scholarly journals Validation of a Video-Based Performance Analysis System (Mediacoach®) to Analyze the Physical Demands during Matches in LaLiga

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4113 ◽  
Author(s):  
Jose Luis Felipe ◽  
Jorge Garcia-Unanue ◽  
David Viejo-Romero ◽  
Archit Navandar ◽  
Javier Sánchez-Sánchez

The aim of the present study was to assess the accuracy of a multi-camera tracking system (Mediacoach®) to track elite football players’ movements in real time. A total of 207 observations of 38 official matches from Liga 1, 2, 3™ (2nd Spanish Division, season 2017/18) were included in the study (88 defenders, 84 midfielders, and 35 attackers of the same team). Total distance (TD, m) distance in zone 4 (DZ4) at a speed of 14–21 km/h, distance in zone 5 (DZ5) at a speed of 21–24 km/h (DZ5), distance in zone 6 (DZ6) at a speed of ≥24 km/h, maximum speed (km/h), and number of sprints (actions above 24 km/h) were registered with the Apex® GPS system (STATSports™, Newry, N. Ireland) and Mediacoach® semi-automatic tracking system (LaLiga™, Madrid, Spain). The level of agreement between variables estimated by the two systems was analyzed. Bias was also calculated by deducting the GPS estimated value from the video estimated value, and then dividing the difference score by the GPS estimated value. All variables showed high ICC values (>0.75) and very large correlations (r > 0.70). However the video-based performance analysis system overestimated the results obtained in the different speed zones (DZ5: +16.59 ± 62.29 m; LOA95%: −105.49 to 138.68; DZ6: +93.26 ± 67.76 m; LOA95%: −39.55 to 226.07), the number of sprints (+2.27 ± 2.94; LOA95%: −3.49 to 8.02), and the maximum speed (+0.32 ± 1.25 km/h; LOA95%: −2.13 to 2.77). The maximum bias was found in DZ6 (47%). This demonstrates that Mediacoach® is as accurate as a GPS system to obtain objective data in real time, adapted to physical and movement demands of elite football, especially for total distance and distances traveled at medium speeds.

10.17159/4842 ◽  
2018 ◽  
Vol 30 (1) ◽  
pp. 1-3
Author(s):  
A Kubayi

Background: Despite the importance of extra-time in determining success in the knockout stages of soccer tournaments, there remains scant information on the physical demands of extra time on elite players. Methods: This study investigated the physical performance profiles of all soccer players (N=59) who completed four matches that went to extra time at the 2016 UEFA Euro Championship. Players were categorised as follows: central defenders (CDs), wide defenders (WDs), central midfielders (CMs), wide midfielders (WMs), and attackers (ATs). Match activities were captured using a validated camera tracking system (InStat®). Results: The findings showed that total distances covered by players during matches consistently decreased by 13% from the first half of the game (112.79±10.17 m) to extra time (103.17±6.39 m). The reduction of the total distance covered, especially in high-intensity running (i.e., high-speed running and sprinting), was more apparent in ATs than players in other positions. Conclusion: Intervention strategies needed to sustain soccer players’ physical performance during extra-time periods and of post-match recovery modalities warrant further investigation.


2018 ◽  
Vol 30 (1) ◽  
pp. 1-3 ◽  
Author(s):  
A Kubayi ◽  
A Toriola

Background: Despite the importance of extra-time in determining success in the knockout stages of soccer tournaments, there remains scant information on the physical demands of extra time on elite players. Methods: This study investigated the physical performance profiles of all soccer players (N=59) who completed four matches that went to extra time at the 2016 UEFA Euro Championship. Players were categorised as follows: central defenders (CDs), wide defenders (WDs), central midfielders (CMs), wide midfielders (WMs), and attackers (ATs). Match activities were captured using a validated camera tracking system (InStat®). Results: The findings showed that total distances covered by players during matches consistently decreased by 13% from the first half of the game (112.79±10.17 m) to extra time (103.17±6.39 m). The reduction of the total distance covered, especially in high-intensity running (i.e., high-speed running and sprinting), was more apparent in ATs than players in other positions. Conclusion: Intervention strategies needed to sustain soccer players’ physical performance during extra-time periods and of post-match recovery modalities warrant further investigation.


2020 ◽  
Vol 13 (2) ◽  
pp. 126-140
Author(s):  
Jing Gan ◽  
Xiaobin Fan ◽  
Zeng Song ◽  
Mingyue Zhang ◽  
Bin Zhao

Background: The power performance of an electric vehicle is the basic parameter. Traditional test equipment, such as the expensive chassis dynamometer, not only increases the cost of testing but also makes it impossible to measure all the performance parameters of an electric vehicle. Objective: A set of convenient, efficient and sensitive power measurement system for electric vehicles is developed to obtain the real-time power changes of hub-motor vehicles under various operating conditions, and the dynamic performance parameters of hub-motor vehicles are obtained through the system. Methods: Firstly, a set of on-board power test system is developed by using virtual instrument (Lab- VIEW). This test system can obtain the power changes of hub-motor vehicles under various operating conditions in real-time and save data in real-time. Then, the driving resistance of hub-motor vehicles is analyzed, and the power performance of hub-motor vehicles is studied in depth. The power testing system is proposed to test the input power of both ends of the driving motor, and the chassis dynamometer is combined to test so that the output efficiency of the driving motor can be easily obtained without disassembly. Finally, this method is used to carry out the road test and obtain the vehicle dynamic performance parameters. Results: The real-time current, voltage and power, maximum power, acceleration time and maximum speed of the vehicle can be obtained accurately by using the power test system in the real road experiment. Conclusion: The maximum power required by the two motors reaches about 9KW, and it takes about 20 seconds to reach the maximum speed. The total power required to maintain the maximum speed is about 7.8kw, and the maximum speed is 62km/h. In this article, various patents have been discussed.


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