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941.
Y. Nagano M. Sakagami H. Ida M. Akai T. Fukubayashi 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):342-350
Landing with the knee in a valgus position is recognized as a risk factor for anterior cruciate ligament (ACL) injury. Using linear and non-linear regression analyses, the purpose of this study was to examine the correlation between two-dimensional (2D) knee valgus and three-dimensional (3D) knee kinematics measured during a jump landing task. Twenty-eight female collegiate athletes participated. All participants were required to perform a continuous jump test. The average maximum angles of abduction and internal tibial rotation during landing were measured using the Point Cluster Technique. Average peak knee valgus angle was measured using a 2D approach. Linear and non-linear regression analyses between 2D valgus and 3D knee abduction, and between 2D valgus and 3D internal tibial rotation, were performed. The R 2 value between 2D valgus and 3D knee abduction was significantly different from zero and had a moderate correlation for all models, whereas the R 2 value between 2D valgus and 3D internal tibial rotation was not significantly different from zero. The 2D approach could be used to screen a specific group of individuals for risk of ACL injury; however, using frontal plane 2D analysis of valgus motion to evaluate internal tibial rotation is not advised. 相似文献
942.
Nicola Bullock David T. Martin Angus Ross Doug Rosemond Terry Holland Frank E. Marino 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):351-360
This study characterizes key elements of the start in elite female World Cup skeleton athletes. The top 20 female competitors in three World Cup races were videotaped within a calibrated space to allow the following components of the start to be quantified: (1) acceleration (velocity at 15-m mark, time to 15-m mark), (2) capacity (time to load, total number of steps to load), and (3) load (velocity at 45-m mark). A correlation analysis was used to establish the relationship between the variables of interest and overall start time (15- to 65-m mark). Velocity at the 15-m mark accounted for 86% of the variance in overall start time at St. Moritz and 85% at Sigulda. A stepwise regression analysis revealed that approximately 89% of the variation in start time could be explained by velocity at the 15-m mark, time to load, and velocity at the 45-m mark. Of the variables analysed in this study, rapid acceleration to attain a high velocity at the 15-m mark was the most important component of a fast overall start time. The importance of the time to load and velocity at the 45-m mark vary according to the different track characteristics. 相似文献
943.
Sarah Nur Marshall Kendall J. Michio Clark T. Blaine Hoshizaki 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):459-469
Goaltenders in ice hockey are the only players that are on the ice for the entire game. Their position exposes them to impacts from collisions with other players, falls to the ice, and puck impacts. In competitive ice hockey leagues, head injuries resulting from puck impacts have been reported with some cases resulting in ending the player’s career. Considerable research has been conducted to assess the performance of hockey helmets; however, few have assessed the performance of goaltenders’ masks. The purpose of this study was to compare the capacity of four goaltenders’ masks for the protection from puck impact as measured by head acceleration and peak force. A Hybrid III headform was fitted with four different goaltender masks and impacted with a hockey puck in three locations at 25 m/s. The masks were found to vary in the level of protection they offered as the mask with the thickest liner resulted in lower forces than the thinnest mask for side impacts; however, the thinnest mask resulted in the lowest force for front impacts. Despite performance differences at specific locations, no one mask proved to be superior as peak acceleration and peak force values did not exceed the thresholds necessary for concussion. 相似文献
944.
Daniel W.T. Wundersitz Kevin J. Netto Brad Aisbett Paul B. Gastin 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):403-412
This study assessed the validity of a tri-axial accelerometer worn on the upper body to estimate peak forces during running and change-of-direction tasks. Seventeen participants completed four different running and change-of-direction tasks (0°, 45°, 90°, and 180°; five trials per condition). Peak crania-caudal and resultant acceleration was converted to force and compared against peak force plate ground reaction force (GRF) in two formats (raw and smoothed). The resultant smoothed (10 Hz) and crania-caudal raw (except 180°) accelerometer values were not significantly different to resultant and vertical GRF for all running and change-of-direction tasks, respectively. Resultant accelerometer measures showed no to strong significant correlations (r = 0.00–0.76) and moderate to large measurement errors (coefficient of variation [CV] = 11.7–23.9%). Crania-caudal accelerometer measures showed small to moderate correlations (r = ? 0.26 to 0.39) and moderate to large measurement errors (CV = 15.0–20.6%). Accelerometers, within integrated micro-technology tracking devices and worn on the upper body, can provide a relative measure of peak impact force experienced during running and two change-of-direction tasks (45° and 90°) provided that resultant smoothed values are used. 相似文献
945.
The effect of research article length, format, and technical quality upon practicing counselors' receptivity to research material was examined. A group of 160 school and rehabilitation counselors were selected by a stratified sampling procedure and assigned at random to one of eight treatment conditions. Each of these treatments represented a combination of predictor variables. Subject ratings of the research articles were analyzed using a least squares analysis of variance procedure. Contrary to much of the available literature, it was found that none of the predictor variables significantly affected scores of counselor receptivity in any consistent direction or between articles of different content. 相似文献
946.
Kevin T. Livingston 《Distance Education》1988,9(1):48-70
Within one year there appeared nine major reports or evaluation studies on Australian distance education — all commissioned by the Australian federal government's former statutory authority advising on tertiary education. The political context in which these studies were initiated is considered first. Then each of the commissioned evaluation studies is examined in turn and finally there is an overall assessment of the likely impact of the reports. 相似文献
947.
This research investigated the effectiveness of a computerized study guide, in comparison to a notetaking condition, as a method to increase textbook comprehension among students with learning disabilities and remedial education pupils enrolled in a ninth-grade world geography class. Results indicated that the computerized study guide produced significantly higher performance than notetaking for both groups of students. There was no significant difference in the performance of the two groups within treatments. Several practical issues concerning the implementation of computerized study guides in secondary programs serving students with academic handicaps are discussed. 相似文献
948.
Four rats were trained to press a bar for food pellets and then were housed in operant chambers for 6 continuous days of choice-testing between obtaining pellets freely or by barpressing. There were two additional 3-day choice periods following more barpress training. It was found that (1) animals preferred to secure food by barpressing when initially placed in the choice situation and immediately following additional barpress training; (2) there was a subsequent decrease to very low levels of response-dependent food taken during choice testing; and (3) opening the chambers for daily maintenance during choice-testing caused a temporary increase in barpressing for food. Thus the previously reported stability of high rates of barpressing in the presence of free food is, at least in part, dependent upon short testing sessions. 相似文献
949.
950.
路易斯·希金斯 《顺德职业技术学院学报》2004,2(1):74-76
分析中国心理学的历史、发展和现状,指出中国文明和心理学在人类历史上辉煌的过去,描述现代心理学在中国的发展和现存的不足,将中西方的心理学进行对比分析。 相似文献