mohammadali esmaeilzadeh

Behavioral studies in team sports are typically constrained by dynamic factors, such as positioning of defenders for interception. Handball player have to coordinate their steps when running to throw a ball on goal from a different positions. In this study were analyzed the movement patterns during locomotors pointing, throwing velocity and accuracy of 12 succesful elite handball players under defensive constraints (defender- absent, defender-far, defender-near, or defender pairing). It was captured data from the locomotors patterns of the attacking participant by speed camera with 120Hz, throwing speed by sports radar gun and throwing accuracy by camera. ANOVA with repeated measures and Bonferroni post hoc test and Friedman test was used to analyze effects of these constraints on gait and throwing parameters. In addition to Pearson and Spearman correlation coefficient test was used to analyze speed-accuracy trade off (P<0.05). The results revealed significant differences in overall mean movement velocity, first and second step mean velocity, first and second step mean length. For the mean foot/gate area distance variability was shown pattern of ascending/descending variability in all defense conditions. Since regulation of offensive players was continuous and based on perception of current and required behaviors, results supported from perception-action coupling and prospective control models of locomotors pointing. Also it is suggested that the technical aspects of the running and throwing in handball can affect by nested tasks constraints.

Behavioral studies in team sports is typically constrained by dynamic factors, such as positioning of defenders for interception. In this study were captured data from the movement velocity with high speed camera, throwing velocity with sports radar gun and throwing accuracy of 12 elite handball players under defensive constraints (defender- absent, defender-far, defender-near, and defender pairing). ANOVA with repeated measures and Bonferroni post hoc test was used to analyze effects of these constraints on gait and throwing parameters (P<0.05). The results revealed significant differences in overall mean horizontal velocity (F(1.335,14.682) = 8.680, P = 0.007 ) and mean ball velocity ( F(3,33) = 12.733, P = 0.000 ) but there was no significant differences in mean ball accuracy ( F(3,33) = 0.400 , P = 0.754 ). When defender was closer to the attacker, mean movement velocity and throwing velocity was shown more decrease. Since regulation of offensive players was continuous and based on perception of current and required behaviors, results supported from perception-action coupling and prospective control models. Also, findings suggest that the technical aspects of the running and throwing in handball can affect by nested tasks constraints.

Adolescents are being threatened by several accidents because of entering the new world of adulthood, separation from families, a greater presence in community individually, the lack of knowledge of rules and risk‑taking spirit of adolescents, and events. The contribution of these damages and their related costs are higher in developing and low‑income countries. The current study was conducted for proper planning focused on reducing accidents that have the highest incidence, evaluating school events, determining the place and time that most accidents happened to students and determining the body part injured. A cross‑sectional study using a multistage cluster sampling was conducted on 6933 students 11–14 years old (middle school) in 2009–2010 in Isfahan Province. The data were collected through observation and a researcher‑made questionnaire and then entered into the EPi6 software, and analyzed by the SPSS 11.5 software and the statistical test of Chi‑square. The findings showed that 49.9% of students were girls (n = 3462) and 50.1% (n = 3471) were boys, 84.5% of students (n = 5860) were living in urban areas and 15.5% of students (n = 1073) were living in rural areas. Frequency distribution of incidents was 53.9% (3739 cases) at school and 10.6% (732 cases) on the commuting route. The most injured body part was hand with 1018 cases (18.5%) and foot with 1267 cases (23.1%), and mostly they were injured in boys. The findings showed that a high percentage of students were injured at school, where the first step to prevent the incidence of such preventable incidents at school is to secure workshop environments and school yards.