提高艺术体操单足转体质量方法的实验研究     

雷雯 《福建师大福清分校学报》1999,(2):63-66

运用生物力学原理就“偷度法”、“留头法”对提高艺术体操单足转体质量对25名学生进行了实验,并与传统的教学方法进行了比较研究。结果表明：“偷度法”与“留头法”对提高艺术体操单足转体质量有显影响;两种方法结合对提高单足转体质量有更显影响。  相似文献   

浅析安徽女子手球运动员膝关节伤病的特色诊疗效验   总被引：1，自引：0，他引：1  

钱忠东  殷方明 《安徽体育科技》2010,31(5):45-47,53

采用文献资料法和统计分析法,对安徽女子手球队全体队员的膝关节伤病进行完整的医学分析,着重研究剖析了4大类常见膝关节伤病的病因及临床表现,总结了一套独具特色的诊疗、康复理论体系,为运动医学中膝关节伤病的诊治提供相关经验及意见。  相似文献   

Differences in hamstring activation characteristics between the acceleration and maximum-speed phases of sprinting     

Ayako Higashihara  Yasuharu Nagano  Takashi Ono  Toru Fukubayashi 《Journal of sports sciences》2018,36(12):1313-1318

This study aimed to investigate activation characteristics of the biceps femoris long head (BFlh) and semitendinosus (ST) muscles during the acceleration and maximum-speed phases of sprinting. Lower-extremity kinematics and electromyographic (EMG) activities of the BFlh and ST muscles were examined during the acceleration sprint and maximum-speed sprint in 13 male sprinters during an overground sprinting. Differences in hamstring activation during each divided phases and in the hip and knee joint angles and torques at each time point of the sprinting gait cycle were determined between two sprints. During the early stance of the acceleration sprint, the hip extension torque was significantly greater than during the maximum-speed sprint, and the relative EMG activation of the BFlh muscle was significantly higher than that of the ST muscle. During the late stance and terminal mid-swing of maximum-speed sprint, the knee was more extended and a higher knee flexion moment was observed compared to the acceleration sprint, and the ST muscle showed higher activation than that of the BFlh. These results indicate that the functional demands of the medial and lateral hamstring muscles differ between two different sprint performances.  相似文献   

Three-dimensional assessment of squats and drop jumps using the Microsoft Xbox One Kinect: Reliability and validity     

Benjamin F. Mentiplay  Ksaniel Hasanki  Luke G. Perraton  Yong-Hao Pua  Paula C. Charlton  Ross A. Clark 《Journal of sports sciences》2018,36(19):2202-2209

The Microsoft Xbox One Kinect? (Kinect V2) contains a depth camera that can be used to manually identify anatomical landmark positions in three-dimensions independent of the standard skeletal tracking, and therefore has potential for low-cost, time-efficient three-dimensional movement analysis (3DMA). This study examined inter-session reliability and concurrent validity of the Kinect V2 for the assessment of coronal and sagittal plane kinematics for the trunk, hip and knee during single leg squats (SLS) and drop vertical jumps (DVJ). Thirty young, healthy participants (age = 23 ± 5yrs, male/female = 15/15) performed a SLS and DVJ protocol that was recorded concurrently by the Kinect V2 and 3DMA during two sessions, one week apart. The Kinect V2 demonstrated good to excellent reliability for all SLS and DVJ variables (ICC ≥ 0.73). Concurrent validity ranged from poor to excellent (ICC = 0.02 to 0.98) during the SLS task, although trunk, hip and knee flexion and two-dimensional measures of knee abduction and frontal plane projection angle all demonstrated good to excellent validity (ICC ≥ 0.80). Concurrent validity for the DVJ task was typically worse, with only two variables exceeding ICC = 0.75 (trunk and hip flexion). These findings indicate that the Kinect V2 may have potential for large-scale screening for ACL injury risk, however future prospective research is required.  相似文献   

A novel approach to the dissection of the human knee     

F. Richard Clemente  Philip A. Fabrizio  Michael Shumaker 《Anatomical sciences education》2009,2(1):41-46

The knee is one of the most frequently injured joints of the human body with injuries affecting the general population and the athletic population of many age groups. Dissection procedures for the knee joint typically do not allow unobstructed visualization of the anterior cruciate or posterior cruciate ligaments without sacrificing the collateral ligaments. In many cases, the relationships of the intraarticular structures are lost as dissection systematically removes superficial structures to gain access to deeper structures. The authors present an alternative technique for dissection of the human knee joint that allows maximal visualization of intraarticular structures such as the cruciate ligaments and menisci with minimal disturbance to the tibial and fibular collateral ligaments, thus preserving the relationships of the ligamentous and intraarticular structures. Anat Sci Ed 2:41–46, 2009. © 2009 American Association of Anatomists.  相似文献   

Multivariate isokinetic asymmetry of the knee and shoulder in elite volleyball players     

《European Journal of Sport Science》2013,13(1):71-80

Abstract

Muscle strength asymmetries have been investigated in athletes under the assumption of their connection to functional discrepancies and injuries. In volleyball, which is a highly asymmetric sport, this assumption becomes a well established research hypothesis. Given the almost complete lack of scientific evidence on this hypothesis, the present study focused on the detailed multivariate quantification of muscle asymmetries in offensive volleyball players. Twenty-four elite athletes (age 24.71±4.44 years, weight 84.62±6.24, height 190.08±5.58) were tested for concentric isokinetic muscle strength (a) of the internal and external rotators of the shoulder and (b) of the quadriceps and hamstrings of the knee at 60^o/s. Significant multivariate results were found for absolute (Max-Min) asymmetry in the upper (Hotteling's T ²=8.801, F=7.447, P=0.001) and the lower limbs (Hotteling's T ²=16.382, F=13.862, P=0.000), for fluctuating asymmetry (Dominant-Non Dominant) in the upper limbs (Hotteling's T ²=5.584, F=4.296, P=0.013) and for directional asymmetry (Left-Right) in the lower limbs (Hotteling's T ²=3.593, F=3.041, P=0.036). It appears that the upper and lower limbs of offensive volleyball players present significant composite muscle strength asymmetries, which should be taken into consideration in training and rehabilitation.  相似文献   

Reproducibility of an isokinetic eccentric muscle endurance task     

《European Journal of Sport Science》2013,13(5):311-319

Abstract

Despite the widespread use of isokinetic eccentric muscle endurance protocols, no research has examined the absolute and relative reliability of such tests. The aim of this study was to examine the reliability of an isokinetic eccentric knee muscle endurance task. Fifteen healthy untrained males volunteered to take part in the study and written informed consent was obtained. The procedures received approval from the University Research Ethics Committee. Participants visited the laboratory on three separate occasions: 2 weeks before testing to familiarize them with the experimental procedures, and on two separate occasions, 2 weeks apart and at the same time of day. Isokinetic eccentric knee extension and flexion movements of the dominant limb were performed using a calibrated dynamometer (Biodex System 3). Range of motion during testing was set using voluntary maximal full extension (0 rad) to 1.57 rad of knee flexion and testing was conducted at 1.56 rad · s^?1. Participants performed four maximal efforts to determine maximal peak torque. After 2 min rest, participants completed the all-out endurance test of 50 continuous eccentric repetitions. Data were gravity corrected and windowed to only include constant velocity periods. Repeated-measures analyses of variance were used to examine differences in maximal peak extension and flexion torque and the maximal torque measurement recorded during the endurance test. Absolute and relative reliability of the torque fatigue index, work fatigue index, and total work were assessed through calculation of intra-class correlation coefficients, coefficients of variation, and absolute 95% limits of agreement using the methods described by Bland and Altman (1986). Differences between the strength test and the endurance trial for peak torque were found to be non-significant for both quadriceps (323 vs. 323 N · m) and hamstrings (183 vs. 178 N · m). The intra-class correlation coefficients revealed significant (P<0.05) positive moderate to strong correlations (r=0.44–0.94) across repeated trials for all parameters except hamstring torque fatigue (P=0.11) and hamstring work fatigue index (P=0.08). Coefficients of variation ranged from 6% to 48% and were large for the work fatigue index and torque fatigue index but acceptable for total work for both the extensors and flexors. The 95% limits of agreement indicated systematic bias in repeated trials for both the work fatigue index and torque fatigue index for extensors and flexors, ranging from ?3% to ?10%, with less fatigue evident in the second test. There was also systematic bias for total work, with more work being performed during the second than the first test for both extensors and flexors. The random error was large for all variables and there was greater random error in the hamstrings compared with the quadriceps. Together with moderate to strong intra-class correlation coefficients and large coefficients of variation, the data suggest that there is small systematic bias in repeated eccentric muscle actions for both the quadriceps and hamstrings, although the random error was large despite habituation procedures. Therefore, data from an isokinetic eccentric muscle endurance task should be viewed with some caution even when participants receive considerable habituation before assessment.  相似文献   

Effects of bicycle frame ergonomics on triathlon 10-km running performance     

Ian Garside  Dominic A. Doran 《Journal of sports sciences》2013,31(10):825-833

It is perceived that, during the triathlon or duathlon, cycling with a steep (>76°) rather than a shallow (?76°) frame geometry might attenuate the fatigue associated with progression from the cycle to run disciplines and improve subsequent 10-km running performance. This is based on anecdotal testimony from athletes purporting to have experienced improved performance; no empirical evidence exists. To evaluate this view, eight male triathletes completed a counterbalanced, 40-km cycle ride at two frame geometries (73° and 81°) at ~70% VO 2peak . Immediately after completion of each 40-km cycle, a self-paced 10-km treadmill time trial was undertaken, during which physiological, kinematic and performance variables were measured. The 10-km run performance (mean - s : 42:55 - 4:19 vs 46:15 - 4:52 min; P ? 0.01) and combined cycle and run performance (1:45:49 - 5:45 vs 1:50:33 - 6:08; P ? 0.001) were faster in the 81° than the 73° condition. Improvements in performance were most prominent during the first 5 km of the run (21:41 - 2:15 vs 24:15 - 2:31 min in the 81° and 73° conditions respectively). These improvements were not evident during the second 5 km of the run. No differences in physiological variables were noted, although heart rate, stride length and stride frequency were increased during the 81° condition ( P ? 0.05). Modifying frame geometry from a seat tube angle of 73° to 81° improves 10-km running and combined cycle plus run performance. These improvements in performance might relate to alterations during the cycling phase, which minimizes the 'residual effect' of this (i.e. the adverse changes in substrate availability, thermoregulatory, cardiovascular and biomechanical factors felt immediately after transition from cycling to running) and attenuates negative changes in physiological and kinematic responses during the 10-km run.  相似文献   

The relationship between torque and joint angle during knee extension in boys and men     

Vicky Marginson  Roger Eston 《Journal of sports sciences》2013,31(11):875-880

The length-tension relationship of muscle contraction is well documented in adults. However, research on this relationship in children has been limited. The aim of this study was to compare differences in the torque-joint angle relationship of the quadriceps muscle in children and adults. Eight boys aged 8-10 years and eight men aged 20-26 years performed two maximal voluntary isometric contractions at six knee joint angles (20°, 40°, 60°, 80°, 90°, 100°). The mean of the two trials was used as the performance measure. Both groups demonstrated an expected increase in relative torque as the joint angle increased (P ? 0.05). The men produced significantly greater relative torque at 20°, 40° and 60° knee flexion (P ? 0.05). The percentage of maximal torque at these angles for the men and boys respectively were: 35.2 - 4.3 vs 15.2 - 12%, 63.6 - 9.1 vs 51.8 - 16.8% and 93.6 - 6.5 vs 84.4 - 14.4%. There were no group differences at 80° or 90°. Peak torque was attained at 80° in men, but decreased significantly (P ? 0.05) at 90° and 100°. For boys, peak torque was attained at joint angles of 80° and 90°. The reduction in peak torque at 100° was not statistically significant, but the relative torque at this angle was lower in men than in boys (77.9 - 13.7 vs 87.1 - 10.4%; P ? 0.05). In conclusion, the relationship between torque and joint angle appears to be affected by age.  相似文献   

Properties of Isokinetic Fatigue at Various Movement Speeds in Adult Males     

David H. Clarke  James M. Manning 《Research quarterly for exercise and sport》2013,84(3):221-226

Abstract

Eighteen male subjects, ages 20–28 years, engaged in three fatigue bouts using an isokinetic dynamometer (Cybex II). Maximum knee extension contractions were given for 100 s at a rate of 30 per minute. The three contraction speeds chosen were 120° · s ^–1 160° · s ^–1 and 200° · s ^–1.Peak torque at 120° · s ^–1 was significantly greater (p <.05) than at 200° · s ^–1 for the first 60 s, and 160° · s ^–1 for the first 50 s. Thereafter, no significant differences existed among conditions. All three curves were found to follow two-component exponential functions as shown by the equation y_t =a ₂ e^k2^t – a ₁ e^k1^t + c. The three curves possessed similar rate constants for both components. Time to peak torque was achieved at similar times for testing at 160 and 200° · s ^–1 (p <.05). It is concluded that peak torque varies inversely with movement speed, and that the pattern of decrement is independent of movement speed. Time to peak torque does not appear to change significantly across trials in isokinetic fatigue.  相似文献