共查询到20条相似文献，搜索用时 0 毫秒
1.
Fiona Wilson Conor Gissane John Gormley Ciaran Simms 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):132-142
Lumbar spine injury in rowers is common and ergometer rowing has been cited as a risk factor for this injury. The purpose of this study is to compare lumbar kinematics between ergometer and single scull rowing and to examine the effect of fatigue on kinematics. The sagittal lumbar spine motion of 19 elite male rowers (lumbar spine injury free in the previous six months) was measured with an electrogoniometer during a ‘step test’ on an ergometer and in a single sculling boat. Maximum range of lumbar flexion was recorded in standing for reference. Power output and heart rate were recorded during the ergometer tests. Heart rate was used as a surrogate for power output in the sculling test. Maximum lumbar flexion increased during the step test and was significantly greater on the ergometer (4.4° ± 0.9°change), compared with the boat (+1.3° ± 1.1°change), (3.1°difference, p = 0.035). Compared to the voluntary range of motion, there is an increase of 11.3% (ergometer) and 4.1% (boat). Lumbar spine flexion increases significantly during the course of an ergometer trial while changes in a sculling boat were minimal. Such differences may contribute to the recent findings linking ergometer use to lower-back injury. 相似文献
2.
Marcos Gutierrez-Davila Manuel Ortega Jose Campos Juan Parraga 《Journal of sports sciences》2013,31(12):1321-1328
Abstract This study seeks to discover whether handball goalkeepers employ a general anticipatory strategy when facing long distance throws and the effect of uncertainty on these strategies. Seven goalkeepers and four throwers took part. We used a force platform to analyse the goalkeeper's movements on the basis of reaction forces and two video cameras synchronised at 500 Hz to film the throw using 3D video techniques. The goalkeepers initiated their movement towards the side of the throw 193 ± 67 ms before the release of the ball and when the uncertainty was reduced the time increased to 349 ± 71 ms. The kinematics analysis of their centre of mass indicated that there was an anticipatory strategy of movement with certain modifications when there was greater uncertainty. All the average scores referring to velocity and lateral movement of the goalkeeper's centre of mass are significantly greater than those recorded for the experimental situation with bigger uncertainty. The methodology used has enabled us to tackle the study of anticipation from an analysis of the movement used by goalkeepers to save the ball. 相似文献
3.
Peter Andreas Federolf 《Journal of sports sciences》2013,31(10):1063-1068
Abstract Alpine ski racing is a popular sport in many countries and a lot of research has gone into optimising athlete performance. Two factors influence athlete performance in a ski race: speed and the chosen path between the gates. However, to date there is no objective, quantitative method to determine instantaneous skiing performance that takes both of these factors into account. The purpose of this short communication was to define a variable quantifying instantaneous skiing performance and to study how this variable depended on the skiers' speed and on their chosen path. Instantaneous skiing performance was defined astime loss per elevation difference dt/dz, which depends on the skier's speed v(z), and the distance travelled per elevation difference ds/dz. Using kinematic data collected in an earlier study, it was evaluated how these variables can be used to assess the individual performance of six ski racers in two slalom turns. The performance analysis conducted in this study might be a useful tool not only for athletes and coaches preparing for competition, but also for sports scientists investigating skiing techniques or engineers developing and testing skiing equipment. 相似文献
4.
Camera techniques are typically used in the study of human movement. However, as the number of joints and markers involved in a study increases, data extraction and calculation become increasingly tedious and complicated. To overcome this challenge, we propose a method of study that simplifies data extraction and calculation by using an electrogoniometer and dual Euler angles. The contribution of the rotation of each arm segment to produce a racket head’s speed was identified in the context of a badminton smash. The contribution of each segment rotation was computed using dual velocity analysis. A set of orthogonal Cartesian frames was established for computing the anatomical rotational velocities for each of the three segments of the upper arm. Electrogoniometers were attached to the subjects during the execution of the smash to obtain measurements of joint angles throughout the motion. To test the algorithm, the calculated velocity of the racket head was compared to the measured velocity. The calculated velocity was derived from an algorithm, while the measured velocity was obtained from a video image. The results are similar, indicating that the dual velocity method is suitable for determining segmental velocities in such kinematic situations. 相似文献
5.
Elena Seminati Alessandra Marzari Oreste Vacondio Alberto E. Minetti 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):216-231
Repetitive stresses and movements on the shoulder in the volleyball spike expose this joint to overuse injuries, bringing athletes to a career threatening injury. Assuming that specific spike techniques play an important role in injury risk, we compared the kinematic of the traditional (TT) and the alternative (AT) techniques in 21 elite athletes, evaluating their safety with respect to performance. Glenohumeral joint was set as the centre of an imaginary sphere, intersected by the distal end of the humerus at different angles. Shoulder range of motion and angular velocities were calculated and compared to the joint limits. Ball speed and jump height were also assessed. Results indicated the trajectory of the humerus to be different for the TT, with maximal flexion of the shoulder reduced by 10 degrees, and horizontal abduction 15 degrees higher. No difference was found for external rotation angles, while axial rotation velocities were significantly higher in AT, with a 5% higher ball speed. Results suggest AT as a potential preventive solution to shoulder chronic pathologies, reducing shoulder flexion during spiking. The proposed method allows visualisation of risks associated with different overhead manoeuvres, by depicting humerus angles and velocities with respect to joint limits in the same 3D space. 相似文献
6.
Christopher Joyce Angus Burnett Jodie Cochrane Alvaro Reyes 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(1):61-75
It is unknown whether skilled golfers will modify their kinematics when using drivers of different shaft properties. This study aimed to firstly determine if golf swing kinematics and swing parameters and related launch conditions differed when using modified drivers, then secondly, determine which kinematics were associated with clubhead speed. Twenty high level amateur male golfers (M ± SD: handicap = 1.9 ± 1.9 score) had their three-dimensional (3D) trunk and wrist kinematics collected for two driver trials. Swing parameters and related launch conditions were collected using a launch monitor. A one-way repeated measures ANOVA revealed significant (p ≤ 0.003) between driver differences; specifically, faster trunk axial rotation velocity and an early wrist release for the low kick point driver. Launch angle was shown to be 2° lower for the high kick point driver. Regression models for both drivers explained a significant amount of variance (60–67%) in clubhead speed. Wrist kinematics were most associated with clubhead speed, indicating the importance of the wrists in producing clubhead speed regardless of driver shaft properties. 相似文献
7.
Rony Ibrahim Gert S. Faber Jaap H. van Dieën 《Sports biomechanics / International Society of Biomechanics in Sports》2017,16(1):45-57
Attaining high speed of the stick head and consequently of the ball is essential for successful performance of the drag flick in field hockey, but the coordination pattern used to maximise stick head speed is unknown. The kinematics of the drag flick was studied in ten elite hockey players who performed twenty shots each towards a target located 1.5 m high. A 150 Hz active marker motion analysis system was used, alongside two force plates to detect foot touchdown. Angular velocity and contribution to stick endpoint speed of upper body joints were analysed. Repeated measures ANOVA was used to compare timing of onset and peak angular velocities between joints. Participants used a kinematic pattern that was close to a proximal-to-distal sequence. Trunk axial rotation and lateral rotation towards the target, right wrist flexion and left wrist extension were the main contributors to stick endpoint speed. Coaches should emphasise trunk rotations and wrist flexion and extension movements for maximising stick head speed. Given the high level of the participants in this study, the coordination of joints motions, as reported here, can serve as a guideline for drag flick training. 相似文献
8.
Kinematic measurements conducted during bike set-ups utilise either static or dynamic measures. There is currently limited data on reliability of static and dynamic measures nor consensus on which is the optimal method. The aim of the study was to assess the difference between static and dynamic measures of the ankle, knee, hip, shoulder and elbow. Nineteen subjects performed three separate trials for a 10-min duration at a fixed workload (70% of peak power output). Static measures were taken with a standard goniometer (GM), an inclinometer (IM) and dynamic three-dimensional motion capture (3DMC) using an eight camera motion capture system. Static and dynamic joint angles were compared over the three trials to assess repeatability of the measurements and differences between static and dynamic values. There was a positive correlation between GM and IM measures for all joints. Only the knee, shoulder and elbow were positively correlated between GM and 3DMC, and IM and 3DMC. Although all three instruments were reliable, 3D motion analysis utilised different landmarks for most joints and produced different means. Changes in knee flexion angle from static to dynamic are attributable to changes in the positioning of the foot. Controlling for this factor, the differences are negated. It was demonstrated that 3DMC is not interchangeable with GM and IM, and it is recommended that 3DMC develop independent reference values for bicycle configuration. 相似文献
9.
Silvia Fantozzi Andrea Giovanardi Fabrício Anício Magalhães Rocco Di Michele Matteo Cortesi Giorgio Gatta 《Journal of sports sciences》2016,34(11):1073-1080
The analysis of the joint kinematics during swimming plays a fundamental role both in sports conditioning and in clinical contexts. Contrary to the traditional video analysis, wearable inertial-magnetic measurements units (IMMUs) allow to analyse both the underwater and aerial phases of the swimming stroke over the whole length of the swimming pool. Furthermore, the rapid calibration and short data processing required by IMMUs provide coaches and athletes with an immediate feedback on swimming kinematics during training. This study aimed to develop a protocol to assess the three-dimensional kinematics of the upper limbs during swimming using IMMUs. Kinematics were evaluated during simulated dry-land swimming trials performed in the laboratory by eight swimmers. A stereo-photogrammetric system was used as the gold standard. The results showed high coefficient of multiple correlation (CMC) values, with median (first–third quartile) of 0.97 (0.93–0.95) and 0.99 (0.97–0.99) for simulated front-crawl and breaststroke, respectively. Furthermore, the joint angles were estimated with an accuracy increasing from distal to proximal joints, with wrist indices showing median CMC values always higher than 0.90. The present findings represent an important step towards the practical use of technology based on IMMUs for the kinematic analysis of swimming in applied contexts. 相似文献
10.
Kam-Ming Mok Roald Bahr 《Sports biomechanics / International Society of Biomechanics in Sports》2018,17(2):157-167
The purpose of this study was to assess the within- and between-session reliability of lower limb biomechanics in two sport-specific sidestep cutting tasks performed by elite female handball and football (soccer) athletes. Moreover, we aimed at determining the minimum number of trials necessary to obtain a reliable measure. Nineteen elite female handball and 22 elite female football (soccer) athletes (M ± SD: 22 ± 4 yrs old, 168 ± 5 cm, 66 ± 8 kg) were tested. The reliability was quantified by intra-class correlations (ICCs), typical error and Spearman’s rank correlation. Only minor improvements in ICC values were seen when increasing the number of trials from 3 to 5. Based on trials 1–3, all variables showed good to excellent within-session reliability (M ICC: 0.91, 95% CI: 0.89–0.93), fair to good between-session reliability (M ICC: 0.73, 95% CI: 0.70–0.76), moderately positive between-session rank correlation coefficients (M: 0.72, 95% CI: 0.69–0.76). A few frontal plane biomechanical variables displayed lower between-session reliability in the football task compared with the handball task. The moderately positive between-session ranking and practically small typical error implies that the measurements could reliably reproduce the ranking of individuals in multiple-session studies. Adequate reliability could be attained from 3 trials, with only minor improvements when adding more trials. 相似文献
11.
Felipe P. Carpes Frederico Dagnese Carlos B. Mota Darren J. Stefanyshyn 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):275-283
This study investigated the three-dimensional (3-D) pedaling kinematics using a noncircular chainring system and a conventional system. Five cyclists pedaled at their preferred cadence at a workload of 300 W using two crank systems. Flexion/extension of the hip, knee and ankle as well as shank rotation, foot adduction/abduction, and pedal angle were measured. Joint range of motion (ROM) and angular displacements were compared between the systems. Sagittal plane ROM was significantly greater (P < 0.05) at the hip (noncircular system = 39 ± 3°; conventional system = 34 ± 4°) the knee (noncircular system = 69 ± 4°; conventional system = 57 ± 10°), and ankle (noncircular system = 21 ± 2°; conventional system = 19 ± 4°) resulting in greater pedal ROM (noncircular system = 43 ± 3°; conventional system = 37 ± 5°) while using the noncircular system. Shank rotation ROM was significantly lower (P < 0.05) while using the noncircular chainring (noncircular system = 10 ± 1°; conventional system = 14 ± 1°). These results support a significant effect of the noncircular chainring system on pedaling kinematics during submaximal exercise. 相似文献
12.
Matthias Gilgien Jörg Spörri Julien Chardonnens Josef Kröll Philippe Limpach Erich Müller 《Journal of sports sciences》2015,33(9):960-969
In the sport of alpine skiing, knowledge about the centre of mass (CoM) kinematics (i.e. position, velocity and acceleration) is essential to better understand both performance and injury. This study proposes a global navigation satellite system (GNSS)-based method to measure CoM kinematics without restriction of capture volume and with reasonable set-up and processing requirements. It combines the GNSS antenna position, terrain data and the accelerations acting on the skier in order to approximate the CoM location, velocity and acceleration. The validity of the method was assessed against a reference system (video-based 3D kinematics) over 12 turn cycles on a giant slalom skiing course. The mean (± s) position, velocity and acceleration differences between the CoM obtained from the GNSS and the reference system were 9 ± 12 cm, 0.08 ± 0.19 m · s-1 and 0.22 ± 1.28 m · s-2, respectively. The velocity and acceleration differences obtained were smaller than typical differences between the measures of several skiers on the same course observed in the literature, while the position differences were slightly larger than its discriminative meaningful change. The proposed method can therefore be interpreted to be technically valid and adequate for a variety of biomechanical research questions in the field of alpine skiing with certain limitations regarding position. 相似文献
13.
14.
为了满足用户对虚拟会展展馆个性化的需要,本文提出了如何建立基于X3D虚拟现实技术的三维虚拟展馆定制系统。该系统具有较好的实用性,既为真实展馆的定制提供仿真的平台,又为如何建立虚拟展馆提供了范例。 相似文献
15.
在对第2届环青海湖国际公路自行车赛全体中、外参赛运动员比赛成绩进行统计处理和全面分析基础上,着重对成绩较好的中、外运动员进行相对成绩、平均排名、速度方差和相对速度方差各项指标的对比分析。结果显示:我国优秀运动员有与国外优秀运动员抗争的实力,而团队整体实力与国外强队仍有一定差距,处于中等水平;在全程速度分配上较为合理,但相对速度能力较差,关键性赛段波动较大,参与激烈竞争的能力远不如国外优秀运动员。 相似文献
16.
17.
18.
体育转播视觉技术发展特征分析 总被引：1，自引：0，他引：1
运用文献资料法、综合归纳法,对体育转播中的视觉技术的发展及其特征进行了分析,体育转播技术经历了从黑白到彩色、从模糊到清晰、从2D到3D的视觉革命,转播中拍摄视角的多维与多样、体育虚拟分析技术的引入以及3D画面转播是当今体育转播视觉技术的发展特征。体育转播视觉技术的发展能够提高大众对体育的关注度,丰富及提高体育视频资源数量和质量。 相似文献
19.
Abstract The aims of the study were to: (1) adapt the “double-push” technique from inline skating to cross-country skiing; (2) compare this new skiing technique with the conventional skate skiing cross-country technique; and (3) test the hypothesis that the double-push technique improves skiing speed in a short sprint. 13 elite skiers performed maximum-speed sprints over 100 m using the double-push skate skiing technique and using the conventional “V2” skate skiing technique. Pole and plantar forces, knee angle, cycle characteristics, and electromyography of nine lower body muscles were analysed. We found that the double-push technique could be successfully transferred to cross-country skiing, and that this new technique is faster than the conventional skate skiing technique. The double-push technique was 2.9 ± 2.2% faster (P < 0.001), which corresponds to a time advantage of 0.41 ± 0.31 s over 100 m. The double-push technique had a longer cycle length and a lower cycle rate, and it was characterized by higher muscle activity, higher knee extension amplitudes and velocities, and higher peak foot forces, especially in the first phase of the push-off. Also, the foot was more loaded laterally in the double-push technique than in the conventional skate skiing technique. 相似文献
20.
An anthropometric analysis was conducted on 35 elite male Australian track cyclists having a mean age of 22.6 years and who had been competing on average for 9 years. The relationship of anthropometric parameters to both bicycle saddle height and cycling performance was also investigated. Subjects were allocated, for purposes of comparison, to an endurance or sprint group on the basis of their competitive event. The group members in total were ectomorphic mesomorphs of height 178±4.8 cm and weight 72.5 ±6.6 kg on average. Percentage of saddle height to lower limb length averaged 99±1.6%, and significant correlations existed between strength and both body mass (r=0.57) and thigh girth (r = 0.55). No significant correlation was seen between any anthropometric parameter and performance in an individual event. Cyclists in the sprint group were heavier (76.2 ± 7.4 vs. 70.0 ± 4.7 kg, P<0.01) and stronger (258 ± 44.4 vs. 216 ± 30.5 Nm, P<0.01), and had larger chest (98.2 ± 6.2 vs. 92.4 ± 2.9 cm, P<0.01), arm (33.0±2.2 vs. 30.7± 1.6 cm, P<0.01), thigh (57.5 ± 3.4 vs. 54.3 ± 2.5 cm, P<0.01) and calf girths (37.8±1.7 vs. 36.2±1.9 cm, P<0.05) than cyclists in the endurance group. They were also more mesomorphic (5.3 ± 0.7 vs. 4.7 ± 0.8, P<0.05) and less ectomorphic (2.3 ± 0.9 vs. 2.9±0.6, P<0.05) than the endurance cyclists. 相似文献