Health-related physical fitness and its relationship to objectively measured physical activity in children

During childhood, physical activity (PA) builds the foundation for a healthy body and is an important determinant of chronic disease risk. Recent reports indicate that children in Canada do not participate in sufficient amounts of PA for optimal health and well-being. Furthermore, certain ethnic groups may be at higher risk of developing chronic disease due to extremely low levels of PA and physical fitness. Literature delineating the relationship between PA and health-related physical fitness in children is inconsistent and has been inhibited by PA measurement tools. Objective measures of PA may overcome many of the limitations associated with other PA measurement tools. The purpose of this investigation was to objectively measure habitual PA, examine differences in PA and health-related physical fitness between Asian and Caucasian children, and determine the relationship between PA and health-related physical fitness. One-hundred seventy boys (n = 79) and girls (n = 91) in grades 4 and 5 from five schools in the Greater Vancouver Region participated. Measures of body composition (Body Mass Index and waist circumference), vascular health (blood pressure), resting heart rate, musculoskeletal fitness (grip strength, sit-and-reach, curl-ups and push-ups) cardiorespiratory fitness (Leger shuttle run) and habitual PA (via accelerometry) were obtained over a 1-week period. Results indicated that boys participated in 134 minutes and girls accumulate 114 minutes of moderate-to-vigorous physical activity (MVPA) per day. Only 30 minutes and 15 minutes per day were accumulated in bouts exceeding 5 minutes in duration in boys and girls respectively. During the school day the percentage of time spent in MVPA for recess, lunch hour and Physical Education class was 28%, 35% and 13% in boys and 18%, 27% and 16% in girls. Caucasian girls accumulated more MVPA per day, had significantly higher counts per minute and had higher aerobic fitness than Asian girls (p<0.05). There was no significant difference in musculoskeletal fitness. Caucasian boys had significantly higher counts per minute, higher aerobic fitness, and significantly higher musculoskeletal fitness scores (p