摘要：Introduction: There is an urgent need for active strategies to promote physical activity (PA) among female adolescents, as they are at greater risk of physical inactivity. In addition to Physical Education (PE) in school, to reach adequate levels of PA, young people need to participate in PA during the school day and/or after-school hours and/or in the before-school period. One week of objectively measured and self-reported information enlightens the status quo of adolescent girls’ PA and the role that PE homework plays. Purpose: The purpose of this study was to examine girls’ objectively measured PA in a lower secondary school as part of the Physical Education Homework Study, a project conducted in Finland. An additional aim was to provide insights into physical education (PE) homework as part of PA. Methods: Different levels of PA (i.e., light, moderate, vigorous), sedentary time, number of total steps and running steps were measured using accelerometers among girls in the 7th, 8th and 9th grades, aged between 12 and 15 years (n = 88) for a period of 1 week. In addition, self-reported structured diaries were used to gather information about after school activities, including PE homework. An analysis of variance (ANOVA) and Tamhane’s post-hoc test was used to compare the different grades on the basis of participants’ PA levels and sedentary time. Data from self-reported PE homework frequencies and time spent on PE homework were analysed using the independent-samples t-test. Results: The PE homework was a small aspect of the participants’ whole-day PA, averaging 34 minutes per week (7th grade girls 20 minutes, 8th grade girls 51 minutes, and 9th grade girls 32 minutes). Half of the girls from the 8th grade reached the 60-minute PA recommendation every day; 38% of all the girls met the recommended levels of PA. For the 7th grade girls, 35% met the recommendation, while 28% of the 9th grade girls reached the PA guidelines. The 7th grade girls recorded an average daily light PA time of 3 hours 28 minutes; this was 34 minutes more than the girls from 8th grade (p = 0.000) and 30 minutes more than the girls from the 9th grade (p = 0.000). Conclusion: The PE homework provided a variety of PA for the adolescent girls’ after-school hours, even if the role of homework was not time-consuming (20 - 51 minutes per week). A possible way of promoting active time among adolescents during after-school hours is to assign them PE homework, hence, active PE assignments could replace sedentary activities in adolescent girls’ lives.
