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Purpose: To determine the accuracy of three systematic observation (SO) tools to estimate energy expenditure (EE) using different skill performance and observation intervals. Method: Three SO tools (Observational System for Recording Physical Activity in Children-Preschool, System for Observing Fitness Instruction Time, and System for Observing Play and Leisure Activity in Youth) were used to observe children (N = 42, M[subscript age] = 8.1 ± 0.7) during motor skill testing sessions. EE was measured using indirect calorimetry (COSMED K4b2). Results: Paired samples t tests, repeated-measures analysis of variance, and regression analyses were performed to compare the EE estimated from SO tools with EE measured by indirect calorimetry. The average mean difference between the estimated metabolic equivalence of task (METS) and actual METS ranged between -1.24 METS (SD = 1.62, p < 0.01) and -3.46 METS (SD = 1.31, p < 0.01) depending on skill performance interval or SO tool analyzed. Conclusions: SO tools did not accurately estimate EE during object control skill testing sessions. Physical educators should consider utilizing discrete motor skill practice to accumulate health-enhancing levels of physical activity while adhering to national standards.

While football/soccer is the most influential sport in the world, it is surprising that developmental sequences of forceful kicking have not been adequately described and validated in the literature. The purpose of this study was to explore potential developmental sequences for forceful kicking using a prelongitudinal screening method. Data were derived from videotapes of 255 children (girls n = 138, boys: n = 117), ages 4-11 years. Seven potential component sequences in their respective developmental order were initially proposed based on biomechanical and motor developmental principles. Each participant was digitally videoed performing five kicks with maximal effort. Trained research staff coded the initial seven components for each kick and the mode of each participant's five kicks was used for data analysis. Component level probability curves for each component sequence across age were evaluated using the threshold based generalized partial credit model (Muraki, 1992) within the item response theory framework. As developmental theory would indicate, component levels generally increased with age for most components. Six component ordinal sequence progressions met model requirements (Rel = 0.88, item fit; p > 0.05). Ordinal levels for two components ("Knee action" and "Follow-through") were altered based on initial empirical model structure fit and the Ball contact component was removed based on a lack of model fit. This study provides sufficient cross-sectional evidence for six component developmental sequences that adequately describe the development of kicking using cross-sectional data. Longitudinal data are required to provide further developmental validation for these sequences.

This study compared the energy expenditure (EE) levels during object projection skill performance (OPSP) as assessed by indirect calorimetry and accelerometry. Thirty-four adults (female n = 18) aged 18-30 (23.5 ± 2.5 years) performed three, 9-min sessions of kicking, over-arm throwing, and striking performed at 6-, 12-, and 30-sec intervals. EE was estimated (METS) using indirect calorimetry (COSMED K4b2) and hip-worn accelerometry (ActiGraph GT3X+). EE using indirect calorimetry demonstrated moderate-intensity physical activity (3.4 ± 0.7 METS--30-sec interval, 5.8 ± 1.2 METS--12-sec interval) to vigorous intensity physical activity (8.3 ± 1.7 METS--6-sec interval). However, accelerometry predicted EE suggested only light-intensity physical activity (1.7 ± 0.2 METS--30-sec interval, 2.2 ± 0.4 METS--12-sec interval, 2.7 ± 0.6 METS--6-sec interval). Hip-worn, ActiGraph GT3X+ accelerometers do not adequately capture physical activity intensity levels during OPSP, regardless of differences in skill performance intervals.