Death and dissection in Belgium     

Jones  Ross L. 《Metascience》2021,30(1):53-55

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The kinematic differences between accurate and inaccurate squash forehand drives for athletes of different skill levels     

Benjamin K. Williams  Ross H. Sanders  Joong Hyun Ryu  Philip Graham-Smith  Peter J. Sinclair 《Journal of sports sciences》2020,38(10):1115-1123

ABSTRACT

To maintain the accuracy of squash shots under varying conditions, such as the oncoming ball’s velocity and trajectory, players must adjust their technique. Although differences in technique between skilled and less-skilled players have been studied, it is not yet understood how players vary their technique in a functional manner to maintain accuracy under varying conditions. This study compared 3-dimensional joint and racket kinematics and their variability between accurate and inaccurate squash forehand drives of 9 highly skilled and 9 less-skilled male athletes. During inaccurate shots, less-skilled players hit the ball with a more open racket, demonstrating a difference in this task-relevant parameter. No joint kinematic differences were found for accuracy for either group. Coordinated joint rotations at the elbow and wrist both displayed a “zeroing-in” effect, whereby movement variability was reduced from the initiation of propulsive joint rotation to a higher consistency at ball-impact; potentially highlighting the “functionality” of the variability prior to the impact that enabled consistent task-relevant parameters (racket orientation and velocity) under varying conditions. Further, highly skilled players demonstrated greater consistency of task-relevant parameters at impact than less-skilled players. These findings highlight the superior ability of highly skilled players to adjust their technique to achieve consistent task-relevant parameters and a successful shot.  相似文献   

Static and dynamic accuracy of a magnetic-inertial measurement unit used to provide racket swing kinematics     

Benjamin Kane Williams  Ross H. Sanders  Joong Hyun Ryu  Pitre C. Bourdon  Philip Graham-Smith  Peter J. Sinclair 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(2):202-214

Magnetic-inertial measurement units (MIMUs) are becoming more prevalent in sports biomechanics and may be a viable tool to evaluate kinematic parameters. This study examined the accuracy of a MIMU to estimate orientation angles under static conditions and dynamically from a squash racket during a forehand drive shot. A MIMU was mounted onto a goniometer and moved through 0–90°, with static data collected at 10° increments during 10 repetitions of all three axes. Typical error analyses showed the MIMU to be very reliable (TE ≤ 0.03°). MIMU accuracy was determined via intraclass correlation coefficients (ICC) (r > 0.999, p < 0.001). An ordinary least products regression showed no proportional bias and minimal fixed bias for all axes. Dynamic accuracy was assessed by comparing MIMU and optical motion capture data of squash racket swing kinematics. A MIMU was fixed onto a racket and 10 participants each hit 10 forehand shots. Mean orientation angle error at ball impact was <0.50° and ICC showed very high correlations (r ≥ 0.988, p < 0.001) for all orientations. Swing phase root mean squared errors were ≤2.20°. These results indicate that a MIMU could be used to accurately and reliably estimate selected racket swing kinematics.  相似文献   

Sport-specific biomechanical responses to an ACL injury prevention programme: A randomised controlled trial     

Jeffrey B. Taylor  Kevin R. Ford  Randy J. Schmitz  Scott E. Ross  Terry A. Ackerman  Sandra J. Shultz 《Journal of sports sciences》2018,36(21):2492-2501

Anterior cruciate ligament (ACL) injury prevention programmes have not been as successful at reducing injury rates in women’s basketball as in soccer. This randomised controlled trial (ClinicalTrials.gov #NCT02530333) compared biomechanical adaptations in basketball and soccer players during jump-landing activities after an ACL injury prevention programme. Eighty-seven athletes were cluster randomised into intervention (6-week programme) and control groups. Three-dimensional biomechanical analyses of drop vertical jump (DVJ), double- (SAG-DL) and single-leg (SAG-SL) sagittal, and double- (FRONT-DL) and single-leg (FRONT-SL) frontal plane jump landing tasks were tested before and after the intervention. Peak angles, excursions, and joint moments were analysed using two-way MANCOVAs of post-test scores while controlling for pre-test scores. During SAG-SL the basketball intervention group exhibited increased peak knee abduction angles (p = .004) and excursions (p = .003) compared to the basketball control group (p = .01) and soccer intervention group (p = .01). During FRONT-SL, the basketball intervention group exhibited greater knee flexion excursion after training than the control group (p = .01), but not the soccer intervention group (p = .11). Although women’s soccer players exhibit greater improvements in knee abduction kinematics than basketball players, these athletes largely exhibit similar biomechanical adaptations to ACL injury prevention programmes.  相似文献   

Going up?     

Spencer Atkins  J. 《Metascience》2019,28(3):515-517

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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 rule induction framework for the determination of representative learning design in skilled performance     

Sam Robertson  Bart Spencer  Nicole Back  Damian Farrow 《Journal of sports sciences》2019,37(11):1280-1285

Representative learning design provides a framework for the extent to which practice simulates key elements of a performance setting. Improving both the measurement and analysis of representative learning design would allow for the refinement of sports training environments that seek to replicate competition conditions and provide additional context to the evaluation of athlete performance. Using rule induction, this study aimed to develop working models for the determination of high frequency, representative events in Australian Rules football kicking. A sample of 9005 kicks from the 2015 Australian Football League season were categorised and analysed according to the following constraints: type of pressure, kick distance, possession source, time in possession, velocity and kick target. The Apriori algorithm was used to develop two models. The first consisted of 10 rules containing the most commonly occurring constraint sets occurring during the kick in AF, with support values ranging from 0.15 to 0.22. None of the rules contained more than three constraints and confidence values ranged from 0.63 to 0.84. The second model considered ineffective and effective kick outcomes and displayed 70% classification accuracy. This research provides a measurement approach to determine the degree of representativeness of sports practice and is directly applicable to various team sports.  相似文献   

The Me in Memory: The Role of the Self in Autobiographical Memory Development     

Josephine Ross  Jacqui Hutchison  Sheila J. Cunningham 《Child development》2020,91(2):e299-e314

This article tests the hypothesis that self-development plays a role in the offset of childhood amnesia; assessing the importance of both the capacity to anchor a memory to the self-concept, and the strength of the self-concept as an anchor. This research demonstrates for the first time that the volume of 3- to 6-year old's specific autobiographical memories is predicted by both the volume of their self-knowledge, and their capacity for self-source monitoring within self-referencing paradigms (N = 186). Moreover, there is a bidirectional relation between self and memory, such that autobiographical memory mediates the link between self-source monitoring and self-knowledge. These predictive relations suggest that the self-memory system is active in early childhood.  相似文献   

The Transition to Reaching: Mapping Intention and Intrinsic Dynamics   总被引：9，自引：0，他引：9  

Esther Thelen  Daniela Corbetta  Kathi Kamm  John P. Spencer  Klaus Schneider  Ronald F. Zernicke 《Child development》1993,64(4):1058-1098

The onset of directed reaching demarks the emergence of a qualitatively new skill. In this study we asked how intentional reaching arises from infants' ongoing, intrinsic movement dynamics, and how first reaches become successively adapted to the task. We observed 4 infants weekly in a standard reaching task and identified the week of first arm-extended reach, and the 2 weeks before and after onset. The infants first reached at ages ranging from 12 to 22 weeks, and they used different strategies to get the toy. 2 infants, whose spontaneous movements were large and vigorous, damped down their fast, forceful movements. The 2 quieter infants generated faster and more energetic movements to lift their arms. The infants modulated reaches in task-appropriate ways in the weeks following onset. Reaching emerges when infants can intentionally adjust the force and compliance of the arm, often using muscle coactivation. These results suggest that the infant central nervous system does not contain programs that detail hand trajectory, joint coordination, and muscle activation patterns. Rather, these patterns are the consequences of the natural dynamics of the system and the active exploration of the match between those dynamics and the task.  相似文献   

College Students' Study Strategies as a Function of Testing: An Investigation into Metacognitive Self-Regulation     

Margaret E. Ross  Samuel B. Green  Jill D. Salisbury-Glennon  Nona Tollefson 《Innovative Higher Education》2006,30(5):361-375

We conducted the present study to investigate whether college students adjust their study strategies to meet the cognitive demands of testing, a metacognitive self-regulatory skill. Participants were randomly assigned to one of the two testing conditions. In one condition we told participants to study for a test that required deep-level cognitive processing and in the other to study for a test that required surface-level cognitive processing. Results suggested that college students adjust their study strategies so that they are in line with the cognitive processing demands of tests and that performance is mediated by the study strategies that are used.Margaret E. Ross is an Associate Professor of Educational Measurement and Statistics at Auburn University. She earned her Ph.D. in Educational Psychology from the University of Kansas. Her research interests include the role assessment plays in influencing student learning strategies, assessment issues and policy, and educational program evaluation. Samuel B. Green is a Professor in the Educational Psychology Department at Arizona State University. He holds a Ph.D. in Measurement and Individual Differences Psychology from the University of Georgia. His research focuses on statistical procedures. Jill Salisbury-Glennon is an Associate Professor teaching Educational Psychology courses at Auburn University. She earned her Ph.D. in Educational Psychology from Pennsylvania. Research interests include college student self-regulation, metacognition, and motivation. Nona Tollefson recently passed away. She was a Professor of Psychology and Research in Education at the University of Kansas and held a Ph.D. from Purdue University. Her research focused on student assessment  相似文献