Successive Shots Research Articles

Physical and technical demands of the extra time: a multiple FIFA World Cups’ analysis

ABSTRACT This study examined the physical and technical demands of the 2010, 2014 and 2018 men’s FIFA World Cups with special reference on extra time. Data were collected from 69 FIFA’s open-access match reports (n= 3,238 individual players’ observations) and scaled by individual playing exposure. Players covered less total distance (TD) from the 1st half to the extra time period (r=0.17–0.27; P<0.05). Moreover, the number of sprints decreased from the 1st half to the extra time (r=0.13–0.25; P<0.01). However, substitutes who started on or came in on the match throughout the 2nd half covered higher TD in the extra time compared to the 2nd half (r=0.11–0.43; P<0.01), and compared to starters during the 2nd half and extra time (r=0.11–0.36; P<0.05). Additionally, substitutes who started on, or came in throughout the extra time covered higher TD and performed more sprints compared to starters during the extra time r=0.12–0.23; P<0.05). Generally, no meaningful differences were observed in successful shots and dribbles between periods of the match and between starting status (P>0.05). The occurrence of extra time appeared to be detrimental to the work rate during the match, which can be counteracted by substitute players.

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

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.

POSSIBILITIES OF ANIMATION IN SYSTEM COMPAS FOR DEVELOPMENT OF SPATIAL THOUGHT OF STUDENTS

Computer-aided design COMPAS-3D is used for the construction of three-dimensional model of frame-clamping unit on the basis of models of details, connected by interfaces. An animation library is intended for simulating of motions of different machines, devices, mechanisms and devices, modelled in the system COMPAS-3D; simulating of processes of assembling-sorting out of wares; creations of video, demonstrating work of yet not existent devices for presentations or interactive technical guides; creations of successive shots for research of motions of mechanisms. Animation of the created model of pump demonstrates principle of work of good, when the rotation of one detail sets all mechanism in motion. Performing similar works with students significantly expands student design opportunities. Mastering 3D modeling skills helps solve problems related to the design and visualization of complex graphic objects in mechanical engineering.The use of graphical technologies helps to fulfill technical documentation according to standards and at the same time develops the ability of students to find creatively.

Visual Fixation in NBA Free-Throws and the Relationship to On-Court Performance

Purpose&#x0D; Although hitting a baseball is often described as the most difficult task in all of sports, shooting baskets during a game likely ranks a close second. Previous studies have described the role of vision in basketball and more specifically a concept termed the “quiet eye” has been shown to be related to basketball performance. How a shooter visualizes the target, how consistent their visual fixation is, and how long they maintain that fixation has been correlated to shooting success. Although the majority of previous reports have included non-professional basketball shooters, we evaluated NBA (National Basketball Association) players to determine if this skill was significant at the professional level.&#x0D; Materials and Methods&#x0D; We evaluated 16 professional NBA players prior to the 2018-2019 NBA season. All players shot 30 consecutive free-throws while wearing Tobii Pro eye-tracking glasses. Following the completion of the task, several metrics were calculated including shooting success rate, as well as four measures of the position and duration of ocular fixation just prior to, during, and immediately after ball release for each shot of each player. Additionally, player performance statistics from the 2018-2019 season were recorded and compared to the visual fixation data. Descriptive statistics as well as correlations between the visual fixation metrics and on-court performance metrics were calculated.&#x0D; Results&#x0D; NBA shooters averaged a 79% success rate in free throw shooting (SD = 14%, min = 56%, max=100%) during the study. Moderate statistically significant correlations were found between the percentage of successful free throws and the four measures of visual fixation (r=0.539 to 0.687). In addition, visual fixation measures were found to be corelated with on-court metrics suggesting that shooters who had more frequent, as well as longer, fixations on the rim where more likely to have lower USG%, and ORB% as well as higher FG3%. The percentage of successful shots in the study was compared to the on-court FT% and found to be moderately correlated (r=0.536).&#x0D; Conclusions&#x0D; The need to maintain ocular fixation on the rim as one shoots seems elementary, but in fact varies greatly among NBA players, as noted in these results. Our data suggests that players who visually fixate longer and more frequently on the rim are more likely to be successful in free throws, as well as more successful in 3-point goals. Likely due to their likely distance from the basket, they do not make as many offensive rebounds. This data set appears to describe basketball guards in contrast to forwards/centers and supports previous research on non-professional basketball players.

Fast Temporal Video Segmentation Based on Krawtchouk-Tchebichef Moments

With the increasing growth of multimedia data, the current real-world video sharing websites are being huge in repository size, more specifically video databases. This growth necessitates to look for superior techniques in processing video because video contains a lot of useful information. Temporal video segmentation (TVS) is considered essential stage in content-based video indexing and retrieval system. TVS aims to detect boundaries between successive video shots. TVS algorithm design is still challenging because most of the recent methods are unable to achieve fast and robust detection. In this regard, this paper proposes a TVS algorithm with high precision and recall values, and low computation cost for detecting different types of video transitions. The proposed algorithm is based on orthogonal moments which are considered as features to detect transitions. To increase the speed of the TVS algorithm as well as the accuracy, fast block processing and embedded orthogonal polynomial algorithms are utilized to extract features. This utilization will lead to extract multiple local features with low computational cost. Support vector machine (SVM) classifier is used to detect transitions. Specifically, the hard transitions are detected by the trained SVM model. The proposed algorithm has been evaluated on four datasets. In addition, the performance of the proposed algorithm is compared to several state-of-the-art TVS algorithms. Experimental results demonstrated that the proposed algorithm performance improvements in terms of recall, precision, and F1-score are within the ranges (1.31 - 2.58), (1.53 - 4.28), and (1.41 - 3.03), respectively. Moreover, the proposed method shows low computation cost which is 2% of real-time.

Video Scenes Segmentation Based on Multimodal Genre Prediction

Abstract Recent technologies’ understanding videos content remain limited due to its complexity and length. However, videos segmentation into small coherent units facilitates indexing and searching task. The subjectivity remains the essential constraint of videos, but the genre (drama, action...) does not present any conflict. In this paper, we present a new approach to video segmentation into scenes based on genre prediction. Initially, the video is divided into shots of equal duration. We used architecture, based on audio-visuals deep features extracted from trained neural networks for genre prediction, and we introduced a transition detection method based on the similarity calculation between shots genre. The originality of this method consists in using the highly level semantic relationship between successive shots for transition detection. We reached good performances on videos of the multi varied genre. We used the RAI dataset and BBC dataset to evaluate our method through a comparison with other state-of-the-art approaches.

Effect of caffeine ingestion on free-throw performance in college basketball players

BackgroundIt is currently unclear whether pre-exercise caffeine ingestion can improve free-throw shooting performance, a vital skill in basketball. The purpose of this study was to investigate the effects of caffeine on free-throw shooting performance in college-aged basketball players. MethodsTwelve males (23.1 ± 1.9 years; 180.1 ± 8.8 cm; 77.1 ± 12.4 kg) and six females (22.0 ± 1.3 years; 169.4 ± 8.9 cm; 67.0 ± 11.1 kg) who competed at the college level ingested 6 mg per kg of body mass of (a) caffeine or (b) maltodextrin (placebo) on two separate occasions in a random order. After 60 min, they performed five sets of a match-simulated basketball protocol comprising six sideline-to-sideline sprints on a standard basketball court followed by two free-throws after each set. The number of successful shots was counted. Heart rate and rating of perceived exertion (RPE) after each sprint set were also recorded. ResultsCaffeine ingestion did not improve overall free-throw success (caffeine = 6.1 ± 1.7 vs. placebo = 5.5 ± 2.0; p = 0.34) compared with placebo across all five sets. There was no change in shooting accuracy across sprint sets in either trial despite significant increases in both heart rate and RPE. Caffeine increased heart rate (p = 0.02) but had no effect on RPE (p = 0.57) across five sets compared with placebo. ConclusionsIngestion of 6 mg of caffeine per kg of body mass did not improve basketball free-throw performance. Free-throw performance did not deteriorate with increasing number of sprint sets.

Analysis Fracture Behaviour of Asphalt Mixtures in Freezing and Thawing Cycles Conditions Using Linear Elastic Fracture Mechanic (LEFM) Technic

Considering the military implementation prohibitions and highly developed technologies of composite materials , this project studies about increasing the power of martial and fire in Gyroplanes and light Helicopters by design, optimization and manufacturing of composite launchers instead of isotropic types. Using composite type launchers have advantage of lower weight, higher life and simplicity in manufacturing. Modeling and analysis accomplished by Abaqus Software and the fiber composite directions improved by coding in Matlab Software. The optimization process completed by linking both softwares. Till now, more than 800 successful shots have been made in several centers using composite launchers. Because of easy manufacturing of this kind of launchers, there is no need to have advanced equipments and all the works have been provided by semi-skilled workers in the simple workshops.

Different Marks in the Pitch Constraint Youth Players’ Performances During Football Small-sided Games

ABSTRACTPurpose: This study aimed to compare players’ performances when manipulating the external markings of the pitch during football small-sided games. Methods: Ten under-15 players performed a 5-a-side (plus goalkeepers) under three conditions: (i) Lines, the game was played in a pitch in which the external boundaries were painted with full lines; (ii) Dashed, the game was played in a pitch in which the external boundaries were painted with dashed lines; (iii) Corners, the game was played in a pitch were the external boundaries were delimited by one marker at each pitch corner. Players’ positional data was used to compute tactical and time-motion variables. Also, technical analysis was comprised using video footage. Results: Results showed similar tactical, physical and technical performances between the Lines and Dashed conditions. In contrast, the Lines condition showed small higher effects than Corners scenario in the time spent synchronized in longitudinal and lateral displacements, game pace, total distance covered, distance covered while jogging, number successful dribbles and shots on target. The Lines scenario has also revealed a lower effective playing space, distance covered at walking and running and a lower number of passes (small effects) compared to Corners. Conclusions: These results highlight that these changes in informational perception constraints modify players movement behavior. Accordingly, pitches with more visible boundaries were likely to decrease team dispersion, which may optimize team synchrony and technical performances, while decreasing the distance covered at higher speeds. Coaches may use this information to modify the types of pitch external boundaries markings, exposing the players to different environmental information.

Various factors affecting successful shots in basketball games

Various factors affecting successful shots in basketball games

Characterization of multi-element impurity deposited on EAST divertor tile using laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) has been applied for the depth-resolved identification of impurity deposited on EAST divertor tile. LIBS spectra show the presence of impurity elements (W, Mo, Li, Na, Ca, Cr) and tile material (C, Si, Ti) in the layer deposited on the graphite tile surface. The analysis of impurity deposition was performed in different positions on tile surface. The results indicate that the interaction of high heat plasma with plasma facing components (PFCs) leads to erosion of Mo from first wall and W from upper divertor. Depth profiling measurements show decay of impurity signals with successive laser shots and non-uniform impurity deposition in the different positions on tile surface. The impurity deposition was also measured at the different depths in the tile. The measurements show a non-uniform deposition at various depths in the deposition layer. Surface morphology and composition of tile were verified by SEM and EDX techniques. The study indicates that LIBS has potential to monitor the erosion and deposition of PFCs in fusion devices. The results obtained from LIBS technique are important for long pulse of H-mode plasma operation in EAST.

Basketball free-throws performance depends on the integrity of binocular vision

ABSTRACT Background: The deterioration of the integrity of binocular vision has a detrimental effect on fine visuomotor skills, however, its impact on sports performance remains unknown. We tested the influence of four viewing conditions (binocular viewing, monocular viewing, binocular viewing with monocular blur, and binocular viewing with binocular blur) on basketball free-throws performance. Methods: Twenty-three male basketball players (19.2 ± 3.4 years) performed 30 free-throws in each viewing condition following a randomised order. Image degradation was induced by the use of Bangerter filters. Complementarily, perceived levels of task load and complexity, as well as visual function were assessed. Results: We found a worse basketball free-throws performance (percentage of successful shots) in the monocular viewing (∼8%) and binocular viewing with monocular blur (∼9%) in comparison to the condition of binocular viewing (corrected p-values = 0.003 and 0.006; and ds = 0.838 and 0.771). The analyses of subjective ratings and visual function allowed us to confirm a successful experimental manipulation. Conclusions: Basketball free-throws performance is subject to the integrity of binocular vision, showing a worse accuracy when the sensory dominant eye was occluded or blurred in comparison to natural (binocular) viewing conditions. However, free-throws performance remains stable when the visual acuity is binocularly degraded. Our findings reveal that an appropriate functioning of the binocular vision is needed for optimal sports performance, and highlight the importance of a comprehensive clinical assessment or management of binocular vision in sport contexts.

Game-Play Characteristics by Field Size in Boys Youth Lacrosse

US Lacrosse’s Athlete Development Model (LADM) currently encourages small-sided game (SG) field dimensions to increase development and skill acquisition for youth athletes. No studies have evaluated changes in game-play subsequent to SG participation in boys’ youth lacrosse (BYL). PURPOSE: To describe game-play characteristics during SG (35-45 yd) and full-field games (FG, 60-70 yd) in BYL. METHODS: Data was collected from 33 BYL players in Virginia (8.5±0.5 years, 138.3±5.7 cm, 35.9±6.5kg) on SG (n=15) and FG (n=18) teams. All games were filmed using a digital camera affixed to a camera lift system. Game-play characteristics were measured by reviewing the game video and coding for characteristics of unsuccessful passes, successful passes, shots on goal, goalie saves, changes of possession, loose balls, and intercepted passes. Descriptive statistics were reported (Frequency, Mean) for all observed game-play characteristics. RESULTS: Teams participated in 12 games total with 159 total athlete-exposures. Total gameplay characteristics were: unsuccessful passes (SG=587, FG=399), successful passes (SG=165, FG=347), shots on goal (SG=81, FG=143), goalie saves (SG=28, FG=79), changes of possession (SG=419, FG=335), loose balls (SG=799, FG=670), and intercepted passes (SG=31, FG=24). The average characteristic per game were: unsuccessful passes (SG=97.8, FG=66.5), successful passes (SG=27.5, FG=57.8), shots on goal (SG=13.5, FG=23.8), goalie saves (SG=4.7, FG=13.2), changes of possession (SG=69.8, FG=55.8), loose balls (SG=133.2, FG=111.7), and intercepted passes (SG=5.2, FG=4.0). Further characteristics included: percent successful passes (SG=22%, FG=47%) and percent of successful shots on goal (SG=60%, FG=41%). CONCLUSION: Generally, FG had a greater percentage of successful passes than SG with comparable attempts per game between the two groups. In addition, SG had a greater successful shot percentage on less shots but had fewer goalie saves per game. Lastly, the SG team had more unsuccessful passes, loose balls, and turnovers. Further research is required to understand the effects of all aspects of the LADM on player development in BYL.

Game-Play Characteristics by Field Size in Girls’ Youth Lacrosse

To facilitate player development, the Lacrosse Athlete Development Model (LADM) recommends the use of small-sided games (SG) and fewer players on the field. Yet, no studies have evaluated if SG change game-play in girls’ youth lacrosse (GYL). PURPOSE: To describe game-play characteristics during SG and full-field games (FG) in GYL. METHODS: Female athletes (N=28, 8.5±0.5 years, 132.4±3.6 cm, 31.4±1.7 kg) participated on either a small-sided (SG, n=13) or a full-field (FG, n=15) 10U level team within a single GYL league in Virginia. Both SG and FG teams participated in 6 games during the season. All games were filmed using a digital camera affixed to a camera lift system. Game-play characteristics were measured by reviewing game video and coding the frequency of observed activities (e.g. successful passes, changes of possession, intercepted passes, shots on goal, and loose balls). Descriptive statistics (Frequency, Mean) for game-play characteristics were calculated. RESULTS: A total of 137 athlete-exposures (AE) occurred across 12 games (SG=59AE, FG=78AE). Total characteristics for the season were: unsuccessful passes (SG=476, FG=378), successful passes (SG=59, FG=110), shots on goal (SG=183, FG=189), goalie saves (SG=58, FG=79), changes of possession (SG=333, FG=281), loose balls (SG=625, FG=575), and intercepted passes (SG=17, FG=10). Average characteristics per game were: unsuccessful passes (SG=79.3, FG=63.0), successful passes (SG=9.83, FG=18.3), shots on goal (SG=30.5, FG=31.5), goalie saves (SG=9.7, FG=13.2), changes of possession (SG=55.5, FG=46.8), loose balls (SG=104.2, FG=95.8), and intercepted passes (SG=2.8, FG=1.7). Further, the FG team had a larger proportion of successful passes (23%) than the SG team (11%). However, the SG team had a larger proportion of successful shots on goal (63%) than the FG team (54%). CONCLUSION: A greater proportion of successful passes were observed in FG than SG with comparable attempts and slightly fewer intercepted passes per game. Further, SG was observed to have a greater proportion of successful shots on goal despite FG having slightly more attempted shots on goal and more goalie saves. Additional research is needed to better understand how all aspects of LADM guidelines affect player development and skill acquisition in GYL.

Learner-adapted practice promotes skill transfer in unskilled adults learning the basketball set shot

The current study used a complex, sport-specific movement skill to explore the effects of a win-shift/lose-stay practice schedule on learning and compared its effectiveness with that of blocked and random practice schedules. Thirty-six adults (24.9 ± 3.3 years) were assigned to blocked, random and learner-adapted training groups. Each participant performed 360 trials of the basketball set shot from multiple locations across six practice sessions. For the learner-adapted group, switching between task variations was performance-contingent; switching between shooting locations occurred only following a successful shot. Shooting success was calculated as the percentage of successful shots performed, and measured during pre-acquisition (i.e. baseline), acquisition (i.e. practice) and post-acquisition (i.e. retention and transfer). Despite scoring less shots throughout practice compared to baseline testing, the learner-adapted group showed a significant improvement for shooting success in transfer (d = 1.02). Blocked practice demonstrated significant improvements for shooting success in immediate retention (d = 1.83), delayed retention (d = 1.69) and transfer (d = 1.39). Random practice significantly improved shooting success in both immediate (d = 1.03) and delayed retention (d = 0.81). The current findings highlight that performance during practice does not necessarily represent the permanency and adaptability of skill learning. The implications of the findings and their practical applications are discussed in the context of practice scheduling during learning of a sports skill.

Determining unstable game states to aid the identification of perturbations in football

ABSTRACTAlternative approaches to the reductionist method for analysing football are needed to better understand factors typically not considered, for example off the ball runs by teammates. The dynamical systems approach, where the complex relationships between players is emphasised, predicts that goal scoring opportunities are preceded by instability in the balance between the two teams’ behaviours. The aim was to create operational definitions for determining unstable game states to facilitate the identification of perturbations, that is the causes of instability. Validity tests involving four English Premier League (EPL) football coaches and two performance analysts and subsequent reliability tests established five unstable game states; penalty box possession, counter attack, ratio of attacking to defending players, successful cross and successful shot. Eighteen EPL matches were analysed to present exemplar statistics for three teams of different standard (based on final league position) suggesting that teams create unstable situations differently, likely due to individual player characteristics, with home advantage and opposition strength effects, suggesting this may be a component of what constitutes a performance indicator for a team. Future studies need to consider individual player actions that create instability as well as provide objective measures that substantiate findings.

Laser-induced fluorescence of C2 and C3 in colliding carbon plasma

The formation of transient molecular species, C2 and C3, was studied in the collision of two laser-produced carbon plasmas using laser-induced fluorescence. In vacuum, two closely neighboring laser-produced plasmas will collide, as they expand into one another or are forced into occupying the same space. This so-called colliding plasma produces a highly collisional composite plasma plume from the two individual plasmas which persists longer with enhanced prevalence of certain plasma processes such as recombination. In an inertial fusion energy (IFE) chamber, successive shots will ablate first wall material (e.g., graphitic carbon). Inwardly collapsing plasma will attain such a colliding plasma state as it converges inwards toward the chamber center. The presented results elucidate the early formation of C2 and C3, precursors to larger carbon structures which may contaminate an IFE chamber.

A comparison of the ground reaction forces of archers with different levels of expertise during the arrow shooting

Summary Objective The purpose of this study was to compare the differences in ground reaction forces (GRFs) of archers with different levels of expertise during arrow shooting. Material and methods Twenty-seven male archers were involved in this study. Anterior-posterior ground reaction force (APGRF-Fy) and medio-lateral ground reaction force (MLGRF-Fx) collected by force platform during the successful shots towards the target from a distance of 18 m. The center of pressure (CoP) excursion was computed during arrow shooting using the GRFs. All statistical analyses were completed using SPSS 22.0 for Windows software (SPSS Inc., Chicago, IL). The level of statistical significance was set as P Results Results demonstrated that elite group had the least CoP sway, APGRF and MLGRF during all phases comparing to both mid-level, beginner level archers. However the differences in APGRF and MLGRF between groups didn’t reach the significance level (P > 0.05). The sway range of CoP values of elite group were significantly smaller than the values of beginner group (P Conclusion In conclusion, it was observed that the relationship between body sway and expertise level. Therefore instantaneous visual force feedback training including APGRF, MLGRF and CoP sway values could be recommended in order to increase shooting performance.

Sensor System for Precision Shooting Evaluation and Real-time Biofeedback

Shooting training is one of the most important trainings in public or private structures such as police, army, security companies, and similar. Shooting is a discipline where precision is of the outmost importance. Technology supported shooting training brings several benefits to the trainees and to the organizations. Trainees spend less time on average for training and the organization potentially saves funds for shooting ranges, coaches, and charges spent. We have designed an application that measures pistol movements during aiming, firing, and post firing phases of each shot. Each successful shot is represented as a hit in a standardized shooting target. The acquired sensor signals are evaluated through target hit results. The measurements include 46 subjects of different ages and different shooting skill levels. The first results show that the hand movement during the aiming phase correlates with the shooting precision. The next step is to find signal features are the most usable for the prediction of shot precision. By using the selected features to detect the unwanted or excessive pistol movement during the aiming phase a trainee can be warned to suspend the current shot and try again later. Such training, incorporating real-time biofeedback application, can lead to accelerated learning, reduces the number of poorly performed shots, and consequently saves time and money.

Influence of the opposition on overhead smash velocity in padel players

Although it is well established that velocity of execution is an important performance factor in ball sports and the presence of opposition influences it, there has been no research done to date on the ball velocity in padel shots. The overhead smash is one of the most successful shots in this sport, and the present study aimed to study the effect of opposition on smash performance in semi-professional and amateur padel players. Forty-four semi-professional (n=14) and amateur (n=30) players volunteered to participate in this study. The overhead smash velocity was recorded for both groups of players with and without opposition using a radar gun. The ball velocity decreased in both groups of players in the presence of opposition (from 133.1±8.2 km·h-1 to 120.72±9.8 km·h-1 in semi-professional players; and from 124.6±9.2 km·h-1 to 104.5±10.0 km·h-1 in amateurs, p&amp;lt;.001). Although the semi-professional players achieved a greater velocity in both situations (p&amp;lt;.001) compared to amateurs, the reduction of velocity in the presence of opposition was greater in the amateurs (p&amp;lt;.001). The greater velocities for the semi-professional padel players could be attributed to a technical and tactical superiority due to their greater experience and higher level of competition. Simulating conditions of opposition could help reduce the velocity-precision trade-off, helping the players increase their overhead smash velocities.