How do athletes cause ball flight path deviation in high-performance interceptive ball sports? A systematic review

2021 ◽  
pp. 174795412110473
Author(s):  
Cody Lindsay ◽  
Brad Clark ◽  
Kane Middleton ◽  
Rian Crowther ◽  
Wayne Spratford
Keyword(s):  
Systematic Review ◽  
High Performance ◽  
Flight Path ◽  
Flight Trajectory ◽  
Task Constraints ◽  
Axis Of Rotation ◽  
Vertical Changes ◽  
Ball Flight ◽  
Change Task ◽  
Path Deviation

Athletes alter ball flight trajectory in interceptive ball sports to change task constraints that their opponents must overcome to successfully meet the ball in flight. This systematic review identified how athletes change their techniques to alter the ball flight trajectory in high-performance interceptive sports where the ball is projected by the hand towards an opponent. Studies that reported the kinematics or ball flight characteristics of these movements were searched for using SportsDiscus, Scopus, MEDLINE and CINAHL Plus databases up to 27 April 2021. Forty-eight articles met the inclusion criteria, including 19 baseball, 12 cricket, five handball, four softball, three volleyball and five water polo studies. Extracted data were presented as ranges and descriptively analysed to report athlete sporting actions. Trajectory deviation can be caused by imparting an altered seam orientation or spin rate and axis of rotation on the ball. Athletes impart sidespin or manipulate seam orientation to cause lateral deviation while topspin and backspin are used to create vertical changes in the flight path. Adjusting the shoulder, forearm, wrist, hand and fingers of the throwing or striking arm can be used to impart an altered seam orientation or spin rate and axis of rotation on the ball. The findings of this review could assist coaches and athletes across a variety of sports to improve the ability to deviate the ball during flight.

Supplementation and Performance for Wheelchair Athletes: A Systematic Review

2021 ◽  
pp. 1-15
Author(s):  
Andreia Bauermann ◽  
Karina S.G. de Sá ◽  
Zilda A. Santos ◽  
Anselmo A. Costa e Silva
Keyword(s):  
Systematic Review ◽  
High Performance ◽  
Nutritional Intervention ◽  
Vitamin D Supplementation ◽  
Nutritional Interventions ◽  
Carbohydrate Supplementation ◽  
Wheelchair Athletes ◽  
Cord Injury ◽  
And Performance ◽  
Intervention Trials

This systematic review aimed to identify nutritional interventions and supplements that improve the performance for wheelchair athletes. Intervention trials involving high-performance wheelchair athletes were analyzed, including those that comprised a nutritional intervention, defined as any intervention related to food, beverages, and supplementation aiming at evaluating the performance of wheelchair athletes. Of the included studies, four evaluated caffeine supplementation, of which one also evaluated sodium citrate supplementation; two studies evaluated vitamin D supplementation; one study assessed creatine monohydrate supplementation; and one assessed carbohydrate supplementation. Most studies were conducted on athletes with spinal cord injury. Athletes who consumed caffeine exhibited an improvement in performance, but this finding is not strong enough to become a recommendation.

scholarly journals Biomechanical Analysis about the Anticipation of the Goalkeepers for the Ball Flight Trajectory in the Soccer Shooting Situation

Biomechanisms ◽  
2020 ◽  
Vol 25 (0) ◽  
pp. 21-32
Author(s):  
Naoki NUMAZU ◽  
Norihisa FUJII ◽  
Taisuke MORIMOTO ◽  
Sekiya KOIKE
Keyword(s):  
Biomechanical Analysis ◽  
Flight Trajectory ◽  
Ball Flight

scholarly journals Gap perception in bumblebees

2018 ◽  
Author(s):  
Sridhar Ravi ◽  
Olivier Bertrand ◽  
Tim Siesenop ◽  
Lea-Sophie Manz ◽  
Charlotte Doussot ◽  
...  
Keyword(s):  
Optic Flow ◽  
Physical Environment ◽  
Longitudinal Velocity ◽  
Flight Tunnel ◽  
Flight Path ◽  
Flight Trajectory ◽  
Lateral Velocity ◽  
Environmental Features ◽  
Aerial Navigation ◽  
Lateral Displacements

AbstractA number of insects fly over long distances below the natural canopy where the physical environment is highly cluttered consisting of obstacles of varying shape, size and texture. While navigating within such environments animals need to perceive and disambiguate environmental features that might obstruct their flight. The most elemental aspect of aerial navigation through such environments is gap identification and passability evaluation. We used bumblebees to seek insights into the mechanisms used for gap identification when confronted with an obstacle in their flight path and behavioral compensations employed to assess gap properties. Initially, bumblebee foragers were trained to fly though an unobstructed flight tunnel that led to a foraging chamber. After the bees were familiar with this situation, we placed a wall containing a gap that unexpectedly obstructed the flight path on a return trip to the hive. The flight trajectories of the bees as they approached the obstacle wall and traversed the gap were analyzed in order to evaluate their behavior as a function of the distance between the gap and a background wall that was placed behind the gap. Bumblebees initially decelerate when confronted with an unexpected obstacle. Deceleration was first noticed when the obstacle subtended around 35° on the retina but also depended on the properties of the gap. Subsequently the bees gradually traded off their longitudinal velocity to lateral velocity and approached the gap increasing lateral displacements and lateral velocity. Bumblebees shaped their flight trajectory depending on the salience of the gap, in our case, indicated by the optic flow contrast between the region within the gap and on the obstacle, which increases with decreasing distance between the gap and the background wall. As the optic flow contrast decreased the bees spent increasing time moving laterally across the obstacles. During these repeated lateral maneuvers the bees are likely assessing gap geometry and passability.

scholarly journals Securing Machine Learning in the Cloud: A Systematic Review of Cloud Machine Learning Security

2020 ◽  
Vol 3 ◽  
Author(s):  
Adnan Qayyum ◽  
Aneeqa Ijaz ◽  
Muhammad Usama ◽  
Waleed Iqbal ◽  
Junaid Qadir ◽  
...  
Keyword(s):  
Machine Learning ◽  
Systematic Review ◽  
Graphics Processing Units ◽  
High Performance ◽  
Cloud Services ◽  
Third Party ◽  
Systematic Evaluation ◽  
Research Issues ◽  
Wide Range ◽  
Attack And Defense

With the advances in machine learning (ML) and deep learning (DL) techniques, and the potency of cloud computing in offering services efficiently and cost-effectively, Machine Learning as a Service (MLaaS) cloud platforms have become popular. In addition, there is increasing adoption of third-party cloud services for outsourcing training of DL models, which requires substantial costly computational resources (e.g., high-performance graphics processing units (GPUs)). Such widespread usage of cloud-hosted ML/DL services opens a wide range of attack surfaces for adversaries to exploit the ML/DL system to achieve malicious goals. In this article, we conduct a systematic evaluation of literature of cloud-hosted ML/DL models along both the important dimensions—attacks and defenses—related to their security. Our systematic review identified a total of 31 related articles out of which 19 focused on attack, six focused on defense, and six focused on both attack and defense. Our evaluation reveals that there is an increasing interest from the research community on the perspective of attacking and defending different attacks on Machine Learning as a Service platforms. In addition, we identify the limitations and pitfalls of the analyzed articles and highlight open research issues that require further investigation.

Ball flight path determination in VR table tennis

2021 ◽  
Author(s):  
Haosong Zhang ◽  
Shi Feng Lim ◽  
Feng Lin ◽  
Liyuan Li ◽  
Hock S. Seah
Keyword(s):  
Flight Path ◽  
Table Tennis ◽  
Ball Flight

scholarly journals Effects of personal and task constraints on limb coordination during walking: A systematic review and meta-analysis

2019 ◽  
Vol 61 ◽  
pp. 1-10
Author(s):  
Mohsen Shafizadeh ◽  
Robert Crowther ◽  
Jonathan Wheat ◽  
Keith Davids
Keyword(s):  
Systematic Review ◽  
Meta Analysis ◽  
Task Constraints ◽  
Limb Coordination ◽  
And Task

Computing the Global Visibility Map Using Slice Geometry for Setup Planning

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Guangyu Hou ◽  
Matthew C. Frank
Keyword(s):  
High Performance ◽  
Cnc Machining ◽  
Numerical Control ◽  
Cnc Milling ◽  
Setup Planning ◽  
Visibility Map ◽  
Axis Of Rotation ◽  
Milling Machines ◽  
Hard Problems ◽  
Rotation Map

This paper introduces a new method that uses slice geometry to compute the global visibility map (GVM). Global visibility mapping is a fundamentally important process that extracts geometric information about an object, which can be used to solve hard problems, for example, setup and process planning in computer numerical control (CNC) machining. In this work, we present a method for creating the GVM from slice data of polyhedron models, and then show how it can help determine around which axis of rotation a part can be machined. There have been various methods of calculating the GVM to date, tracing back to the well-known seminal methods that use Gaussian mapping. Compared to the considerable amount of work in this field, the proposed method has an advantage of starting from feature-free models like stereolithography (STL) files and has adjustable resolution. Moreover, since it is built upon slicing the model, the method is embarrassingly parallelizable in nature, thus suitable for high-performance computing. Using the GVM obtained by this method, we generate an axis of rotation map to facilitate the setup planning for four-axis CNC milling machines as one implementation example.

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