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.     

Biomechanical Effects of Fatigue on 10,000 Meter Running Technique

Abstract

A study of the effect of fatigue on the mechanical characteristics of running during a 10,000 meter race was undertaken using high speed cinematography and a computer analysis technique. Eight highly skilled male subjects were filmed at four intervals throughout the event. An analysis of variance for trends was conducted for each of the dependent variables indicating the adjustments made by the runners that accompanied fatigue over the four stages of the event. Runners countered fatigue by changing sections of their total gait pattern (stride length, stride rate, segmental body positions) and reducing running velocity. Toward the end of the race the runners became less competent in the positioning of the foot and leg at foot-strike, which increased the potential for a retarding effect. A more extended lower limb increased the energy requirements of the recovery phase during the latter stages of the race. Fatigue caused these highly skilled runners to systematically alter their technique throughout the race. These adjustments, however, were not excessive.     

不同步频和步幅的5km跑过程中运动员心率变化的对比研究

为了观察中长跑运动员长距离跑过程中步频和步幅的变化对身体机能反应的影响,8名运动员在跑台上分别采取主动加大步幅和主动减小步幅而增快步频的跑法,以相同的速度进行了两次5km跑,记录运动员在跑步过程中心率的变化并进行对比。结果显示,在相同速度5km跑的过程中,运动员采取主动减小步幅的跑法,其心率均值显著低于采取主动加大步幅的跑法。提示,长距离跑过程中,运动员采取主动减小步幅,或加大步频的跑法较为省力。     

浅谈步频对青少年短跑运动成绩的影响

本文运用文献资料综合法和调查访问法,对短跑运动员步幅的大小和短跑运动成绩的影响进行了研究。分析短跑的技术对成绩的影响和如何解决步幅小的问题进行了阐明。从中发现我国短跑运动员的步幅还处于较落后的状态。原因是一方面部分教练员只能过直观分析认为我国男子100米运动员步频有余,步幅不足;另一方面是决定速度的两个因素没有充分认识。     

从步长、步频的角度分析我国男子百米跑成绩滞后原因

本文通过文献资料法收集国内外优秀男子百米运动员的运动技术参数,并加以统计,从影响跑速的步长、步频因素对我国男子百米跑运动员成绩滞后的因素进行分析。结果表明：我国百米运动员的步长能力不足是影响速度能力和成绩提高的主要原因,应在优化步长、步频关系的基础上,以提高步长能力为突破口,强调运动员整体训练水平的提高,从而提高最大速度能力和运动水平。     

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。     

析100m速度特征之加速跑距离及其步态变化

通过对世界优秀运动员100m速度特征及其相关报道的结论与分析得出结论：1当代100m跑加速跑距离的研究室一个误区,加速跑距离长是高水平运动员最大速度大的外在表现特征,不能通过调整加速步态而达到提高成绩的目的;2运动员加速能力强的特征是加速度大而不是加速距离长;3步态特征之步长步频的变化是运动员高速跑中的自然协调,步长和步频应该作为一个整体来理解才有意义,简单的定论步长与步频谁代表了短跑的发展方向是误导;4建议100m训练重点放在技术与最大速度训练上,尽可能的发展动作速度．     

体院学生100m成绩与步长步频变化规律及特点分析

步长、步频是决定跑速的两个主要因素。体院学生 10 0m跑步长、步频在短跑教学后发生了怎样的变化 ?笔者就此进行了初步研究 ,结果表明 ,通过短跑教学后 ,绝大多数学生的步长、步频得到了改善和提高 ,步长和步频两个参数产生了新的组合 ,使 10 0m跑成绩得到了提高。在步长和步频两个因素中 ,男生表现为步长提高率大于步频提高率 ,而女生则表现为步频提高率大于步长提高率。     

分析比较中外短跑运动员途中跑技术的差异

通过文献资料、分析对比等方法,对短跑途中跑技术进行分析,发现我国运动员在途中跑“后蹬屈膝式”技术及放松、步幅、节奏等技术方面与国外优秀选手存在一定差距。     

世界优秀短跑运动员100m各分段步频、步长、平均速度变化规律的研究

利用数理统计法对世界优秀短跑运动员100m跑的各分段步频、步长等运动学指标进行评析，研究表明：世界优秀短跑运动员100m跑中长时间保持高速的途径是依靠自己的步长，而不是努力提高步频来保持；全程跑的加速节奏对全程的成绩有较大的影响；在各分段步长与步频对跑速的贡献具有显性差异。     

中长跑运动员步频步幅与摄氧量关系的研究

通过分析研究中长跑运动员的跑速和步频步幅与摄氧量、肺通气量和心率等心肺功能的关系,以及心肺功能和身体状况探讨长跑运动员跑步中生理特点与运动规律,为改进运动员的长跑运动技术,提高训练效果和运动成绩,科学有效制定训练计划和比赛的战术提供理论依据。     

Emotional responses during repeated sprint intervals performed on level,downhill and uphill surfaces

The purpose of this study was to test emotional responses during sprint intervals performed on a level, down and up surface. Fifty trained participants performed a maximal effort during a 60-m sprint and 10 repetitions of 60 m running sprints on a level, down and up surface on a 5.9% slope. Running speeds, emotional responses and heart rate were measured. Self-selected speeds were correlated with the rating of perceived exertion, the affective balance, the desire to stop and the resources needed for the task in all conditions whereas the pleasure, the desire to continue and the capacity to realise the task were correlated with speeds only during level and uphill running. Mean values of emotional parameters were significantly different (P < 0.05) during running on a flat surface, downhill and uphill. When the gradient of running surface is changed, the pattern of emotional responses was just translated, i.e. most of the slope between the evolution of emotional parameters and the repetitions were not significantly different whereas Y-intercepts were different.

Consented effort is highly correlated with the resources needed for the task (P < 0.001, r² = 0.72). We propose that the difference in the resources needed for the task between level, downhill and uphill running (F _{2, 1499} = 166.5, P < 0.001, Eta² = 0.18) is the most important key that explains our results.     

从速度滑冰的支撑特点看支撑方式对频幅组合与步速关系 的影响

运用3D技术对速度滑冰中频幅组合与步速关系进行了探讨，首次提出了在周期性项目中区分定点支撑方式与动态支撑方式的概念。分析得出．由低速向高速滑行时。在步频与步速关系中，动态支撑方式遵循定点支撑方式的变化规律；但在步长与步速关系中，动态支撑方式却有与定点支撑方式相反的结果。     

中长跑途中跑适宜步长的影响因素

从影响跑速的基本因素和支撑阶段的运动学参数两个方面对中长跑途中跑适宜步长进行了分析。结果表明：步长指数和步频能力与适宜步长的确定直接相关，而支撑时间与腾空时间的比值、支撑腿离地瞬间膝关节角度、支撑阶段身体重心水平位移距离等运动学参数则是影响适宜步长的主要因素。采用专项耐力指数对运动员的专项能力进行了分级，给出了不同专项能力水平运动员步长指数的适宜范围。     

The Effects of Muscular Fatigue on the Kinetics of Sprint Running

Abstract

In order to compare the kinematic and kinetic effects of fatigue on the mechanics of sprint running, 15 male subjects were filmed in the saggital plane while performing a short (50 meter) maximal exertion sprint and a long (400 meter) fatiguing sprint. The short sprint was filmed at 40 meters, while the long sprint was filmed at 40 and 380 meters. The films were reduced utilizing a digitizer coupled to a computer terminal. Analysis results were generated via a human motion analysis program. Kinematic and kinetic results were entered into the statistical analysis as differences between non-fatigued and fatigued values. Initially, quality of the performance (measured by the change in horizontal velocity of the body center of gravity) was statistically related to change in the kinetic variable of integrated muscle moment at each of the body joints. The kinetic variables found to be significant were then statistically compared to logically related changes in kinematic variables (temporally adjacent or concurrent). Changes in the generated moments about the hip and knee during ground contact were found to be related to the quality of the performer. Kinematic changes related to the significant moment changes indicated that, while the better sprinter (smaller velocity loss) closely maintained the kinetic and kinematic patterns, the poorer sprinter (larger velocity loss) inefficiently deviated in both areas. The lack of significance between the changes in upper limb moments and change in average velocity indicated that productive arm effort does not affect the level of performance in the fatigued condition.     

主观疲劳量表（RPE）评估足球运动员训练负荷的实证研究

应用主观疲劳量表（RPE）评价训练负荷的过程是一个心理生理过程,量化结果具有较大的主观性和不确定性,需将RPE训练负荷量化结果与生理指标测试结果进行结合分析。对16名大学生足球运动员的多次训练进行跟踪,采集每名运动员每次训练的训练前RPE值、训练后RPE值和整个训练过程的实时心率;采取训练后RPE值（Foster1算法）和训练累积RPE值（Foster2算法）,4种心率算法（Banister1、Banister2、Edwards和Stagno）对每名运动员每次训练的内部负荷进行测算;采用相关分析,对两种RPE算法所得每名运动员每次训练的内部训练负荷值与4种心率算法所得的内部训练负荷值的相关性进行检验。显示：两种RPE算法估算的运动负荷：与Banister1算法测算出的相关性平均分别为0.91和0.79;与Banister2算法测算出的相关性平均分别为0.62和0.57;与Edwards算法测算出的相关性平均分别为0.75和0.69;与Stagno算法测算出的相关性平均分别为0.55和0.54。显示：RPE能够有效地量化评估足球运动员的训练负荷,且“训练后RPE值”比“训练累积RPE值”能更加准确地反映足球运动员的训练负荷。     

Effects of cold water immersion on lower extremity joint biomechanics during running

The purpose of this study was to identify the influence of cryotherapy on lower extremity running biomechanics. Twenty-six healthy male volunteers were randomised into two intervention groups: cold water (cold water at ~11°C) or tepid water (tepid water at ~26°C). They were required to run at 4.0 ± 0.2 m · s^?1 before and after they underwent water immersion for 20 min. Differences between pre- and post-intervention were used to compare the influence of water intervention during running. Peak joint angles, peak joint moments, peak ground reaction forces (GRF) and contact time (CT) were calculated using three-dimensional gait analysis. Independent t-tests were applied with a significant alpha level set at 0.05. Decreased peak propulsive and vertical GRF, decreased plantarflexion moments, increased hip flexion angle and longer CT were observed following cold water immersion. Although cold water immersion (cryotherapy) affected the running movement, none of the alterations have been related to running biomechanical patterns associated with injuries. Therefore, our results indicated that cold water immersion appears safe prior to running activities.     

短跑途中跑支撑摆动技术生物力学机制研究

研究目的:深入认识短跑途中跑支撑摆动动作系统中各环节协同的关系,完善短跑技术和专项力量训练理论。研究方法:采用生物力学测试、系统分析和数理统计等方法。结论:优秀运动员支撑摆动技术的主要运动学趋势,是支撑腿和摆动腿的髋角、膝角和踝角在支撑过程中均较小,两大腿的剪绞速度更快、幅度更大;短跑技术的本质特征是两大腿以髋为轴的剪绞—制动;积极着地是合理的短跑技术的基础;途中跑中前支撑段的技术效果是提高和保持最高跑速的主要影响因素;跑的主要动力是体后支撑阶段与人体运动方向相同的支撑反作用力的水平分力;两大腿的剪绞—制动力量和支撑腿膝、踝关节的低位趋等长力量,是短跑专项力量的核心。     

Effects of compression garments on surface EMG and physiological responses during and after distance running

BackgroundThe few previous studies that focused on the effects of compression garments (CG) on distance running performance have simultaneously measured electromyogram, physiological, and perceptual parameters. Therefore, this study investigated the effects of CG on muscle activation and median frequency during and after distance running, as well as blood-lactate concentration and rating of perceived exertion (RPE) during distance running.MethodsEight healthy male recreational runners were recruited to randomly perform two 40 min treadmill running trials, one with CG, and the other with control garment made of normal cloth. The RPE and the surface electromyography (EMG) of 5 lower extremity muscles including gluteus maximus (GM), rectus femoris (RF), semitendinosus (ST), tibialis anterior (TA), and gastrocnemius (GAS) were measured during the running trial. The blood-lactate levels before and after the running trial were measured.ResultsWearing CG led to significant lower muscle activation (p < 0.05) in the GM (decreased 7.40%–14.31%), RF (decreased 4.39%–4.76%), and ST (decreased 3.42%–7.20%) muscles; moreover, significant higher median frequency (p < 0.05) in the GM (increased 5.57%) and ST (increased 10.58%) muscles. Wearing CG did not alter the RPE values or the blood-lactate levels (p > 0.05).ConclusionWearing CG was associated with significantly lower muscle activation and higher median frequency in the running-related key muscles during distance running. This finding suggested that wearing CG may improve muscle function, which might enhance running performance and prevent muscle fatigue.