Irán
The purpose of present study was to compare the influence of Challenge and non-Challenge Games in dynamical environment on the dribbling and overarm throwing Skills development of (5-6) preschool children. Thirty children were selected from two kindergartens in Tehran and were two grouped according to pretest scores. The intervention was 15 days. Primary level skills before of intervention were assessed. The games were designed for developing manipulative skills in both groups; however, the task difficulty of these games was increased in challenging group according knowing the child from his/her own, while in non-challenging group it was kept constant. Test of Gross Motor Development – second version was used in the beginning and the end of the intervention and for fallow test. Results presented that challenge and non-challenge games cause the improvement of overarm throwing and dribbling skills development of children. But influence development challenge game relative to non-challenge game in overarm throwing is significant, but dribbling skill isn't significant. According to results, appear existence option and control for individuals about appointment task difficulty level, even in during childhood could the benefit; of course the effective depended to factors for example task complication.