The Test of Gross Motor Development (TGMD) is one of the most common tools for assessing the fundamental movement skills (FMS) in children between 3 and 10 years. This study aimed to examine the intra-rater and inter-rater reliability of the TGMD-3rd Edition (TGMD-3) between expert and novice raters using live and video assessment. Five raters [2 experts and 3 novices (one of them BSc in Physical Education and Sport Science)] assessed and scored the performance of the TGMD-3 of 25 healthy children [Female: 60%; mean (standard deviation) age 9.16 (1.31)]. Schoolchildren were attending at one public elementary school during the academic year 2019-2020 from Santiago de Compostela (Spain). Raters scored each children performance through two viewing moods (live and slow-motion). The ICC (Intraclass Correlation Coefficient) was used to determine the agreement between raters. Our results showed moderate-to-excellent intra-rater reliability for overall score and locomotor and ball skills subscales; moderate-to-good inter-rater reliability for overall and ball skills; and poor-to-good for locomotor subscale. Higher intra-rater reliability was achieved by the expert raters and novice rater with physical education background compared to novice raters. However, the inter-rater reliability was more variable in all the raters regardless of their experience or background. No significant differences in reliability were found when comparing live and video assessments. For clinical practice, it would be recommended that raters reach an agreement before the assessment to avoid subjective interpretations that might distort the results.
Keywords: TGMD-3; agreement; assessment; fundamental motor skills; live; raters; slow-motion.