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Background/objectives Prediction equations generated from anthropometric measures are frequently used to quantify paediatric body composition. We tested the agreeability and predictive power of select (Lingwood and Aris) fat mass prediction equations against body fat measured via ADP; and generated and evaluated new anthropometry-based models for use in the first 6 months of life. Subjects/methods Data were obtained from 278 white European Australian infants at birth, 3 and 6 months. Prediction models (i.e. Baby-bod models) were generated for each time point via stepwise linear regression and compared for agreeability with ADP via limits of agreement, mean difference and total bias in Bland-Altman analyses. Predictive power of all equations in comparison to ADP were assessed using linear regression analysis. Results Overall, there was poor agreeability between percent body fat predicted via published equations and ADP. Proportional bias was detected for both methods (i.e. published equations and Baby-bod models) of body fat prediction. At birth, both Lingwood and BB0 equations overestimated percent body fat at the lower end of the FM spectrum. This trend was repeated at 3 months with all equations displaying a propensity to overestimate body fat at lower FM levels and underestimate at higher FM levels. Conclusions The results indicate that anthropometry, although less costly and relatively easier to implement, does not always produce comparable results with objective measures such as ADP. Given the importance of the accurate assessment of physical growth, including body composition in early life, it is timely to recommend the increased utilisation of techniques such as ADP., Author(s): Sisitha Jayasinghe [sup.1] , Manoja P. Herath [sup.1] , Jeffrey M. Beckett [sup.1] , Kiran D. K. Ahuja [sup.1] , Nuala M. Byrne [sup.1] , Andrew P. Hills [sup.1] [...]

The purpose of this study was to verify within- and between-day repeatability and variability in children's oxygen uptake (VO[subscript 2]), gross economy (GE; VO[subscript 2] divided by speed) and heart rate (HR) during treadmill walking based on self-selected speed (SS). Fourteen children (10.1 plus or minus 1.4 years) undertook three testing sessions over 2 days in which four walking speeds, including SS were tested. Within- and between-day repeatability were assessed using the Bland and Altman method, and coefficients of variability (CV) were determined for each child across exercise bouts and averaged to obtain a mean group CV value for VO[subscript 2], GE, and HR per speed. Repeated measures analysis of variance showed no statistically significant differences in within- or between-day CV for VO[subscript 2], GE, or HR at any speed. Repeatability within- and between-day for VO[subscript 2], GE, and HR for all speeds was verified. These results suggest that submaximal VO[subscript 2] during treadmill walking is stable and reproducible at a range of speeds based on children's SS. (Contains 3 tables and 3 figures.)

Walking is a common activity of daily life and researchers have used the range 3-6 km.h[superscript -1] as reference for walking speeds habitually used for transportation. The term self-selected (i.e., individual or comfortable walking pace or speed) is commonly used in the literature and is identified as the most efficient walking speed, with increased efficiency defined by lower oxygen uptake (VO[subscript 2]) per unit mechanical work. Self-selected speed (SS) should be determined using a consistent protocol to ensure an individual's representative walking speed is identifiable and subsequently applicable in a walking project. Controversy exists regarding whether walking tests should be performed on a treadmill or over ground. While some studies using the two methods have found significant differences in energy and performance, others have reported equivalence in these measures. Both methods have advantages. Treadmill testing, for example, allows easy concurrent measurement of physiologic data, such as gas exchange; overground walking requires minimal equipment, more closely replicates everyday walking, and is clinically applicable. However, many of the comparisons reported involved older adults or rehabilitation patients who had cardiac or pulmonary disease, most with limited activity levels and exercise capacity. Indirect calorimetry is often used to measure energy expenditure during treadmill walking. However, assessing individual and group differences in metabolic energy expenditure using oxygen uptake requires individuals to be comfortable with, and able to accommodate to, the equipment. To ensure the data from a treadmill walking protocol does not simply reflect an adaptation to the test, participants traditionally are familiarized with walking on the treadmill before testing. Participants with insufficient exposure to the apparatus may be unable to make the necessary adjustments to achieve a stable and consistent gait pattern, which introduces bias to the measurements. The literature is not consistent about the length of this exposure, with wide variability in exposure time reported, such as 15-20 s, 2 min, 2-3 min, 5 min, and 8 min. Despite the reported variability in time, Morgan et al. (1997) showed that the majority of gait adjustments for young children occurred during the initial 10-min walking period or the familiarization sessions. The results of the study conducted by the authors show no significant differences between SS determined overground and on a treadmill. The mean difference between overground and treadmill step length was 0.06 m. This value, despite being statistically significant, has no clinical importance. (Contains 4 figures.)