Event-specific impact test protocol for ice hockey goaltender masks

ABSTRACT

Goaltenders in the sport of ice hockey are at high risk for concussions from falls to the ice, player collisions and puck impacts. However, current methods used to certify helmets only consider head accelerations for drop tests which may not describe all common injury mechanisms relating to concussion. The purpose of this study was to describe the characteristics of 3 events associated with concussions for ice hockey goaltenders. A helmeted medium National Operating Committee on Standards for Athletic Equipment (NOCSAE) headform was impacted under conditions representing 3 injury events. Three impact locations’ velocities were selected for each event based on video analysis of real-world concussive events. Peak resultant linear acceleration, rotational acceleration and rotational velocity of the headform were measured. The University College Dublin Brain Trauma Model (UCDBTM) was used to calculate maximum principal strain (MPS) and von Mises stress in the cerebrum. Each impact event produced a unique dynamic response and brain stress and strain values. This demonstrates that a single impact event (i.e. falls) cannot adequately describe all impact events. As a result, impact protocols which assess multiple impact events such as the protocol described in this study should be used to evaluate ice hockey goaltender masks.     

A comparison of the reverse and power punches in oriental martial arts

Abstract

In this study, we compared mechanical factors in the reverse and three-inch power punches. Twelve expert male martial artists stood on a force plate, and executed reverse and power punches against a padded target fixed to a wall-mounted force plate. The force plates measured horizontal forces, and subsequently impulses and body centre of mass velocity changes. The motions of four markers attached to the arm were also collected, and were used to compute the horizontal velocities of the knuckle and of the arm centre of mass. The power punch produced smaller velocities immediately before impact than the reverse punch for the whole-body centre of mass (0.14 vs. 0.31 m · s^?1), for the arm centre of mass (2.86 vs. 4.68 m · s^?1), and for the knuckle (4.09 vs. 6.43 m · s^?1). The peak force exerted by the fist was much smaller in the power punch than in the reverse punch (790 vs. 1450 N). However, the linear impulse exerted by the fist during the first 0.20 s of contact was slightly larger in the power punch than in the reverse punch (43.2 vs. 37.7 N · s). The results indicate that the power punch is less potent than the reverse punch, but slightly more effective for throwing the opponent off balance.     

Three-dimensional kinematics of the knee and ankle joints for three consecutive push-offs during ice hockey skating starts

Little biomechanical research has been conducted recently on hockey skating despite the sport's worldwide appeal. One reason for this lack of biomechanical knowledge stems from the difficulty of collecting data. The lack of accuracy, the disputable realism of treadmills, and the large field of view required are some of the technical challenges that have to be overcome. The main objective of the current study was to improve our knowledge of the joint kinematics during the skating stroke. A second objective was to improve the data collection system we developed and the third was to establish if a kinematic progression exists in the hockey skating stroke similar to that in speed skating. Relative motions at the knee and ankle joints were computed using a joint coordinate system approach. The differences at the knee joints in push-offs indicated that the skating skill was progressively changing with each push-off. The relative stability of the ankle angles can be attributed to the design of the skate boots, which have recently become very rigid. Further research on ice hockey skating is warranted and should include more skaters and investigate the effect various starting strategies and variations in equipment have on skaters' performance.     

Detailed description of Division I ice hockey concussions: Findings from the NCAA and Department of Defense CARE Consortium

Objective:Since concussion is the most common injury in ice hockey,the objective of the current study was to elucidate risk factors,specific mechanisms,and clinical presentations of concussion in men’s and women’s ice hockey.Methods:Ice hockey players from 5 institutions participating in the Concussion Assessment,Research,and Education Consortium were eligible for the current study.Participants who sustained a concussion outside of this sport were excluded.There were 332(250 males,82 females)athletes who participated in ice hockey,and 47(36 males,11 females)who sustained a concussion.Results:Previous concussion(odds ratio(OR)=2.00;95%confidence interval(95%CI):1.02‒3.91)was associated with increased incident concussion odds,while wearing a mouthguard was protective against incident concussion(OR=0.43;95%CI:0.22‒0.85).Overall,concussion mechanisms did not significantly differ between sexes.There were specific differences in how concussions presented clinically across male and female ice hockey players,however.Females(9.09%)were less likely than males(41.67%)to have a delayed symptom onset(p=0.045).Additionally,females took significantly longer to reach asymptomatic(p=0.015)and return-to-play clearance(p=0.005).Within the first 2 weeks post-concussion,86.11%of males reached asymptomatic,while only 45.50%of females reached the same phase of recovery.Most males(91.67%)were cleared for return to play within 3 weeks of their concussion,compared to less than half(45.50%)of females.Conclusion:The current study proposes possible risk factors,mechanisms,and clinical profiles to be validated in future concussions studies with larger female sample sizes.Understanding specific risk factors,concussion mechanisms,and clinical profiles of concussion in collegiate ice hockey may generate ideas for future concussion prevention or intervention studies.     

Three-dimensional kinematics of the knee and ankle joints for three consecutive push-offs during ice hockey skating starts

Little biomechanical research has been conducted recently on hockey skating despite the sport's worldwide appeal. One reason for this lack of biomechanical knowledge stems from the difficulty of collecting data. The lack of accuracy, the disputable realism of treadmills, and the large field of view required are some of the technical challenges that have to be overcome. The main objective of the current study was to improve our knowledge of the joint kinematics during the skating stroke. A second objective was to improve the data collection system we developed and the third was to establish if a kinematic progression exists in the hockey skating stroke similar to that in speed skating. Relative motions at the knee and ankle joints were computed using a joint coordinate system approach. The differences at the knee joints in push-offs indicated that the skating skill was progressively changing with each push-off. The relative stability of the ankle angles can be attributed to the design of the skate boots, which have recently become very rigid. Further research on ice hockey skating is warranted and should include more skaters and investigate the effect various starting strategies and variations in equipment have on skaters' performance.     

Forecheck,backcheck, health check: the benefits of playing recreational ice hockey for adults in Canada

More than 1 million Canadian adults play recreational ice hockey. Compared to elite players, very little is known about the physical and health characteristics of people who play the game for fun. Analyzing data from Statistics Canada’s 2011/12 Canadian Community Health Survey, the paper found that there is an association between physically active males age 35 or over who play ice hockey regularly (at least once a week) and enhanced health more so than other physically active males. While these players are larger in body size, they have significantly lower rates of diabetes, high blood pressure and heart disease and report significantly higher rates of self-assessed health. Given the potential health benefits associated with this high intensity sport, the paper discusses ways in which participation can be promoted among less physically active adults and people who are new to the game or who have historically lower levels of participation including women and recent immigrants. Finally, the paper argues that compared to the very high costs associated with child and youth hockey, participation in adult recreational ice hockey is quite affordable.     

Performance of football shin guards for direct stud impacts

Football shin guards were evaluated against a kick from a studded boot.The bending stiffness of their shells, and their response when impacted by a stud, were assessed using finite element analysis (FEA) and determined experimentally.A test rig was constructed with the leg muscle simulated by flexible foam, with the force distribution along the tibia and to the lateral muscle measured using flexible force sensors.High-speed photography confirmed deformation mechanisms predicted by FEA.Load spreading from the stud impact site correlated with the guard shell bending stiffness.The best guards use shells of complex shape to increase their transverse bending stiffness.     

A biomechanical comparison in the lower limb and lumbar spine between a hit and drag flick in field hockey

Research has revealed that field hockey drag flickers have greater odds of hip and lumbar injuries compared to non-drag flickers (DF). This study aimed to compare the biomechanics of a field hockey hit and a specialised field hockey drag flick. Eighteen male and seven female specialised hockey DF performed a hit and a drag flick in a motion analysis laboratory with an 18-camera three-dimensional motion analysis system and a calibrated multichannel force platform to examine differences in lower limb and lumbar kinematics and kinetics. Results revealed that drag flicks were performed with more of a forward lunge on the left lower limb resulting in significantly greater left ankle dorsiflexion, knee, hip and lumbar flexion (Ps<0.001) compared to a hit. Drag flicks were also performed with significantly greater lateral flexion (P < 0.002) and rotation of the lumbar spine (P < 0.006) compared to a hit. Differences in kinematics lead to greater shear, compression and tensile forces in multiple left lower limb and lumbar joints in the drag flick compared to the hit (P < 0.05). The biomechanical differences in drag flicks compared to a hit may have ramifications with respect to injury in field hockey drag flickers.     

Effects of structural components of artificial turf on the transmission of impacts in football players

The third generation of artificial turf systems (ATS) has matched the mechanical behaviour of natural grass, but today a high heterogeneity at structural level and mechanical behaviour in the new ATS also exists. The objective was to analyse the effect of the structural components of ATS football pitches and running speed on the capacity of impact attenuation. A total of 12 athletes were evaluated at three speed conditions (3.33 m/s, 4 m/s and maximum speed) on four different ATS, classifying them by their components (length of fibre, type of in-fill and sub-base). Impact attenuation was significantly higher in ATS3, characterised by longer fibre compared to other ATS with less fibre length. The ATS4 with a higher length fibre and built on compacted granular material proportioned significantly lower values in the maximum peaks of tibia acceleration. Finally, as speed increases, the peak tibia impacts were significantly higher. Longer fibre length and the capacity to accommodate a higher quantity of infill facilitate higher impact attenuation. Equally, a compacted granular sub-base is related to lower magnitude of maximum tibia peaks. Finally, the magnitude of the tibia acceleration peaks is dependent of running speed for all ATS analysed, being higher as speed increases.     

运动员形象权的法律保护

运动员形象权的概念来自美国法,它是一种有别于隐私权、姓名权等人身权的无形财产权,美国有些州法将之规定为一项独立的知识产权.世界各国关于运动员形象权的保护规定不一,主要有民法典关于人身权的一般规定及其类推适用,受知识产权法、反不正当竞争法等保护,独立规定形象权的国家很少.运动员形象利益是运动员的一项重要的财产利益,在不同的项目、不同的运动员身上表现不同.运动员与经纪人、俱乐部、赞助商等关于运动员形象权开发方面存在利益冲突,运动员往往处于弱势,需要明确的法律规定子以调整.我国现行法律规定类似于大陆法系国家的做法,并未规定独立的形象权,要顺应国际趋势加以规定.     

自由式滑雪空中技巧运动员出台技术、下肢力量与落地稳定性关系研究

以国家自由式滑雪空中技巧男、女运动员为研究对象,以运动生物力学的研究手段为依托,以运动员最佳技术状态参加第21届冬奥会为最终研究目标,从运动员技术分析评价、运动员下肢环节肌力特点分析、冲击力实验推测3周台冲力范围等方面进行研究,推测出3周台冲击力分布范围,为女子运动员冲击3周台动作的安全性提供了科学依据;揭示了运动员的出台技术、落地稳定性的关系,为运动员高质量地完成空中动作,同时获得稳定的、安全的落地提供了依据,为运动员冲击难度动作时能安全高质量地完成提供科技保障,为运动员在第21届冬奥会中取得优异成绩提供了科技支撑。     

洛伦兹力与动生电动势产生机理的再探讨

本文对洛伦兹力和安培力的关系以及动生电动势产生机理进行了再探讨,认为安培力是载流导线中所有电荷所受的洛伦兹力的总和;从动生电动势的产生过程进一步讨论了洛伦兹力的做功问题,洛伦兹力所做的总功为零,但其分力可以做功。洛伦兹力的分力提供了产生动生电动势的非静电力。     

不同膝角静态蹲跳的生物力学研究

运用三维测力系统,对不同膝角静态蹲跳的测试结果进行比较分析：着重讨论了最大力值、蹬伸时间、冲量值等主要生物力学指标的变化规律及其对纵跳高度的影响。     

A comparison of two methods for the calculation of accumulated oxygen deficit

Abstract

The aim of this study was to compare accumulated oxygen deficit data derived using two different exercise protocols with the aim of producing a less time-consuming test specifically for use with athletes. Six road and four track male endurance cyclists performed two series of cycle ergometer tests. The first series involved five 10 min sub-maximal cycle exercise bouts, a VO_2peak test and a 115% VO_2peak test. Data from these tests were used to estimate the accumulated oxygen deficit according to the calculations of Medbø et al. (1988). In the second series of tests, participants performed a 15 min incremental cycle ergometer test followed, 2 min later, by a 2 min variable resistance test in which they completed as much work as possible while pedalling at a constant rate. Analysis revealed that the accumulated oxygen deficit calculated from the first series of tests was higher (P<0.02) than that calculated from the second series: 52.3±11.7 and 43.9±6.4 ml·kg^?1, respectively (mean±s). Other significant differences between the two protocols were observed for VO_2peak, total work and maximal heart rate; all were higher during the modified protocol (P<0.01 and P<0.02, respectively). Oxygen kinetics were also significantly faster during the modified 2 min maximal test. We conclude that the difference in accumulated oxygen deficit between protocols was probably due to a reduced oxygen uptake, possibly caused by a slower oxygen on-response during the 115% VO_2peak test in the first series, and VO₂—power output regression differences caused by an elevated VO ₂ during the early stages of the second series.     

A comparison of two methods for the calculation of accumulated oxygen deficit

The aim of this study was to compare accumulated oxygen deficit data derived using two different exercise protocols with the aim of producing a less time-consuming test specifically for use with athletes. Six road and four track male endurance cyclists performed two series of cycle ergometer tests. The first series involved five 10 min sub-maximal cycle exercise bouts, a VO2peak test and a 115% VO2peak test. Data from these tests were used to estimate the accumulated oxygen deficit according to the calculations of Medb? et al. (1988). In the second series of tests, participants performed a 15 min incremental cycle ergometer test followed, 2 min later, by a 2 min variable resistance test in which they completed as much work as possible while pedalling at a constant rate. Analysis revealed that the accumulated oxygen deficit calculated from the first series of tests was higher (P < 0.02) than that calculated from the second series: 52.3 +/- 11.7 and 43.9 +/- 6.4 ml x kg(-1), respectively (mean +/- s). Other significant differences between the two protocols were observed for VO2peak, total work and maximal heart rate; all were higher during the modified protocol (P < 0.01 and P < 0.02, respectively). Oxygen kinetics were also significantly faster during the modified 2 min maximal test. We conclude that the difference in accumulated oxygen deficit between protocols was probably due to a reduced oxygen uptake, possibly caused by a slower oxygen on-response during the 115% VO2peak test in the first series, and VO2-power output regression differences caused by an elevated VO2 during the early stages of the second series.     

竞赛特质焦虑干扰优势反应抑制的神经准备过程:ERP的证据

竞赛焦虑对操作表现的影响是运动心理学的重要研究领域,注意控制理论对二者关系从执行功能的角度进行了新的阐释,认为焦虑干扰执 行功能中的抑制功能。近年来,运动心理学对抑制功能探讨较多,对优势反应和任务无关刺激的抑制是抑制功能的2个重要成分,但以往研究大多 集中于抑制无关刺激,对优势反应抑制的探讨相对欠缺,而后者却是竞技场上运动员时常需要面对的问题。已有行为学研究发现,竞赛特质焦虑对 优势反应抑制功能有干扰效应,但其神经机理尚待探讨。本研究采用ERP技术探讨竞赛特质焦虑干扰优势反应抑制的神经基础,假设竞赛特质焦 虑干扰前脑区域（额区和中央区）优势反应抑制的神经准备过程。招募26名研究参与者,根据《赛前情绪量表32×6》测试得分,二分法划分竞赛特质 焦虑高分组和低分组。2组均完成代表优势反应抑制功能的反向眼跳任务,分析抑制“线索”出现前-100~0 ms时程的ERP成分,发现反向眼跳的准 备期在额区和中央区诱发出一负成分,竞赛特质焦虑高分组的波幅小于低分组。以上结果部分支持了假设,竞赛特质焦虑对优势反应抑制的神经 准备期有干扰效应,且主要由前脑区域控制,此结果为注意控制理论在竞赛焦虑领域的适用性提供了神经生理学的部分证据。     

中、美两国政府财政补贴大型体育场（馆）建设的比较研究

通过查阅文献,采用逻辑分析方法对中、美两国政府财政补贴大型体育场（馆）建设的原因进行探讨。认为大型体育场（馆）对于城市经济发展的积极影响非常有限,甚至可能带来消极的影响。政府财政补贴大型体育场（馆）建设的合理原因可能来自于社会效益层面。两国在体育发展条件,体育管理模式,体育场地设施建设与人均占有量等方面的差异导致政府补贴的原因和效果存在差异：中国政府在大型场（馆）建设的财政补贴上带有强烈的公益性,进而在大型体育场（馆）的经营中亦注重公益性导向,而忽略了其产业属性,因而会对中国体育场（馆）业发展造成不利影响。美国体育始终是在市场经济制度中依据市场逻辑发展,因而,美国体育场（馆）业产业属性明显,政府在大型体育场（馆）的财政补贴上亦具有很强产业特征,可视作国家对体育场（馆）业的经济扶持政策。鉴于中国大部分城市现阶段还不具备足够的体育市场来消化大型体育场（馆）,在今后的大型体育场（馆）建设中尤应采取审慎的态度,并且应该注重发挥市场的导向作用,使市场在资源配置中起决定性的作用。