PREDICTORS OF CARDIOVASCULAR FITNESS IN YOUTH: BMI, MATURATION, AGE AND SEX

PREDICTORS OF CARDIOVASCULAR FITNESS IN YOUTH:
BMI, MATURATION, AGE AND SEX

By Sarah B. Livingstone

Thesis Advisor: Dr. Stephen Butterfield

A Lay Abstract of the Thesis Presented
in Partial Fulfillment of the Requirements for the
Degree of Master of Science
(in Kinesiology and Physical Education)
August, 2012

Several factors are associated with youth aerobic capacity, including age, sex, maturation and BMI. Aerobic capacity and its association with obesity remains a concern to physical educators. Aerobic capacity is important as it represents functional limits of the 02-delivery chain and is therefore an indicator of cardiovascular health. Obesity is associated with reduced cardiovascular performance and is a precursor of serious diseases. Given the importance of children's cardiovascular health, and in light of secular trends related to height (leveled off), and weight (accelerating) current data is needed on aerobic capacity in children and youth. The Progressive Aerobic Cardiovascular Endurance Run (PACER) was used to examine associations of selected predictor variables with cardiovascular fitness. The purpose of this study was to examine cardiovascular fitness in youth. The design was cross-sectional and correlational. Children ages 9-19, enrolled in 19 Maine public schools (N=1931) were tested on the PACER by state certified physical educators trained in fitness assessment. Procedures outlined in the FITNESSGRAM test manual were followed.
BMI and maturation offset were calculated for each child. Maturation offset was determined by separate regression equations for boys and girls. Performance on the PACER and controls (Age, Sex, BMI, & Maturation) were analyzed by multiple regression. Controlling for age, sex, BMI, and maturation, each unit increase in BMI was associated with a 1.495 (lap) decline in PACER score (p<. 001). Applying similar controls, boys achieved PACER scores 4.064 laps higher than girls (p<. 001). Controlling for sex, BMI, and maturation, each one year increase in age was associated with a 4.361 point increase in PACER score. Including selected controls, children's PACER performance was explained to a considerable extent by BMI, age and sex. Any conclusions drawn by the present maturation offset equations must be done with considerable caution.