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1.
In elite swimming, a broad range of methods are used to assess performance, inform coaching practices and monitor athletic progression. The aim of this paper was to examine the performance analysis practices of swimming coaches and to explore the reasons behind the decisions that coaches take when analysing performance. Survey data were analysed from 298 Level 3 competitive swimming coaches (245 male, 53 female) based in the United States. Results were compiled to provide a generalised picture of practices and perceptions and to examine key emerging themes. It was found that a disparity exists between the importance swim coaches place on biomechanical analysis of swimming performance and the types of analyses that are actually conducted. Video-based methods are most frequently employed, with over 70% of coaches using these methods at least monthly, with analyses being mainly qualitative in nature rather than quantitative. Barriers to the more widespread use of quantitative biomechanical analysis in elite swimming environments were explored. Constraints include time, cost and availability of resources, but other factors such as sources of information on swimming performance and analysis and control over service provision are also discussed, with particular emphasis on video-based methods and emerging sensor-based technologies.  相似文献   

2.
Abstract

In freestyle swimming the arm action is routinely quantified by stroke count and rate, yet no method is currently available for quantifying kick. In this study, we assessed the validity and reliability of inertial sensor technology (gyroscope) to assess kick count and rate. Twelve Paralympic swimmers completed a 100-m freestyle-swimming time-trial and freestyle kicking-only time-trial three times each in a season. An algorithm was developed to detect the up and down beat of individual kicks from the gyroscope trace. For comparative purposes, underwater video analysis provided the criterion measure. The standard error of the estimate (validity) for kick count, expressed as a coefficient of variation, was 5.9% (90% confidence interval 5.5 to 6.4) for swimming, and 0.6% (0.5 to 0.6) for kicking-only trials. The mean bias for kick count was ?1.7% (?2.4 to ?1.1) for swimming, and ?0.1% (?0.2 to ?0.1) for kicking-only trials. Correlations between the sensor and video for kick count were 0.96 (0.95 to 0.97) for swimming, and 1.00 (1.00 to 1.00) for kicking-only trials. The typical error of the measurement (reliability) between trials was approximately 4% for kick count and rate. The inertial sensors and associated software used generated sufficient validity and reliability estimates to quantify moderate to large changes in kick count and rate in freestyle swimming.  相似文献   

3.
The aim of this study was to evaluate the influence of dry-land inertial training (IT) on muscle force, muscle power, and swimming performance. Fourteen young, national-level, competitive swimmers were randomly divided into IT and control (C) groups. The experiment lasted four weeks, during which time both groups underwent their regular swimming training. In addition, the IT group underwent IT using the Inertial Training Measurement System (ITMS) three times per week. The muscle groups involved during the upsweep phase of the arm stroke in front crawl and butterfly stroke were trained. Before and after training, muscle force and power were measured under IT conditions. Simultaneously with the biomechanical measurements on the ITMS, the electrical activity of the triceps brachii was registered. After four weeks of training, a 12.8% increase in the muscle force and 14.2% increase in the muscle power (p?<?.05) were noted in the IT group. Moreover, electromyography amplitude of triceps brachii recorded during strength measurements increased by 22.7% in the IT group. Moreover, swimming velocity in the 100?m butterfly and 50?m freestyle improved significantly following the four weeks of dry-land IT (?1.86% and ?0.76%, respectively). Changes in the C group were trivial. Moreover, values of force and power registered during the ITMS test correlated negatively with the 100?m butterfly and 50?m freestyle swimming times (r value ranged from ?.80 to ?.91). These results suggest that IT can be useful in swimming practice.  相似文献   

4.
Persistent biomechanical and jumping capacity alterations have been observed among female athletes who have sustained anterior cruciate ligament (ACL) injuries. The purpose of this study was to examine if biomechanical jumping differences persist among a cohort of elite female handball players with previous ACL reconstruction several years after return to top-level competition. In order to achieve this goal, a direct mechanics simplified analysis by using a single Inertial Sensor Unit (IU) was used. Twenty-one elite female (6 anterior cruciate ligament reconstructed and 15 uninjured control players) handball players were recruited and evaluated 6.0 ± 3.5 years after surgical anterior cruciate ligament reconstruction. Bilateral and unilateral vertical jumps were performed to evaluate the functional performance and a single inertial sensor unit was employed in order to collect 3D acceleration and 3D orientation data. Previously ACL-reconstructed analysed athletes demonstrated significant (p < 0.05) alterations in relation to the three-dimensional axis (X–Y–Z) supported accelerations and differing jump phase durations, including jumping performance values, in both bilateral and unilateral jumping manoeuvres several years after ACL reconstruction. Identification of the encountered deficits through the use of an IU devise could provide clinicians with a new reliable tool for movement analysis in a clinical setting.  相似文献   

5.
刘卉  于冰 《体育科研》2020,(5):65-71
动作技术生物力学分析是竞技体育科技助力和全民健身科学研究的重要组成部分。以目标为导向，以模型为方法，合理采用恰当的数据分析方法，是动作技术生物力学分析的主要思路。本文的目的是针对竞技体育动作技术分析与诊断的实际需要，以田径和游泳项目为例，介绍以提高运动成绩为目标的动作技术分析的模型建立步骤和数据分析方法，并提出进行动作技术生物力学分析应注意的问题，以期为运动生物力学研究者和实践者提供借鉴，更准确高效地为运动训练提供科技助力。  相似文献   

6.
ABSTRACT

Athletes’ energy distribution over a race (e.g. pacing behaviour) varies across different sports. Swimming is a head-to-head sport with unique characteristics, such as propulsion through water, a multitude of swimming stroke types and lane-based racing. The aim of this paper was to review the existing literature on pacing behaviour in swimming. According to PRISMA guidelines, 279 articles were extracted using the PubMed and Web of Science databases. After the exclusion process was conducted, 16 studies remained. The findings of these studies indicate that pacing behaviour is influenced by the race distance and stroke type. Pacing behaviours in swimming and time-trial sports share numerous common characteristics. This commonality can most likely be attributed to the lane-based racing set-up. The low efficiency of swimming resulting from propulsion through the water induces a rapid accumulation of blood lactate, prompting a change in swimmers’ biomechanical characteristics, with the goal of minimising changes in velocity throughout the race. Although the literature on youth swimmers is scarce, youth swimmers demonstrate more variable pacing profiles and have more difficulty in selecting the most beneficial energy distribution.  相似文献   

7.
ABSTRACT

Cross-country skiing is a complex endurance sport requiring technical skills, in addition to considerable physiological and tactical abilities. This review aims to identify biomechanical factors that influence the performance of cross-country skiers. Four electronic databases were searched systematically for original articles in peer-reviewed journals addressing the relationship between biomechanical factors (including kinematics, kinetics, and muscle activation) and performance while skiing on snow or roller skiing. Of the 46 articles included, 22 focused exclusively on the classical technique, 18 on the skating technique, and six on both. The indicators of performance were: results from actual or simulated races (9 articles); speed on specific tracts (6 articles); maximal or peak speed (11 articles); skiing economy or efficiency (11 articles); and grouping on the basis of performance or level of skill (12 articles). The main findings were that i) cycle length, most often considered as a major determinant of skiing speed, is also related to skiing economy and level of performance; ii) higher cycle rate related with maximal speed capacity, while self-selected cycle rate improves skiing economy at sub-maximal speeds; iii) cross-country skiing performance appears to be improved by joint, whole-body, ski, and pole kinematics that promote forward propulsion while minimizing unnecessary movement.  相似文献   

8.
The aim of this study was to compute a swimming performance confirmatory model based on biomechanical parameters. The sample included 100 young swimmers (overall: 12.3?±?0.74 years; 49 boys: 12.5?±?0.76 years; 51 girls: 12.2?±?0.71 years; both genders in Tanner stages 1–2 by self-report) participating on a regular basis in regional and national-level events. The 100?m freestyle event was chosen as the performance indicator. Anthropometric (arm span), strength (throwing velocity), power output (power to overcome drag), kinematic (swimming velocity) and efficiency (propelling efficiency) parameters were measured and included in the model. The path-flow analysis procedure was used to design and compute the model. The anthropometric parameter (arm span) was excluded in the final model, increasing its goodness-of-fit. The final model included the throw velocity, power output, swimming velocity and propelling efficiency. All links were significant between the parameters included, but the throw velocity–power output. The final model was explained by 69% presenting a reasonable adjustment (model's goodness-of-fit; x2/df?=?3.89). This model shows that strength and power output parameters do play a mediator and meaningful role in the young swimmers’ performance.  相似文献   

9.
Motor proficiency in childhood has been recently recognised as a public health determinant, having a potential impact on the physical activity level and possible sedentary behaviour of the child later in life. Among fundamental motor skills, ballistic skills assessment based on in-field quantitative observations is progressively needed in the motor development community. The aim of this study was to propose an in-field quantitative approach to identify different developmental levels in overarm throwing. Fifty-eight children aged 5–10 years performed an overarm throwing task while wearing three inertial sensors located at the wrist, trunk and pelvis level and were then categorised using a developmental sequence of overarm throwing. A set of biomechanical parameters were defined and analysed using multivariate statistics to evaluate whether they can be used as developmental indicators. Trunk and pelvis angular velocities and time durations before the ball release showed increasing/decreasing trends with increasing developmental level. Significant differences between developmental level pairs were observed for selected biomechanical parameters. The results support the suitability and feasibility of objective developmental measures in ecological learning contexts, suggesting their potential supportiveness to motor learning experiences in educational and youth sports training settings.  相似文献   

10.
Undulatory underwater swimming (UUS) occurs in the starts and turns of three of the four competitive swimming strokes and plays a significant role in overall swimming performance. The majority of research examining UUS is comparative in nature, dominated by studies comparing aquatic animals' undulatory locomotion with the UUS performance of humans. More recently, research directly examining human forms of UUS have been undertaken, providing further insight into the factors which influence swimming velocity and efficiency. This paper reviews studies which have examined the hydromechanical, biomechanical, and coordination aspects of UUS performance in both animals and humans. The present work provides a comprehensive evaluation of the key factors which combine to influence UUS performance examining (1) the role of end-effector frequency and body amplitudes in the production of a propulsive waveform, (2) the effects of morphology on the wavelength of the propulsive waveform and its subsequent impact on the mode of UUS adopted, and (3) the interactions of the undulatory movements to simultaneously optimise propulsive impulse whilst minimising the active drag experienced. In conclusion, the review recommends that further research is required to fully appreciate the complexity of UUS and examine how humans can further optimise performance.  相似文献   

11.
Understanding the relationships between front crawl swimming technique and the corresponding fluid dynamics is important to athletes seeking improved performance and an edge over their rivals. Computational fluid dynamics (CFD) swimming modelling provides a controlled and unobtrusive capability that provides many previously immeasurable quantities including full flow fields and information on the forces experienced by the body throughout the stroke. In this study, a coupled biomechanical-smoothed particle hydrodynamics (SPH) method is used to determine when peak arm thrust occurs and how the ratio of arm–leg thrust changes with stroke rate. A dynamic biomechanical model of a female national-level swimmer was generated from a three-dimensional laser body scan of the athlete and multi-angle videos of sub-maximal swimming trials. This was coupled to the SPH method to simulate the fluid moving around the body during front crawl swimming. Two distinct peaks in net streamwise thrust were found during the stroke coinciding with the underwater arm strokes. The peak arm thrust occurred during the transition from pull to push (left arm) and midway during the push (right arm). Finally, the ratio of arm thrust to leg thrust was found to increase with increasing stroke rate.  相似文献   

12.
This study aimed to analyse the effect of growth during a summer break on biomechanical profile of talented swimmers. Twenty-five young swimmers (12 boys and 13 girls) undertook several anthropometric and biomechanical tests at the end of the 2011–2012 season (pre-test) and 10 weeks later at the beginning of the 2012–2013 season (post-test). Height, arm span, hand surface area, and foot surface area were collected as anthropometric parameters, while stroke frequency, stroke length, stroke index, propelling efficiency, active drag, and active drag coefficient were considered as biomechanical variables. The mean swimming velocity during an all-out 25 m front crawl effort was used as the performance outcome. After the 10-week break, the swimmers were taller with an increased arm span, hand, and foot areas. Increases in stroke length, stroke index, propelling efficiency, and performance were also observed. Conversely, the stroke frequency, active drag, and drag coefficient remained unchanged. When controlling the effect of growth, no significant variation was determined on the biomechanical variables. The performance presented high associations with biomechanical and anthropometric parameters at pre-test and post-test, respectively. The results show that young talented swimmers still present biomechanical improvements after a 10-week break, which are mainly explained by their normal growth.  相似文献   

13.
We propose a new method, based on inertial sensors, to automatically measure at high frequency the durations of the main phases of ski jumping (i.e. take-off release, take-off, and early flight). The kinematics of the ski jumping movement were recorded by four inertial sensors, attached to the thigh and shank of junior athletes, for 40 jumps performed during indoor conditions and 36 jumps in field conditions. An algorithm was designed to detect temporal events from the recorded signals and to estimate the duration of each phase. These durations were evaluated against a reference camera-based motion capture system and by trainers conducting video observations. The precision for the take-off release and take-off durations (indoor < 39 ms, outdoor = 27 ms) can be considered technically valid for performance assessment. The errors for early flight duration (indoor = 22 ms, outdoor = 119 ms) were comparable to the trainers' variability and should be interpreted with caution. No significant changes in the error were noted between indoor and outdoor conditions, and individual jumping technique did not influence the error of take-off release and take-off. Therefore, the proposed system can provide valuable information for performance evaluation of ski jumpers during training sessions.  相似文献   

14.
游泳运动对大鼠股骨和腰椎骨生物力学特性影响的研究   总被引：1，自引：1，他引：0  
步斌 《体育科学》2005,25(11):55-57
实验目的:探讨游泳训练对大鼠股骨和腰椎骨生物力学特性的影响。实验方法:以36只SD大鼠为实验对象,以大鼠游泳训练为运动模型,分为对照组(n=18)和实验组(n=18),每天训练30min,共6周。取双侧股骨第5腰椎制成试件,在日产万能试验机和力学参数测试系统中做3点弯曲的生物力学特性测试(弹性模量、最大载荷、屈服应力、最大应力、能量吸收等)及对骨的横断面积和骨矿含量进行测定。实验结果:股骨3点弯曲数据显示两组间的弹性模量、最大载荷、屈服应力、屈服应变无明显变化(P>0.05),而最大应力、最大应变和能量吸收则有显著下降的趋势(P<0.05),横断面积和骨矿含量无明显变化(P>0.05)。腰椎骨压缩试验的结果显示,实验组除能量吸收外(P>0.05),其最大载荷、屈服应力、最大应力、屈服应变和骨矿含量等参数均有显著增加(P<0.05)。提示,游泳对腰椎的刺激较大,可使腰部生物力学特性产生适应性变化。根据国内、外的相关研究,游泳运动是防治腰部骨质疏松和下腰部疼痛较好的锻炼方法之一,值得在临床上进一步研究。  相似文献   

15.
Starting block performance in swimming is of crucial importance in the individual competitions for the shorter swimming distances as well as for the relay events. The significance of this swim start performance will increase with the introduction of a new starting block with a longer and slightly steeper surface in conjunction with a push-off support for the feet and laterally adjustable handles. As grab starts and track starts were equally observed in international swimming competitions there are good reasons to assume that only the latter will remain the dominant starting technique. This report aims to summarize existing knowledge on the biomechanics of the swim start performed on a traditional starting block as a new starting block is introduced and new starting techniques are going to be developed. Following some introductory remarks on the assessment of the swim start performance, results will be discussed on the merit of different take-off techniques, on the entry behaviour, and on the force development profiles on the starting block. In conclusion, a tendency in favour of the rear-weighted track start was found in conjunction with a flat entry. In addition, it could be shown that an angular momentum around the transverse body axis combined with a dolphin kick (and a previously hyperextended hip joint) may provide hydrodynamic conditions to enter the water with a rather steep centre of mass trajectory. Finally, existing biomechanical knowledge will be presented on the relay start as well as on a possible change in the starting technique using the new block.  相似文献   

16.
Velocity profiling using inertial sensors for freestyle swimming   总被引：1，自引：1，他引：0  
The ability to unobtrusively measure velocity in the aquatic environment is a fundamental challenge for engineers and sports scientists and important in assessing the skill level. The aim of this research was to develop a method for velocity profiling in freestyle swimming utilising a purpose-built inertial sensor. Seventeen swimmers with different experience levels participated in this study performing a total of 159 laps in the velocity range from 0.79 to 2.04 m s?1. Data were collected using a triaxial accelerometer and a tethered velocity meter. The collected acceleration data were filtered using a 0.5 Hz Hamming-windowed FIR filter to remove the gravitational acceleration before the lap velocity profiles were calculated. These calculated lap velocity profiles were then compared with the velocity profiles measured by the velocity meter using Bland–Altman analysis. The scattering follows a normal distribution with a mean skewness of 0.96 ± 0.47 and kurtosis of 2.93 ± 1.12. The results show that an inertial sensor alone can be used to determine a lap velocity profile from single point acceleration records.  相似文献   

17.
游泳运动对老年男性骨质代谢影响的研究   总被引：5，自引：0，他引：5  
通过对长期参加游泳运动的老年人和不经常参加运动的老年人骨密度及骨代谢有关的生化指标的比较,探讨游泳运动对老年男性骨代谢的影响。结果显示,长期进行游泳运动的老年男性骨密度和血液中血钙、雌二醇、睾酮水平均显著高于对照组,同时,游泳Ⅰ组的骨密度显著高于游泳Ⅱ组。提示,长期游泳运动能够预防老年男性骨丢失和骨质疏松,且泳龄越长,效果越明显。  相似文献   

18.
Abstract

Inertial sensors may provide the opportunity for broader and more cost effective gait analysis; however some questions remain over their potential use in this capacity. The aim of the study was to determine whether an inertial sensor could discriminate between normal walking, fast walking, and running. A single group crossover design was used to compare acceleration profiles between three gait conditions: normal walking, fast walking, and running. An inertial sensor was placed on the sacrum of 12 participants (6 male, 6 female) who performed 3 trials of each gait condition on both overground and treadmill settings. A significant difference (P < 0.001) in the occurrence of heel strike in the gait cycle was found between running and both walking conditions. No differences were seen between overground and treadmill in any condition or variable. The results indicate that a single sacral mounted inertial sensor can differentiate running from normal walking and fast walking using temporal gait event measures. This study indicates that inertial sensors can differentiate walking from running gait in healthy individuals which may have potential for application in the quantification of physical activity in the health and exercise industry.  相似文献   

19.
Abstract

The capturing of movements by means of wearable sensors has become increasingly popular in order to obtain sport performance measures during training or competition. The purpose of the current study was to investigate the feasibility of using body worn accelerometers to identify previous highlighted performance related biomechanical changes in terms of substantial differences across skill levels and skating phases. Twenty-two ice hockey players of different caliber were equipped with two 3D accelerometers, located on the skate and the waist, as they performed 30 m forward skating sprints on an ice rink. Two measures of the temporal stride characteristics (contact time and stride time) and one measure of the propulsive power (stride propulsion) of a skating stride were calculated and checked for discriminating effects across (i) skill levels and (ii) sprint phases as well as for their (iii) strength of association with the sprint performance (total sprint time). High caliber players showed an increased stride propulsion (+22%, P?<?0.05) and shorter contact time (?5%, P?<?0.05). All three analysed variables highlighted substantial biomechanical differences between the accelerative and constant velocity phases (P?<?0.05). Stride propulsion of acceleration strides primarily correlated to total sprint time (r?=??0.57, P?<?0.05). The results demonstrate the potential of accelerometers to assess skating technique elements such as contact time or elements characterizing the propulsive power such as center of mass acceleration, to gauge skating performance. Thus, the findings of this study might contribute to establishing wearable sensors for in-field ice hockey skating performance analysis.  相似文献   

20.
The existing literature suggests that crank inertial load has little effect on the responses of untrained cyclists. However, it would be useful to be aware of any possible effect in the trained population, particularly considering the many laboratory-based studies that are conducted using relatively low-inertia ergometers. Ten competitive cyclists (mean VO(2max) = 62.7 ml x kg(-1) x min(-1), s = 6.1) attended the human performance laboratories at the University of Wolverhampton. Each cyclist completed two 7-min trials, at two separate inertial loads, in a counterbalanced order. The inertial loads used were 94.2 kg x m(2) (high-inertia trial) and 2.4 kg x m(2) (low-inertia trial). Several physiological and biomechanical measures were undertaken. There were no differences between inertial loads for mean peak torque, mean minimum torque, oxygen uptake, blood lactate concentration or perceived exertion. Several measures showed intra-individual variability with blood lactate concentration and mean minimum torque, demonstrating coefficients of variation > 10%. However, the results presented here are mostly consistent with previous work in suggesting that crank inertial load has little direct effect on either physiology or propulsion biomechanics during steady-state cycling, at least when cadence is controlled.  相似文献   

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