotion of prevention programmes that have not yet been empirically examined are also discussed. Based on these observations future directions are recommended.     

The menstrual cycle and its effect on the immune status of female endurance runners

Twenty highly trained, eumenorrhoeic female endurance runners were studied over three consecutive menstrual cycles. Average training distance per week, total years training and mood states were recorded throughout the three cycles. Salivary progesterone and menstrual cycle diaries were recorded over the first two cycles to identify luteal phase onset and the presence of any menstrual irregularities. Saliva samples were collected daily over the third cycle for analysis of immunoglobulin A (IgA) concentration and secretion and saliva flow rate. Twoway analysis of variance (ANOVA) revealed no significant differences in mood states across the phases of the menstrual cycle ( P > 0.05). Training logs indicated that training did not alter throughout the 3 month study. One-way ANOVArevealed no significant differences in IgA concentration ( P = 0.92), secretion rate ( P = 0.84) or saliva flow rate ( P = 0.95) across the phases of the menstrual cycle. Pearson's product-moment correlation revealed no relationship between IgA concentration and progesterone between the phases of the cycle ( r = 0.39). We conclude that, in ovulatory female endurance runners whose physical and emotional stress are stable, IgA concentration is not significantly affected by fluctuations in progesterone during the menstrual cycle.     

The impact of breathing on HRV measurements: Implications for the longitudinal follow-up of athletes

Abstract

The purpose of the present work was to compare daily variations of heart rate variability (HRV) parameters between controlled breathing (CB) and spontaneous breathing (SB) sessions during a longitudinal follow-up of athletes. HRV measurements were performed daily on 10 healthy male runners for 21 consecutive days. The signals were recorded during two successive randomised 5-minutes sessions. One session was performed in CB and the other in SB. The results showed significant differences between the two respiration methods in the temporal, nonlinear and frequency domains. However, significant correlations were observed between CB and SB (higher than 0.70 for RMSSD and SD1), demonstrating that during a longitudinal follow-up, these markers provide the same HRV variations regardless of breathing pattern. By contrast, independent day-to-day variations were observed with HF and LF/HF frequency markers, indicating no significant relationship between SB and CB data over time. Therefore, we consider that SB and CB may be used for HRV longitudinal follow-ups only for temporal and nonlinear markers. Indeed, the same daily increases and decreases were observed whatever the breathing method employed. Conversely, frequency markers did not provide the same variations between SB and CB and we propose that these indicators are not reliable enough to be used for day-to-day HRV monitoring.     

Normative data for regional sweat sodium concentration and whole-body sweating rate in athletes

The purpose of this study was to establish normative data for regional sweat sodium concentration ([Na⁺]) and whole-body sweating rate in athletes. Data from 506 athletes (367 adults, 139 youth; 404 male, 102 female) were compiled from observational athlete testing for a retrospective analysis. The participants were skill/team-sport (including American football, baseball, basketball, soccer and tennis) and endurance (including cycling, running and triathlon) athletes exercising in cool to hot environmental conditions (15–50°C) during training or competition in the laboratory or field. A standardised regional absorbent patch technique was used to determine sweat [Na⁺] on the dorsal mid-forearm. Whole-body sweat [Na⁺] was predicted using a published regression equation (y = 0.57x+11.05). Whole-body sweating rate was calculated from pre- to post-exercise change in body mass, corrected for fluid/food intake (ad libitum) and urine output. Data are expressed as mean ± SD (range). Forearm sweat [Na⁺] and predicted whole-body sweat [Na⁺] were 43.6 ± 18.2 (12.6–104.8) mmol · L^–1 and 35.9 ± 10.4 (18.2–70.8) mmol · L^–1, respectively. Absolute and relative whole-body sweating rates were 1.21 ± 0.68 (0.26–5.73) L · h^–1 and 15.3 ± 6.8 (3.3–69.7) ml · kg^–1 · h^–1, respectively. This retrospective analysis provides normative data for athletes’ forearm and predicted whole-body sweat [Na⁺] as well as absolute and relative whole-body sweating rate across a range of sports and environmental conditions.     

Normative fat-free mass index values for a diverse sample of collegiate female athletes

The purpose of this study was to establish normative fat-free mass index (FFMI) ranges in collegiate female athletes. A sample of 266 female athletes (Mean±SD; Age: 19.7 ± 1.5 yrs, Height: 166.0 ± 6.4 cm, Weight: 63.2 ± 8.8 kg) were included in analyses. Dual-energy X-ray absorptiometry measured bone mineral content (BMC; kg) and lean mass (LM; kg). Fat-free mass index was calculated as follows: FFMI = (BMC + LM)/Height². Participants were classified by sport: cross-country (XC), field hockey, football, gymnastics, lacrosse, resistance-trained, swimming track. Mean, range and percentile ranks of FFMI were calculated for the full sample for each cohort. For all females, mean FFMI was 16.9 ± 1.7 kg/m², FFMI values ranged from 13.3 to 25.5 kg/m². The XC athletes had the lowest FFMI (15.3 ± 0.96 kg/m²; p < 0.001). Mean FFMI measures were similar between all other female athletes. Percentile ranks varied across sport; median FFMI was highest for football (18.0 kg/m²), lowest for XC (15.1 kg/m²) and ranged between 16.4 and 17.3 kg/m² for all other athletes. Establishing sport-specific FFMI values for female athletes may be beneficial for athletes and coaches by leading to more appropriate body composition goals based on FFM.     

优秀运动员竞技运动项目迁移的项群训练理论分析

采用文献资料法、分析归纳法等,以优秀运动员作为研究对象,运用田麦久的项群训练理论,对优秀运动员竞技运动项目的迁移进行了归纳分析,旨在探寻出优秀运动员竞技运动项目迁移的特征和规律.