Using the 2017-2018 National Health and Nutrition Examination Survey (weighted population size = 35,460,209; 8-18 years old; 52.1% males), we compared the obesity prevalence in children and adolescents between body mass index-based (BMI-based) and total percent body fat-based (BF%-based, measured by the dual-energy x-ray absorptiometry) cutoffs.…

Obesity has been found to relate to urine-assessed hypohydration risk at the population level, but studies have often failed to account for lean mass, which influences urine solute load. Adults (n = 8,699) from the National Health and Nutrition Examination Survey were categorized as hypohydrated or not using five urine-based methods. Hypohydration…

The purpose of this study was to validate an alternative skinfold equation for women created from dual-energy x-ray absorptiometry (DXA). Anthropometrics and a whole-body DXA scan were completed on 77 women (mean age: 28.0 ± 10.2 years). Four Jackson-Pollack (JP) skinfold prediction equations and the DXA criterion (DC) equation were compared to…

Higher relative adiposity is independently associated with adverse health consequences. As such, accurate estimates of body composition in field settings are of utmost importance. The aim of this study was to examine the validity of the Body Adiposity Index (BAI) and Relative Fat Mass (RFM) as measures of total body adiposity. BAI and RFM were…

We developed plank test standards, based on trunk lean mass-to-fat mass (LM/FM) ratio, in a sample of healthy Portuguese 10--18 year olds (n = 474, 46.4% female). Height and weight were measured and muscular endurance was assessed using the prone plank test. Trunk LM/FM ratio was determined using dual-energy x-ray absorptiometry. Plank standards…

BodyMetrix BX2000 A-mode ultrasound software offers nine options for estimating body fat percentage (%BF) from fat thickness measurements. These formulas were evaluated against %BF estimated from air displacement plethysmography in a sample of 42 men. Compared to the Bod Pod, three of the nine equations -- Jackson and Pollock 3 site (JP3), Jackson…

We developed age- and sex-specific smoothed percentiles for vertical and long jump, as well as vertical jump power, in healthy 10-18 year olds (n = 529, 47.1% female). Jump height and distance were measured and vertical jump power was assessed via mechanography. LMS regression was used to create smoothed age-specific reference curves, separated by…

We designed grip strength standards for youth by back-extrapolating cutpoints based on weakness at age 65. Existing standards, based on insufficient bone mineral content (BMC), were also compared in a nationally representative sample. Altogether, 6837 participants (n = 2199 [less than or equal to] 18.9 years of age) from the National Health and…

This study evaluated test-equating methods to enable comparisons and conversions between the vertical jump (VJ) and standing long jump (SLJ) tests. A total of 528 youth (280 males) performed VJ and SLJ, and their scores were randomly split as the calibration (C) sample (n = 478) and cross-validation (CV) sample (n = 50). SLJ scores of the C sample…

The purpose was to determine the effect of 30-minutes of moderate intensity (45-55% of heart rate reserve) on post-exercise (PE) body composition (BC) measurements. Pre-exercise (PreE) BC measurements were taken using air displacement plethysmography (ADP) and bioelectrical impedance analysis including lower-body (LBIA), whole-body (WBIA), and…

Childhood physical fitness relative to adult health outcomes coupled with scant longitudinal research indicates that tracking of fitness components throughout childhood/adolescence is imperative. The study examined the stability/tracking of 9 measures of fitness for boys and girls at 5 points throughout childhood/adolescence. Tracking coefficients…

Incorporation of the vertical jump (VJ) test in health-related fitness batteries is predicated on the availability of prediction equations to accurately estimate VJ power. The purpose was to develop and validate a generalizable equation to estimate VJ power from VJ height, body mass, age, and sex in 10- to 18-year-olds. The sample (N = 529)…

Body composition (BC) is a valuable indicator of health and performance. Air-displacement plethysmography (ADP) is a popular, efficient, and reliable method for assessing BC. A-mode ultrasonography (AUS) is another method, and its affordability, mobility, and practicality make it a plausible device for industry and health professionals. This study…

The activPAL is a widely-used measure of sedentary time but few studies have evaluated its ability to estimate physical activity intensity. This study determined the accuracy of the algorithm used by the activPAL to predict metabolic equivalents (METs) from cadence and a curvilinear cadence-METs equation individualized for height. Thirty-six…

This study examined the predictive validity of musculoskeletal fitness tests for identifying sarcopenia in youth. The sample was 529 participants age 10 to 18 years. Indices included: total lean body mass (LBM) normalized for height (LBM index, LBMI, kg/m2), appendicular LBMI (aLBMI, kg/m[superscript 2]), and LBM to fat body mass (FBM) ratio…