Age at menarche in competitive figure skaters: variation by competency and discipline.

We estimated age at menarche in a cross-sectional sample of 159 competitive figure skaters aged 11-22 years. The sample represented three standards (test stream, pre-elite, elite) and three disciplines (free skaters, pair skaters, dancers). The status quo (yes/no) and retrospective methods were used. Estimated age at menarche based on probit analysis of the status quo data was 14.2 +/- 0.5 years, with 95% confidence intervals of 13.2 to 15.2 years. Mean recalled age at menarche for 67 skaters aged 16 years or over was 13.6 +/- 1.2 years. Comparisons of skaters by standard and discipline were limited to skaters > or = 16 years. Menarche was, on average, significantly later (P < 0.01) in elite (n = 36; 14.0 +/- 1.4 years) than in test stream (n = 15; 12.9 +/- 0.8 years) skaters. Age at menarche in pre-elite skaters (n = 16; 13.5 +/- 0.9 years) did not differ significantly from the other two groups. By discipline, menarche was, on average, significantly later (P < 0.01) in pair skaters (n = 12; 14.5 +/- 1.3 years) than in both free skaters (n = 38; 13.4 +/- 1.0 years) and dancers (n = 17; 13.4 +/- 1.4 years). Early maturing girls (menarche < 12.0 years; n = 2) were not represented in this sample of competitive figure skaters. Mean recalled age at menarche of mothers of skaters (n = 84) was 13.7 +/- 1.3 years and the mother-daughter correlation (n = 56 pairs) was 0.45 (P < 0.01). Later maturation was thus characteristic of competitive figure skaters, particularly in elite and more specialized pair skaters, and there was a significant familial resemblance.     

Testosterone concentrations in female athletes and ballet dancers with menstrual disorders

Menstrual disorders are common among female athletes and ballet dancers. Endocrine changes, such as high testosterone (HT) levels and high luteinizing hormone (LH)/follicle-stimulating hormone (FSH) ratios, may suggest functional ovarian hyperandrogenism which may induce such dysfunction. The aim of this study was therefore to evaluate endocrine status in female athletes and ballet dancers with menstrual disorders. Their nutritional status and dietary habits were analysed in relation to the testosterone levels. In a cross-sectional approach, 31 female athletes (18.1 ± 2.6 years) and 21 ballerinas (17.1 ± 0.9) with menstrual disorders participated in the study. The levels of serum LH, FSH, progesterone (P), estradiol (E2), prolactin (PRL), thyroid-stimulating hormone, testosterone (T) and sex hormone-binding globulinwere measured to assess hormonal status. In addition, the free androgen index (FAI) was calculated. Nutritional status, total daily energy expenditure and nutritional habits were evaluated. Girls were assigned to one of the following groups: low testosterone (LT) level, normal testosterone level or HT level. There were significant differences between ballerinas and other female athletes in terms of testosterone levels, FAI, age at the beginning of training, length of training period and age at menarche. The PRL level was lowest in the LT group while the FAI index was highest in the HT group. Daily energy and carbohydrate intakes were significantly lower in the HT group. T levels in the study subjects were found to be associated with nutritional factors, energy availability, age at the beginning of training and frequency of training. This is the first report of HT levels being associated with the status of a female ballet dancer, the age of menarche and the length of the training history. Further research is necessary to confirm the results in a larger study group.     

Food attitudes in female athletes: association with menstrual cycle length

The aim of this study was to examine the relationship between indicators of risk of disordered eating, body image and varied menstrual cycle lengths. Altogether, 151 female athletes were invited from 16 sports and 70 female non-athletic controls were recruited from a university lecture class. The participants completed several surveys, including demographics, menstrual cycle history, physical activity, Eating Disorder Inventory (EDI) and the Three Factor Eating Questionnaire (TFEQ). Selected EDI subscales were summed to reflect eating disorder risk and body image. Menstrual cyclicity was based on self-reported cycle length for the last 6 months (normal cycles = 26-32 days, irregular cycles < or =26 or >32 days). Athletes overall had more irregular cycles (29.1%) than the non-athletes (15.7%) (P < 0.05). There were significant differences in scores for eating disorder risk, body dissatisfaction, drive for thinness, cognitive restraint (TFEQ) and disinhibition (TFEQ), only when athletes were divided based on menstrual cyclicity (i.e. irregularly cycling athletes had higher scores than athletes with normal menstrual cycle lengths). No differences in these scores were found between non-athletes with normal or irregular menstrual cycle lengths. In conclusion, irregularly short or long menstrual cycle length is associated with subtle indications of higher risk of disordered eating in female athletes.     

山东水上项目女运动员月经情况调查与治疗方法初探

目的:通过对水上项目女运动员月经情况的调查,分析痛经和月经不调产生的可能原因,并对治疗方法进行初步探讨.方法:通过问卷调查收集了51例山东省水上项目皮划艇、赛艇、帆船、帆板女运动员月经的基本情况,并通过专家的指导对治疗方法进行了初步探讨.结果:(1)水上项目女运动员月经不调的发生频率高达49.02%,痛经的发生频率高达90.20%.(2)月经失常是由训练环境潮湿阴冷、饮食不足、训练量过大等多方面因素造成的.(3)月经失调需要综合性的治疗方法,其中中药调理收到了比较好的效果.     

我国优秀青年短道速滑运动员耐力特征的实验研究

通过研究我国优秀青年短道速滑运动员有氧耐力和无氧耐力的特征,为地方队教练和基层教练的训练和选材提供参考依据.方法:以22名我国优秀青年短道速滑运动员为测试对象,利用Monark 839E功率自行车和metamex 3b最大摄氧量测试仪,分别测定队员的10 s,30 s,60s无氧功和最大摄氧量.结果:青年男子运动员10 s,30 s,60s无氧功分别为9.84±0.72 w/kg,9.02±0.43 w/kg,7.20±0.57 w/kg,最大摄氧量为68.73±4.78 ml/min·kg;青年女子运动员10s,30s,60s无氧功分别为8.67±0.69w/kg,8.12±0.41w/kg,6.67±0.42 w/kg,最大摄氧量为56.76±3.91 ml/min·kg.结论:青年男子、女子的10 s无氧功明显低于速滑运动员,但是30 s和60s无氧功明显高于速滑运动员,该项目运动员的最大摄氧量水平较低.     

中外优秀田径运动员竞技年龄特征之比较研究

运用文献资料调研和数理统计法，对当今世界与中国优秀田径运动员在亚类项群、亚类分组项目的竞技年龄结构特征进行比较，分析两者之间的差异，旨在为我国田径项目多年训练过程的合理规划提供理论依据.     

运动员安静时脉搏声谱特征研究

运用自研的脉搏声谱检测仪,对不同项目和不同水平的运动员在训练前的脉搏声进行了测试。结果发现:正常安静时的脉搏声时域谱图的波峰都是单峰,且曲线平滑;当运动员前一天的疲劳没有恢复或出现其它情况时,其安静时脉搏声波峰为多峰且有拐点出现;不同水平的运动员在同样负荷后,其安静时脉搏声谱图的能量面积存在着较大差异。     

辽宁省青少年田径运动员运动损伤调查研究

对部分青少年运动员运动损伤原因进行调查,总结其共性,提出预防措施,以期为教练员和运动员在今后的训练和比赛中预防和减少运动损伤的发生提供参考。     

Neuromuscular characteristics of endurance- and power-trained athletes

In response to chronic physical training, the human neuromuscular system undergoes significant and specific adaptations. More importantly, these influences are the result of the type and quantity of physical activity. One of the simplest neuromuscular mechanisms is the spinal stretch reflex. The reflex system was previously viewed as inflexible, with a relatively fixed response that could vary only slightly. However, more recent data have identified an adaptive plasticity in the reflex system. In this respect, the reflex system can be used to assess training and aging adaptations of the human neuromuscular system. Due to their methodological simplicity, both the tendon-tap reflex and the electrically evoked Hoffmann reflex (H-reflex) can be used to assess training adaptations of the human neuromuscular system. The purpose of this paper is to review briefly the tendon-tap and H-reflex paradigms and delineate the research findings pertaining to changes in the reflex system with physical training. For purposes of clarity, this discussion will be divided into the following: (a) differences observed in the tendon-tap reflex, (b) differences observed in the H-reflex, and (c) role of interneurons in mediating these changes.     

Vertical jumping height and horizontal overhead throwing velocity in young male athletes

Abstract

The purpose of this study was to examine the effects of calendar and skeletal age, anthropometric dimensions, training history and their interactions on vertical jumping height and horizontal overhead throwing velocity in a cross‐section of 318 young male athletes (age range 9–16 years) participating in cross‐country skiing (n = 70), basketball (n = 40), apparatus gymnastics (n = 19), ice hockey (n = 50), track and field (n = 89) and wrestling (n = 50). Vertical jumping height was measured with four different loads held on the shoulders and then interpolated for loads representing 0 and 40% body mass. Horizontal overhead throwing velocity using both hands was determined for seven balls of different weights and then interpolated for weights representing 1 and 5% body mass.

Both vertical jumping height and overhead throwing velocity were found to increase (P< 0.01) from the skeletally youngest to the oldest cohort when the effects of body height and mass were controlled. The inter‐event comparisons did not reveal statistically significant differences in respect of vertical jumping height. Also in the overhead throwing tests, the inter‐event differences were small, although the analysis of variance revealed statistically significant (P< 0.001) differences for the skeletal age cohorts of 13 and 14 years. While the quantity of training had no effect on vertical jumping height, it explained the results in the overhead throwing test.

The effects of training on vertical jumping and horizontal overhead throwing among adolescent athletes were considered to be small, while maturational processes and anthropometric development followed by increase in calendar age were deemed to be of greater importance.     

我国学生运动员的特征分析和对策研究

通过研究表明,我国学生体育竞赛体制因推行体育举国体制而具有鲜明的特点,学训合一和学训分离并存是其主要特征;指出了影响学生体育竞赛管理体制的诸因素,主要包括管理结构单一、方法滞后,急功近利和运动员输送不畅,以及后勤保障相对薄弱;本文还提出了完善学生竞技体育管理体制的相应对策和建议。     

欧洲运动员义务教育阶段文化教育的特点及其启示

欧洲运动员义务教育阶段的文化教育具有灵活性、强制性和权责明确的特点.要解决我国运动员义务教育阶段的文化教育不足的问题,应充分认识到运动员义务教育阶段文化教育的重要性是前提,成立专门的组织机构,加快制度建设是保障,采取多种措施保证运动员义务教育阶段文化教育的质量是基础.     

我国优秀举重运动员成材的年龄特征

以我国现役举重运动员为研究对象,以年龄为依据,分析达到各运动级别的最佳年龄段,并以此勾画出我国优秀举重运动员的成材轨迹.结果表明：我国优秀举重运动员年龄意义上的成材轨迹表现为：15～18岁是成为一级运动员的最佳年龄段;17～22岁是达到健将级运动员的最佳年龄段;2025岁时的竞技能力已经过渡到国际健将级运动员水平.另外,通过对我国优秀举重运动员各训练阶段的年龄分布情况的分析,证明运动员各训练阶段与各等级运动员最佳年龄段的分布呈现出一致性.     

我国青年女子排球运动员的身体形态和专项身体素质

对97名参加2006年全国青年女排集训的运动员的身体形态和专项身体素质进行研究。结果表明，我国青年女子排球运动员的身高、指高和体重等身体形态指标与成年运动员还有较大差距，特别是缺乏身材高大的运动员，助跑摸高、连续摸高等专项身体素质水平还有待提高。     

Vertical jumping height and horizontal overhead throwing velocity in young male athletes.

The purpose of this study was to examine the effects of calendar and skeletal age, anthropometric dimensions, training history and their interactions on vertical jumping height and horizontal overhead throwing velocity in a cross-section of 318 young male athletes (age range 9-16 years) participating in cross-country skiing (n = 70), basketball (n = 40), apparatus gymnastics (n = 19), ice hockey (n = 50), track and field (n = 89) and wrestling (n = 50). Vertical jumping height was measured with four different loads held on the shoulders and then interpolated for loads representing 0 and 40% body mass. Horizontal overhead throwing velocity using both hands was determined for seven balls of different weights and then interpolated for weights representing 1 and 5% body mass. Both vertical jumping height and overhead throwing velocity were found to increase (P < 0.01) from the skeletally youngest to the oldest cohort when the effects of body height and mass were controlled. The inter-event comparisons did not reveal statistically significant differences in respect of vertical jumping height. Also in the overhead throwing tests, the inter-event differences were small, although the analysis of variance revealed statistically significant (P < 0.001) differences for the skeletal age cohorts of 13 and 14 years. While the quantity of training had no effect on vertical jumping height, it explained the results in the overhead throwing test. The effects of training on vertical jumping and horizontal overhead throwing among adolescent athletes were considered to be small, while maturational processes and anthropometric development followed by increase in calendar age were deemed to be of greater importance.     

我国艺术体操运动员身体形态特征研究

采用文献资料法、测试法以及数理统计法,对我国17名艺术体操队现役一线优秀运动员和47名各省市艺术体操后备力量进行了形态指标的测试分析,旨为我国艺术体操运动员的选材和训练提供理论和实践依据.结果表明:身体形态对于艺术体操运动员来说是从事本项目的首要条件,尤其是身体各环节间长度的比例,指间距-身高、跟腱长/小腿长A×100及坐高/下肢长C×100是艺术体操优秀运动员的典型形态指标.     

Influence of recovery intensity on time spent at maximal oxygen uptake during an intermittent session in young, endurance-trained athletes

In this study, we examined the effects of three recovery intensities on time spent at a high percentage of maximal oxygen uptake (t90[Vdot]O(2max)) during a short intermittent session. Eight endurance-trained male adolescents (16 +/- 1 years) performed four field tests until exhaustion: a graded test to determine maximal oxygen uptake ([Vdot]O(2max); 57.4 +/- 6.1 ml x min(-1) . kg(-1)) and maximal aerobic velocity (17.9 +/- 0.4 km x h(-1)), and three intermittent exercises consisting of repeat 30-s runs at 105% of maximal aerobic velocity alternating with 30 s active recovery at 50% (IE(50)), 67% (IE(67)), and 84% (IE(84)) of maximal aerobic velocity. In absolute values, mean t90[Vdot]O(2max) was not significantly different between IE(50) and IE(67), but both values were significantly longer compared with IE(84). When expressed in relative values (as a percentage of time to exhaustion), mean t90[Vdot]O(2max) was significantly higher during IE(67) than during IE(50). Our results show that both 50% and 67% of maximal aerobic velocity of active recovery induced extensive solicitation of the cardiorespiratory system. Our results suggest that the choice of recovery intensity depends on the exercise objective.     

Influence of recovery intensity on time spent at maximal oxygen uptake during an intermittent session in young,endurance-trained athletes

Abstract

In this study, we examined the effects of three recovery intensities on time spent at a high percentage of maximal oxygen uptake (t90[Vdot]O_2max) during a short intermittent session. Eight endurance-trained male adolescents (16 ± 1 years) performed four field tests until exhaustion: a graded test to determine maximal oxygen uptake ([Vdot]O_2max; 57.4 ± 6.1 ml · min^?1 · kg^?1) and maximal aerobic velocity (17.9 ± 0.4 km · h^?1), and three intermittent exercises consisting of repeat 30-s runs at 105% of maximal aerobic velocity alternating with 30 s active recovery at 50% (IE₅₀), 67% (IE₆₇), and 84% (IE₈₄) of maximal aerobic velocity. In absolute values, mean t90[Vdot]O_2max was not significantly different between IE₅₀ and IE₆₇, but both values were significantly longer compared with IE₈₄. When expressed in relative values (as a percentage of time to exhaustion), mean t90[Vdot]O_2max was significantly higher during IE₆₇ than during IE₅₀. Our results show that both 50% and 67% of maximal aerobic velocity of active recovery induced extensive solicitation of the cardiorespiratory system. Our results suggest that the choice of recovery intensity depends on the exercise objective.     

Oxidative stress in elite athletes training at moderate altitude and at sea level

Using a controlled parallel group longitudinal trial design, we investigated the effects of different training interventions on the prooxidant/antioxidant status of elite athletes: living and training at moderate altitude for 3 (Hi-Hi3) and 4 weeks (Hi-Hi), and for 4 weeks too, living high and training high and low (Hi-HiLo) and living and training at sea level (Lo-Lo). From 61 swimmers, 54 completed the study. Nitrites, carbonyls, and lipid peroxidation (LPO) levels were assessed in plasma. Enzymatic antioxidants glutathione peroxidase (GPx) and glutathione reductase (GRd), and non-enzymatic antioxidants total glutathione (GST), reduced glutathione (GSH) and oxidized glutathione (GSSG) were analysed in the erythrocyte fraction. At the end of the intervention, nitrites levels were similar in all altitude groups but higher than in the Lo-Lo controls (P?=?.02). Hi-HiLo had greater GPx activity than Hi-Hi and Hi-Hi3 during most of the intervention (P?≤?.001). GRd activity was higher in Lo-Lo than in Hi-Hi at the end of the training camp (P?≤?.001). All groups showed increased levels of LPO, except Lo-Lo, and carbonyls at the end of the study (P?≤?.001). Training at altitude for 3 or 4 weeks drives oxidative stress leading to cellular damage mainly by worsening the antioxidant capacities. The GSSG/GSH ratio appears to be related to perceived exertion and fatigue. The stronger antioxidant defence showed by the Hi-HiLo group suggests an inverse relationship between redox alterations and performance. Further studies are required to investigate the role of oxidative stress in acclimatization, performance, and health.     

山东省优秀游泳运动员专项柔韧素质测量与分析

采用文献资料法、问卷法、专家调查法、测试法,筛选出对游泳运动成绩有显著影响的专项柔韧素质指标,对山东省26名优秀游泳运动员的专项柔韧素质进行了测量和分析.通过分析,掌握山东省优秀游泳运动员专项柔韧素质的整体情况,找出不足,并提出针对性的训练建议,从而为科学诊断和改善游泳运动员专项柔韧素质发展水平,提高训练效果提供参考.