Physical activity measurements in adolescents: accelerometry vs PAI

• Autor(a) principal: São Marcos, Ana Jorge Romão
• Data de Publicação: 2014
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/13732
• topic: Fisioterapia; Exercício físico - Adolescentes; Respiração

Background: Practicing physical activity (PA) has shown to present health benefits at all ages, namely in paediatrics. There are several methods to evaluate PA, however the most frequently used are the self-report questionnaires and accelerometry. The latter is an objective measuring tool, however it requires the use of relatively expensive devices. Questionnaires are easy and quick to apply, and therefore a useful tool to evaluate PA. Despite the existence of some questionnaires to evaluate PA in adolescents, there is still none validated against accelerometry for the Portuguese population. This validation is important, since questionnaires present an error associated to inaccuracies in recall activity. Aims: To validate the Physical Activity Index (PAI), by comparing it with accelerometry in adolescents according to gender and to explore if adolescents follow the physical activity recommendations established for their age. Methods: In this cross-sectional study, adolescents were recruited from 3 basketball teams, 2 classrooms from a school in Aveiro, and an orchestra band classroom. Socio-demographic, anthropometric data and spirometry were collected from the adolescents who participated in this study. Physical Activity (PA) was assessed with accelerometers (Actigraph model - GT3XPlus, Actigraph MTI, Manufacturing Technology Inc., Pensacola, FL, USA) worn during 7 days and the PAI. Pearson correlation coefficients (rs) were calculated to explore the correlations of moderate-to-vigorous PA (MVPA) (min.day-1) and steps per day vs. the PAI. To analyse participants’ ability to follow the recommendations of PA levels, 60 minutes of MVPA and 10,000 to 11,700 steps per day were considered. Chi-square (χ2) tests were used to explore differences between male and female’s ability to reach international recommendations of physical activity levels. Results: Forty nine adolescents (57.14% female; mean age 14.43 ±0.96 years old) participated in this study. Female and male presented similar PA levels measured with a subjective or an objective measure. Correlations between objective and subjective measures were significant and positive only for male (MVPA: r=.514, p=.017; Steps per day: r=.460, p=.041). Most participants were sedentary when analysing the objective data and considering the PA recommendations. Only 1 female (3.57%) and 3 males (14.29%) surpassed the 60 min.day-1 mark and, in terms of steps per day, only 13 females (46.43%) and 13 males (61.90%) registered over 10000 steps per day. Conclusion: When compared with accelerometry the PAI presented as a valid measuring tool only for male adolescents. Adolescents of both genders presented similar levels of PA with both measuring tools, and accelerometry results showed that the majority of adolescents were sedentary. Thus, it is necessary to investigate further in the future about the correlation between accelerometry and the PAI, as well as about the sedentary habits of adolescents.