Defensive pressure affects basketball technical actions but not the time-motion variables.

BACKGROUND: Novel player tracking technologies can change the understanding of performance determinants in team sports by allowing to accurately measuring the activity demands. The aim of this study was to identify how the defensive pressure affects the time-motion variables and the technical actions in basketball. METHODS: Twenty international male players (age: 16.05 ± 2.09 years, weight: 73.13 ± 8.10 kg, height: 183.10 ± 5.88 cm) played two 10 min basketball quarters, where they used a man-to-man 1/4-court defense until the 4th min (F1/4), changed to man-to-man full court (FULL) for 3 min and, from the 7th to the 10th min returned to 1/4-court defense (S1/4). A computerized notational analysis was performed using Simi Scout and positional data were captured with the Ubisense Real Time Location System (mean sampling rate 3.74 ± 0.45 Hz per transmitter/player). RESULTS: The time-motion variables presented similar results between defensive conditions, showing a total distance covered around 90 m/min. However, results suggested possible vertical jump impairments in S1/4 periods. There was more distance covered while jogging in the offensive court (38.15 ± 12.17 m/min offensive court vs. 32.94 ± 10.84 m/min defensive court, p < 0.05) and more distance covered while running in the defensive court (16.41 ± 10.27 m/min offensive court vs. 19.56 ± 10.29 m/min defensive court, p < 0.05). CONCLUSION: These results suggest how to improve task representativeness during specific conditioning or game-based training situations and also to help coaches' strategic decisions during the games.

Accuracy of an UWB-based position tracking system used for time-motion analyses in game sports.

The main aim of this study was to determine the accuracy of the ultra-wideband (UWB)-based positioning system Ubisense, which is used for time-motion analysis in sports. Furthermore, some alternatives for positioning the system's transponders on the atheletes, as well as the accuracy depending on the location of measurement, were tested. Therefore, in a pre-study, some basic issues were examined (measurement assumptions and consistency and location of the system's transponder used for position detection), and position measurements at the borders and in the centre of a basketball field were performed. In the main study, 13 male basketball players (15.8 years ± 0.6; 187.9 height ± 3.4; 77.5 weight ± 3.7), equipped with a Ubisense transponder mounted on top of their heads, handled a trundle wheel during simulated match play. The players with the trundle wheel participated passively in the match by following one of the ten competing players. The distance measurements of the trundle wheel were used as reference values and compared to the Ubisense distance estimations. Best results were found with the measurements of a single mounted transponder on top of the athlete's heads. No differences were detectable in the accuracy between measurements in the centre and at the borders of the basketball field. The (Ubisense) system's difference to the (trundle wheel) reference was 3.45 ± 1.99%, resulting in 95% limits of agreement of -0.46-7.35%. The study indicates the examined system's sufficient accuracy for time-motion analysis in basketball.

Accuracy of the LPM tracking system considering dynamic position changes.

This study investigates the accuracy of the tracking system LPM (local position measurement). The goal was to determine detailed error values of the system in the context of sports performance analyses. Six moderately trained male soccer players (amateur level) performed 276 runs on three different courses at six different speeds. Additionally, ten small-sided game plays were carried out. All runs and game plays were recorded with the LPM tracking system and the motion capture system VICON simultaneously. VICON served as the reference system. The absolute error of all LPM position estimations was on average 23.4±20.7 cm. The estimation for average velocities varied between 0.01 km h(-1) and 0.23 km h(-1), the maximum speed estimations differed by up to 2.71 km h(-1). In addition, the results showed that the accuracy of the LPM system is highly dependent on the instantaneous dynamics of the player and decreases in the margins of the observation field. These dependencies were quantified. Considering commonly used applications of position tracking systems in sports (Leser, Ogris, & Baca, 2011), the accuracy of LPM is acceptable for position and velocity estimations. The system provides valuable results for average velocities but seems to be far less reliable when dealing with high dynamic movements and measuring instantaneous velocities.

Local positioning systems in (game) sports.

Position data of players and athletes are widely used in sports performance analysis for measuring the amounts of physical activities as well as for tactical assessments in game sports. However, positioning sensing systems are applied in sports as tools to gain objective information of sports behavior rather than as components of intelligent spaces (IS). The paper outlines the idea of IS for the sports context with special focus to game sports and how intelligent sports feedback systems can benefit from IS. Henceforth, the most common location sensing techniques used in sports and their practical application are reviewed, as location is among the most important enabling techniques for IS. Furthermore, the article exemplifies the idea of IS in sports on two applications.

Effectiveness of multimedia-supported education in practical sports courses.

Multimedia-assisted teaching and learning have become standard forms of education. In sports, multimedia material has been used to teach practical aspects of courses, such as motor skills. The main goal of this study is to examine if multimedia technology impacts learning in the field of sport motor skill acquisition. This question was investigated during a practical sports education course involving 35 students who participated in a university soccer class. The whole course was split into two groups: Group A was taught traditionally with no assistance of multimedia and Group B was prepared with multimedia-assisted instructional units. To quantify selected skills of soccer technique and tactic, the test subjects performed a specific passing test and a tactical assessment. Furthermore, a ques-tionnaire was used to assess the subjective impressions of the test subjects. All testing instruments were applied before and after a six-week-long teaching period. A comparison of the gathered data between the two groups resulted in no significant differences, neither concerning the results of the technique test nor concerning the tactic test. However, the results of the ques-tionnaire showed a positive agreement among the participants in the usability and assistance of multimedia for the sports practical course. Considering the reviewed conditions, it can be concluded that the use of multimedia content doesn't affect the learning effects. Key pointsMultimedia-assisted learning showed no positive learning effects on technical skills in soccer.Multimedia-assisted learning showed no positive learning effects on tactical skills in soccer.Students participating in practical sports courses have very good attitudes towards the use of multi-media learning material. This may be considered for motivational effects.