The purpose of this study is to determine construct validity and three reliability aspects of Test of Gross Motor Development (TGMD-2; Ulrich, 2000) in Tehranian children aged 3:0¬¬¬-10:11. TGMD-2 which includes two subtests (locomotor and object control) is designed to assess movement pattern development of 12 fundamental movement skills. The TGMD-2 was administered to 1438 children. Internal consistency reliability for locomotor and object control score and also for total composite score averaged 0.78, 0.74 and 0.80, respectively. Internal consistency reliability was high for females and males, too. Test-retest reliability ranged from 0.65 to 0.81, and intra-rater reliability was above 0.95. To investigate construct validity, Ulrich’s (2000) two-factor model was postulated and this hypothesis was tested through confirmatory factor analysis. According to the model, six variables or skills measuring child’s ability for moving into space were loaded on one factor (locomotor), while the other six variables measuring ability for controlling and manipulating objects were loaded on the other factor (object control). According to the findings, two-factor structure of TGMD-2 and also proper assignment of skills to locomotor and object control factors were supported for our population, too. Additionally, the correlation coefficients between age and subtests’ score provided support for another aspect of construct validity, that is, developmental nature of TGMD-2; the resulting coefficients indicated that TGMD-2 is capable of differentiating between ages. In conclusion, this study indicated that TGMD-2 can be used with confidence to assess gross motor development of the studied population.
Key words: TGMD-2, construct validity, internal consistency, test-retest, intra-rater reliability.