共查询到20条相似文献，搜索用时 812 毫秒
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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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《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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Jack E.T. Wells Laura H. Charalambous Andrew C.S. Mitchell Daniel Coughlan Simon L. Brearley Roger A. Hawkes 《Journal of sports sciences》2019,37(12):1381-1386
A number of field-based investigations have evidenced practically significant relationships between clubhead velocity (CHV), vertical jump performance and maximum strength. Unfortunately, whilst these investigations provide a great deal of external validity, they are unable to ascertain vertical ground reaction force (vGRF) variables that may relate to golfers’ CHVs. This investigation aimed to assess if the variance in European Challenge Tour golfers’ CHVs could be predicted by countermovement jump (CMJ) positive impulse (PI), isometric mid-thigh pull (IMTP) peak force (PF) and rate of force development (RFD) from 0–50 ms, 0–100 ms, 0–150 ms and 0–200 ms. Thirty-one elite level European Challenge Tour golfers performed a CMJ and IMTP on dual force plates at a tournament venue, with CHV measured on a driving range. Hierarchical multiple regression results indicated that the variance in CHV was significantly predicted by all four models (model one R2 = 0.379; model two R2 = 0.392, model three R2 = 0.422, model four R2 = 0.480), with Akaike’s information criterion indicating that model one was the best fit. Individual standardised beta coefficients revealed that CMJ PI was the only significant variable, accounting for 37.9% of the variance in European Challenge Tour Golfers’ CHVs. 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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《European Journal of Sport Science》2013,13(5):490-498
Abstract Pre-programmed and stretch-induced muscle activities of agonist muscles can play important roles during stretch-shortening cycle exercises. It is still not clear how the antagonist muscles function when the drop and rebound intensities are varied during drop jump (DJ) exercises. The purpose of the present study was to examine the regulation of agonist–antagonist muscle activation during DJ with different drop and rebound heights. The subjects performed DJs with two drop heights (0.2 and 0.4 m) and three different efforts (maximal rebound height, 50% effort of maximal rebound height and landing without rebound). Ankle and knee joint angles, and vertical ground reaction force together with an electromyogram of the lower leg muscles (medial gastrocnemius [MG], soleus [SOL] and tibialis anterior [TA]) were measured simultaneously during DJ. Our results clearly showed that the pre-activation of the antagonist TA was increased with increasing rebound height. Our results further showed that the coactivations of agonist and antagonist muscles during the post-impact 30-ms phase were increased with increasing rebound height. These results suggested that not only the pre-programmed agonist MG muscle activation, but also the pre-programmed antagonist TA activation and the coactivation of the post-impact 30-ms phase may play important roles in the control of rebound height. 相似文献
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A plausible explanation for the ancient long jump records from Greek antiquity is sought on the basis of pictorial and written sources, and corroborated with practical tests. Ancient sources report that athletes jumped more than 15 m with weights in their hands, which enabled them to jump further than without these weights. It is proposed that the ancient Greek long jump was a continuous succession of five standing broad jumps, in which the landing phase of one jump was also the countermovement for the next jump. Four trained athletes jumped further with (14.64 +/- 0.76 m, range 13.64-15.63 m) than without weights (13.88 +/- 0.70 m, range 12.60-14.75 m; P = 0.001). These results show that this technique is executable, fits with ancient written and pictorial sources, and allows trained modern athletes to jump distances well over 15 m. The extra distance jumped when using weights may be due to changes in the position of the jumper's centre of mass at take-off and at landing, and an increase in take-off velocity stemming from several biomechanical mechanisms. 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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In the collision between a striking implement and ball, the term “sweet spot” represents the impact location producing best results. In football kicking, it is not known if a sweet spot exists on the foot because no method to measure impact location in three-dimensional space exists. Therefore, the aims were: (1) develop a method to measure impact location on the foot in three-dimensional space; (2) determine if players impacted the ball with a particular location; (3) determine the relationship between impact location with kick performance; (4) discuss if a sweet spot exists on the foot. An intra-individual analysis was performed on foot-ball impact characteristics of ten players performing 30 Australian football drop punt kicks toward a target. (1) A method to measure impact location was developed and validated. (2) The impact locations were normally distributed, evidenced by non-significant results of the Shapiro-Wilk test (p > 0.05) and inspection of histograms, meaning players targeted a location on their foot. (3) Impact location influenced foot-ball energy transfer, ball flight trajectory and ankle plantar/dorsal flexion. (4) These results indicate a sweet spot exists on the foot for the Australian football drop punt kick. In conclusion, the impact location is an important impact characteristic. 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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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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人为万物之灵,由男精（精子）（阳）,女血（孵子）（阴）,男女交配时精卵结合而成受精卵,道医称之为“混元体”,经十月怀胎,降生母体而为新生婴儿。 相似文献
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男子100米9.3秒,1500米3分16秒,跳高2.60米,三级跳远20米,铁饼78.30米,百米自由泳45秒……这些诱人的成绩是田径专家们为我们描述的25年后的世界纪录.不过,要达到这些目标,必须借助于现代科学技术的进一步发展.爱德华兹两破世界纪录,奥秘何在?刚刚结束的第5届世界田径锦标赛共创造了3项新的世界纪录,其中最引人注目的是男子三级跳.英国选手爱德华兹连续两次刷新世界纪录,把这一项目的纪录提高了30多厘米.他成功的奥秘何在?一个由瑞典、丹麦的运动医学专家组成的分析小组运用电脑对他的动作作了分析.他们发现,如果他能减少失误,还有可能把成绩提高到19米.记者有机会看到了专家们用电脑勾画出的爱德华兹三级跳远中最后一级跳的图形.他起跳后,大腿部与上身几乎形成直角,双臂自然举起,双脚尽可能与身体重心保持垂直. 相似文献
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<正> 王晓明老师: 听了您对症状的描述之后,初步诊断困扰您的“病”是在当前体育教学改革逐步深入、新旧教学理论转换的条件下,产生的一种常发型“流行病”。“病因”恐怕是旧教学理论的后遗症和对新教学理论的消化不良所致。此“病”在现阶段的体育教学改革时期堪称顽症,如不及时医治,将会对体育教学改革的生命产生很大的危害。 相似文献
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本文对我国的体育课程教学中“带着铁链跳舞”“放羊”“满堂灌”“科学放羊”“教师主导”“学生主体”“课堂常规”“自主学习”等诸多概念和说法逐一进行辨析。以期体育教师对“自主学习”有正确的理解和认识,从而在教学实践中能有效地进行课堂教学。 相似文献
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几天前,有朋友问我,咱们的《茶馆牌友众生相》要写到“十一”了,大小人物也出场了二十位,什么时候能排到我啊？我听了甚是欣慰,至少朋友们没将我所写的东东视为亵渎,已经有些黔驴技穷的我,终于又有了一些坚持下去的动力。 相似文献
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一、含蓄 芗斋老先生在拳论中所描写的“含蓄”,在实作中,遇敌好似虎扑羊(老虎在扑猎物前瞬间呈现的含蓄状态)。势如龙驹扭丝缰(烈马被骑手拽住缰绳,使马首回扭时马所处的含蓄态,这时骑手 相似文献
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唐宋以前的古人称“壶”和“瓶”,与我们今人“壶”和“瓶”的称呼正好相反。古人所谓的“壶”和今人称之为“瓶”的形象相似;反之,唐朝人称之为“瓶”的器物上却有柄曰“錾”,有嘴曰“流”,与今天的“壶”的形象相差无几。由此可见世事沧桑,斗转星移,竟然连器物的名称也倒转了过来。 相似文献