Swimmer simulation using robot manipulator dynamics under steady water

To help swimmers improve, we have developed a computational swimming model using underwater manipulator dynamics. We formulate the equations of the underwater manipulator dynamics using the fluid drag, which is proportional to the square of the velocity. We construct a swimming model consisting of several links based on these equations. The distance traveled by the optimal swimming motion is derived using the model. The input parameters are the joint torques. The arm and leg positions in the model are determined from the joint torques. The force transmitted from the water to the manipulator is defined to be the action force, and the force transmitted from the manipulator to the water is defined to be the reaction force. This reaction force is defined to be the propulsion force. By combining the propulsion force generated by the arms and legs and the frictional drag with respect to the body we can calculate the distance traveled. To optimize the propulsion, which depends on the swimmer’s motion, a variational approach using the Lagrange function is applied. We can use the model to simulate 2D pseudo-backstroke motion. Our model has a lower cost than other techniques in the literature, because it does not require computational fluid dynamics (CFD). The swimmer velocity calculated by our model agrees quite closely with the results in the literature. The model qualitatively captures the movement of an actual swimmer.

Heavy metal stress induced hyperglycemia in blue swimmer crab, Portunus pelagicus

The study was to find out the effect of cadmium and mercury on levels of hemolymph glucose, crustacean hyperglycemic hormone（CHH） and hepatopancreas glycogen in the blue swimmer crab Portunus pelagicus. The experiments were performed in both intact and eyestalk ablated crabs. Quantification of CHH was done by the indirect ELISA with the aid of primary anti-Carcinus maenas-CHH antibody. Higher glucose concentration was observed on exposure to 8×10^–6 of cadmium（（825.6±5.42） μg/m L） and 6×10^–6 of mercury（（90.5±6.25） μg/m L）after 48 h and 24 h respectively. Higher level of hemolymph glucose was observed in eyestalk intact crabs on exposure to cadmium and mercury than eyestalk ablated crabs. Decrease in the levels of CHH was observed in both eyestalk intact and ablated crabs on heavy metal exposure. Decline of the hepatopancreas glycogen level was also witnessed with the exposure to heavy metal, which validated its utilization in the production of glucose. Thus this study brings to light, the variations in hemolymph glucose, CHH and hepatopancreas glycogen on heavy metal stress. These carbohydrate metabolites can be used as biomarkers in assessing heavy metal contamination in water bodies.

A Reanalysis of the Two Swimmers Problem, as Frequent Model of Michelson’s Interferometric Experiment Demonstrating that Transversal Path Is Not an Isosceles but a Right Triangle and the Race Will End in a Tie

The article initially reviews various works describing the physical model (PM) of Michelson’s interferometric experiment (ME), represented by the race between two swimmers Sw1, Sw2 (or boats, or planes, or sound signals, etc.). The two swimmers must each swim the same distance, but Sw1 will swim along the river flow, and Sw2 will swim perpendicularly to this direction. In all such works, it is considered that Sw2’s path will require less time and that it will reach the start point first. However, in this work, it has been determined that in order to make this possible, Sw2 must not observe the orthogonality rule of his start direction. This action would be deceitful to the arbiters and thus considered as non-fair-play towards Sw1. The article proves by swimming times calculus, that if the fair-play rules are observed, then the correct crosswise path (in water reference frame) is a right triangle instead of the isosceles triangle considered by Michelson. Consequently, the two times shall be perfectly equal and the race ends in a tie, and the myth of Sw2 as the race winner shall be debunked. Note that the same result shall also be applicable to Michelson’s interferometric experiment (ME) as well as to any similar experiment. Therefore, utilising the isosceles triangle as the transversal path in PM and also in ME is an erroneous act.

The Escaping and Returning of“The Swimmer”from the Symbolic Point of View

"The Swimmer"is the representative of John Cheever and it is one of the most famous short stories in present America.The story is simple and it is not long, but it has profound meaning because many imageries are been used in the story. It tries to analyze the escaping and returning from the symbolic point of view, for escaping is an important motif in modern society and in the end, only returning can realize self-redemption.

Prospects for Chinese Swimmers at the Atlanta Olympics

ＰｒｏｓｐｅｃｔｓｆｏｒＣｈｉｎｅｓｅＳｗｉｍｍｅｒｓａｔｔｈｅＡｔｌａｎｔａＯｌｙｍｐｉｃｓＢｙＨＯＮＧＴＡＯＬｅＪｉｎｇｙｉ，ａｗｏｍａｎｓｗｉｍｍｅｒｆａｍｏｕｓｉｎｆｒｅｅｓｔｙｌｅ．ＡＴＴＨＥｌａｓｔＯｌｙｍｐｉｃＧａｒｍｅｓｔｈｅＣｈｉｎ...

Swimmer with submerged SiO_(2)/Al/LiNbO_(3) surface acoustic wave propulsion system

Acoustic propulsion system presents a novel underwater propulsion approach in small scale swimmer.This study introduces a submerged surface acoustic wave(SAW)propulsion system based on the SiO_(2)/Al/LiNbO_(3) structure.At 19.25 MHz,the SAW propulsion system is proposed and investigated by the propulsion force calculation,PIV measurements and propulsion measurements.3.3 mN propulsion force is measured at 27.6 V_(pp).To evaluate the miniature swimmer,the SAW propulsion systems with multiple frequencies are studied.At 2.2 W,the submerged SAW propulsion system at 38.45 MHz demonstrates 0.83 mN/mm^(2) propulsion characteristics.At 96.13 MHz and 24 V_(pp),the movements of miniature swimmer with a fully submerged SAW propulsion system are recorded and analyzed to a maximum of 177 mm/s.Because of miniaturization,high power density,and simple structure,the SAW propulsion system can be expected for some microrobot applications,such as underwater drone,pipelinerobotand intravascularrobot.

不同运动水平和性别游泳运动员功能动作筛查得分比较

目的:采用功能动作筛查(FMS)评分方法对比分析不同竞技水平和性别游泳运动员的功能动作质量和均衡性。方法:以161名游泳运动员为研究对象,按竞技水平分为优秀组(n=60)和一般组(n=101),进行FMS测试并采集数据。结果:①两组运动员之间和组内男女运动员之间,FMS总分无显著性差异(P>0.05);②优秀组与一般组比较,分别在肩部灵活性、主动直腿抬高(P<0.05)和旋转稳定性(P<0.01)3项得分上存在显著性差异;③优秀组在线性弓步、主动直腿抬高(P<0.05)和躯干稳定俯卧撑(P<0.01)3项得分上存在明显的性别差异;④一般组在深蹲、线性弓步和主动直腿抬高3项得分上存在明显的性别差异(P<0.05);⑤在功能动作质量方面,优秀组与一般组相比,分别在深蹲、躯干稳定俯卧撑(P<0.05)和旋转稳定性(P<0.01)3项动作质量上存在显著性差异;⑥在功能动作均衡性方面,优秀组两侧不均衡性主要表现在线性弓步和跨栏步,分别占31.67%和30%;而一般组两侧不均衡性最明显的是肩部灵活性,占比31.68%。结论:FMS总分未能反映游泳运动员的竞技水平和性别差异。优秀游泳运动员有较好的肩部灵活性和均衡性,其中男运动员核心稳定性和力量优于女运动员;一般游泳运动员有较好的核心稳定性和腘绳肌柔韧性,其中男运动员深蹲能力优于女运动员。与男运动员相比,两组女运动员均表现出较好的腘绳肌柔韧性。

World Class Elite Breaststrokers Downward Kick EMG Muscle Activity of the Gluteus Maximus, Quadriceps Femoris, Hamstring, Gastrocnemius Medialis, Rectus Abdominal, and Erector Spinae

This study analyzed the difference between using a downward breaststroke kick and a horizontal breaststroke kick in a sample of world class elite swimmers.We compared average muscle activity of the gluteus maximus,quadriceps femoris(vastus medialis and rectus femoris),hamstring/long head of the biceps femoris,gastrocnemius medialis,rectus abdominal,and erector spinae when using the downward breaststroke kick technique.We find that when this sample of swimmers utilized the downward breaststroke kick,max speed and velocity per stroke increased,measured by 12,788 EMG samples,where the results are highly correlated to duration of the aerodynamic buoyant force in breaststroke kick technique.The increases in performance observed from measuring the world class elite swimmers is highly correlated to the duration of the kick aerodynamic buoyant force.Among this sample of elite swimmers,the longer a swimmer demonstrates a buoyant force breaststroke kick,the lower the time in a 100 breaststroke.

青少年游泳运动员专项运动素质指标体系研究

游泳是以体能为主导的周期性项目,其专项运动素质是游泳运动员竞技能力的重要组成部分。本研究运用层次分析等方法对青少年游泳运动员专项运动素质的相关指标进行研究,旨在构建青少年游泳运动员专项运动素质指标体系,以期为青少年游泳运动员选材、训练提供理论参考。研究表明,青少年游泳运动员专项运动素质指标体系包含了一级指标6个,二级指标8个,三级指标12个。其中,一级指标及其权重为:速度专项素质(0.25)、力量专项素质(0.21)、耐力专项素质(0.17)、柔韧专项素质(0.15)、灵敏专项素质(0.12)、协调专项素质(0.1);二级指标及其权重为:位移速度(0.19)、快速力量(0.17)、有氧耐力(0.16)、力量耐力(0.14)、专项柔韧(0.12)、反应速度(0.09)、专项灵敏(0.07)、专项协调(0.06);三级指标及其权重为:50m游(0.16)、400m游(0.12)、5X100m划手游(0.11)、25m冲刺游(0.1)、5X100m打腿游(0.1)、伸肩(0.08)、1分钟跳绳(0.07)、出发反应时(0.05)、立定跳远(0.06)、坐位体前屈(0.05)、20秒反复横跨(0.05)、T测试(0.05)。

The Influence of Swimming Athletes’ Burnout on Their Sports Participation Motivation in Hunan, China

Objective:This study aims to explore the effect of swimming athletes’burnout on their sports motivation in Hunan University,China.It seeks to understand how burnout influences various motivational factors,providing insights for optimizing swimming sports courses and enhancing student participation.Method:Employing random sampling,the study surveyed 260 swimming athletes from Hunan University.The research utilized a questionnaire divided into three parts:demographic information,the Athlete Burnout Questionnaire(ABQ),and the Intrinsic Motivation Inventory(IMI).Pearson’s r correlation analysis was conducted using SPSS to examine the relationships between burnout dimensions and motivational factors.Results:The study found significant correlations between a reduced sense of accomplishment and various motivational dimensions,including“interest/enjoyment,”“perceived competence,”“perceived choice,”and particularly“perceived tension.”Physical exhaustion showed a significant correlation only with“perceived tension,”indicating a strong link between psychological stress and physical fatigue.Sports devaluation was significantly correlated with“perceived tension,”suggesting that psychological stress impacts athletes’valuation of their sport.Conclusion:The findings highlight the complex interplay between burnout and motivation in swimming athletes.Psychological stress,as indicated by“perceived tension,”emerges as a key factor influencing both the physical and emotional aspects of burnout.The study underscores the need for holistic training approaches that balance physical training with psychological well-being,personalized coaching,and supportive environments to enhance intrinsic motivation and manage stress effectively.

“大数据+人工智能”在游泳运动员训练中的应用研究

人工智能和大数据技术的快速发展已经在各个领域取得了一定的成就,其中包括体育领域,但在其与游泳的结合方面还处于初期探索阶段。该文通过文献资料法等方法,结合智能可穿戴设备和图像视频等数据,运用人工智能分析及大数据技术进行综合采集和高效处理,以此精准矫正运动员的游泳姿势。研究结果表明,人工智能和大数据技术在运动员训练中的应用能够为他们提供更全面和个性化的数据支持,为运动员提供更深入的运动表现分析和技术改进的机会。这一发现强调了大数据和人工智能技术在提升运动员表现和技术指导方面的重要性。

高水平男性游泳运动员自由泳滚翻转身指标研究

目的:通过对8名高水平男性游泳运动员自由泳滚翻转身技术的数据分析,客观评判自由泳滚翻转身效果中权重最高的前五指标,并提供理论优化建议。方法:通过相关文献和专家访谈建立自由泳滚翻转身指标,使用Klistler和Dartfish获得运动员滚翻转身的运动学数据,采用CRITIC法和熵权法得到权重。结果:自由泳滚翻转身指标中权重最高的前五指标分别为蹬壁峰力值(13.53%)、滚翻前速度(9.60%)、触壁时间(9.45%)、转体时间(7.07%)和转身屈髋(6.15%),累计贡献达45.80%。结论:1)游近距离、出水位置、重心距离、游近速度等指标的累积权重达26.40%,因此,这些影响因素值得进一步深入研究;2)加快滚翻前速度、避免滚翻前抬头、保证适当的转身屈髋角度,增加屈髋角速度,稳定触壁时间的同时,提高蹬壁峰力值有助于高水平男性游泳运动员自由泳滚翻转身的运动表现。

渐进性离心收缩训练对高水平游泳运动员半月板损伤后康复及伸膝力量的影响研究

目的:探讨渐进性离心收缩训练对高水平游泳运动员半月板损伤康复的影响,特别关注伸膝力量的改善。方法:通过文献综述、实验和数据分析等方法,研究两组运动员的治疗效果。研究对象是高水平游泳运动员,半月板损伤对他们的运动表现和生活质量产生重要影响。实验组接受了渐进性离心收缩训练,对照组接受传统康复方法。结果显示:在肢体对称功能、膝关节活动度和Lysholm膝关节功能评分方面,实验组的治疗效果明显优于对照组,这些差异在统计学上也得到了支持。

速度节奏对高水平400 m个人混合泳运动员竞赛成绩影响的实证研究

速度节奏是400 m个人混合泳比赛中速度的变化特征,是制约高水平400 m个人混合泳运动员竞赛成绩的关键要素。目的:探究速度节奏对高水平400 m个人混合泳运动员的竞赛表现,以性别、竞技能力为分类变量,从而确定高水平400 m个人混合泳运动员在世界大赛中的速度节奏差异。方法:以参加400 m个人混合泳比赛(2012—2023赛季)运动员的竞赛成绩为研究对象,将男、女运动员按照比赛成绩分为奖牌组和非奖牌组,运用独立样本T检验、相关分析、回归分析研究400 m个人混合泳运动员各分段成绩、分段速度、速度系数等之间的关系。结果:(1)400 m个人混合泳的速度节奏呈“U”形曲线轨迹(两头高,中间低),即采用积极加速策略游进。其中,第六分段为最低点,第一和第八分段为高点,第四分段为小加速现象;(2)男子奖牌组分段速度、速度系数与非奖牌组、女子组有显著差异(P<0.05),女子奖牌组与非奖牌组之间均差异显著(P<0.05)。高水平400 m个人混合泳运动员在第一、二、七、八分段为加速游(蝶泳、自由泳分段),而在第二至第六分段为减速游(仰泳、蛙泳分段);(3)男子运动员第一至第七分段与总成绩显著正相关(P<0.05),第二分段相关性最强(R=0.779),第三分段其次(R=0.701),女子运动员第三至第八分段与总成绩显著正相关(P<0.05),相关性最强的是第七分段(R=0.828),第四分段其次(R=0.676),且均拟合方程。结论:“U”形游进节奏是400 m个人混合泳运动员比赛采用的常用节奏(蝶泳、自由泳阶段为加速游,仰泳、蛙泳阶段为减速游),第四分段、第六分段、第八分段的速度节奏分配策略、竞技能力是400 m个人混合泳比赛制胜的关键,运动员们应该在提高绝对速度、合理分配体能的基础上,着重提高四种泳式技术、速度耐力、爆发力,确保比赛中各分段能量系统的最优利用。

Purcell's Swimmer Revisited

Purcell’s swimmer was proposed by E. M. Purcell to explain bacterial swimming motions. It has been proved experimentally that a swimmer of this kind is possible under inertial-less and high viscous environment. But we could not investigate all the aspects of this mechanism through experiments due to practical difficulties. The computational fluid dynamics (CFD) provides complementary methods to experimental fluid dynamics. In particular, these methods offer the means of testing theoretical advances for conditions unavailable experimentally. Using such methodology, we have investigated the fluid dynamics of force production associated with the Purcell’s swimmer. By employing dynamic mesh and user-defined functions, we have computed the transient flow around the swimmer for various stroke angles. Our simulations capture the bidirectional swimming property successfully and are in agreement with existing theoretical and experimental results. To our knowledge, this is the first CFD study which shows the fact that swimming direction depends on stroke angle. We also prove that for small flapping frequencies, swimming direction can also be altered by changing frequency-showing breakdown of Stokes law with inertia.

浅谈公共图书馆少儿读者活动策划——以贵阳市图书馆为例

本文以贵阳市图书馆的“书海小泳将”活动为例,探讨了公共图书馆少儿读者活动策划的实践与思考。少儿读者活动的策划与实施,对于激发少儿阅读兴趣、培养阅读习惯、提升综合素养以及促进社会交往具有至关重要的意义。公共图书馆少儿读者活动策划的关键因素包括深入了解少儿需求、明确具体活动目标、精心设计活动内容、合理安排时间和地点、有效宣传推广活动以及加强活动组织和管理。未来,公共图书馆应加强合作,开展多样活动,注重创新和发展,加强评估和研究,为少儿读者提供更好的服务。

针灸法治疗青少年游泳运动员腰肌劳损的可行性研究

使用文献资料法、问卷调查法、实验法、数据统计法对福建省若干青少年游泳运动员进行研究,对其中36名腰伤运动员进行针灸治疗。在治疗前中后期对运动员进行视觉模拟评分(VAS)、日本骨科学会腰椎疾患综合评分(JOA)、Oswestry功能障碍指数(ODI)、腰椎活动度(ROM)评分及检测神经传导速度变化,分析对运动员竞技状态的影响。结果表明,急性腰损伤在治疗14D后,慢性腰肌劳损在治疗30D后,腰伤运动员的各项评分相比较具有显著性差异。治疗前后腓总神经和腓浅神经传导速度有所提高,可见将针灸可有效应用于青少年游泳运动员腰伤治疗,能够缓解疼痛、肿胀、功能受限等症状。治疗后,运动员的竞技状态基本恢复,无不良反应。建议:提高腰部力量训练、准备活动充分、重视训练后的恢复工作及制定合理的训练计划来加强青少年游泳运动员的预防保护措施。

心理疲劳对高水平游泳运动员运动成绩的影响研究:来自行为和EEG的关联性证据

目的:考察心理疲劳对游泳运动员运动成绩的影响及其认知神经机制以及脑电活动变化与运动成绩变化的关系。方法:采用单因素被试内研究设计,共招募20名国家一级及以上水平游泳运动员,利用Stroop范式诱导心理疲劳,利用静息态脑电(EEG)技术记录无心理疲劳、心理疲劳两种实验环境下的脑电数据,以及记录两种实验环境下的运动成绩。结果:(1)从运动成绩来看,与心理疲劳诱导前相比,游泳运动员在心理疲劳诱导后的运动成绩显著降低(各时间段均显著降低)。(2)从EEG指标来看,与心理疲劳诱导前相比,游泳运动员在心理疲劳诱导后颞叶Alpha波、颞叶Theta波和顶叶Theta波呈显著上升,额叶Theta波、中央区Theta波和枕叶Delta波呈显著下降。结论:心理疲劳对游泳运动员的运动成绩与脑神经活动均有影响,后续可利用脑电即时监测专业游泳运动员心理疲劳以减少心理疲劳对其运动成绩的影响。

行经期干预对女性游泳运动员重大比赛成绩影响的个案报道

目的:探讨女性游泳运动员行经期干预对比赛成绩的影响。方法:运用饮食疗法对运动员行经期进行干预,使运动员行经期与重大比赛时间不冲突,并对比月经周期不同阶段比赛成绩的影响。结果:(1)通过饮食疗法的干预,该运动员行经期提前3天,行经期与奥运会比赛时间完全不重合。(2)月经周期不同阶段,运动员表现出的运动能力、竞技能力各不相同。行经期身体状态最差,运动能力和竞技能力相对较差,其比赛成绩也最差。结论:应根据运动员自身情况进行饮食疗法,调整行经期与重大比赛时间不冲突,女性运动员在排卵期和黄体期,其身体状态较好,能取得较好的比赛成绩。

现代竞技体育游泳专项运动员体能训练思路研究

随着健康运动理念的普及,大众对于竞技类运动的关注度日益提高。游泳作为奥运会中的重点项目,许多国家都针对竞赛的规则、项目设置等开展训练活动,保障国家能够获得更多的荣誉。而要想提升运动员自身的运动水平,需要强化基础体能训练,为更好地完成技术动作提供良好的基础。为此,该文对竞技类游泳运动员体能训练的要求作出分析,并提出落实体能训练的方法和对策,以期提升运动员的竞技水平。