Adiposity, Aerobic and Anaerobic Fitness in Middle School Aged Children

Abstract

National data suggest that aerobic fitness and adiposity are negatively correlated in children, but this relationship was established using submaximal exercise tests and skinfold measurements (NCHS Data Brief. 2014 May;(153):1‐8). This study extended previous investigations by evaluating the influence of adiposity on both aerobic and anaerobic fitness in N=458 male and N=304 female middle school aged students (mean±SD, age 13.3±0.6 y). BMI averaged 22.2±5.2 and 22.9±5.2 kg/m2 in boys and girls, respectively, with 37% of boys and 36% of girls classified as overweight or obese using CDC BMI‐for‐age growth charts. Adiposity was assessed using air‐displacement plethysmography (BOD POD, Cosmed, Rome, Italy), VO2max through a maximal, graded treadmill test (Bruce protocol) with continuous metabolic measurement (Cosmed Fitmate system, Rome, Italy), and aerobic fitness with the 30‐second Wingate test (Lode cycle ergometer, Groningen, The Netherlands). Average test scores for male and female students were as follows: body fat, 19.8±11.0 and 24.6±8.7 %, respectively; anaerobic capacity, 7.2±1.4 and 5.7±1.2 watts/kg; and VO2max, 45.1±10.8 and 33.9±8.1 ml.kg‐1.min‐1. Body fat % was negatively correlated with VO2max in boys (r=‐0.65) and girls (r=‐0.56), and with anaerobic capacity in boys (r=‐0.71) and girls (r=‐0.58) (all P<0.001). Aerobic fitness was below adequate levels (boys 42 and girls 36 ml.kg‐1.min‐1) in 39% of boys and 60% of girls, with proportions increasing in direct proportion to adiposity (P<0.001). These data indicate that over one‐third of the N=762 middle school‐aged boys and girls tested were classified as overweight/obese, and that body fat % was inversely related to aerobic and anaerobic fitness.Funding, Golden Leaf Foundation STEM Initiative