Stresses in the plantar region for long- and short-range throws in women basketball players

Abstract

This study aimed to assess plantar pressure pattern modifications caused by short- and long-distance shots in women basketball players. To this end, 24 experienced national- and regional-level basketball players performed 3 trials of 4 technical gestures (free throw, jump stop shot, three-point shot and lay-up) barefoot on a pressure platform placed in fixed positions on the court. Raw data were processed to calculate location and magnitude of pressure peaks in three sub-regions (forefoot, midfoot and rearfoot), and the increase ratio was calculated relative to plantar pressure measured during a static bipedal and unipedal upright stance. The results showed significant increases (p<0.001) in plantar pressure peaks in forefoot (but not midfoot and rearfoot) for all the gestures that involved the use of both legs. Particularly large increases were detected for the three-point shot. All three sub-regions underwent significant changes of the pressure peak in the case of lay-up (forefoot and rearfoot: p<0.001, midfoot: p=0.002). The high levels of contact stress detected for routinely performed technical gestures suggest that a detailed knowledge of changes in the physiological patterns of plantar stresses that take place during play is crucial in reducing the risk of foot injuries and establishing proper training and rehabilitation protocols.     

隋盛胜四号位扣球起跳技术足底压力分布与传导的力学特征研究

运用鞋垫式足底压力测试系统,对前中国男排主攻队员隋盛胜四号位扣球起跳技术的足底压力参数进行了采集和分析。结果表明：右腿贡献大于左腿;右足后区首先着地,之后由足中区过渡到足前区。左足后区首先着地,之后依次是足前区和足中区,足后区、足前区和足中区的着地时间均相差2ms;蹬伸到离地阶段,左、右足均有内旋动作;左、右足的最大压力峰值和平均压力按从大到小的顺序均出现在足前区、足后区和足中区。     

速度轮滑双蹬技术足底压力分布及传递特征

为揭示速度轮滑双蹬技术的规律和特征,正确理解速度轮滑双蹬技术动作原理,为寻找更先进和省力的速度轮滑技术提供科学依据。运用足底压力分布测试系统,以专业轮滑运动员为研究对象,获取不同速度滑行过程运动员在双蹬技术一个单步中的足底动力学参数。结果说明足底压力随时间变化是影响速度轮滑蹬动效果的主要因素;不同的足底压力传递特征体现了不同的技术动作,从而形成不同的运动效果;在快速滑行中双蹬技术更有利于保持身体平衡。     

2006年我国速度滑冰项目在重大国内、国际赛事上的表现综述

通过对2006年全国速度滑冰联赛(第2站)比赛的观摩与研究,分析当前我国速度滑冰人才的分布情况,并从比赛成绩中着重分析了前3名选手的成绩与全国纪录之间的差距,以及中国速度滑冰队在亚洲和世界上的整体水平,并回顾中国选手在都灵冬奥会和2006年世界锦标赛上的表现,进而对我国速度滑冰运动概况和发展进行综述和评价.     

The effect of alterations in foot centre of pressure on lower body kinematics during the five-iron golf swing

ABSTRACT

The research aimed to evaluate the effects of an intervention aimed at altering pressure towards the medial aspect of the foot relating to stability mechanisms associated with the golf swing. We hypothesised that by altering the position of the foot pressure, the lower body stabilisation would improve which in turn would enhance weight distribution and underpinning lower body joint kinematics. Eight professional golf association (PGA) golf coaches performed five golf swings, recorded using a nine-camera motion analysis system synchronised with two force platforms. Following verbal intervention, they performed further five swings. One participant returned following a one-year intervention programme and performed five additional golf swings to provide a longitudinal case study analysis. Golf performance was unchanged evidenced by the velocity and angle of the club at ball impact (BI), although the one-year intervention significantly changed the percentage of weight experienced at each foot in the final 9% of downswing, which provided an even weight distribution at BI. This is a highly relevant finding as it indicates that the foot centre of pressure was central to the base of support and in-line with the centre of mass (CoM), indicating significantly increased stability when the CoM is near maximal acceleration.     

Effect of bag holding on the center of foot pressure and the lower leg muscle activities

Abstract

This study examined the influence of holding a bag with one hand on the center of foot pressure (COP) and the electromyographic responses in lower leg muscles. Thirteen healthy male adults participated in this study to keep an upright posture while holding a load with the dominant hand with four bag weight conditions (0%, 15%, 30%, and 45% of maximal voluntary contraction (MVC) of the jerk strength). Integrated Electromyography (iEMG) and mean power frequency (MPF) of EMG were calculated to estimate the degree of muscle activity and fatigue in the tibialis anterior and soleus that are involved in ankle joint control. Body sway was evaluated by the mean position of left-right (X) and front-back (Y) axis sway and the following 4 body sway factors; unit time sway factor (F1), front-back sway factor (F2), left-right sway factor (F3), high frequency band power spectrum factor (F4). When holding a bag at 45% MVC or more of the jerk strength with a single hand for one minute, muscle activity in the lower leg on the side of the bag increased markedly, and muscle fatigue was induced in the antigravity muscles of both legs. As a result, anteroposterior sway increased to a short, quick sway.     

Relationship of performance on the sensory organization test to landing characteristics

Jump landing tasks have been used to assess landing characteristics and require significant sensorimotor feedback to maintain functional joint stability (FJS) throughout the task. Postural stability (PS) also requires significant sensorimotor feedback and control and would seemingly involve similar sensory feedback pathways. However, previous literature clarifying the relationship between these two processes, maintaining FJS and PS, is limited. 80 Special Tactics Operators. PS was assessed using the Sensory Organization Test (SOT). SOT variables included: Composite, Somatosensory, Visual, Vestibular, and Preference scores. Landing characteristics were assessed using motion analysis during a double-legged (DLSJ) and single-legged (SLSJ) stop jump task. Pearson’s correlation coefficients were calculated to assess the relationship between SOT scores and landing characteristics (α < .05). For the DLSJ, significant correlations were found between: Composite and peak posterior ground reaction forces (?.257), Vestibular and peak knee abduction moment (?.237), and Preference and initial contact hip flexion (?.297), peak hip flexion (?.249). For the SLSJ, significant correlations were found between: Somatosensory and peak vertical ground reaction forces (?.246); Preference and initial contact hip flexion (?.295), peak hip flexion (?.262). The results indicate that the SOT may not be a sensitive enough tool to assess sensorimotor control in a healthy, athletic population.     

脑力、体力劳动者足底压力参数分布特征及评定

通过分析脑力、体力劳动者自然行走过程中峰力值（maxforce,MF）、达峰力值时间（time to max force）、冲量（impulse）等参数特征,探讨职业对足底压力分布的影响。采用比利时Footscan USB2平板式足底压测试系统对50名普通健康脑力劳动者和63名普通健康体力劳动者进行自然行走过程中动态足底压力测试。结果显示：脑力、体力劳动者左脚Toel、Toe2-5、Heel Lateral区域平均峰值（MF）存在显著性差异,右脚Mid foot、Meta5区域MF差异存在非常显著性（P〈0．01）,左、右双足平均峰力值（MF）最大值均出现在足跟内侧（Heel Medial）。脑力、体力劳动者足底各区域达峰力值的时间（TMF）,左右双足差异均存在非常显著性（P〈0．01）。脑力劳动者与体力劳动者行走过程中左足在Toel、Toe2-5、Meta1、Heel Medial、Heel Lateral区域的冲量（Impulse,IP）,体力劳动者明显大于脑力劳动者且具有显著性差异〈0．01）,体力劳动者与脑力劳动者的足底MF与足弓接触面积及足角度存在不同程度的相关。结果说明：脑力劳动者与体力劳动者行走过程中左右双足的平均峰力值、接触面积、冲量等参数都存在不同程度的差异,可能与长期从事的职业不同有关,建议经常进行体育锻炼或定制矫形鞋垫,可以缓解足底压力高压区的过度集中,不断维护足健康水平。     

竞走项目最大速度能力和足底压力特征研究

通过二维录像解析和足底压力分布实验测试,对竞走项目运动员最大速度能力和足底压力分布特征进行相关的基础研究,以获得竞走项目运动员在特定的技术规则规定下,世界级优秀竞走运动员的极限最大速度能力、关键运动学参数和足底压力分布特征参数情况,并对这些运动学和动力学参数进行了相关分析.     

The elite player performance plan: the impact of a new national youth development strategy on injury characteristics in a premier league football academy

The objective of this study was to investigate the injury incidence and patterns in elite youth football at a category 1 Premier League Academy before and after the introduction of a new development strategy, the Elite Player Performance Plan (EPPP). A prospective study was performed over six consecutive seasons encompassing three years before and after the introduction of the EPPP. The findings revealed a most likely moderate increase in total exposure per player per season when the post-EPPP football exposure (640.86 ± 83.25 hours per player per year) was compared with the pre-EPPP football exposure (539.08 ± 71.59). The total injury incidence pre-EPPP was 3.0/1000 hours compared to 2.1/1000 hours post-EPPP (rate ratio 1.43). 6% of all injuries were re-injuries (20.24 ± 33.43 days) but did not result in a substantially longer absence (16.56 ± 15.77 days). The injury burden decreased for the U12-U15 from pre- to post-EPPP, whereas the injury burden increased for the U16-U18 (respectively 125 and 47% higher). These findings suggest that following the introduction of the EPPP there has been a reduction in injuries in the younger age groups U12-U15 but in the older age groups U16-U18 there has been an increase in the severity of the injuries sustained at this club.     

竞赛压力对不同结果期待倾向男子足球运动员状态自信的影响

采用问卷调查和数理统计方法探讨了男子足球运动员的乐观、悲观倾向与运动状态自信的关系以及竞赛压力可能的调节作用.结果表明:(1)乐观倾向、悲观倾向既相对独立又显著相关,在男子运动员个体运动状态自信的变异中,乐观倾向具有保护性作用.悲观倾向具有破坏性作用,比较而言,悲观倾向的消极作用比乐观倾向的保护性作用更强.(2)竞赛压力是结果期待倾向与运动状态自信的显著调节因素,主要作用表现为随着压力水平的增高,乐观倾向对状态自信的保护意义具有增强的趋势.     

Factors associated with concussion-symptom knowledge and attitudes toward concussion care seeking in a national survey of parents of middle-school children in the US

Background:Developing appropriate concussion prevention and management paradigms in middle school(MS)settings requires understanding parents’general levels of concussion-related knowledge and attitudes.This study examined factors associated with concussion-symptom knowledge and care-seeking attitudes among parents of MS children(aged 10-15 years).Methods:A panel of 1224 randomly selected U.S.residents,aged ≥18 years and identifying as parents of MS children,completed an online questionnaire capturing parental and child characteristics.The parents’concussion-symptom knowledge was measured using 25 questions,with possible answers being“yes”,“maybe”,and“no”.Correct answers earned 2 points,“maybe”answers earned 1 point,and incorrect answers earned 0 point(range:0-50;higher scores=better knowledge).Concussion care-seeking attitudes were also collected using five 7-point scale items(range:5-35;higher scores=more positive attitudes).Multivariable ordinal logistic regression models identified predictors of higher scores.Models met proportional odds assumptions.Adjusted odds ratios(aORs)with 95%confidence intervals(95%CIs)(excluding 1.00)were deemed statistically significant.Results:Median scores were 39(interquartile range:32-44)for symptom knowledge and 32(interquartile range:28-35)for care-seeking attitude.In multivariable models,odds of better symptom knowledge were higher in women vs.men(aOR=2.28;95%CI:1.71-3.05),white/non-Hispanics vs.other racial or ethnic groups(aOR=1.88;95%CI:1.42-2.49),higher parental age(10-year-increase aOR=1.47;95%CI:1.26-1.71),and greater competitiveness(10%-scale-increase aOR=1.24;95%CI:1.13-1.36).Odds of more positive care-seeking attitudes were higher in white/non-Hispanics vs.other racial or ethnic groups(aOR=1.45;95%CI:1.06-1.99)and in older parental age(10-year-increase aOR=1.24;95%CI:1.05-1.47).Conclusion:Characteristics of middle school children’s parents(e.g.,sex,race or ethnicity,age)are associated with their concussion-symptom knowledge and care-seeking attitudes.Parents’variations in concussion knowledge and attitudes warrant tailored concussion education and prevention.     

Identifying the optimal body shape and composition associated with strength outcomes in children and adolescent according to place of residence: An allometric approach

The purpose of the study was to identify the optimal body shape and composition associated with physical fitness levels of children living in urban and rural areas of Italy. A total of 7102 children (11–14 years) were assessed for weight, height, percentage body fat (FM%), sit-and-reach flexibility (SAR), standing broad jump (SBJ) and sit-ups (SUP). A multiplicative allometric model, Y = a · mass^k1 · height^k2 ·ε, was used to predict the physical outcome variables Y = SBJ and SUP. The model was expanded to incorporate FM% and SAR as follows Y = a · mass^k1 · height^k2 · FM%^k3 · exp(b· FM% + c· SAR) ·ε. Note that FM% was incorporated as a “gamma function” that allows an initial growth, and subsequent decline in Y as FM% increases in size. Although having an ectomorph body shape appears advantageous, being too thin appears detrimental to the strength outcomes. Being flexible would also benefit physical fitness levels. Finally, our results indicate that ursban children aged 11–14 have superior strength outcomes compared with rural children, having controlled for differences in body shape and composition, a finding that may be associated with rural environments having fewer exercise facilities compared with urban conurbations.