A method for personalising the blade size for competitors in flatwater kayaking

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.     

A method of providing accurate velocity feedback of performance on an instrumented kayak ergometer

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.     

我国优秀皮划艇运动员有氧能力的评价

目的:探讨我国优秀皮划艇运动员有氧能力的评价方法,为制定针对性的训练计划提供参考。方法:以备战伦敦奥运会国家皮划艇队运动员为研究对象,包括8名男子皮艇、7名女子皮艇和6名划艇运动员。利用皮划艇测功仪采用逐级递增负荷至力竭测最大摄氧量、利用4级1 000 m递增强度划船测试乳酸阈(4 mmol/l对应的船速)。结果:伦敦奥运周期我国优秀男子皮艇、女子皮艇和划艇运动员的绝对最大摄氧量分别为(5.25±0.22)l/min、(3.58±0.22)l/min、(4.85±0.13)l/min;相对最大摄氧量分别为(57.28±3.8 1)ml/(kg·min-1)、(50.92±3.78)ml/(kg·min-1)、(54.72±5.3)1ml/(kg·min-1),,经过3个月训练后男子皮艇和划艇运动员最大摄氧量无明显变化,女子皮艇运动员明显提高;男子皮艇、女子皮艇和划艇运动员乳酸阈船速经过3个月的训练后都明显提高,提高幅度分别为11.92%、3.77%和14.37%。结论:我国伦敦周期优秀皮划艇运动员的最大摄氧量高于国际优秀皮划艇运动员的平均水平,和最大摄氧量比较,乳酸阈表现出更好的训练可塑性,能够更为准确的反映皮划艇运动员有氧能力的动态变化。     

静水皮艇200 m供能特征

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.     

The dynamics of elite paddling on a kayak simulator

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.     

Does local dynamic stability of kayak paddling technique affect the sports performance? A pilot study

During competition, kayak athletes must optimally adapt to environmental factors (e.g. wind, waves) to achieve peak performance. However, the ability to adapt to such perturbations has never been assessed in kayak paddling. Therefore, the aim of the current study was to evaluate the local dynamic stability in sports technique of youth sprint kayak athletes. In a cross-sectional study, 14 healthy male athletes were recruited from an elite youth sprint kayak squad. During an incremental kayak ergometer test, mean power, heart rates and local dynamic technique stability of hands, arms, trunk and paddle were registered and the association with the athletes 2000?m free-water times were estimated using mixed models. The 2000?m free-water performance significantly predicted the paddles (p?=?.037) local dynamic stability whereas no association was found for the trunk or the upper extremity kinematics. In conclusion, kayak athletes with high-performance capability over 2000?m paddling depict high local dynamic technique stability. This emphasizes the importance of a stable technique for advanced kayak skills, especially regarding paddling movements.     

Sprint kayaking and canoeing performance prediction based on the relationship between maturity status,anthropometry and physical fitness in young elite paddlers

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.     

国内外优秀女子皮艇运动员单人艇划桨节奏的比较研究

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。     

Scapulohumeral kinematic assessment of the forward kayak stroke in experienced whitewater kayakers

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 nondominant 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 +/- 0.093m, 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.     

优秀短距离自行车运动员无氧代谢能力特征研究

目的:比较不同性别和训练水平运动员无氧能力的差异,探讨短距离自行车运动员高能磷酸原供能、糖酵解供能和混合无氧供能能力的特征。方法:对16名优秀短距离自行车运动员进行10s(女)、15s(男)、30s和60s的无氧功测定,测定运动后即刻、运动后3min恢复心率和血乳酸。结果:1)磷酸原代谢能力表现出明显的性别差异,男运动员最大功率、相对最大功率、平均功率、相对平均功率、最大圈数都明显高于女运动员;2)30s和60s两种测试中,运动员爆发力表现出相同水平,但糖酵解代谢持续供能能力随运动时间的延长而明显下降;3)男子优秀运动员组15s无氧功最大功率、平均功率明显高于普通组。男、女最大圈数大于普通组,达到最大圈数时间小于或等于普通组;4)男子优秀组运动员30s、60s平均功率高于普通运动员组。女子优秀运动员组30s、60s平均功率、最大圈数明显高于普通运动员组,60s最大功率明显高于普通运动员组(P<0.05)。结论:1)优秀短距离自行车运动员具有较强的磷酸原代谢能力,男运动员明显强于女运动员;2)较强的糖酵解代谢能力是短距离自行车运动员无氧代谢能力的特征;3)评定磷酸原系统能力时,男、女运动员都使用10s无氧功测试为好;4)不同水平运动员的无氧代谢能力表现出明显差异,优秀运动员组强于普通运动员组。     

Conference communications

Abstract

The objective of this study was to provide anthropometric, physiological, and performance characteristics of an elite international handball team. Twenty-one elite handball players were tested and categorized according to their playing positions (goalkeepers, backs, pivots, and wings). Testing consisted of anthropometric and physiological measures of height, body mass, percentage body fat and endurance ([Vdot]O_2max), performance measures of speed (5, 10, and 30 m), strength (bench press and squat), unilateral and bilateral horizontal jumping ability, and a 5-jump horizontal test. Significant differences were found between player positions for some anthropometric characteristics (height and percentage body fat) but not for the physiological or performance characteristics. Strong correlations were noted between single leg horizontal jumping distances with 5-, 10-, and 30-m sprint times (r = 0.51–0.80; P < 0.01). The best predictors of sprint times were single leg horizontal jumping with the dominant leg and the distance measured for the 5-jump test, which when combined accounted for 72% of the common variance associated with sprint ability. In conclusion, performance abilities between positions in elite team-handball players appear to be very similar. Single leg horizontal jumping distance could be a specific standardized test for predicting sprinting ability in elite handball players.     

Scapulohumeral kinematic assessment of the forward kayak stroke in experienced whitewater kayakers

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.     

Effects of high-intensity interval training on canoeing performance

The purpose of this study was to compare the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) utilizing a canoeing ergometer on endurance determinants, as well as aerobic and anaerobic performances among flat-water canoeists. Fourteen well-trained male flat-water canoeists were divided into an HIIT group or an MICT group. All subjects performed a continuous graded exercise test (GXT) and three fixed-distance (200, 500, and 1000?m) performance tests on a canoeing ergometer to determine canoeing economy, peak oxygen uptake (VO₂peak), and power at VO₂peak, and to calculate the critical velocity (CV) and anaerobic work capacity before and after the training programmes. The training programme involved training on a canoeing ergometer three times per week for four weeks. HIIT consisted of seven 2 min canoeing bouts at an intensity of 90% VO₂peak separated by 1 min of rest. The MICT group was trained at an intensity of 65% VO₂peak continuously for 20 min. After four weeks of training, performance in the 200-m distance test and the power at VO₂peak significantly improved in the HIIT group; performance in the 500?m and 1000?m distances and CV significantly improved in the MICT group. However, all variables were not significantly different between groups. It is concluded that HIIT for four weeks is an effective training strategy for improvement of short-distance canoeing performance. In contrast, MICT improves middle-distance canoeing performances and aerobic capacity.     

Effects of intermittent sprint and plyometric training on endurance running performance

PurposeThe purpose of this study was to compare the effects of intermittent sprint training and plyometric training on endurance running performance.MethodsFourteen moderately trained male endurance runners were allocated into either the intermittent sprint training group (n = 7) or the plyometric training group (n = 7). The preliminary tests required subjects to perform a treadmill graded exercise test, a countermovement jump test for peak power measurement, and a 10-km time trial. Training included 12 sessions of either intermittent sprint or plyometric training carried out twice per week. On completion of the intervention, post-tests were conducted.ResultsBoth groups showed significant reduction in weekly training mileage from pre-intervention during the intervention period. There were significant improvements in the 10-km time trial performance and peak power. There was also significant improvement in relative peak power for both groups. The 10-km time trial performance and relative peak power showed a moderate inverse correlation.ConclusionThese findings showed that both intermittent sprint and plyometric training resulted in improved 10-km running performance despite reduction in training mileage. The improvement in running performance was accompanied by an improvement in peak power and showed an inverse relationship with relative peak power.     

The influence of short‐term endurance training on maximum oxygen uptake,submaximum endurance and the ability to perform brief,maximal exercise

The hypothesis that endurance training impairs sprinting ability was examined. Eight male subjects undertook a 30‐s sprint test on a cycle ergometer before and after 6 weeks of cycling training for endurance. Maximum oxygen uptake (VO₂ max) and submaximum endurance were determined to evaluate the influence of the training regimen on endurance performance. Endurance was defined as the time to exhaustion at a relative exercise intensity of 85% VO₂ max. Maximum oxygen uptake was increased by 18% post‐training (3.29 ± 0.291 min^–1 versus 3.89±0.491 min^–1; P <0.01), but endurance at the same absolute work rate as pre‐training was increased by more than 200% (32.2 ±11.4 min versus 97.8 + 27.3 min; P <0.01). These improvements were accompanied by changes in the cardiovascular and metabolic responses to standard, submaximum exercise. Despite the improvements in endurance, neither performance during the cycle sprint test nor the increase in blood lactate concentration during the sprint was influenced by endurance training. For short‐term cycling training, these findings reinforce the concept of training specificity whilst demonstrating that decrements in sprint performance are not a necessary consequence of improved endurance.     

The effect of an intermittent,high-intensity warm-up on supramaximal kayak ergometer performance

It has previously been shown that the metabolic acidaemia induced by a continuous warm-up at the 'lactate threshold' is associated with a reduced accumulated oxygen deficit and decreased supramaximal performance. The aim of this study was to determine if an intermittent, high-intensity warm-up could increase oxygen uptake (VO2) without reducing the accumulated oxygen deficit, and thus improve supramaximal performance. Seven male 500 m kayak paddlers, who had represented their state, volunteered for this study. Each performed a graded exercise test to determine VO2max and threshold parameters. On subsequent days and in a random, counterbalanced order, the participants then performed a continuous or intermittent, high-intensity warm-up followed by a 2 min, all-out kayak ergometer test. The continuous warm-up consisted of 15 min of exercise at approximately 65% VO2max. The intermittent, high-intensity warm-up was similar, except that the last 5 min was replaced with five 10 s sprints at 200% VO2max, separated by 50 s of recovery at approximately 55% VO2max. Significantly greater (P < 0.05) peak power (intermittent vs continuous: 629 +/- 199 vs 601 +/- 204 W) and average power (intermittent vs continuous: 328 +/- 39.0 vs 321 +/- 42.4 W) were recorded after the intermittent warm-up. There was no significant difference between conditions for peak VO2, total VO2 or the accumulated oxygen deficit. The results of this study indicate that 2 min all-out kayak ergometer performance is significantly better after an intermittent rather than a continuous warm-up.     

The effect of an intermittent,high-intensity warm-up on supramaximal kayak ergometer performance

It has previously been shown that the metabolic acidaemia induced by a continuous warm-up at the 'lactate threshold' is associated with a reduced accumulated oxygen deficit and decreased supramaximal performance. The aim of this study was to determine if an intermittent, high-intensity warm-up could increase oxygen uptake (V02) without reducing the accumulated oxygen deficit, and thus improve supramaximal performance. Seven male 500 m kayak paddlers, who had represented their state, volunteered for this study. Each performed a graded exercise test to determine V02max and threshold parameters. On subsequent days and in a random, counterbalanced order, the participants then performed a continuous or intermittent, high-intensity warm-up followed by a 2 min, all-out kayak ergometer test. The continuous warm-up consisted of 15 min of exercise at approximately 65% V02max. The intermittent, high-intensity warm-up was similar, except that the last 5 min was replaced with five 10 s sprints at 200% V02max, separated by 50 s of recovery at ~55% V02max. Significantly greater (P<0.05) peak power (intermittent vs continuous: 629 ± 199 vs 601 ± 204W) and average power (intermittent vs continuous: 328±39.0 vs 321 ±42.4 W) were recorded after the intermittent warm-up. There was no significant difference between conditions for peak V02, total V02 or the accumulated oxygen deficit. The results of this study indicate that 2 min all-out kayak ergometer performance is significantly better after an intermittent rather than a continuous warm-up.     

Morphological characteristics of Olympic slalom canoe and kayak paddlers

Abstract

Sidney and Shephard (1973) were the first to report on the morphology of slalom paddlers and characterized them as having “a substantial standing height and lean body mass, good general muscle development with particular emphasis on the leg muscles”. The purpose of this study was to analyse the morphological characteristics of Olympic slalom kayak and canoe paddlers to determine whether they possess unique physique or structural characteristics that provide an advantage for their sport. Thirty-one male and 12 female slalom paddlers were measured using a battery of 36 anthropometric dimensions in the 15-day period before competition at the 2000 Olympic Games. Male slalom paddlers were older, lighter, shorter, and leaner than previously reported slalom paddlers and had similar height and weight to a reference population of non-athletes. Compared with Olympic sprint paddlers, male slalom paddlers were older, lighter and shorter, and had similar body fat and almost identical proportionality characteristics. Female slalom paddlers were taller, lighter, older, and less fat than those reported previously. They were taller and lighter than the reference population of non-athletes and of similar age and height but lighter and leaner than the Olympic sprint paddlers. While a high brachial index was reported for both male and female slalom paddlers, the Best male paddlers (those ranked in the top 10 placings) were more compact, had smaller proportional hip girth, and showed a tendency for smaller proportional hip breadth but a larger proportional waist girth than the Rest (those not ranked in the top 10 placings). Changes to the technical aspect of the events and to competition rules and the nature and approach to training were explored as possible reasons for some of these differences. We outline the contribution this research makes to talent identification and highlight the need for further research.     

Three-dimensional kinematic analysis and power output of elite flat-water kayakers

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 (Int_L), high (Int_H) and maximal (Int_M) 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 Int_H compared to Int_L and for Int_M compared to Int_L 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 (Int_L 59.3 ± 6.3; Int_H 108.0 ± 6.8; Int_M 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.     

A deterministic model based on evidence for the associations between kinematic variables and sprint kayak performance

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.