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Abstract The drop jump is a popular form of plyometric exercise often undertaken to enhance countermovement jump ability (jump height). Despite its popularity the effects of drop jump training on countermovement jump height are often inconsistent. Such inconsistencies may be as a result of differences in the drop jump technique being employed. Two recognised forms of drop jump are the “countermovement” drop jump and the “bounce” drop jump and the current study examined the effects of eight weeks of training with these drop jump techniques on countermovement jump height. Methods: A kinetic and kinematic analysis of each participant's countermovement jump, bounce- and countermovement drop jumps was undertaken prior to training. Participants were then randomly assigned to a bounce drop jump training group (n = 34), a countermovement drop jump training group (n = 35) or a control group (n = 34). Changes in jump height were examined following training. Results: The countermovement drop jump training group increased their countermovement jump height by 2.9 cm (6%), which was a significant change (P < 0.05) in comparison to that experienced by the bounce drop jump (-0.2 cm, -0.4%) and the control group (-0.1 cm, 0.2%). Conclusion: The countermovement drop jump may be more effective than the bounce drop jump at enhancing countermovement jump height. 相似文献
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We tested the hypothesis that the performance of rapid movements represents body size-independent indices of muscle power. Physical education students (n = 159) were tested on various vertical jump (jump height and average power calculated from the ground reaction force) and muscle strength tests. When non-normalized data were used, a principal components analysis revealed a complex and inconsistent structure where jump height and muscle power loaded different components, while muscle strength and power partially overlapped. When the indices of muscle strength and power were properly normalized for body size, a simple and consistent structure of principal components supported the hypothesis. Specifically, the recorded height and muscle power calculated from the same jumps loaded the same components, separately for the jumps predominantly based on concentric actions and jumps based on a rapid stretch--shortening cycle of the leg extensors. The finding that the performance of rapid movements assesses the same physical ability as properly normalized tests of muscle power could be important for designing and interpreting the results of batteries of physical performance tests, as well as for understanding some basic principles of human movement performance. 相似文献
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Designing tomorrow’s snow park jump 总被引：1，自引：1，他引：0
Recent epidemiological studies of injuries at ski resorts have found that snow park jumps pose a significantly greater risk
for certain classes of injury to resort patrons than other normal skiing activities. Today, most recreational jumps are built
by skilled groomers without an engineering design process, but the Snow Skiing Committee (F-27) of the American Society for
Testing and Materials is considering the inclusion of recreational jumps in their purview which may lead to a greater role
for engineering jump designs in the US in the future. Similar efforts are underway in Europe as well. The purpose of this
work is to review the current state of the science of snow park jumps, describe the jump design process, and outline the role
that modelling will play in designing tomorrow’s snow park jumps. 相似文献
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Katis A Kellis E 《Sports biomechanics / International Society of Biomechanics in Sports》2011,10(1):35-45
Cutting in soccer is a common skill used to avoid the opponent's pressure but the potential effects of such a skill on instep kicking performance have not been previously investigated. The purpose of this study was to examine the differences in lower limb biomechanics between straight approach soccer kicks and kicks performed following a cutting maneuver task. Ten young amateur soccer players performed, in a random order, instep kicks after a two-step straight approach run and kicks after a double "faking" cutting maneuver task. The results showed that kicking after a cutting maneuver task displayed significantly lower ball speed values compared with the straight approach instep kicking (16.73 vs. 19.78 m/s, respectively; p < 0.05). Moreover, analysis of variance showed significant differences between the two kicking conditions in ankle, knee and hip joint displacements. The present study indicated that performing instep kicks after a double-cutting maneuver reduces ball and foot speed probably due to increasing joint frontal and transverse plane rotations. Improvements in the performance of the cutting maneuver task through training might result in better transfer of energy and speed to the kicking task thus permitting players to perform more powerful kicks under realistic game conditions. 相似文献
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Moisés de Hoyo Daniel Dylan Cohen Borja Sañudo Luis Carrasco Alejandro Álvarez-Mesa Juan José del Ojo 《Journal of sports sciences》2016,34(14):1363-1370
ABSTRACTWe analysed the time course of recovery of creatine kinase (CK) and countermovement jump (CMJ) parameters after a football match, and correlations between changes in these variables and match time–motion parameters (GPS-accelerometry) in 15 U-19 elite male players. Plasma CK and CMJ height (CMJH), average concentric force (CMJCON) and average eccentric force (CMJECC) were assessed 2 h before and 30 min, 24 h and 48 h post-match. There were substantially higher CK levels 30 min, 24 h and 48 h (ES: 0.43, 0.62, 0.40, respectively), post-match. CMJECC (ES: ?0.38), CMJH (ES: ?0.35) decreased 30 min post, CMJCON (ES: ?0.35), CMJECC (ES: ?0.35) and CMJH (ES: ?1.35) decreased 24 h post, and CMJCON (ES: ?0.41) and CMJH (ES: ?0.53) decreased 48 h post. We found correlations between distance covered at velocities ≤21 km · h?1 and changes in CK at 24 h (r = 0.56) and at 48 h (r = 0.54) and correlations between CK and distance covered >14 km · h?1 (r = 0.50), accelerations (r = 0.48), and decelerations (r = 0.58) at 48 h. Changes in CMJCON 30 min and 24 h post (both r = ?0.68) correlated with impacts >7.1·G. Decelerations >2 m · s?2 correlated with changes CMJCON (r = ?0.49) at 48 h and CMJECC (r = ?0.47) at 30 min. Our results suggest that match GPS-accelerometry parameters may predict muscle damage and changes in components of neuromuscular performance immediately and 24–48 h post-match. 相似文献
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Daniel J Hiscock Brian Dawson Michael Clarke Peter Peeling 《Journal of sports sciences》2018,36(2):191-197
This study examined the influence of differing volume load and intensity (%1 repetition maximum[%1RM]) resistance exercise workouts on session rating of perceived exertion (sRPE) countermovement jump (CMJ) performance and endocrine responses. Twelve participants performed a workout comprising four exercises (bench press, back squat, deadlift and prone bench pull) in randomised order as either power (POW); 3 sets × 6 repetitions at 45%1RM × 3 min inter-set rest, strength (ST); 3 sets × 3 repetitions at 90%1RM × 3 min inter-set rest, or hypertrophy (HYP); 3 sets × 10 repetitions at 70%1RM × 1 min inter-set rest in a randomised-crossover design. CMJ performance and endocrine responses were measured immediately pre-, post-, 12, 24, 48 and 72 h post-exercise. POW sRPE (3.0 ± 1.0) was lower than ST (4.5 ± 1.0) (P = 0.01), and both were lower than HYP (8.5 ± 1.0) (P = 0.01). Duration of CMJ decrement was longer (P ≤ 0.05) for HYP (72 h) compared to POW (12 h) and ST (24 h). Testosterone concentration was greater (P ≤ 0.05) immediately post-exercise in HYP compared to POW and ST. In conclusion, less inter-set rest, greater volume load and intensity (%1RM) may increase sRPE, duration of CMJ performance decrement and testosterone responses in resistance exercise. 相似文献
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Moataz Eltoukhy Adam Kelly Chang-Young Kim Hyung-Pil Jun Richard Campbell 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(1):89-102
Cost effective, quantifiable assessment of lower extremity movement represents potential improvement over standard tools for evaluation of injury risk. Ten healthy participants completed three trials of a drop jump, overhead squat, and single leg squat task. Peak hip and knee kinematics were assessed using an 8 camera BTS Smart 7000DX motion analysis system and the Microsoft Kinect® camera system. The agreement and consistency between both uncorrected and correct Kinect kinematic variables and the BTS camera system were assessed using interclass correlations coefficients. Peak sagittal plane kinematics measured using the Microsoft Kinect® camera system explained a significant amount of variance [Rangehip = 43.5–62.8%; Rangeknee = 67.5–89.6%] in peak kinematics measured using the BTS camera system. Across tasks, peak knee flexion angle and peak hip flexion were found to be consistent and in agreement when the Microsoft Kinect® camera system was directly compared to the BTS camera system but these values were improved following application of a corrective factor. The Microsoft Kinect® may not be an appropriate surrogate for traditional motion analysis technology, but it may have potential applications as a real-time feedback tool in pathological or high injury risk populations. 相似文献
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对"体育教育学"的词源--德语"Sportp(a)dagogik"在德语、英语及中文中的概念演变进行了探讨,认为体育教育学是一门从教育角度考察人类各种体育活动的学科,它涉及教育学的基础知识,主要关注人类各种体育活动与教育意义上的活动(如教学、教养、抚育、训诫)之间的关系,注重通过体育活动使人获得教育意义上的发展.针对我国体育教育学的学科研究,建议在概念表述上回归德语"Sportp(a)dagogik"概念的内涵,在研究对象上进一步丰富,在研究内容上进一步充实,在研究方法上明确两个要点,在未来的发展上注重使人们获得"教育意义上的发展",并通过"教育意义上的发展"这个纽带将体育科学体系内的不同分支学科联系起来. 相似文献
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《运动与健康科学(英文)》2023,12(4):544-552
PurposeThis study aimed to examine the reliability and validity of load−velocity (L–V) relationship variables obtained through the 2-point method using different load combinations and velocity variables.MethodsTwenty men performed 2 identical sessions consisting of 2 countermovement jumps against 4 external loads (20 kg, 40 kg, 60 kg, and 80 kg) and a heavy squat against a load linked to a mean velocity (MV) of 0.55 m/s (load0.55). The L–V relationship variables (load-axis intercept (L0), velocity-axis intercept (v0), and area under the L–V relationship line (Aline)) were obtained using 3 velocity variables (MV, mean propulsive velocity (MPV), and peak velocity) by the multiple-point method including (20–40–60–80–load0.55) and excluding (20–40–60–80) the heavy squat, as well as from their respective 2-point methods (20–load0.55 and 20–80).ResultsThe L–V relationship variables were obtained with an acceptable reliability (coefficient of variation (CV) ≤ 7.30%; intra-class correlation coefficient ≥ 0.63). The reliability of L0 and v0 was comparable for both methods (CVratio (calculated as higher value/lower value): 1.11–1.12), but the multiple-point method provided Aline with a greater reliability (CVratio = 1.26). The use of a heavy squat provided the L–V relationship variables with a comparable or higher reliability than the use of a heavy countermovement jump load (CVratio: 1.06–1.19). The peak velocity provided the load–velocity relationship variables with the greatest reliability (CVratio: 1.15–1.86) followed by the MV (CVratio: 1.07–1.18), and finally the MPV. The 2-point methods only revealed an acceptable validity for the MV and MPV (effect size ≤ 0.19; Pearson's product-moment correlation coefficient ≥ 0.96; Lin's concordance correlation coefficient ≥ 0.94).ConclusionThe 2-point method obtained from a heavy squat load and MV or MPV is a quick, safe, and reliable procedure to evaluate the lower-body maximal neuromuscular capacities through the L–V relationship. 相似文献
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ABSTRACTThe aims of this study are (a) to describe the evolution of neuromuscular performance over an 18 year period within a Spanish elite reserve team; (b) to check if there were any relation between the playing position and sprint and jump performances and (c) to look into the alleged impact of this factor on the top playing level attained by the soccer players. We considered the physical tests (5 m and 15 m sprint times and countermovement jump (CMJ) height) made by 235 players enrolled in the reserve team of the Club from 1994 to 2012 and the highest competitive-level they achieved: Spanish first (n = 39) and second divisions (n = 36) and semi-professional (n = 160). Furthermore, the players were classified according to their playing positions. The main findings were a very-likely/most-likely lower neuromuscular performance (ES = 0.48–0.68, small to moderate) in the last six-season term (2006–2012) than in the first term (1994–2000); possibly/very-likely lower performances in sprinting and CMJ (ES = 0.22–0.55, small) by central defenders (CDs) and midfielders than by other playing positions; very-likely better performances in sprinting and jumping by first and second divisions central defenders than by semi-professional central defenders (ES = 0.90–1.02, moderate). Sprint and jump performances are not a relevant physical parameter to promote to the top level of soccer in Spain except for one in six of the playing positions: CDs. 相似文献
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人们在生活中总免不了有一些烦恼的事儿.有些烦恼来自外界,必须正视;而大多数困扰则源于内心,这就是所谓的"自寻烦恼". 有个和尚,每次坐禅都幻觉有一只大蜘蛛跟他捣蛋,无论怎样也赶不走,他把这件事告诉了师父. 相似文献
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美国有个研究幸福的实验是这样的:心理学家让受试者造句,规定以“我希望”起头,例如“我希望我像比尔·盖茨那样富有”、“我希望我是贝肯汉姆的情人”、“我希望我中百万乐透头奖”。然后,心理学家要求受试者再造三个句子,以“还好我不是”起头,例如说“还好我不是绝症患者”、“还好我不是乞丐”、“还好我老公没有暴力倾向”等等。调查结果显示:同样一批人,在完成“我希望”的 相似文献
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人们常认为,只要常吃补药、补品,身体就会好,其实不然.随着社会的发展,人们生活水平的提高,食物营养的摄取和补充已经基本上得到了保障,进补已不属于重要的问题,问题只是出在人体内有害物质的逐渐增多,并对健康构成严重的威胁.因此,有关保健专家提出了"清毒"重于"进补"的现代保健新观念. 相似文献
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过去有句老话叫“包子有肉不在褶上”，讲的就是凡事不张扬，要有谦虚的态度。“披萨”就是把馅儿全展现在面上，把自己的才能、智慧充分展现出来。只有在当好“包子”的同时，当好“披萨”，才能事半功倍，早日站稳讲台，走进先进教师的行列。 相似文献
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1.飞镖的制作1)准备材料一根竹筷、一把小刀、一枚钢针、一根长约15cm的细铁丝、一根细线绳和一张边长为10～12cm的正方形厚纸。2)制作步骤1)取竹筷约10cm长,将竹筷的一端从中间用小刀劈成约3cm长的两半,另一端劈成约1cm长的四半。(如图1)2)把钢针插入竹筷一端的中间露出约1cm,然后用细铁丝将筷子缠绕加固,注意缠绕要集中些。3)把纸的中线和对角线分别对折后再沿中线向内对折成“十”字形(如图2),把其尖角插入筷子另一端,最后用细线绳缠绕加固。这样,一个“飞镖”就制作完成了。(如图3)2.镖靶的制作可以用软木(如梧桐)、塑料泡沫片或者纸箱… 相似文献
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