Patterns of daily activity and time spent in bed of adult women and adolescent and preadolescent girls from a rural community in Senegal (West Africa) Running title: Physical activity of female subjects in Senegal

Background: In rural Africa, women and adolescent girls sustain a high burden of domestic and agricultural tasks. This could result in energy imbalance and impair their nutritional status. Objective: The aim of the study was to investigate activity during the day and time spent in bed during the night of adult women and adolescent and preadolescent girls living in the same household. Our hypothesis was that more prolonged physical inactivity and time spent in bed could be an efficient means for lowering energy expenditure and hence maintaining an adequate nutritional state. Methods: Physical activity during the day was qualitatively recorded using “spot observation” (Super 1989), and quantitatively using accelerometers. A total of 110 females, 55 adult women, 45 adolescents and 10 preadolescents, were included in the study. Anthropometric measurements (weight, height and 4 subcutaneous skinfolds) served as indicators of nutritional status. Results: Day-to-day reliability of accelerometry counts was acceptable (average intraclass correlation coefficient=0.73). Differences in daytime activity varied according to age group. Adolescent and preadolescent girls had higher overall activities than adults (p<0.01). Preadolescent girls went to bed earlier and for longer periods than adult women (p<0.001). There existed significant relationships between time spent in bed and activity during the day in adult women but not in adolescent or preadolescent girls. A significant relationship between nutritional status and physical activity indices was observed in preadolescent and adolescent girls, but not in women. ird -0 01 92 17 1, v er si on 1 5 D ec 2 00 7