Computing and Evaluating Relationships Between Equal and Differential Factor Weighting for Fundamental Movement Skills and Physical Activity with Guided Active Play During Childhood

<b>Background/Objectives:</b> The Test of Gross Motor Development (TGMD-2) totals assume equal weighting of the 12 locomotor (LOC) and object control (OC) skills, yet validation studies indicate differential contributions. The study compared equal- and differential-weighted scores for LOC and OC skills, with three fitness and two physical activity (PA) outputs during guided active play (GAP). <b>Methods:</b> Children's (n = 82; 7.6 ± 1.5 years) TGMD-2 LOC and OC differential factor weights were estimated with Exploratory Factor Analysis (EFA) and compared to equal weights with multiple linear regression (two, five, and eight predictors) and Chi-square analyses. Predictor variables included fitness, BMI, sex, age stages, and PA assessed by energy expenditure (PAEE) and intensity (MVPA) estimated using accelerometry during 1 h GAP. <b>Results:</b> EFA supported a two-factor structure (variance explained = 51.1%) with ≥0.500 loadings for 9/12 skills. Differential- and equal-weighted LOC and OC scores showed varied contributions from individual skills. Multiple linear regression analysis showed similar explained variances (R²) of 53% (PAEE), 40% (MVPA), 31% (OC), and 14% (LOC) for equal or differential scores with eight predictors. Although β coefficients varied, going from two, five, and eight predictors, the impact of equal and differential weights was comparable. Chi-square analysis indicated high OC associated with MVPA (X² (4) = 9.42, <i>p</i> ≤ 0.05), LP, and STR with PAEE. <b>Conclusions:</b> TGMD-2 outputs with equal- and differential-weighted scores are adequate for clinical/educational use, which show similar relationships with PA and HRF variables. Differential-weighted TGMD-2 scores comprise different contributions of movement skills and may hold promise for intervention studies focused on varied or target tasks and movement abilities.