The Effects of Temporal Variability within and between Series of Stimuli on Reaction Time and Movement Time     

Craig A. Wrisberg 《Research quarterly for exercise and sport》2013,84(4):518-522

  相似文献   

Developing Coincident Timing Skill in Children: A Comparison of Training Methods     

Craig A. Wrisberg  Barbara J. Mead 《Research quarterly for exercise and sport》2013,84(1):67-74

Abstract

The present study attempted to determine whether the nature of training experiences influences the development of coincident timing skill in young children. The task involved visual tracking of a moving light sequence and a 43 cm arm movement to a padded target. Subjects attempted to tap the target coincident with the completion of the light sequence. Sixty first grade children were randomly assigned to one of five groups, with an equal number of males and females in each group. Subjects assigned to the training groups received 48 trials on each of two days, with stimulus speeds that were either slow (179 cm/sec or 4 mph), fast (313 cm/sec or 7 mph), varied-random (179, 224, 268, 313 cm/sec or 4, 5, 6, 7 mph), or varied-blocked (i.e., 6 consecutive trials with one speed before changing to another). Control subjects performed a neutral coloring activity during the training phase of the experiment. All subjects were then given 10 trials on a third day with each of two stimulus speeds not experienced previously; one slow (134 cm/sec or 3 mph) and one fast (358 cm/sec or 8 mph). During transfer trials all groups were more accurate with the fast than with the slow speed stimulus. Training method mattered most during slow speed transfer trials, with the most accurate performance demonstrated by the group receiving varied-blocked speeds during training. The least effective methods were fast speed training, especially for males, and varied-random speed training. It was concluded that training sessions for the development of coincident timing skill in young children should emphasize slower speed stimuli and blocking of additional speeds which are more rapid.  相似文献   

Yearly Changes in the Body Composition and Muscular Strength of High School Wrestlers     

Terry J. Housh  Glen O. Johnson  Roger A. Hughes  Craig J. Cisar  William G. Thorland 《Research quarterly for exercise and sport》2013,84(3):240-243

Abstract

The purpose of this investigation was to determine the yearly changes in body composition as well as absolute and relative isokinetic forearm flexion and extension strength of high school wrestlers. Evaluations of body composition (underwater weighing) were performed on 27 high school wrestlers prior to three consecutive seasons. In addition, isokinetic forearm flexion and extension strength values at 180°/s (Cybex II) were available for 20 of the subjects. The mean ages at the times of laboratory testing were 15.5 (± .5), 16.5 (± .5), and 17.5 (± .5) years. Repeated measures ANOVA or ANCOVA with Tukey post-hoc comparisons were used to locate significant (p<.05) differences across age for height, body weight, relative fat, body density, fat weight, fat-free weight, absolute muscular strength, and muscular strength covaried for body weight and fat-free weight. There were yearly increases in all variables except fat weight, forearm flexion covaried for fat-free weight and forearm extension covaried for fat-free weight. The results of this study indicated that the improved wrestling performance and the increase in weight classification which normally occurs during high school are, in part, a function of yearly changes in body composition and muscular strength.  相似文献   

The Variability of Practice Hypothesis: Further Tests and Methodological Discussion     

Craig A. Wrisberg  Timothy P. Winter  Jolynn S. Kuhlman 《Research quarterly for exercise and sport》2013,84(4):369-374

Abstract

In the present study experimental subjects practiced variations in movement distance and/or movement time during training trials on a closed timing task. Control subjects trained with single distance-time combinations. During transfer trials all subjects attempted (without knowledge of results) a distance-time combination that was different (except in the case of one control condition) from any performed during training. The results revealed that the timing accuracy of the two experimental conditions that practiced a variety of times was significantly poorer than that of most of the other conditions during the training phase. However, transfer analyses revealed several significant differences between the performance of variable-trained and constant-trained conditions, in all cases favoring the former. It was concluded that the transfer benefits of variable practice are (a) not due to the particular movement component selected for variation during training, and (b) to some extent always determined by the similarity of training and transfer conditions experienced by constant-practice subjects.  相似文献   

Isokinetic Leg Flexion and Extension Strength of Elite Adolescent Female Track and Field Athletes     

Terry J. Housh  William G. Thorland  Gerald D. Tharp  Glen O. Johnson  Craig J. Cisar 《Research quarterly for exercise and sport》2013,84(4):347-350

Abstract

Sixty-two elite adolescent (age: 16.39 ± 1.62 yrs) female track and field athletes volunteered to be measured isokinetically for peak torque of the leg flexors and extensors. The sample included 16 throwers, 11 jumpers, 12 middle-distance runners (> 400 m), and 23 sprinters. A Cybex II isokinetic dynamometer was used to measure dominant leg strength at 180°/sec. One-way ANOVA revealed significant between group differences for absolute flexion and extension (Nm), extension/body weight (Nm/Kg), and extension/lean body weight (Nm/Kg). Scheffe post-hoc comparisons showed that, for absolute leg extension strength, throwers were stronger than middle-distance runners (by 54.4%), sprinters (35.6%), and jumpers (23.6%). For absolute leg flexion movements, throwers were stronger than middle distance runners (37.4%) and sprinters (32.1%). Jumpers had greater extension peak torque values than middle-distance runners relative to body weight (14.0%), and throwers were stronger than middle-distance runners for extension/lean body weight (14.9%)). No other comparisons were significant. However, when strength was expressed relative to body weight or lean body weight, there were few differences between events for flexion or extension. Given that absolute strength scores were correlated with body weight and lean body weight, peak torque/body weight or peak torque/lean body weight may be more sensitive than absolute values as indicators of underlying factors (such as training status or fiber type composition) responsible for the differences in muscular strength between groups.  相似文献   

A Field Test of the Activity-Set Hypothesis for Warm-Up Decrement in an Open Skill     

Craig A. Wrisberg  Mark H. Anshel 《Research quarterly for exercise and sport》2013,84(1):39-45

Abstract

To determine the relative effectiveness of different warm-up activities in eliminating postrest warm-up decrement (WUD), 65 highly skilled tennis players performed 60 forehand and 60 backhand groundstrokes, rested for either 5 or 15 min, engaged in one of five interpolated activities (additional rest, running in place, imagery, practice swings, or air dribbling), and then performed 12 additional forehands and backhands. An analysis of differences between prerest and postrest arousal measures (heart rate, positive cognitive arousal, and negative cognitive arousal) revealed that all of the interpolated activities except additional rest restored arousal to levels near those found at the end of prerest trials. Postrest WUD was also eliminated by practice swings and air dribbling and, to a slightly lesser extent, by running in place. We concluded that an effective warm-up for open skills such as the tennis groundstroke should include some form of overt physical activity that directs the attention of the performer to task-relevant cues.  相似文献   

The effect of coaching intervention on elite fast bowling technique over a two year period     

Craig Ranson  Mark King  Angus Burnett  Peter Worthington  Kevin Shine 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(4):261-274

Fast bowling in cricket is an activity that is well recognised as having high injury prevalence and there has been debate regarding the most effective fast bowling technique. The aim of this study was to determine whether two-year coaching interventions conducted in a group of elite young fast bowlers resulted in fast bowling technique alteration. Selected kinematics of the bowling action of 14 elite young fast bowlers were measured using an 18 camera Vicon Motion Analysis system before and after two-year coaching interventions that addressed specific elements of fast bowling technique. Mann-Whitney tests were used to determine whether any changes in kinematic variables occurred pre- and post-intervention between those who had the coaching interventions and those who didn't. The coaching interventions, when applied, resulted in a more side-on shoulder alignment at back foot contact (BFC) (p = 0.002) and decreased shoulder counter-rotation (p = 0.001) however, there was no difference in the degree of change in back and front knee flexion angles or lower trunk side-flexion. This study has clearly shown that specific aspects of fast bowling technique are changeable over a two-year period in elite level fast bowlers and this may be attributed to coaching intervention.  相似文献   

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

Craig A. Wassinger  Joseph B. Myers  Timothy C. Sell  Sakiko Oyama  Elaine N. Rubenstein  Scott M. Lephart 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):98-109

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.  相似文献   

Using VoiceThread to Create Meaningful Receptive and Expressive Learning Activities for Young Children     

Afton Gillis  Katie Luthin  Howard P. Parette  Craig Blum 《Early Childhood Education Journal》2012,40(4):203-211

Development of receptive and expressive language skills is an important foundational skill in early childhood education. Recently, early childhood education professionals have begun using Web-based technology to assist in developing these skills. One Web-based technology that holds potential to support children’s learning is VoiceThread which has unique features that support Universal Design for Learning. This paper provides practical recommendations for use of VoiceThread in meaningful learning activities that can easily be implemented. A step-by-step guide is presented to create and use VoiceThread.  相似文献   

Humanities in Gross Anatomy Project: A novel humanistic learning tool at Des Moines University     

Craig A. Canby  Traci A. Bush 《Anatomical sciences education》2010,3(2):94-96

Gross anatomy affords physical therapy students an opportunity to discover human morphology by intimately studying the dead. Moreover, it also exposes future physical therapists to the humanistic aspects of the profession. In 2007, anatomy faculty decided to socialize students to the humanities with a new course requirement: Humanities in Gross Anatomy Project (HuGA) Project. At the end of the course, students, either individually or as a group, submitted a project that described how they had been personally touched by the donor's gift and how the gift contributed to their professional growth and education. The submission could be in the form of a narrative, poem, song, video, etc. All students met the three grading criteria that were established; thus taking the first step in socializing themselves to the humanistic domain of their professional education. In summary, the HuGA project is a novel educational tool that formally provided physical therapy students with humanistic learning opportunities in a gross anatomy course and appeared to facilitate reflective learning. The utilization of reflection as it relates to clinical decision making and patient interaction is critical for physical therapy practice. Anat Sci Educ 3: 94–96, 2010. © 2010 American Association of Anatomists.  相似文献