基于有限元法速滑运动员腰椎受力特点研究

利用CT扫描数据建立具有高度几何材料相似性的腰椎运动节段(L4-L5)的三维有限元模型,分析速滑运动员进行运动时脊柱腰椎节段受力特点,以便对速滑运动员腰部损伤进行积极的预防,减少伤病的发生.结果表明:速度滑冰运动员在进行运动时,其椎间盘所受应力主要集中在外层纤维的中前部,在前部更为明显;椎体应力集中在椎体前部,其值高于其下方髓核应力值,邻近椎体终板应力明显高于其他部位,此部位出现应力集中现象.运动员椎体所受应力分布在皮质骨椎弓周围及邻近终板的地方,椎体后部结构应力集中在小关节上下关节突与椎弓根等位置.     

我国优秀男子举重运动员抓举技术结构研究

采用录像解析、动力测试、数理统计等方法 ,对我国优秀男子举重运动员抓举技术动作进行三维动力学和二维运动学测试分析 ,根据技术动作的用力特征和运动轨迹的定量描述 ,得出抓举技术结构特征和主要技术影响因素 ,指出抓举技术的主要生物力学因子。     

举重抓举和下蹲翻运动学比较与用力特征分析

本研究的目的,是运用生物力学的研究方法,对我国高水平的女子举重运动员的抓举和下蹲翻进行运动学比较分析,并对其力量的特点进行比较分析;此外,运用逆向动力学对两种技术动作的主要关节的净力矩进行了分析,为更深刻地理解抓举和下蹲翻动作的差异和力量特点提供参考的依据。本文研究对象是:参加2003年4月在河南平顶山举行的全国女子举重锦标赛的10名运动员。结论:本研究运用生物力学的分析方法,对举重的抓举和下蹲翻技术动作,在动作的结构、力量的特点以及关节受力等方面进行了较为全面的比较分析,对于更深一步地了解其动作的结构和力量的特…     

艺术体操运动员脊柱腰段损伤现状及规律

分析优秀艺术体操运动员脊柱腰段损伤现状，探讨损伤的规律。结果表明：97．5％的运动员患有腰部损伤，10096的运动员表示有过不同程度的腰部疼痛；发病率前5位的损伤部位是腰椎间盘突出、腰椎峡部裂、棘突偏歪、腰椎错位和腰肌劳损；损伤多发生在重要赛事前准备期。腰部损伤规律主要表现在技术结构的特殊性、脊柱腰段过度的伸展性、技术水平的不均衡性、个人集体项目的差异性和形态与机能交化外显的不一致性。     

奥运冠军石智勇抓举技术运动学分析

运用三维运动学的研究方法,对参加2005年全国第十届体育运动会举重比赛的运动员石智勇的抓举技术进行运动学分析。结果表明,提铃过程中人杠重心间距控制合理,杠铃平均加速度超过2 m/s2,体现了优异的爆发力和出色的提铃技术;引膝阶段的技术与常规引膝技术已有了很大的改变,该阶段用时很短,膝关节角度也几乎没产生变化,通过对膝关节的制动充分发挥了腰背部肌肉力量,使抓举时杠铃最高加速度的值出现在引膝阶段而非发力阶段,这是最体现石智勇抓举技术特点的地方;抓举发力阶段,身体用力协调,各关节角度的把握也恰到好处;抓举下蹲支撑阶段技术动作堪称完美,人杠重心间距控制合理,杠铃回落距离仅为13.6 cm,人体重心向下的平均加速度为11.2 m/s2,两项均属于世界顶级选手的技术指标;在起立阶很好地利用了杠铃的弹性势能,与杠铃同步起立,同时人杠重心间距仅为0.002 m,确保了起立的稳定性。     

优秀女子举重运动员抓举技术的生物力学分析

通过三维运动图像分析手段对我国5名优秀女子举重运动员的抓举技术动作进行测试,通过对比分析不同运动员在抓举过程中各动作技术阶段(第一发力阶段、过渡阶段、第二发力阶段和惯性上升阶段)的时间比、杠铃上升高度比、做功比和平均功率等关键指标,揭示我国优秀女子举重运动员的抓举技术特征.     

运动员腰椎峡部裂的防治

峡部裂是脊椎峡部裂的简称,又称为脊椎峡部不连、椎弓崩裂。人体生长完全的脊椎,可分为椎体、椎弓、椎板、上下关节突、横突与棘突。上下关节突之间较为狭小的部分称为椎弓根峡部。如果一侧或两侧峡部骨质不连续,则称为脊椎峡部不连。腰椎峡部裂是临床上下腰痛的常见病因之一,其基本病变是峡部骨断裂,至椎体小关节对抗剪切应力能力的丧失,腰椎失稳,最终导致椎体向前滑脱。     

举重抓举和下蹲翻运动学比较与用力特征分析

运用三维运动学的研究方法对参加2003年全国女子举重锦标赛的10名运动员的抓举和下蹲翻进行运动学分析并对力量的特点进行比较分析;运用逆向动力学方法对两种技术动作的主要关节的净力矩进行比较分析。结果表明,膝关节角度在提铃离地时刻有显著性的差异;对力量参数回归分析表明,运动员抓举杠铃重量的能力很大程度上取决于运动员所能够输出的最大功率,而运动员下蹲翻杠铃重量的能力很大程度上取决于运动员对杠铃的作用力的积累过程;对于抓举和下蹲翻动作髋关节净力矩分析表明,对于抓举,髋关节最大净力矩与对应此时刻的髋关节角度呈负相关,而对于下蹲翻,髋关节最大净力矩则与所试举的杠铃重量呈正相关。     

2001-2011年国内抓举技术研究成果述评

运用文献资料法对2001～2011年间国内学者对举重运动中抓举技术的研究成果进行梳理希望能为后续研究者提供一些借鉴。结果显示：近十年间研究者主要从运动生物力学和训练学两个角度对抓举技术进行了研究。运动生物力学的运用以三维运动学为主结合动力学进行研究,涌现了红外光点捕获、杠杆端点自动识别、三维运动仿真等较新技术;训练学角度的研究者以一线教练员为主,通过对自身经验的传递促进了整体抓举技术训练水平的提高。     

优秀运动员谌利军与冯吕栋抓举技术对比研究

运用三维运动学研究方法,对参加2019年亚洲举重锦标赛暨东京奥运会资格赛的我国男子举重67kg公斤级优秀运动员谌利军与冯吕栋抓举技术进行对比分析。研究结果认为:提铃准备阶段,冯吕栋身体姿势更符合抓举中“近”的技术要求;总体上,冯吕栋伸膝提铃和引膝提铃阶段技术动作优于谌利军,谌利军发力和惯性上升及接铃阶段技术动作优于冯吕栋。谌利军抓举过程中主要存在伸膝提铃阶段髋关节打开过早,引膝提铃阶段膝关节回屈角度小以及整个抓举过程中杠铃重心左右偏移量过大的问题;冯吕栋主要存在发力和惯性上升阶段“两心”前后距离过大,杠铃相对于运动员水平运动幅度大,垂直运动幅度小以及接铃过程中杠铃下落距离长,下降速度过快的问题。建议谌利军加强膝关节主要屈伸肌群的力量训练以及进行身体左右侧力量平衡的评估;冯吕栋应掌握在发力和惯性上升阶段正确的用力方向,并改善接铃节奏。     

In vivo lumbo-sacral forces and moments during constant speed running at different stride lengths

The aim of this study was to introduce a Newton-Euler inverse dynamics model that included reaction force and moment estimation at the lumbo-sacral (L5-S1) and thoraco-lumbar (T12-L1) joints. Data were collected while participants ran over ground at 3.8 m x s(-1) at three different stride lengths: preferred stride length, 20% greater than preferred, and 20% less than preferred. Inputs to the model were ground reaction forces, bilateral lower extremity and pelvis kinematics and inertial parameters, kinematics of the lumbar spine and thorax and inertial parameters of the lumbar segment. Repeated measures ANOVA were performed on the lower extremity sagittal kinematics and kinetics, including L5-S1 and T12-L1 three-dimensional joint angles, reaction forces and moments at touchdown and peak values during impact phase across the three stride conditions. Results indicated that L5-S1 and T12-L1 vertical reaction forces at touchdown and during the impact portion of the support phase increased significantly as stride length increased (P < 0.001), as did peak sagittal L5-S1 moments during impact (P = 0.018). Additionally, the transverse T12-L1 joint moment increased as running speed increased (P = 0.006). We concluded from our findings that our model was sensitive to our perturbations in healthy runners, and may prove useful in future mechanistic studies of L5-S1 mechanics.     

In vivo lumbo-sacral forces and moments during constant speed running at different stride lengths

Abstract

The aim of this study was to introduce a Newton–Euler inverse dynamics model that included reaction force and moment estimation at the lumbo-sacral (L5-S1) and thoraco-lumbar (T12-L1) joints. Data were collected while participants ran over ground at 3.8 m · s^?1 at three different stride lengths: preferred stride length, 20% greater than preferred, and 20% less than preferred. Inputs to the model were ground reaction forces, bilateral lower extremity and pelvis kinematics and inertial parameters, kinematics of the lumbar spine and thorax and inertial parameters of the lumbar segment. Repeated measures ANOVA were performed on the lower extremity sagittal kinematics and kinetics, including L5-S1 and T12-L1 three-dimensional joint angles, reaction forces and moments at touchdown and peak values during impact phase across the three stride conditions. Results indicated that L5-S1 and T12-L1 vertical reaction forces at touchdown and during the impact portion of the support phase increased significantly as stride length increased (P < 0.001), as did peak sagittal L5-S1 moments during impact (P = 0.018). Additionally, the transverse T12-L1 joint moment increased as running speed increased (P = 0.006). We concluded from our findings that our model was sensitive to our perturbations in healthy runners, and may prove useful in future mechanistic studies of L5-S1 mechanics.     

A cervical spine model to predict injury scenarios and clinical instability

A complete and detailed three-dimensional finite element model of the human cervical spine (C1–C7), including soft and hard tissues, was created using a digitized geometric measurement tool. The model was validated against existing experimental studies in flexion, extension, lateral bending, and axial rotation. The aims of this study were to use the model to simulate the mechanisms of injury scenarios, such as diving and football accidents, and to correlate the external and internal responses of the spinal components to disc herniation and clinical instability. It was determined that a shear-generated flexion moment of about 10 Nm or a compression-flexion load of 450 N would generate significant stresses and strains in the discs, together with sufficient posterior-anterior displacement and rotational angulation of the vertebrae, to place the mid and lower cervical spine at risk of clinical instability or disc herniation. The results revealed that the location of the maximum stresses in the discs could not be directly correlated with the type of loads. In addition, for the loadings considered, the maximum displacement of the spine could be reduced by as much as 50% when the restraint of the cervical spine is changed from a C7–T1 to C7–T1 and C1–C2 fixed conditions.     

Lumbar spinal loads and muscle activity during a golf swing

This study estimated the lumbar spinal loads at the L4-L5 level and evaluated electromyographic (EMG) activity of right and left rectus abdominis, external and internal obliques, erector spinae, and latissimus dorsi muscles during a golf swing. Four super VHS camcorders and two force plates were used to obtain three-dimensional (3D) kinematics and kinetics of golf swings performed by five male collegiate golfers. Average EMG levels for different phases of golf swing were determined. An EMG-assisted optimization model was applied to compute the contact forces acting on the L4-L5. The results revealed a mean peak compressive load of over six times the body weight (BW) during the downswing and mean peak anterior and medial shear loads approaching 1.6 and 0.6 BW during the follow-through phases. The peak compressive load estimated in this study was high, but less than the corresponding value (over 8 BW) reported by a previous study. Average EMG levels of different muscles were the highest in the acceleration and follow-through phases, suggesting a likely link between co-contractions of paraspinal muscles and lumbar spinal loads.     

核心肌群训练对腰椎间盘突出症的改善作用

探讨核心肌群训练在腰椎间盘突出症治疗中的价值。对120名腰椎间盘突出症患者进行了5个月的核心肌群训练。结合螺旋CT、MRI造影技术对患处进行分析对比。结果表明实验组患者生理曲线改善程度显著高于参照组(P<0.05),实验组患者腰部疼痛感大腿麻木感较参照组有较大明显改善(P<0.01)。实验结论:通过核心肌群训练能够明显改善腰椎间盘周围韧带的牵张力消除肌肉粘连稳定腰椎等积极作用,对预防和治疗腰椎间盘突出症,防止再次复发具有重要的临床价值。     

The impact of different types of physical activity on total and regional bone mineral density in young Brazilian athletes

Bone turnover is affected by exercise throughout the lifespan, especially during childhood and adolescence. The objective of this study was to investigate the impact of different sports on total and regional bone mineral density in male Brazilian adolescent athletes. Forty-six adolescents aged 10-18 years participated in the study: 12 swimmers, 10 tennis players, 10 soccer players, and 14 sedentary individuals. The athletes had engaged in physical activities for more than 10 h per week in the previous 6 months. Bone mineral density of the lumbar spine (L1-L4), left proximal femur region, and whole body was evaluated by dual-energy X-ray absorptiometry. Results showed higher mean values in the proximal femur region of tennis and soccer players (1.02 ± 0.18; 0.96 ± 0.16, respectively) than swimmers and controls (0.91 ± 0.14 and 0.87 ± 0.06, respectively) (P < 0.05). In relation to the impact of sporting activities based on bone age determination, we observed significant differences in bone mineral density at all evaluated sites at the end of puberty (16-18 years) compared with 10-12 years, with increases of 78% in the lumbar spine, 47% in the proximal femur, and 38% in the whole body.     

内翻式落地足跖骨力学反应研究

根据足三维有限元模型探究跖骨在不同角度内翻状态下力学状态变化。研究结果显示内翻态峰值应力集中于第五跖骨基底,体现了落地时前掌跖骨应力分布。该模型大致反映了足部结构在非正常落地时前掌支撑力学功能,并为损伤原理提供一定指导。     

Lumbar spinal loading during bowling in cricket: a kinetic analysis using a musculoskeletal modelling approach

The objective of the study was to evaluate two types of cricket bowling techniques by comparing the lumbar spinal loading using a musculoskeletal modelling approach. Three-dimensional kinematic data were recorded by a Vicon motion capture system under two cricket bowling conditions: (1) participants bowled at their absolute maximal speeds (max condition), and (2) participants bowled at their absolute maximal speeds while simultaneously forcing their navel down towards their thighs starting just prior to ball release (max-trunk condition). A three-dimensional musculoskeletal model comprised of the pelvis, sacrum, lumbar vertebrae and torso segments, which enabled the motion of the individual lumbar vertebrae in the sagittal, frontal and coronal planes to be actuated by 210 muscle-tendon units, was used to simulate spinal loading based on the recorded kinematic data. The maximal lumbar spine compressive force is 4.89 ± 0.88BW for the max condition and 4.58 ± 0.54BW for the max-trunk condition. Results showed that there was no significant difference between the two techniques in trunk moments and lumbar spine forces. This indicates that the max-trunk technique may not increase lower back injury risks. The method proposed in this study could be served as a tool to evaluate lower back injury risks for cricket bowling as well as other throwing activities.     

山东省优秀男子举重运动员抓举技术动作生物力学分析

根据定性与定量相结合的原则,采用摄像解析及三维测力相结合的方法,对山东省男子举重队6名运动员的抓举动作进行诊断和评价,为其改进技术动作,提高运动成绩提供参考依据.研究结果表明,抓举过程中杠铃中心点运动轨迹应尽可能成垂直直线向上,S型弧度要小,发力后杠铃应达到一定最大速度,部分优秀运动员下蹲时加速度大于自由落体加速度,杠铃上抛中心点与身高的比值应控制在70%左右.抓举过程中人体膝关节角度曲线成双峰,而髋关节角度曲线为单峰,髋关节不可过早打开,躯干也不可过早用力.抓举整个过程环环相扣,每个阶段的发挥对下一阶段均有重要影响,对抓举的技术分析应采用系统的思考方法.