The Relationship Between Running Economy and Biomechanical Variables in Distance Runners

In this study, we analyzed the relationship between running economy (RE) and biomechanical parameters in a group running at the same relative intensity and same absolute velocity. Sixteen homogeneous male long-distance runners performed a test to determine RE at 4.4 m.s^-1, corresponding to 11.1% below velocity at the ventilatory threshold. We found significant correlations between RE and biomechanical variables (vertical oscillation of the center of mass, stride frequency, stride length, balance time, relative stride length, range of elbow motion, internal knee, ankle angles at foot strike, and electromyographic activity of the semitendinosus and rectus femoris muscles). In conclusion, changes in running technique can influence RE and lead to improved running performance.     

Effect of Stride Length Variation on Oxygen Uptake during Level and Positive Grade Treadmill Running

Abstract

Sixteen men were studied during 6-min bouts of motorized treadmill running at 230 m · min^–1 and 0% and 4% grade to compare [Vdot]O₂ while using freely chosen stride lengths (CSL) and stride lengths approximately 8% shorter (SSL) and longer (LSL) than CSL. The study also attempted to determine whether stride length variations of these proportions altered [Vdot]O₂ differently at the two grades. CSL were greater (p<.05) at 0% than 4% with mean values of 133.5 and 131.5 cm, respectively. Two-way ANOVA (Stride x Grade) with repeated measures yielded significant F values (p<.05) for the main effects of both stride length and grade but not for interaction between the two factors. Mean [Vdot]O₂ values were 44.95 and 56.80 ml · kg¹ · min^–1 at 0% and 4% grade, respectively. The Tukey w procedure was used for comparing the main effect means across both grades for the three stride lengths. These means were 50.94, 49.88, and 51.80 ml · kg¹ · min^–1 for SSL, CSL, and LSL, respectively, with the CSL mean significantly less than the SSL and LSL means (p<.05). Stride length variations of approximately ±8% did not alter [Vdot]O₂ differently at the two grades, and although [Vdot]O₂ for SSL and LSL was not different, [Vdot]O₂ was significantly (p<.05) increased by 2.1% for SSL and 3.8% for LSL. Not all individual patterns followed the group norm, however, in that three subjects were more economical with short stride lengths and two were more economical with longer strides.     

跑台上走、跑能量消耗与运动速度的相关关系研究

目的:研究走、跑模式下健康成年男子单位时间单位体重的能量消耗与运动速度的相关关系以及单位距离单位体重的能量消耗与运动速度的相关关系;探讨相同速度走、跑两种不同的运动模式下能量消耗特征;方法:19名男性大学生作为研究对象。使用跑台控制速度,采用走、跑两种运动模式,每一速度至少测试6min,以速度递增的方式进行测试,走、跑模式转换时休息至安静状态。使用VO2000测试安静以及运动中的气体代谢参数,PO-LAR表测试心率;结果:建立走模式以及跑模式下的能量消耗与速度之间的拟合方程;单位时间单位体重的能耗与走速二次曲线拟合方程的复相关系数r2=0.88;单位时间单位体重的能耗与跑速线性拟合方程的复相关系数r2=0.72;两条拟合曲线的交点坐标为(2.35m/s,141.7cal/kg/min);在测试速度范围之内,同等速度下走与跑的单位时间的能耗具有显著性差异(P<0.01),跑的能耗显著大于走的能耗。单位距离单位体重的能耗与走速的2次拟合曲线的复相关系数r2=0.98,曲线最低点的坐标为(1.14m/s,0.553cal/kg/m),单位距离单位体重的平均能耗与跑速拟合曲线的复相关系数r2=0.68;结论:1)单位时间单位体重的能耗与走速呈二次曲线关系,单位时间单位体重的能耗与跑速呈线性递增关系;2)单位距离单位体重的能耗与走速呈"U"型曲线关系;单位距离单位体重的能耗与跑速呈线性递减趋势,说明在一定速度范围内随着跑速的增加单位距离单位体重的能耗降低。     

Aerobic Demand of Running Shoes Designed to Exploit Energy Storage and Return

This qualitative case study used tenets of critical race theory and a single focus group and individual interviews with 4 African American football athletes at a predominantly White institution of higher education (PWIHE) in an effort to bring the voices of this marginalized group into the dialogue on issues concerning institutional integrity in college sport. Institutional integrity involves an athletic program's actual commitment to the educational interests of college athletes as expressed through their structures, functions, and activities. Three themes emerged from the data: (a) there is a need for more African American role models in leadership positions within the athletic departments of these PWIHE; (b) there is a need for more financial support for athletes; and (c) African American athletes should be given a platform to voice concerns. These findings have implications for those educational stakeholders and researchers who are genuinely concerned with institutional integrity in college sport.     

Ground Reaction Force Symmetry during Walking and Running

Abstract

The purpose of this study was to determine the effect of triathlon training using multiple, short cycle-run sequences (multicycle-run training) on cycle-run performance. Twelve competitive triathletes, randomized into two groups, underwent multicycle-run training or normal training for 6 weeks. During this period, baseline training remained the same for both groups, and only the high-intensity component differed. The differentiated exercises were performed at or above 100% maximal aerobic velocity. The improvements in overall cycle-run performance were similar (3.3 ± 1.4 % and 6.1 ± 1.7 % rise in performance in multicycle-run and normal training, respectively). However, the improvement in performance was significantly greater for the multicycle-run training (- 11.2 ± 6.8 s versus ?1.2 ± 7.7 s for multicycle-run training and normal training, respectively) during both the cycle-run change and the first 333-m lap, which together are termed the cycle-run transition. We concluded that 6 weeks of multicycle-run training did not induce greater improvement in cycle-run performance than did normal training in competitive triathletes. However, it did induce significant improvement in the cycle-run transition. This finding indicates that multicycle-run training may help competitive triathletes to develop greater skill and better physiological adaptations during this critical transition period of the triathlon race.     

改进体育课中长跑教学的措施

体育课中长跑教学需要教师在教学中采用多种形式的教学措施来改进目前较为枯燥和辛苦的教学方法 ,使学生能积极自觉地参与中长跑项目的学习和练习 ,促进学生身体素质的发展。     

Running quietly reduces ground reaction force and vertical loading rate and alters foot strike technique

This study aimed to determine if a quantifiable relationship exists between the peak sound amplitude and peak vertical ground reaction force (vGRF) and vertical loading rate during running. It also investigated whether differences in peak sound amplitude, contact time, lower limb kinematics, kinetics and foot strike technique existed when participants were verbally instructed to run quietly compared to their normal running. A total of 26 males completed running trials for two sound conditions: normal running and quiet running. Simple linear regressions revealed no significant relationships between impact sound and peak vGRF in the normal and quiet conditions and vertical loading rate in the normal condition. t-Tests revealed significant within-subject decreases in peak sound, peak vGRF and vertical loading rate during the quiet compared to the normal running condition. During the normal running condition, 15.4% of participants utilised a non-rearfoot strike technique compared to 76.9% in the quiet condition, which was corroborated by an increased ankle plantarflexion angle at initial contact. This study demonstrated that quieter impact sound is not directly associated with a lower peak vGRF or vertical loading rate. However, given the instructions to run quietly, participants effectively reduced peak impact sound, peak vGRF and vertical loading rate.     

黑龙江长跑运动员不同跑速下步频与步幅的研究

为了深入研究长跑运动中步频、步幅对运动员身体机能和训练水平的影响,对黑龙江省体工队长跑项目的10名运动员进行了不同跑速下的步频、步幅及对心率变化的影响的测试。并根据测试结果,分析讨论了运动员不同跑速下步频、步幅的变化规律,及对心率变化的影响,发现随跑速的增加,步频、步幅会产生相应的变化,且心率有增加趋势;并且在同一跑速下,运用不同的步频跑,心率变化存在差异性;还发现步频的变化与体脂含量存在较大的相关性,相关系数达到0.85(P<0.05)。希望通过长跑运动中的步频、步幅的研究,为实现长跑技术的优化,提高训练效果,制定科学的训练计划提供理论基础。     

论跳远成绩与助跑速度中几个相关因素的关系

助跑速度是决定跳远成绩的重要因素。影响助跑速度的充分发挥又是多方面的。本从理论上分析了影响跳远运动成绩的助跑速度中几个相关的因素，并提出了提高快速助跑效果的理论间接和方法。     

学生中长跑猝死的影响因素及预防对策

本文以近两年频繁发生的学生中长跑猝死事件为研究对象,重点研究学生中长跑猝死的影响因素：心脏、学生体质、学生不良生活习惯、心理应急反应对猝死的影响。并提出预防对策：学校体育应该改革现有体育评价机制,激励学生积极主动参与中长跑运动;宣传和普及中长跑猝死的急救知识和方法;建立学生体育运动意外伤害保险机制。家长应做好学生早期心脏检查和体育意识培养;学生自身做好自我医务监督,掌握运动保健知识。     

男、女大学生哈佛台阶试验指数与中跑评价标准的比较实验研究

为了研究男、女大学生的哈佛台阶试验指数与其1000m、800m跑的测试的评价标准的一致性，进一步完善男、女生的台阶试验评价标准，依据《学生体质健康标准》(试行方案)的内容，通过对大学生的现场测试与资料研究、比较研究以及运用SPSS10．O统计分析软件包进行数理统计。实验研究与数理统计表明，男生的台阶试验得分与中跑得分两个评价标准不完全一致；而女生的台阶试验得分与中跑得分这两个评价标准基本一致。     

铁人三项自行车-跑换项过程的调整与训练

探讨了造成铁人三项自行车-跑换项过程中运动员常会出现不适感的原因.呼吸肌疲劳、脱水、糖原耗竭和感受器的传导反馈调整落后于身体活动变化,引起生物力学指标的不利改变,使跑的效率下降,可能是造成不适感的主要原因.自行车赛段的骑行位置和最后阶段的蹬车频率会对换项调整产生显著影响,运动员应注意根据自己的特点确定战术.换项过程中运动员身体所承受的特殊变化提示,针对比赛中将会遇到的情况进行专门训练,可能有助于提高运动员的耐受性,加快感受器的调整适应,减小生物力学指标的不利改变,减少运动损伤.     

大学生惧怕中长跑的成因及对策

通过调查研究分析大学生惧怕中长跑产生的 原因,结合体育教学实践,提出避免或消除大学生对中长跑惧怕、厌烦的心理的有效措施和方法。     

Epistemology and the Use of the .05 Level of Significance: A Rebuttal to Inductionism

In the first part of this study, the football potential of 67 football players was predicted from their scores on a football-potential test. The test battery consisted of motor ability items as well as football skill items. Substantial correlations were obtained between most test items and the test criterion, the sum of T scores. Size, as depicted by McCloy's classification index (C.I.), had a negative, nonsignificant correlation with the criterion. The discriminative power of the battery was evidenced by the highly significant correlation between the test criterion and the coaching staff's ranking of individual players (rho = .840). It was concluded that athletic potential in football can be predicted by testing. In the second part of the study, football teams from three different strata of competition were evaluated on the basis of the test battery. The battery substantiated a step-wise progression between the teams on most items, with significant differences being noted. The test showed validity, in that the test criterion (the sum of T scores) was significantly different between the teams.     

有效促进中学生中长跑能力的相关因素分析

中长跑运动作为一项运动量较大,且运动形式较为单一的体育运动项目,既需要耐力又需要速度,既需要力量又需要协调、灵敏性;在技术上要求跑得轻松、协调、身体重心平衡,有良好的节奏。要在日常训练中提升训练效率并获得较好的训练成果并非易事,只有把各种有效因素完美结合起来训练,才能促进训练的整体效率与质量。     

高校开展中长跑教学的现状及提高教学效果的方法与手段

采用问卷调查法，对大学生所喜爱的运动项目与动机进行调查。揭示了高校中长跑教学的难点及问题，并有针对性地提出注重学生意志品质的培养、增加趣味性教学内容、运用启发性教学、变换跑的形式、变换练习的环境和游戏比赛法等手段。     

女大学生身体自尊与体育学习项目兴趣及选择意向关系研究

通过随机抽取1 100名女大学生作为研究对象,研究女大学生身体自尊水平与体育学习项目兴趣和选择意向的关系。相关分析表明,女大学生身体自尊水平与体育学习项目兴趣与选择意向相关;女大学生身体自尊及各个下维维度是引起某些学习项目兴趣和选择意向不一致的重要因素。并提出相应身体自尊的干预措施,引导女大学生正确地进行选课。     

从单向传播到一体化:体育组织与媒介关系形态研究

采用文献资料调研和逻辑分析法回顾了体育组织与媒介关系发展的历史,从两者相互交织的利益取向出发,将体育组织与媒介关系分为:媒介对体育及体育组织的介入期、体育组织与媒介关系稳定发展期和共生成熟期。研究结果认为,体育组织与媒介关系形态表现为单向传播关系、合作关系和共生关系;这3种关系形态不仅仅是纵向的、历史演变的结果,同时也是一种横向的、在当今社会也同时存在的关系形态;决定体育组织与媒介关系形态的因素包括体育制度与媒介制度、媒介传播力以及受众对媒体的依赖程度。     

出生体重与3～6岁幼儿身体形态特征相关研究

运用比较分析法,对出生体重与3~6岁幼儿身体形态特征相关研究。结果表明:出生体重与3~6岁幼儿身体形态特征存在一定的关联度,不同出生体重幼儿身体形态特征的差异,主要体现在重与轻两组幼儿。出生体重重的幼儿身体形态发育处于领先,出生体重轻的幼儿身体形态发育低于其他幼儿;不同出生体重幼儿身体形态指标,随着年龄增长而增长,但增长速度不同,体重增长速度最快,其次是身高、坐高、克托莱指数、胸围,增长速度最慢。     

The Relationship of the Sit and Reach Test to Criterion Measures of Hamstring and Back Flexibility in Young Females

Abstract

The purpose of the present investigation was to determine the relationships of the sit and reach test, a component of the American Alliance for Health, Physical Education, Recreation and Dance Health Related Fitness Test, 1980, with criterion measures of back and hamstring flexibility. Young females (N = 100) with a mean age of 14.08 years ± .825 were administered two trials of three tests. The measurements included the sit and reach test, passive hamstring flexibility using a Leighton Flexometer, and a test of back flexibility using a protocol suggested by Macrae and Wright in 1969. Test-retest reliability estimates exceeded .90 for all measurements. Results indicated that the sit and reach test had a moderate relationship (r = .64) with passive hamstring flexibility. The correlations between the sit and reach test and total back flexibility (r = .07), upper back flexibility (r = ?.16), and lower back flexibility (r = .28) were low. These findings indicate the sit and reach test has moderate criterion-related validity when used as an assessment of hamstring flexibility, but appears not to provide a valid assessment of back and, in particular, low back flexibility which is one of the reasons it was included in the Health Related Fitness Test.