Ojectively Measured Physical Activity Patterns of Severely Obese Children and Adolescents Age and Gender Differences

Low physical activity has an important role in the development of obesity in youth. To date, little evidence exists on the physical activity patterns of severely obese young people and no study has examined their habitual activity using objective measurements. The aims of this study were to 1) objectively determine physical activity patterns of severely obese children and adolescents and 2) assess the within-sample gender and age differences Subjects-recruited from an obesity clinic- were 16 children (M plus or minus SD = 9.4 plus o minus 1 .9 years) and 12 adolescents (14.8 plus or minus L7 year’s), all above the 99th percentile of the UK body mass index reference curves They were given the Computer Science and Applications Inc (CSA, 7164) uni-axial accelerometer to wear during waking hours for a period of seven days! The CSA can store onboard minute by minute activity data. After’ the measurement period, the recorded CSA data were retrieved and the average minutes of moderate or greater intensity physical activity (AMA) per registered hour were computed using age- specific CSA cut points. The average weekday and weekend day activity patterns were plotted for all four subgroups and the whole sample Using log transformed AMA scores, paired and independent samples t-tests assessed differences between weekdays and weekends within each sub-group and between the age and gender subgroups, respectively The graphic representation of the AMA revealed a sharp decrease in activity after 16.00 h across all sub-groups and the sample as a whole Over the 7 days, adolescents (4 6 plus or minus 2.2 vs 3 2 plus or minus 2.2 min/hr, log transformed t = 3.366, df= 11, p .006) and girls (6.6 plus or minus 4.6 vs 5 8 plus or minus 5.0 mm/hr2 log transformed t = 2.20, df 16, p = 04) were significantly less active at the weekends compared with weekdays. The between-groups comparisons found that children performed significantly more AMA minutes per registered hour than adolescents on weekdays (10. 1 plus or minus 4.9 vs 4 6 plus or minus 2.2 min/hr, tog transformed t 3.93, df= 26, p 001) arid on weekend days (10.1. plus or minus 5.9 vs 3.2 plus or minus 2.2 min/hr, log transformed t = 4.68, df=26, p 000). Results indicate that severely obese children and adolescents tend to be sedentary when they have the choice, i.e. afternoons after school and in the weekends. Future obesity interventions on young people may need to place particular emphasis on adolescents and try to promote weekend activity for adolescents and girls.