Aim: To examine the latent structure of the Test of Gross Motor Development—Third Edition (TGMD-3) with a bifactor modeling approach. In addition, the study examines the dimensionality and model-based reliability of general and specific contributions of the test’s subscales and measurement invariance of the TGMD-3. Methods: A convenience sample of (N = 496; Mage = 7.23 ± 2.03 years; 53.8% female) typically developed children participated in this study. Three alternative measurement models were tested: (a) a unidimensional model, (b) a correlated two-factor model, and (c) a bifactor model. Results: The totality of results, including item loadings, goodness-of-fit indexes, and reliability estimates, all supported the bifactor model and strong evidence of a general factor, namely gross motor competence. Additionally, the reliability of subscale scores was poor, and it is thus contended that scoring, reporting, and interpreting of the subscales scores are probably not justifiable. Conclusions: This study shows the advantages of using bifactor approach to examine the TGMD-3 factor structure and suggests that the two traditionally hypothesized factors are better understood as “grouping” factors rather than as representative of latent constructs. In addition, our findings demonstrate that the bifactor model appears invariant for sex.

Motor competence (MC) has been extensively examined in children and adolescents, but has not been studied among adults nor across the lifespan. The Test of Motor Competence (TMC) assesses MC in people aged 5–85 years. Among Iranians, aged 5–85 years, we aimed to determine the construct validity and reliability of the TMC and to examine associations between TMC test items and the participants’ age, sex, and body mass index (BMI). We conducted confirmatory factor analysis (CFA) to evaluate the TMC’s factorial structure by age group and for the whole sample. We explored associations between the TMC test items and participant age, sex, and BMI using a network analysis machine learning technique (Rstudio and qgraph). CFA supported the construct validity of a unidimensional model for motor competence for the whole sample (RMSEA = 0.003; CFI = 0.998; TLI = 0.993) and for three age groups (RMSEA <0.08; CFI and TLI >0.95). Network analyses showed fine motor skills to be the most critical centrality skills, reinforcing the importance of fine motor skills for performing and participating in many daily activities across the lifespan. We found the TMC to be a valid and reliable test to measure MC across Iranians’ lifespan. We also demonstrated the advantages of using a machine learning approach via network analysis to evaluate associations between skills in a complex system.

Purpose: To examine the factor structure and measurement invariance of the Körperkoordinations Test Für Kinder (KTK) and covariates of motor competence in a sample of Iranian children aged 5–14 years. Methods: Participants were children aged 5–14 years (N = 432, 61% boys). Age, sex, and body mass index were collected. Confirmatory factor analysis (CFA) was conducted to investigate the factorial structure of KTK and multigroup CFA carried out to test measurement invariance across sexes and age groups. In addition, we calculated a model with covariates to identify the association between KTK items with age, sex, and body mass index z score. Results: CFA supported the construct validity of a one-factor model with an appropriate fit indices that the four subtests loaded on the same factor namely motor competence. Furthermore, according to the magnitude of changes in root mean square error of approximation and comparative fit index between nested models, the assumption of KTK measurement invariance across age-groups and sex were valid. Finally, adequate fit indices were found for the multigroup CFA path model of KTK with the covariates sex, age, and body mass index z score. Conclusion: The KTK is a valid, reliable, and valuable instrument for assessing motor competence of Iranian children and adolescents.

Aim: To examine the latent structure of the Test of Gross Motor Development, 3rd Edition (TGMD-3) with a bifactor modeling approach. Furthermore, the study examines the dimensionality, model-based reliability of general and specific contributions of the test's subscales and measurement invariance of the TGMD-3. Methods: Using a sample of 496 Iranian children (M age = 7.23±2.03 years; 53.8 female) from the five main geographic regions of Tehran city, three alternative measurement models were tested: (a) a unidimensional model, (b) a correlated 2-factor model, (c) a bifactor model. Results: The totality of results including item loadings, goodness-of-fit indexes and reliability estimates all supported the bifactor model and strong evidence of general fundamental movement factor. Additionally, the reliability of subscale scores was poor, it is thus contended that scoring, reporting and interpreting of the subscales scores are probably not justifiable. Suggesting that the 2 traditionally hypothesized factors are better understood as “grouping” factors rather than as representative of latent constructs. Furthermore, the bifactor model appears invariant for gender. Conclusion: This study is the first to address the bifactor model and new insights regarding the application and interpretation of the test battery most widely used with children.