Association of physical activity and sedentary behavior with body mass index and perceived fitness in eighth graders
Lizana Rojas, Suheil (2015)
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Lizana Rojas, Suheil
2015
Master's Degree Programme in Health Sciences
Terveystieteiden yksikkö - School of Health Sciences
Hyväksymispäivämäärä
2015-06-10
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202002202243
https://urn.fi/URN:NBN:fi:tuni-202002202243
Tiivistelmä
Purpose: The purpose of this study was to examine the association of physical activity (PA) and sedentary behavior (SB) with body mass index (BMI) and perceived fitness of girls and boys attending eighth grade.
Methods: The participants in this study were from a Kids Out – intervention conducted in 14 schools with 1,550 students in Tampere, Finland. Adolescents completed a questionnaire during one school lesson and were offered an accelerometer for 7 consecutive days. A total of 1,312 (85%) students completed the questionnaire and 372 (24%) used the accelerometer. The questionnaire elicited the number of days with 1) walking or cycling to/from school (0-5), 2) MVPA for one hour or more (0-7), 3) structured exercise training (0-7), 4) screen time for two hours or more (0-7). Weight and height were self-reported as well as perceived fitness in relation to their peers (much better/somewhat better/equal/somewhat worse/much worse). The minutes of total and intensity-specific daily average PA and SB were derived from the raw acceleration signal by using mean amplitude deviation and its universal cut-points. Chi-square was used in examining the statistical significance (p<0.05) of the associations of PA and SB with BMI and perceived fitness.
Results: Based on the questionnaire, cycling and walking to school showed no relationship with either BMI or perceived fitness. In boys higher levels of MVPA and structured exercise training were associated with lower BMI (p=0.008 and p=0.005) and better perceived fitness (p <0.001 and p <0.001), and in girls with better perceived fitness (p <0.001 and p <0.001). Lower number of 2-hour screen days was associated with lower BMI in girls (p=0.001) and with better perceived fitness in both girls and boys (p <0.001 and p <0.001). Based on accelerometer data, the daily duration of vigorous-intensity PA was inversely associated with boys’ BMI (p= 0.058). In girls daily durations of light and vigorous-intensity PA were associated with better perceived fitness (p= 0.013 and p <0.001) and in boys similar associations with better perceived fitness were detected in all intensity categories (light p= 0.030, moderate p=0.002, vigorous p <0.001). SB was inversely associated with perceived fitness in boys (p=0.007).
Conclusions: The present study indicates that for eight graders from the Tampere region in Finland engaging in MVPA and structured exercise training, as well as reducing the amount of screen time per week is associated to lower BMI and better perceptions about fitness. Thus, future efforts should aim to increase daily MVPA as well as decreasing SB, which nowadays does not only include television watching, but also computer usage, mobile phones and handheld devices.
Methods: The participants in this study were from a Kids Out – intervention conducted in 14 schools with 1,550 students in Tampere, Finland. Adolescents completed a questionnaire during one school lesson and were offered an accelerometer for 7 consecutive days. A total of 1,312 (85%) students completed the questionnaire and 372 (24%) used the accelerometer. The questionnaire elicited the number of days with 1) walking or cycling to/from school (0-5), 2) MVPA for one hour or more (0-7), 3) structured exercise training (0-7), 4) screen time for two hours or more (0-7). Weight and height were self-reported as well as perceived fitness in relation to their peers (much better/somewhat better/equal/somewhat worse/much worse). The minutes of total and intensity-specific daily average PA and SB were derived from the raw acceleration signal by using mean amplitude deviation and its universal cut-points. Chi-square was used in examining the statistical significance (p<0.05) of the associations of PA and SB with BMI and perceived fitness.
Results: Based on the questionnaire, cycling and walking to school showed no relationship with either BMI or perceived fitness. In boys higher levels of MVPA and structured exercise training were associated with lower BMI (p=0.008 and p=0.005) and better perceived fitness (p <0.001 and p <0.001), and in girls with better perceived fitness (p <0.001 and p <0.001). Lower number of 2-hour screen days was associated with lower BMI in girls (p=0.001) and with better perceived fitness in both girls and boys (p <0.001 and p <0.001). Based on accelerometer data, the daily duration of vigorous-intensity PA was inversely associated with boys’ BMI (p= 0.058). In girls daily durations of light and vigorous-intensity PA were associated with better perceived fitness (p= 0.013 and p <0.001) and in boys similar associations with better perceived fitness were detected in all intensity categories (light p= 0.030, moderate p=0.002, vigorous p <0.001). SB was inversely associated with perceived fitness in boys (p=0.007).
Conclusions: The present study indicates that for eight graders from the Tampere region in Finland engaging in MVPA and structured exercise training, as well as reducing the amount of screen time per week is associated to lower BMI and better perceptions about fitness. Thus, future efforts should aim to increase daily MVPA as well as decreasing SB, which nowadays does not only include television watching, but also computer usage, mobile phones and handheld devices.