Effect of different stretching strategies on the kinetics of vertical jumping in female volleyball athletes

Purpose： The present study aimed to examine the effect of static stretching （SS） and a sport-specific dynamic stretching （DS） session at two specific post-stretch time intervals in highly trained female athletes （age 19.90 ± 1.60 years; height 1.80 ±0.06 m; mass 76.87 ± 9.95 kg） on kinetic parameters of peak force, time-to-takeoff, and rate of force development. Methods： The data were collected over 3 days （randomized within subject design with control session）. Following each stretch session （SS vs. DS vs. control） of equal duration （7 min total： 30 s per targeted muscle group） participants performed countermovement jumping on a force platform at 1 and 15 rain after stretching. Results： The DS session significantly improved upon kinetic variables of rate of force development, peak force, and time-to-takeoffrelative to SS at 1 min after stretching. No significant effect was found at 15 min. Conclusion： Together these findings suggest that when training and competing to jump quickly and maximally the female athlete should incorporate DS instead of SS as part of their pre-competition warm-up, but conduct performance within 15 min of their warm-up to elicit maximal gains

On the change of some biochemistry indexes and nutrition intervention in weight loss trials of female Judo athletes

This thesis expounds the body function state change of the female judo athletes and attempts to probe the method of improving the capacity of sports of female judo athletes,through the research of biochemistry index change and nutritional interveution effect during their weight loss period.The research objects are 24 judo athletes from Inner Mongolia and they are randomly divided into groups of common loss of weight(n=8),loss of weight with common nutrition(n=8) and loss of weight with nutrition intervening(n=8) according to their weight.The experiment period is 2 weeks.Conclusion:(1)The judo athletes should be enforced with the food rich in Fe and protein to avoid anemia.(2)The nutritional complement like glutamine et cetera can improve the athletes body function and capacity of sports,and relieve fatigue efficiently.

Analysis of stress fractures in athletes based on our clinical experience

AIM:To analyze stress fractures in athletes based on experience from our sports medicine clinic.METHODS:We investigated the association between stress fractures and age,sex,sports level,sports activity,and skeletal site in athletes seen at our sports medicine clinic between September 1991 and April 2009.Stress fractures of the pars interarticularis were excluded from this analysis.RESULTS:During this period(18 years and 8 mo),14276 patients(9215 males and 5061 females)consulted our clinic because of sports-related injuries,and 263 patients(1.8%)[171 males(1.9%)and 92 females(1.8%)]sustained stress fractures.The average age of the patients with stress fractures was 20.2 years(range 10-46 years);112 patients(42.6%)were 15-19 years of age and 90(34.2%)were 20-24 years of age.Altogether,90 patients(34.2%)were active at a high recreational level and 173(65.8%)at a competitive level.The highest proportion of stress fractures was seen in basketball athletes(21.3%),followed by baseball(13.7%),track and field(11.4%),rowing(9.5%),soccer(8.4%),aerobics(5.3%),and classical ballet(4.9%).The most common sites of stress fractures in these patients were the tibia(44.1%),followed by the rib(14.1%),metatarsal bone(12.9%),ulnar olecranon(8.7%)and pelvis(8.4%).The sites of the stress fractures varied from sport to sport.The ulnar olecranon was the most common stress fracture site in baseball players,and the rib was the most common in rowers.Basketball and classical ballet athletes predominantly sustained stress fractures of the tibia and metatarsal bone.Track and field and soccer athletes predominantly sustained stress fractures of the tibia and pubic bone.Aerobics athletes predominantly sustained stress fractures of the tibia.Middle and long distance female runners who sustained multiple stress fractures had the female athlete triad.CONCLUSION:The results of this analysis showed that stress fractures were seen in high-level young athletes,with similar proportions for males and females,and that particular sports were associated with specific sites for stress fractures.Middle and long distance female runners who suffered from multiple stress fractures had the female athlete triad.

Sex differences in injury rates in team-sport athletes:A systematic review and meta-regression analysis

Background:Team-sport players have a particularly high injury risk.Although female sex is considered a risk factor,it is still unknown whether female and male team-sport players,in fact,differ in their injury rates.We aimed to compare injury rates between female and male players by systematically reviewing and meta-analyzing injury surveillance studies of both sexes in order to evaluate sex-specific differences in team-sport injuries.Methods:Studies that prospectively collected injury data for high-level female and male players(age≥16 years)in basketball,field hockey,football(soccer),handball,rugby(union and sevens),and volleyball were included.Two reviewers(AZ and ALR)independently assessed study quality and extracted data for overall,match,training,and severe injuries(>28 days’time loss)as well as data regarding injury locations and types.Incidence rate ratios(IRRs)were pooled in a meta-analysis,and meta-regression analysis was performed when 10 or more studies were available.Results:Of 20 studies,9 studies reported injury data from football,3 studies from rugby,3 studies from handball,1 study from basketball,1 study from field hockey,2 studies from volleyball,and 1 study from basketball and field hockey.For overall injuries,the pooled IRR=0.86(95%confidence interval(95%CI):0.76-0.98)indicated significantly more injuries in male than in female players.For injury location,the pooled IRR showed higher injury rates in male athletes than in female athletes for upper extremity,hip/groin,thigh,ande foot injuries.Female players had a significantly higher rate of anterior cruciate ligament injuries(IRR=2.15,95%CI:1.27-3.62)than male players.No significant sex-specific differences in IRR were found for match,training,severe injuries,concussions,or ankle sprains.Conclusion:Our meta-analysis provides evidence for sex-specific differences in the injury rates in team sports.Further epidemiological studies including both sexes in sports other than football are needed in order to strengthen the evidence.

Magnetic Resonance Imaging-Measured Adductor Muscle Volume and 100 m Sprint Running Performance in Female Sprinters

The purpose of this study was to determine the specific muscles that may contribute to sprint performance. Eleven female 100-m sprinters and nine non-sprinters volunteered. Thigh muscle volume (MV) was measured using magnetic resonance imaging (MRI) images obtained from the spina iliaca anterior-superior to below the distal end of the femur. The MV of the adductors, quadriceps and hamstrings was calculated. Evidence for the null/alternative hypothesis was provided thorough the calculation of Bayes Factors (BF10). Differences represented as median δ(95% credible interval). Absolute MVs in the quadriceps [1.287 (0.315, 2.39), BF10: 14.3], hamstrings [3.032 (1.886, 4.482), BF10: 9487.4] and adductors [3.22 (1.994, 4.654), BF10: 23,360.2] were greater in sprinters than in non-sprinters. This was also observed when MV was normalized to body mass (cm3/kg). Absolute and relative MVs in the adductor longus, the adductor brevis, the adductor magnus, pectineus, and gracilis were also greater in the sprinters. However, percentage of component adductor relative to total adductors MV appeared similar between the two groups. There was no evidence for a correlation between sprint time and quadriceps, hamstrings and adductors MV relative to body mass. Within the adductors, there was evidence for a correlation between sprint time and adductor brevis MV relative to body mass [r = −0.652, BF10: 3.028, δ−0.548 (−0.870, 0.040)]. Although the credible interval was wide, our results suggest that the adductor brevis may contribute to sprint running performance in female sprinters. This may be related, in part, to supporting the flexion and medial rotation of the thigh.

Bone Quality in Female Ballet Dancers: A Possible Determinant of Bone Health

Hypotheses:Values of serum markers related to bone quality are abnormal in young female ballet dancers. Methods: In 13 elite Japanese female ballet dancers (average age, 22 years), markers related to bone quality were investigated. These included: serum homocystein (HC), a marker of increased oxidative stress;pentosidine (Pent), a marker of glycation- or oxidation-induced non-enzymatic cross-links;markers of bone metabolism (bone alkaline phosphatase, BAP;tartrate-resistant acid phosphatase 5b, TRAP5b) and bone mineral density (BMD). It was determined whether there is a relationship between bone quality markers’ levels are related to amenorrhea and/or fatigue fractures. Results: Two dancers had fatigue fractures and 3 had a history of secondary amenorrhea. The average BMD was 1.305 ± 0.12 (g/cm2), in all these cases the Z-score was higher than -1.0. Although the serum levels of BAP, TRAP5b, and HC were normal in all examined dancers, in 2 out of 3 dancers with a history of secondary amenorrhea, pentosidine serum levels were increased. No relationship between bone quality markers’ levels and fatigue fractures was found. Conclusion: Latent deterioration of bone quality may occur in female athletes with secondary amenorrhea and otherwise normal BMD and calcium metabolism markers.

Vitamin D Status and Bone Mineral.Density in Female Collegiate Dancers and Cheerleaders

Bone mineral density reflects an athlete＇s cumulative history of energy availability, physical activity, and menstrual status, as well as nutritional and environmental factors. Although sports with high-impact loading are associated with higher bone mineral density than low-impact or non-impact sports, confounding variables are differences in the athletes＇ body size and sport-specific training. The purpose of this study was to determine if bone mineral density （BMD） and vitamin D status are different between two groups of female collegiate athletes who have comparable body size/weight requirements, but who engage in qualitatively different training regimens. Full body, spine and dual femur BMD was assessed by dual energy X-ray absorptiometry （DXA） in members of a university pep-dance team （n = 10） or cheer team （n = 9）, ages 18-22. Plasma vitamin D status was assessed by ELIZA. There was no significant difference between the groups for total body BMD （1.23 g/cm^2 dance vs 1.22 g/cm^2 cheer, P = 0.70）, spine BMD （1.39 g/cm^2 dance vs 1.36 g/cm^2 cheer, P = 0.72） or dual femur BMD （1.20 g/cm^2 dance vs 1.11 g/cm^2, P = 0.23）. Insufficient serum vitamin D status （20-32 ng/mL） was found in 74% of the athletes （27 ± 4 ng/mL, dance and 25 ± 8 ng/mL, cheer）. In addition, estimated daily vitamin D and calcium intakes were less than the RDA for both dancers and cheerleaders. Despite nutritional insufficiencies, BMD was not significantly different between the low-impact activity pep dance team and high-impact activity cheer team, suggesting that the type of physical activity was not as important for BMD in these athletes as participating in 20＋ hours a week of physical activity, which could have counteracted the negative effects of the nutrient insufficiencies on their bone health.

Comparison of the‘Seattle’and‘International’Criteria Electrocardiogram Interpretation in Division II Female Collegiate Athletes:A Preliminary Study

Purpose A 12-lead electrocardiogram(ECG)is a screening tool to detect abnormalities that may predispose athletes to sud-den cardiac death.Newer standardized criteria have been introduced to better interpret ECG data,however this research has predominantly focused on male athletes.It is important to include female athletes in research to better define ECG character-istics in this population.The purpose of this study was to compare the Seattle and International Criteria ECG abnormalities in Division II female collegiate athletes of various ethnicities.Methods Fifty-six females(age 20.2±1.4 years;height 1.70±0.7 m;weight 69.5±8.9 kg)completed a resting 12-lead ECG protocol.ECG data was classified as‘normal’and‘abnormal’according to the parameters of each criterion and abnormal conditions were noted.Chi-square analysis was used to assess statistical comparisons between criteria.Results There was a significant difference in abnormal classifications as the total number of ECGs identified as abnormal using the Seattle Criteria decreased from 12(21.4%)to 2(3.6%)when using the International Criteria(P<0.05).African American athletes had a higher number of abnormal ECG’s compared to White and Latina athletes using the Seattle Criteria(P=0.03).Conclusions The International Criteria significantly reduces the total number of abnormal ECG readings in female collegiate athletes compared to the Seattle Criteria and did not overly identify African American athletes with abnormalities.Further research is necessary to expand on this study and clearly define criteria for female athletes of various ethnicities.

中国女性运动员媒介形象的架构分析

本项研究基于认知语言学架构理论分析《中国日报(英文版)》女性运动员相关报道,形成了以下发现:第一,报道主要包括“战争,旅程,表演,自然和建筑”隐喻性架构和“能力、竞争、自信、努力、成果、伤病”非隐喻性表层架构;第二,这些表层架构激活了“为国争光与自我价值相统一”“技能价值与精神价值相融合”的深层架构;第三,报道整合了连贯、凸显、递进升格等多种架构机制,塑造了多元化的女性运动员媒介形象,展示了中国以人为本的体育人文精神和积极活力的国家形象,其报道策略能为其他媒体讲好中国体育故事提供借鉴。

我国优秀女子高尔夫球员短杆挥杆技术运动学分析

目的:探究中国优秀女子高尔夫球员的短杆挥杆技术特征,为高尔夫球项目的科学化训练提供理论支持。方法:采用三维高帧录像解析法,对比赛过程中的12名中国优秀女子职业球员长草区短杆挥杆动作进行拍摄分析。研究结果:①挥速(32.42±6.27 km/h)与球速(32.23±4.96 km/h)均值相近,水平飞行距离与挥速、球速呈正相关(p<0.05),起飞角度与水平飞行距离负相关(p<0.05)。②上挥杆阶段的右髋角变化量与水平飞行距离正相关(p<0.05)。③上杆顶点时,在额状面上髋转动幅度分别与起飞角度、水平飞行距离、滚动距离及站位宽度皆呈负相关(p<0.05)。④下挥杆用时(0.28±0.03s)与送杆用时(0.29±0.09s)相近,下挥杆用时约为上挥杆用时(0.68±0.10s)的1/2。研究结论:①挥速与球速均值相近,在实际短杆击球环境下杆头速度不能完全转化为球速。②上挥杆阶段,减少右肩、右肘和右腕角度是提高挥速、球速有效方式。此阶段,增大髋向右转动幅度可有效增加水平飞行距离。③站位宽度减少,有利于上挥杆阶段重心上移幅度减少,进而增加起飞角度。

优秀女子柔道运动员产后恢复训练的个案研究

目的:探索女性运动员产后恢复训练的系统性体能康复训练方案和监控方法,为女性运动员产后恢复训练提供参考。方法:以优秀女子柔道运动员于颂产后恢复训练为例,从产后问题改善、伤病康复防治、体能恢复提高等三个方面制定为期18周的系统性体能康复训练和监控记录方案,并对其后续训练比赛进行跟踪服务保障。结果:通过18周系统性体能康复训练,使运动员的产后问题和体能得到改善,伤病问题控制良好,上肢力量呈递增式提高,下肢力量更加均衡,最终顺利恢复实战训练并取得优异比赛成绩。结论:产后运动员通过系统性体能康复训练和监控,仍能取得优异成绩,该产后恢复训练方案对延长女性运动员运动寿命具有积极意义。

“她力量”的彰显:北京冬奥会中我国女性运动员媒介形象构建——框架理论视域下《体坛周报》报道审析

随着国际奥委会倡导的性别平等和女性社会地位的提升,女性运动员在媒体报道中日趋形成一股“她力量”。基于框架理论,对2022年北京冬奥会比赛期间《体坛周报》针对我国女性运动员的新闻报道情况进行统计和梳理。发现报道内容以介绍运动员获奖情况为主,报道立场以正面态度为主,报道主题以传播比赛内容和体育精神为主,展现出我国女性运动员自立自信、勇敢坚韧、追求成功与突破自我的性格特质,构建起“享受体育的自我突破者”“绽放个性的青年奋斗者”和“重塑定义的女性支持者”的媒介形象。进一步分析媒介形象的构建机理,得出其受社会环境变化、价值观念引导、国家政策以及媒介自身的实践规律等因素的影响,希望更多媒体能够关注和建立我国女性运动员的媒介形象,以“她力量”促进新时代体育价值观和体育精神的传播。

山西省女子摔跤运动员2018—2022年比赛和训练期间免疫指标变化分析

目的:探讨山西省女子摔跤运动员比赛和训练期间的身体机能和免疫状态,为教练员采取合理有效的训练措施和方案提供数据支撑,为体育管理者制定科学系统的比赛程序和阶段任务提供方案指引。方法:采用文献资料法、专家访谈法、实验法、数理统计法,对山西省10名女子摔跤运动员2018—2022年比赛和训练期间的免疫指标变化情况进行分析。结果:(1)运动员的免疫机能在冬季集训期整体偏低,在其他3个阶段基本维持正常范围,并呈一定规律波动。(2)备赛期,随着训练强度增大,免疫功能短期变弱;经过干预后,参赛期内免疫功能先升后降,其中赛前升至最佳状态,赛后出现短期降低;调整训练期内,随着身体恢复,免疫机能整体升高,训练强度加大后有所下降,经辅助调理后,9~10月份回升至较佳状态。(3)2018—2022年运动员免疫机能呈现相似的变化规律,无显著性年度差异。结论:山西省10名女子摔跤运动员在2018—2022年参赛和训练期间各免疫相关细胞群和生化指标及变化趋势均处于较理想状态。

体育性暴力规制的国际经验及其启示——以美国、德国、韩国为例

体育性暴力是全球体育界逐渐增多的暴力形式之一。如何有效规制是当下迫切需要解决的问题。笔者采用文献资料法和逻辑分析法,对美国、德国以及韩国体育性暴力的规制实践进行分析。研究表明,美国、德国和韩国体育性暴力规制实践在立法、预防、调查、救济预防等方面各具特色,对我国构建完善的体育性暴力规制体系具有重要的经验借鉴意义。其中,美国在规制过程中判例法与成文法并重,救济渠道完备;德国在立法的基础上注重事前预防与体育队伍建设;韩国建立了教练“黑名单”,成立了专门的调查组。结论:我国应在现有的基础上进一步完善立法,为规制体育性暴力提供制度保障;构建专项的防控机制,实现体育性暴力的事前预防;成立专业调查机构,为运动员提供专业的救济措施等。

中国女排运动员的媒介形象研究——以《新体育》2013—2022年报道为例

运用文献资料、内容分析、文本分析等研究方法,对《新体育》2013—2022年间的报道数量、篇幅、主题和倾向进行分析,发现《新体育》重视对女排运动员的报道,报道以长篇报道为主,辅以短篇报道,主题聚焦在女排的赛场表现,积极正向的报道较多,以相对客观、公正的视角呈现了女排运动员的集体形象和个体形象。为进一步优化对女性运动员媒介形象的塑造,体育新闻业应继续培养相关领域的专业人才;提高采编人员的性别意识和敏锐度;借鉴国际奥委会的《展现方式指南》,制定符合国情的展现方式指南;积极承担社会责任,做好舆论引导。

高水平女性运动员离心超负荷跳深及下肢生物力学表现研究

目的:研究旨在探究高水平女性运动员在执行离心超负荷跳深任务(AEL-DJ)时下肢关节的生物力学特征,明晰离心超负荷的最佳参数值,以期为女性运动员制定跳深训练计划时提供一定的理论参考。方法:10名女子高水平运动员完成下落高度(20cm、30cm、40cm、50cm和60cm)联合负重(10%~20%BW,20%~30%BW)的AEL-DJ测试。采用三维动态捕捉系统与测力台同步采集受试者完成AEL-DJ过程中下肢刚度、关节力矩及功率等指标数据。结果:高水平女性运动员在执行AEL-DJ过程中,选择重负重搭配50~60cm高度时,下肢刚度、膝踝关节力矩、功率以及腾空高度等指标表现较好(P<0.05);当选择轻负重搭配20~30cm高度时,膝踝关节功率和腾空高度等指标表现较好(P<0.05)。研究结论:结果表明,在重负重下,选择50~60cm下落高度进行AEL-DJ练习,可释放最佳蹬伸功率及腾空高度,但膝踝关节外翻损伤风险高。轻负重搭配20~30cm下落高度,既表现较好腾空高度又兼备高下肢刚性,在提高跳跃表现的同时避免损伤,因此推荐女性运动员选择此组合练习。

女子竞技体操运动员的合理膳食研究

女子竞技体操作为技能主导类表现难美类项群的一种,不仅需要运动员重视体育运动技能的提升,还需要保持良好的身体形态。合理的营养膳食对于提高运动员的体能、改善身体形态具有重要意义。本文基于女子竞技体操的基本特点,以及在比赛和平时训练时所需要的营养物质的要求,总结出女子竞技体操运动员合理膳食的需求以及存在的问题,并提出合理的膳食建议。

Pelvic region bone density,soft tissue mass,and injury frequency in female professional ballet dancers and soccer athletes

We recently observed a high prevalence of low pelvic bone mineral density(BMD)in female professional ballet performers.Because this population is susceptible to musculoskeletal overuse injuries,we aimed to determine which regions of the pelvis may be at greatest risk compared to general population females(GENPOP)as well as professional female soccer players(SOCCER,a comparison to other elite athletes regularly subjected to high degrees of loading).Three groups of age-matched females[(GENPOP;n=38,27±1yrs),(BALLET;single com-pany,n=36,26±3yrs),(SOCCER;single NWSL■club,n=34,25±1yrs)]consented to have their BMD and body composition assessed(DEXA,GE■).In addition to soft tissue and total and regional BMD analyses,a segmental analysis of the pelvis was performed to determine site-specific BMD for the iliac fossa,iliac fossa/iliac crest/ilium combined,pubic bone,ischium,and sacrum.A mixed-model ANOVA followed by a Tukey's post-hoc test was used to compare the groups(Type-I error;α=0.05).The BALLET group had lower pelvic BMD for all measures(Avg.%Diff.=15%-27%,p<0.001)compared to the SOCCER group and for the ischium(Avg.%Diff.=8%;p=0.007)and sacrum(Avg.%Diff.=7%;p=0.028)compared to the GENPOP group.The BALLET group had lower lean mass for all measures compared to the other groups(Avg.%Diff.=12%-18%;p<0.01).Professional ballet performers exhibit reduced pelvic region soft tissue and site-specific BMD not previously detected using standard DEXA analyses.These findings highlight which pelvic regions may benefit from preventative strength training and/or nutritional interventions.

网络媒体冬奥会报道中的女性运动员形象呈现研究

运用文本分析法、词频分析法、聚类分析法等研究方法,选取四大门户网站平昌2018冬奥会和北京2022冬奥会报道为研究文本,对冬奥会女性运动员形象呈现特征与影响因素进行解析。从视觉呈现、聚类呈现和议题呈现三个维度,文章得出女性运动员形象主要呈现特征:视觉叙事成为形象呈现的新选择,体育精神成为形象呈现的新标签,并呈现出坚持不懈、敢于突破自我的“新巾帼英雄”形象;敢于展示温柔孝顺、贤妻良母的“多重家庭”形象;积极向上、阳光正面的新时代“社会楷模”形象以及缺失个性、模式固化的“泛娱乐”网红形象等视角多元、内涵丰富的女性运动员形象议题。网络媒体冬奥会女性运动员形象呈现的影响因素包括:性别文化建构的“政治符号”与“身体景观”;消费主义表征的“商品符号”与“价值偏差”;新闻框架映射的“刻板印象”与“角色偏离”。文章从扩散女性运动员榜样与示范效应,营造良好冬奥内外舆论环境;消除被符号化的媒介形象偏差,客观多元塑造女性运动员形象;建构网络议程引导公众议程,消除媒介的刻板印象及角色偏差等三个方面对大型体育赛事新媒体实践提出启示与借鉴。