scholarly journals Volume and Intensity of Locomotor Activity in International Men's Field Hockey Matches Over a 2-Year Period

2021 ◽  
Vol 3 ◽  
Author(s):  
Carl A. James ◽  
Oliver R. Gibson ◽  
Aishwar Dhawan ◽  
Craig M. Stewart ◽  
Ashley G. B. Willmott
Keyword(s):  
High Speed ◽  
Negative Relationship ◽  
International Competition ◽  
Intensity Data ◽  
Field Hockey ◽  
Time Data ◽  
Average Speed ◽  
Speed Range ◽  
Playing Time ◽  
Physical Preparation

The locomotor demands of international men's field hockey matches were investigated across positions (DEF, MID, FWD) and playing quarters. Volume (i.e., total values) and intensity (i.e., relative to playing time) data were collected using 10-Hz GPS/100-Hz accelerometer units from the #11 world-ranked (WR) team, during 71 matches, against 24 opponents [WR 12 ± 11 (range, 1–60)]. Mean ± SD team total distance (TD) was 4,861 ± 871 m, with 25% (1,193 ± 329 m) “high-speed running” (>14.5 km h−1) and 8% (402 ± 144 m) “sprinting” (>19.0 km h−1). Reduced TD (range, −3 to 4%) and average speed (range, −3.4 to 4.7%) occurred through subsequent quarters, vs. Q1 (p < 0.05). A “large” negative relationship (r = −0.64) was found between playing duration and average speed. Positional differences (p < 0.05) were identified for all volume metrics including; playing duration (DEF, 45:50 ± 8:00 min; MID, 37:37 ± 7:12 min; FWD, 33:32 ± 6:22 min), TD (DEF, 5,223 ± 851 m; MID, 4,945 ± 827 m; FWD, 4,453 ± 741 m), sprinting distance (DEF, 315 ± 121 m; MID, 437 ± 144 m; FWD, 445 ± 129 m), and acceleration efforts (>2 m s−2; DEF, 48 ± 12; MID, 51 ± 11; FWD, 50 ± 14). Intensity variables similarly revealed positional differences (p < 0.05) but with a different pattern between positions; average speed (DEF, 115 ± 10 m min−1; MID, 132 ± 10 m min−1; FWD, 134 ± 15 m min−1), sprinting (DEF, 7 ± 3 m min−1; MID, 12 ± 4 m min−1; FWD, 14 ± 4 m min−1), and accelerations (DEF, 1.1 ± 0.3 n min−1; MID, 1.4 ± 0.2 n min−1; FWD, 1.5 ± 0.3 n min−1). Physical outputs reduced across playing quarters, despite unlimited substitutions, demonstrating the importance of optimizing physical preparation prior to international competition. Volume and intensity data highlight specific positional requirements, with forwards displaying shorter playing durations but greater high-intensity activities than defenders.

Relationships between physiological characteristics and match demands in elite-level male field hockey players

2021 ◽  
pp. 174795412199806
Author(s):  
Wayne P Lombard ◽  
Xudan Cai ◽  
Michael I Lambert ◽  
Xiaoping Chen ◽  
Lijuan Mao
Keyword(s):  
High Speed ◽  
Negative Relationship ◽  
Time Trial ◽  
Field Hockey ◽  
Physiological Variables ◽  
Body Strength ◽  
Hockey Players ◽  
Elite Level ◽  
Gps Devices ◽  
Repeat Sprint Ability

This study investigated the physical characteristics, match demands and their relationships in elite-level male field hockey players (n = 23; 24 ± 3 years). Testing data were collected to investigate the physiological profiles of the players, while match demands were quantified with GPS data over 26 matches. There were significant differences (p = <0.05) between positional groups for pull ups, relative and absolute lower body strength, and body composition. Average total match distance for all the players was (5420 ± 1518 m). There were significant differences between positional groups for defenders (5770 ± 1419 m) vs strikers (4739 ± 1409 m) and midfielders (5549 ± 1545 m) vs strikers. The most high-speed-running (>4.5 ms−1) distance was covered by midfielders (950 ± 275 m) and strikers (908 ± 284 m). Midfielders (116 ± 15 m min) and strikers (120 ± 20 m min) achieved higher intensities during matches compared to defenders (105 ± 13 m min). There were small differences between positional groups for physiological variables, but large variation between positional groups for match demands. There was a significant negative relationship between 2.4 km time trial vs high-speed running (p = <0.05), player load.min and match speed (p = <0.001). Also, there was a negative association between repeat sprint ability total time and high-speed running distance (p = <0.02) and match speed (p = <0.02). The countermovement jump height was associated with match speed (p = <0.05) and there was a negative relationship between body fat % and match speed (p = <0.02). When considering key performance indicators while using GPS devices, match speed (m.min) provides the most valuable information in field hockey players.

scholarly journals High-enthalpy hypersonic flows

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Joseph J. S. Shang ◽  
Hong Yan
Keyword(s):  
Hypersonic Flow ◽  
High Speed ◽  
Quantum Physics ◽  
Nonequilibrium Thermodynamic ◽  
Strong Shock ◽  
Hypersonic Flows ◽  
Electrically Conducting ◽  
High Enthalpy ◽  
Speed Range ◽  
Flow Theories

Abstract Nearly all illuminating classic hypersonic flow theories address aerodynamic phenomena as a perfect gas in the high-speed range and at the upper limit of continuum gas domain. The hypersonic flow is quantitatively defined by the Mach number independent principle, which is derived from the asymptotes of the Rankine-Hugoniot relationship. However, most hypersonic flows encounter strong shock-wave compressions resulting in a high enthalpy gas environment that always associates with nonequilibrium thermodynamic and quantum chemical-physics phenomena. Under this circumstance, the theoretic linkage between the microscopic particle dynamics and macroscopic thermodynamics properties of gas is lost. When the air mixture is ionized to become an electrically conducting medium, the governing physics now ventures into the regimes of quantum physics and electromagnetics. Therefore, the hypersonic flows are no longer a pure aerodynamics subject but a multidisciplinary science. In order to better understand the realistic hypersonic flows, all pertaining disciplines such as the nonequilibrium chemical kinetics, quantum physics, radiative heat transfer, and electromagnetics need to bring forth.

An Efficient Match Search Approach Using Two-Dimensional Hash Function in Hardware-Based Dictionary Compression

2019 ◽  
Vol 28 (06) ◽  
pp. 1950106
Author(s):  
Qian Dong ◽  
Bing Li
Keyword(s):  
Compression Ratio ◽  
Hash Function ◽  
High Speed ◽  
Two Dimensional ◽  
Time Data ◽  
Search Result ◽  
Compression Speed ◽  
Real Time Data ◽  
Real Time Data Processing ◽  
Search Approach

The hardware-based dictionary compression is widely adopted for high speed requirement of real-time data processing. Hash function helps to manage large dictionary to improve compression ratio but is prone to collisions, so some phrases in match search result are not true matches. This paper presents a novel match search approach called dual chaining hash refining, which can improve the efficiency of match search. From the experimental results, our method showed obvious advantage in compression speed compared with other approach that utilizes single hash function described in the previous publications.

Influence of Neuromuscular Fatigue on Accelerometer Load in Elite Australian Football Players

2013 ◽  
Vol 8 (4) ◽  
pp. 373-378 ◽  
Author(s):  
Stuart J. Cormack ◽  
Mitchell G. Mooney ◽  
Will Morgan ◽  
Michael R. McGuigan
Keyword(s):  
High Speed ◽  
Neuromuscular Fatigue ◽  
Football Players ◽  
Countermovement Jump ◽  
Baseline Measure ◽  
Running Activity ◽  
Australian Football ◽  
Percent Contribution ◽  
Playing Time ◽  
The Impact

Purpose:To determine the impact of neuromuscular fatigue (NMF) assessed from variables obtained during a countermovement jump on exercise intensity measured with triaxial accelerometers (load per minute [LPM]) and the association between LPM and measures of running activity in elite Australian Football.Methods:Seventeen elite Australian Football players performed the Yo-Yo Intermittent Recovery Test level 2 (Yo-Yo IR2) and provided a baseline measure of NMF (flight time:contraction time [FT:CT]) from a countermovement jump before the season. Weekly samples of FT:CT, coaches’ rating of performance (votes), LPM, and percent contribution of the 3 vectors from the accelerometers in addition to high-speed-running meters per minute at >15 km/h and total distance relative to playing time (m/min) from matches were collected. Samples were divided into fatigued and nonfatigued groups based on reductions in FT:CT. Percent contributions of vectors to LPM were assessed to determine the likelihood of a meaningful difference between fatigued and nonfatigued groups. Pearson correlations were calculated to determine relationships between accelerometer vectors and running variables, votes, and Yo-Yo IR2 score.Results:Fatigue reduced the contribution of the vertical vector by (mean ± 90% CI) –5.8% ± 6.1% (86% likely) and the number of practically important correlations.Conclusions:NMF affects the contribution of individual vectors to total LPM, with a likely tendency toward more running at low speed and less acceleration. Fatigue appears to limit the influence of the aerobic and anaerobic qualities assessed via the Yo-Yo IR2 test on LPM and seems implicated in pacing.

On-Road Gaseous Emission Characteristics of China IV CNG Bus in Shanghai

2013 ◽  
Vol 690-693 ◽  
pp. 1864-1871 ◽  
Author(s):  
Di Ming Lou ◽  
Si Li Qian ◽  
Zhi Yuan Hu ◽  
Pi Qiang Tan
Keyword(s):  
Emission Factor ◽  
High Speed ◽  
Idle Time ◽  
Operating Conditions ◽  
Vehicle Emission ◽  
Emission Characteristics ◽  
Emission Measurement ◽  
Gaseous Emissions ◽  
Average Speed ◽  
Portable Emission Measurement System

In this paper, on-road CO, THC, NOX, CO2 gaseous emissions characteristics of china IV CNG bus were analyzed based on on-road vehicle emission test in the peak and non-peak hours of city traffic in Shanghai using a portable emission measurement system (PEMS). The experimental results reveal that: compared with the condition results in the non-peak hours, it (conditions in the peak hours) have lower average speed, longer idle time and shorter high speed time; the NOX emission factor and rate in the peak hour reduced by 5.66% and 70.2%; the CO, HC, CO2 emissions factors are increased by 47.2%, 32.6%, 20.8%, and the CO, HC, CO2 emissions rates reduced by 1.94%, 26.5%, 48.7% respectively, compared with that in the non-peak hours; The CO, HC, NOX, CO2 emissions factors all decreased as bus speed increased, while they increased as bus acceleration increased; the gaseous emissions rates all increased as bus speed increased; both the emissions factors and emissions rates contributions are highest at accelerations, higher at cruise speeds, and the lowest at decelerations for non-idling buses; the emissions rates under the condition of idling is lowest; gaseous emissions contribution under the various operating conditions has displayed certain correlations with the percentage of the time for different operating conditions.

Windows High-Speed Drawing Technology Research

2013 ◽  
Vol 441 ◽  
pp. 660-665 ◽  
Author(s):  
Zhen Dong Chou
Keyword(s):  
Real Time ◽  
High Speed ◽  
Technology Research ◽  
Time Data ◽  
Real Time Data ◽  
Real Time Data Processing ◽  
Graphics Engine ◽  
Realtime System ◽  
Huge Challenge ◽  
Drawing Method

The display speed of image and large real-time data processing is a huge challenge for realtime system. This paper completed a thorough research on existing drawing technology on the platform of windows; analyzed adaptive characteristics of using the general high-speed drawing techniques for high speed drawing and its merits and demerits. Finally, through a lot of experiments and simulations of high speed drawing process after optimization and combination, tested their drawing performance and efficiency in order to select an appropriate drawing method to develop a high-speed graphics engine for large real-time data.

scholarly journals Effect of Changing Match Format from Halves to Quarters on the Performance Characteristics of Male University Field Hockey Players

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5490
Author(s):  
Elliot P. Lam ◽  
Caroline D. Sunderland ◽  
John G. Morris ◽  
Laura-Anne M. Furlong ◽  
Barry S. Mason ◽  
...  
Keyword(s):  
Heart Rate ◽  
High Speed ◽  
National Level ◽  
Performance Characteristics ◽  
Field Hockey ◽  
Heart Rate Monitors ◽  
Total Distance ◽  
Random Intercept ◽  
Hockey Players ◽  
The Uk

The study examined whether the performance characteristics of male university field hockey players differed when the match format was 2 × 35 min halves compared to 2 × 2 × 17.5 min quarters. Thirty-five male university field hockey players (age 21.2 ± 3.0 years, height 1.81 ± 0.07 m, body mass 75.1 ± 8.9 kg), competing at national level in the UK, were monitored over 52 matches played across the 2018–2019 (2 × 35 min halves) and 2019–2020 (2 × 2 × 17.5 min quarters) seasons using 15 Hz Global Positioning System units and heart rate monitors. Total distance, high-speed running distance (≥15.5 km·h−1), accelerations (≥2 m·s−1), decelerations (≤−2 m·s−1), average heart rate and percentage of time spent at >85% of maximum heart rate were recorded during both match formats. Two-level random intercept hierarchal models (Match—level 1, Player—level 2) suggested that the change in format from 2 × 35 min halves (2018–2019 season) to 2 × 2 × 17.5 min quarters (2019–2020 season) resulted in a reduction in total distance and high-speed running distance completed during a match (by 221 m and 120 m, respectively, both p < 0.001). As no significant cross-level interactions were observed (between season and half), the change from 35 min halves to 17.5 min quarters did not attenuate the reduced physical performance evident during the second half of matches (total distance: −235 m less in second half; high-speed running distance: −70 m less in second half; both p < 0.001). Overall, the findings suggest that the change in match format did alter the performance characteristics of male university field hockey players, but the quarter format actually reduced the total distance and high-speed running distance completed during matches, and did not attenuate the reduction in performance seen during the second half of matches.

GPS Analysis of an International Field Hockey Tournament

2012 ◽  
Vol 7 (3) ◽  
pp. 224-231 ◽  
Author(s):  
Denise Jennings ◽  
Stuart J. Cormack ◽  
Aaron J. Coutts ◽  
Robert J. Aughey
Keyword(s):  
Exercise Intensity ◽  
High Speed ◽  
Team Sport ◽  
Field Hockey ◽  
Positioning Systems ◽  
Large Margin ◽  
Global Positioning ◽  
Percent Difference ◽  
World Class ◽  
Multiple Games

Purpose:The purpose of this study was to investigate the influence of multiple games on exercise intensity during a world-class hockey tournament.Methods:15 players (mean ± SD age 27 ± 4 y, stature 179 ± 5 cm, body mass 77 ± 5 kg, and estimated VO2 64.2 ± 3.1 mL · kg−1 · min−1) competing in the Champions Trophy (CT). Global-positioning systems assessed total distance (TD), low-speed activity (LSA; 0.10–4.17 m/s), and high-speed running (HSR; >4.17 m/s) distance. Differences in movement demands (TD, LSA, HSR) between positions and matches were assessed using the effect size and percent difference ± 90% confidence intervals. Two levels of comparison were made. First, data from subsequent matches were compared with match 1, and, second, data from each match compared with a tournament average (TA).Results:In all matches, compared with game 1, midfielders performed less HSR distance. However, the amount of HSR did not decrease as the tournament progressed. When compared with the TA, defenders showed more variation in each match. All positions showed lower movement outputs when the team won by a large margin.Conclusions:It was possible for elite team-sport athletes to maintain exercise intensity when playing 6 matches in a period of 9 days, contrary to the only other investigation of this in elite male field hockey.

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