Before the study, intra-rater reliability had been evaluated for 10 examiners fulfilled
the selection procedure (one week training process with final examination). For the evaluation of intra-rater reliability, videotapes with the own observation and assessment of two
playgrounds for each examiner, had been recorded. One month later, each examiner watched
the same videos and scored again. The 3.1 intra-class correlation coefficient was used for
statistical analysis and found to be excellent (ranged from R=.88 to R=.91).