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1.
By understanding the normal humeral and scapular kinematics during the kayak stroke, inferences about the relationship of kayaking technique and shoulder injury may be established. The purpose of this study was to describe scapular and humeral kinematics and to compare dominant versus non-dominant symmetry in healthy whitewater kayakers performing the forward stroke. Twenty-five competent whitewater kayakers (mean age: 34.1 ± 9.4 years, mean height: 1.768 ± 0.093 m, mean mass: 78.2 ± 13.0 kg) underwent humeral and scapular kinematic assessment, using an electromagnetic tracking device, while kayaking on a kayak ergometer. Paired t-tests were used to determine symmetry. Scapular and humeral kinematic means and standard deviations at six time points during the kayak stroke were described. Scapular and humeral kinematics were shown to be similar upon bilateral comparison. The greatest potential for injury during the forward stroke may be at thrust paddle shaft vertical when the humerus is maximally elevated in internal rotation and adduction as subacromial structures may be mechanically impinged. The relationship between scapulohumeral kinematics related to injury at other time points are also described.  相似文献   

2.
The aim of this narrative review was to propose a deterministic model based on a review of previous research documenting the evidence for the associations between average kayak velocity and kinematic variables in sprint kayaking. Literature was reviewed after searching electronic databases using key words ‘kayak,’ ‘biomechanics,’ ‘velocity,’ ‘kinematics,’ and ‘performance.’ Our kinematic deterministic model for sprint kayaking performance shows that the average kayak velocity is determined by kayak stroke displacement and stroke time. Stroke time had the strongest correlation with 200-m race time (r = 0.86, p < 0.001), and stroke rate (inversely proportional to stroke time) was strongly correlated with average horizontal velocity over two consecutive strokes at race pace (r = ? 0.83, p < 0.05). Increased stroke rate via decreased absolute water phase time and increased relative water phase time were indicative of more elite performance. There was no significant relationship between stroke displacement and velocity; however, a large decrease in stroke displacement may be detrimental to performance. Individual characteristics may be responsible for a paddlers’ ability to achieve and sustain a given stroke rate. Coaches should theoretically focus interventions on increasing stroke rate while maintaining stroke displacement; however this hypothesis should be confirmed with prospective studies.  相似文献   

3.
During kayak paddling, athletes attempt to maximize kayak velocity with the generation of optimal paddle forces. The aim of the current study was to examine ten elite kayakers and identify a number of key biomechanical performance variables during maximal paddling on a custom kayak simulator. These included analysing the effect of side (left and right) and period (beginning, middle, and end of the kayak simulation) on paddle force, paddle angle, mechanical efficiency, and stroke timing data. Paddle kinetics and kinematics were measured with strain gauge force transducers attached to either end of the ergometer paddle and using a 3D motion analysis system respectively. Results indicated a significantly greater mechanical efficiency during the right paddle stroke compared with the left (P < 0.025). In addition, analysing the effect of period, peak paddle force demonstrated a significant reduction when comparing the beginning to the middle and end of the simulated race respectively (P < 0.025). Examination of individual force profiles revealed considerable individuality, with significant variation in the time course of force application. Analysis of the profiles presented may provide meaningful feedback for kayakers and their coaches.  相似文献   

4.
为了改进和完善国家队队员的技术,分析了备战北京奥运会的国家队女皮队员单人艇一桨周期的划桨节奏,并和国外优秀女选手的相应指标进行比较。采用录像分析法对一桨周期动作的时相进行分析,水中拉桨时间比例和空中回桨时间比例国家队平均为67％比33％;国外优秀队员为68％比32％。其中曾获得雅典奥运会前3名的国外队员的数据平均为70％比30％。国外优秀队员水中拉桨比例的增大体现在后拉桨阶段比例的增大。因此,国家队队员拉桨中要注意后拉桨阶段的转体幅度,延长拉桨距离。  相似文献   

5.
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6.
This study aimed (1) to describe and compare scapular kinematics between three groups of swimmers of different levels and a group of non-swimmers, and (2) to assess whether swimming practice alters the asymmetries in scapular kinematics between the dominant and non-dominant sides, both during unilateral arm raising and lowering in the scapular plane. Scapular kinematics were assessed bilaterally during arm raising and lowering in the scapular plane using an electromagnetic system in 42 healthy males, which were split into four groups: control (n?=?11), adolescent elite swimmers (n?=?11), adult elite swimmers (n?=?10), and club-level adult swimmers (n?=?10). One-Way ANOVA SPM(t) on two repeated measures showed that the three groups of swimmers had more protracted shoulder between 30° and 90° of arm raising and lowering (p?p?p?≤?.02), who presented similar scapular positioning in internal rotation. In conclusion, the findings of the study pointed out that swimming practice generated protracted shoulders and removed bilateral differences in scapular upward rotation during scaption, while accumulation of swimming practice at elite level enlarged scapular internal rotation.  相似文献   

7.
The purpose was to examine power output and three-dimensional (3D) kinematic variables in the upper limbs, lower limbs and trunk in elite flat-water kayakers during kayak ergometer paddling. An additional purpose was to analyse possible changes in kinematics with increased intensity and differences between body sides. Six male and four female international level flat-water kayakers participated. Kinematic and kinetic data were collected during three tasks; low (IntL), high (IntH) and maximal (IntM) intensities. No differences were observed in any joint angles between body sides, except for shoulder abduction. Significantly greater range of motion (RoM) values were observed for IntH compared to IntL and for IntM compared to IntL in trunk and pelvis rotation, and in hip, knee and ankle flexion. The mean maximal power output was 610 ± 65 and 359 ± 33 W for the male and female athletes, respectively. The stroke frequencies were significantly different between all intensities (IntL 59.3 ± 6.3; IntH 108.0 ± 6.8; IntM 141.7 ± 18.4 strokes/min). The results showed that after a certain intensity level, the power output must be increased by other factors than increasing the joint angular RoM. This information may assist coaches and athletes to understand the relationship between the movement of the kayaker and the paddling power output.  相似文献   

8.
In white-water kayaking, the legs play a vital part in turning, stabilising and bracing actions. To date, there has been no reported information on neuromuscular activation of the legs in an authentic white-water environment. The aim of the current study was to identify lower body muscle activation, using ‘in-boat’ electromyography (EMG), whilst navigating a white-water run. Ten experienced male kayakers (age 31.5?±?12.5 yr, intermediate to advanced experience) completed three successful runs of an international standard white-water course (grade 3 rapids), targeting right and left sides of the course, in a zigzag formation. Surface EMG (sEMG) outputs were generated, bilaterally, for the rectus femoris (RF), vastus lateralis, biceps femoris and gastrocnemius, expressed as a percentage of a dynamic maximal voluntary contraction (dMVC). Only RF showed significantly higher activation than any muscle on the left side of the body, and only on the left side of the course (P?=?.004; ETA2?=?0.56). Other results showed no significant difference between muscle activation in the right and left legs during each run, nor when assessed at either the right or left side of the course (P?>?.05). These findings indicate that contralateral symmetry in lower limb muscle activation is evident during white-water kayaking. This symmetry may provide a stable base to allow more asymmetrical upper body and trunk movements to be fully optimised. Lower body symmetry development should be considered useful in targeted training programmes for white-water kayakers.  相似文献   

9.
Scapular dyskinesis is recognized as an abnormality in the kinetic chain; yet, there has been little research quantifying scapular motion during sport tasks. Tennis forehand drives of eight highly skilled tennis players were studied to assess the scapulothoracic kinematics and evaluate repeatability using video-based motion analysis. Scapulothoracic downward/upward rotation, posterior/anterior tilt, and internal/external rotation were computed using an acromial marker cluster. On average, the upward rotation, anterior tilt, and internal rotation varied from 1° to 26°, from 7° to 32°, and from 42° to 100°, respectively, during the tennis forehand drive. During the backswing and forward swing phases of the forehand stroke, small changes were observed for the three scapular angle values, while all angles increased rapidly during the follow-through phase. This suggests that the tennis forehand drive may contribute to scapula dyskinesis, mainly due to the great amplitude in scapulothoracic anterior tilt and internal rotation observed during the follow-through phase. Knowledge of normal scapula motion during sport tasks performed at high velocity could improve the understanding of various sport-specific adaptations and pathologies.  相似文献   

10.
On a kayak ergometer, an accurate simulation of the athlete-paddle-kayak system kinematics is essential for analysing the relationship between technique and performance. The purpose of this study was to establish a strong relationship between performances on flatwater and performances on an ergometer by means of propulsive force measurement and drag models. Two trials were performed by 12 kayakers in which they were first timed over 250 m of flatwater kayaking (the reference test) and were then asked to perform a trial of the same duration on the ergometer with the same perceived physical exertion. Three techniques for measuring propulsive force and three drag models generated nine combinations, which were all evaluated for their ability to estimate kayak velocity. For each combination, the distance covered by the athlete on the ergometer was simulated. A kayakers’ ergometer ranking was based on the average velocity in the ergometer trial. Both distance and ranking were compared to the on-water results. The simulation with the best combination of force measurement and drag model gave an accurate estimate of distance (253 ± 10.5 vs. 250 m) and ranking compared to the reference test.  相似文献   

11.
Lower to upper extremity sequencing of energy and force is linked by virtue of the scapula. It was the purpose of this study to examine the relationship between passive hip rotational range of motion and scapular kinematics during baseball pitching. Nineteen youth baseball players (11.3 ± 0.6 years; 151.8 ± 8.8 cm; 45.9 ± 10.9 kg) with no history of injury participated. Bilateral hip passive rotational range of motion was measured pre and post pitching a simulated game. Scapular kinematics at the position of shoulder maximum external rotation during the pitching cycle were recorded in the first and last innings of the simulated game. Post simulated game, stance leg hip passive internal rotation revealed significant correlations (r = ?0.57, P = 0.01) with scapula anterior/posterior tilt at the pitching event of maximum humeral external rotation. The current study reveals that pitching a simulated game results in alterations throughout the kinetic chain. Specifically, this study strengthens the notion that lumbopelvic-hip complex parameters play a significant role in shoulder motion. With this link identified, it is suggested that clinical focus be directed musculature about the lumbopelvic-hip complex as well as muscles that work to stabilise the scapula during dynamic movement.  相似文献   

12.
The kinematic analysis of competition breaststroke swimming has tended to focus on the mean values of swimming speed, stroke rate and stroke length; values in individual lengths, as well as the start, turns and finish, have largely been ignored. This study includes all such variables and aims to improve the coach's holistic understanding of breaststroke racing by determining the relationships and differences between and within these selected kinematic variables. We also compare 100-m events with 200-m events to determine if there are characteristic differences between them. Competitive breaststroke swimming performances in 100-m events (males: n = 159, finishing time = 65.05 +/- 2.62 s; females: n = 158, finishing time = 74.04 +/- 3.66 s) and 200-m events (males: n = 159, finishing time = 141.47 +/- 6.15 s; females: n = 158, finishing time = 158.66 +/- 7.87 s) were collected and analysed from 12 world, international and national championships. The better 100-m and 200-m breaststroke swimmers were found to demonstrate greater competency in the kinematic variables measured, except stroke kinematics, which were unique to each individual. These findings suggest that coaches should place emphasis on all of the kinematic components in training and that they should attempt to identify the stroke rate to stroke length ratio most appropriate for the individual. Finally, characteristic differences do exist between the 100-m and 200-m events, which has implications for how swimmers might train for each event.  相似文献   

13.
We present a study of the hydrodynamic characteristics of sea kayak paddles without taking into account the kayaker. We focus on traditional paddles used in the Arctic, one from Greenland and one from the Aleutian Islands. A basic modern European paddle is included in the study for comparison. First the paddle stroke parameters specific to sea kayaking are identified because previous studies were devoted to a competition context. The hydrodynamic force generated by the blade motion is detailed: two terms are identified, one involving the inertia of the water surrounding the blade at the beginning of its motion, and the second term is the classical drag/lift force. Drag and lift force coefficients were measured in a wind tunnel. The data allow computation of the hydrodynamic force during a paddle stroke. The European paddle was shown to be more efficient than the traditional paddles because of its shorter length to width ratio which contributed to a larger inertia effect. However, the force obtained with the traditional paddles better follows the imposed motion by the kayaker so that they are more comfortable and less tiring in the context of long distance trips, as those practiced in sea kayaking.  相似文献   

14.
Adult overhead athletes without a history of shoulder injury show scapular adaptations. There is a lack of detailed assessment of scapular kinematics in junior overhead athletes. This study aims to investigate three-dimensional scapular kinematics in junior overhead athletes. We recruited a total of 20 junior tennis players and 20 healthy children without participation in any overhead sports in this study. Bilateral scapular kinematic data were recorded using an electromagnetic tracking device for scapular plane glenohumeral elevation. The data were further analysed at 30°, 45°, 60°, 90° and 120° during glenohumeral elevation and lowering. Statistical comparisons of the data between groups (junior overhead athletes and non-overhead athletes) and sides (serve dominant and non-dominant shoulders of the overhead athletes) were analysed with the ANOVA. Comparisons showed that, in general, the scapula was more upwardly rotated and anteriorly tilted in overhead athletes when compared to non-overhead athletes, however there was no side-to-side differences when serve dominant and non-dominant shoulders compared in junior overhead athletes. The serve dominant arm of junior overhead athletes had alternations in scapular kinematics when compared with the non-overhead athletes. These findings provide clinical evaluation implications and the need for clinicians to assess for potential adaptations in junior overhead athletes.  相似文献   

15.
The intent of this project was to explore the feasibility of personalising the paddle blade size for individual flatwater kayakers based on their power output profiles. Twelve elite male kayakers performed on a kayak ergometer at the same intensity and resistance that they would normally experience while paddling at race pace for 500 m on the water. The kayak ergometer was instrumented so that power profiles could be determined from the instantaneous force and velocity of the representative centre point of the paddle blade. From the power profile information, the researchers calculated a personalised blade size that was expected to improve performance for those kayakers differing more than 5% from the calculated ‘ideal’ size. For the elite kayakers studied, it was recommended that seven of the paddlers should increase their blade size by approximately 5–10%. For the remaining five paddlers, the results indicated that their current blade sizes were within the expected measurement error of their predicted ideal value and should be retained. It is anticipated that this research will provide the theoretical rationale for elite kayakers to see the need to personalise their blade size based on their own muscle power profiles.  相似文献   

16.
This study aimed to identify the maturity-related differences and its influence on the physical fitness, morphological and performance characteristics of young elite paddlers. In total, 89 kayakers and 82 canoeists, aged 13.69 ± 0.57 years (mean ± s), were allocated in three groups depending on their age relative to the age at peak height velocity (pre-APHV, circum-APHV and post-APHV) and discipline (kayak and canoe). Nine anthropometric variables, a battery of four physical fitness tests (overhead medicine ball throw, countermovement jump, sit-and-reach test and 20 m multistage shuttle run test) and three specific performance tests (1000, 500 and 200 m) were assessed. Both disciplines presented significant maturity-based differences in all anthropometric parameters (except for fat and muscle mass percentage), overhead medicine ball throw and all performance times (pre > circum > post; P < 0.05). Negative and significant correlations (P < 0.01) were detected between performance times, chronological age and anthropometry (body mass, height, sitting height and maturity status), overhead medicine ball throw and sit and reach for all distances. These findings confirm the importance of maturity status in sprint kayaking and canoeing since the more mature paddlers were also those who revealed largest body size, physical fitness level and best paddling performance. Additionally, the most important variables predicting performance times in kayaking and canoeing were maturity status and chronological age, respectively.  相似文献   

17.
Few studies have investigated the incidence of injuries in kayakers. The aim was to study the prevalence of shoulder pain in competitive flatwater kayakers and to evaluate any differences in range of motion or scapula stability of the shoulder joint among kayakers with or without the history of shoulder pain. Thirty-one kayakers were participated in the study, and a questionnaire including background data was used. Shoulder range of motion was measured with a goniometer, and the participants were observed for scapula dyskinesis in flexion and abduction. Of the participating kayakers, 54.8% (n = 17) had experienced shoulder pain. Kayakers who had experienced shoulder pain showed a significantly lower degree of internal rotational range of motion versus kayakers with no reported shoulder pain, with a mean degree of internal rotation in the right shoulder 49.3 vs 60.0 (P = 0.017) and the left shoulder 51.9 vs 66.0 (P = 0.000). Kayakers who had experienced shoulder pain were also observed with a scapular dyskinesis (n = 15 of 17 kayakers) to a significantly higher degree (P = 0.001) than kayakers with no reported shoulder pain. Findings suggest that screening for scapular dyskinesis and testing for rotational range of motion in the shoulder joint is essential in order to treat and maybe prevent shoulder pain in kayakers.  相似文献   

18.
为探究静水皮艇200nm能量供应特征,文章选取了29名青少年皮艇运动员在测功仪上进行200 m比赛的模拟（40 s）.通过采集受试者气体代谢和血乳酸数据,并按Beneke等人提出的计算方法进行能量代谢的计算.结果表明,静水皮艇200 m三大供能系统的供能比例分别为39.4％（无氧无乳酸）、28.8％（无氧乳酸）和31.8％（有氧）.静水皮艇200 m前10 s能量供应主要来自无氧无乳酸系统,第10～20 s（或30s）能量供应主要来自无氧乳酸系统,有氧供能对于最后10～20 s的运动能力有重要意义.我国目前对静水皮艇200 m的认识低估了有氧供能的重要性.静水皮艇200 m能量代谢的时序特征可以作为制定训练计划和评价运动能力的重要生物学基础.  相似文献   

19.
国际大赛中男女皮艇运动员划桨节奏的比较研究   总被引：7，自引：0，他引：7  
采用现场摄影法,比较世界杯赛中男女皮艇运动员的桨频和划桨节奏。结果显示：男桨手左右两侧的桨频比较和女桨手左右两侧的桨频比较均无差异;大赛中实际应用时两侧计算桨频无差异。动作节奏上．男桨手左右两侧和女桨手右侧无差异;只有女桨手左侧与前三者有差异,可能是女子两侧专项素质发展及技术完善的同步性不如男子。男桨手提高桨频可能靠减少回桨时间而女桨手靠减少拉桨时间获得;高桨频时男桨手容易保持水中效果而女桨手容易丢失效果。  相似文献   

20.
Abstract

While the effect of lower body compression garments on performance and physiological responses are well documented, no studies have examined the effect of upper body compression garments (UBCG) on upper-body dominant exercise. This study examined the effects of wearing UBCG on performance and physiological responses during simulated flat-water kayaking. Five male (mean values±s: 21.8±2.8 years; 83.5±9.2 kg; 63.0±5.5 ml·kg?1·min?1) and two female (mean values±s: 25.0±4.2 years; 71.4±2.7 kg; 51.0±4.8 ml·kg-1·min-1) elite flat-water kayakers completed a six-step incremental test followed by a four-minute maximal performance test (4minPT) in both UBCG and control (no shirt or sports training bra) conditions in a randomized counter-balanced order. Heart rate and oxygen consumption (O2) as well as performance measures (power, distance covered, stroke rate) were recorded during the tests, and blood lactate was measured immediately after each incremental step and three minutes following the 4minPT. Near-infrared spectroscopy-derived measures of blood flow and oxygenation of the flexor carpi radialis were monitored continuously for all tests. No significant differences between the UBCG and control conditions were evident for any performance, cardiorespiratory or oxygenation measure across the incremental step test and 4minPT. It was concluded that wearing UBCG did not provide any significant physiological or performance benefits during simulated flat-water kayaking.  相似文献   

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