Tracking of wheelchair rugby players in the 2008 Demolition Derby final

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The kinematics of male wheelchair rugby players (n=8) during the final match of the 2008 Demolition Derby were assessed using two cameras (10 Hz) and a tracking method based on image-processing techniques. The players' on-court trajectory, total and accumulated distances covered, distances covered during working and stopped game clock, and average velocity were calculated. The players covered 2294.7+/-391.5 m in the first half and 2245.4+/-431.5 m in the second half. The average velocity was 14.5% greater in the first (1.22+/-0.21 m . s(-1)) than in the second half (1.05+/-0.20 m . s(-1)). The reduction in velocity was most marked in players with less functional capacity. The working game clock represented 48% of total game time (32 of 66.8 minutes) and the distance covered by all players during working game clock was 60% of the overall distance covered during the whole game (36,323 m). The results provide new information regarding the dynamics of a wheelchair rugby match and should aid coaches in planning effective training and coaching strategies.282193200Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CAPES [0131/05-9]FAPESP [00/01293-1]CNPq [451878/2005-1

Measuring handball players trajectories using an automatically trained boosting algorithm

The aim of the present paper is to propose and evaluate an automatically trained cascaded boosting detector algorithm based on morphological segmentation for tracking handball players. The proposed method was able to detect correctly 84% of players when applied to the second period of that same game used for training and 74% when applied to a different game. Furthermore, the analysis of the automatic training using boosting detector revealed general results such as the training time initially increased with the number of figures used, but as more figures were added, the training time decreased. Automatic morphological segmentation has shown to be a fast and efficient method for selecting image regions for the boosting detector and allowed an improvement in the automatic tracking of handball players.141536

Analysis of the distances covered by first division Brazilian soccer players obtained with an automatic tracking method

Methods based on visual estimation still is the most widely used analysis of the distances that is covered by soccer players during matches, and most description available in the literature were obtained using such an approach. Recently, systems based on computer vision techniques have appeared and the very first results are available for comparisons. The aim of the present study was to analyse the distances covered by Brazilian soccer players and compare the results to the European players', both data measured by automatic tracking system. Four regular Brazilian First Division Championship matches between different teams were filmed. Applying a previously developed automatic tracking system (DVideo, Campinas, Brazil), the results of 55 outline players participated in the whole game (n = 55) are presented. The results of mean distances covered, standard deviations (s) and coefficient of variation (cv) after 90 minutes were 10,012 m, s = 1,024 m and cv = 10.2%, respectively. The results of three-way ANOVA according to playing positions, showed that the distances covered by external defender ( 10642 +/- 663 m), central midfielders ( 10476 +/- 702 m) and external midfielders ( 10598 +/- 890 m) were greater than forwards ( 9612 +/- 772 m) and forwards covered greater distances than central defenders ( 9029 +/- 860 m). The greater distances were covered in standing, walking, or jogging, 5537 +/- 263 m, followed by moderate-speed running, 1731 +/- 399 m; low speed running, 1615 +/- 351 m; high-speed running, 691 +/- 190 m and sprinting, 437 +/- 171 m. Mean distance covered in the first half was 5,173 m ( s = 394 m, cv = 7.6%) highly significant greater ( p < 0.001) than the mean value 4,808 m ( s = 375 m, cv = 7.8%) in the second half. A minute-by-minute analysis revealed that after eight minutes of the second half, player performance has already decreased and this reduction is maintained throughout the second half.6223324

Severe intestinal bleeding due to sinistral portal hypertension after pylorus-preserving pancreatoduodenectomy

A rare case of severe intestinal bleeding caused by sinistral portal hypertension after pylorus-preserving pancreatoduodenectomy is reported. Examinations revealed that the developed collateral vessels adjacent to the pancreas and elevated jejunum in the right upper abdomen were the source of the intestinal bleeding, and typical gastric varices were not identified. The present case showed atypical development of collateral vessels due to the postoperative state, which made diagnosis difficult. © Springer Science+Business Media, LLC 2009