High School Students' Accelerometer-Measured Physical Activity and Sedentary Behavior by Motivational Profiles Toward Physical Activity.

Purpose: Based on a Self-Determination Theory with a person-centered approach, the purposes were: (1) to identify motivational profiles toward physical activity (PA) among high school students, and (2) to compare students' accelerometer-measured PA and sedentary behavior (SB) levels between the motivational profiles toward PA. Methods: The present study followed a cross-sectional design. A total of 394 high school students (173 females; final sample = 360 and 198 for the purposes 1 and 2, respectively) aged 12–16 years completed the study. Participants' PA and SB levels were objectively measured by ActiGraph GT3X+ accelerometers (right hip) during seven consecutive days. Later, motivation toward PA was measured by the Behavioral Regulation in Exercise Questionnaire. Results: Based on a two-stage cluster analysis approach, the results identified three clusters: (1) "Self-determined motivational profile toward PA" (65.3%); (2) "Non-self-determined motivational profile toward PA" (23.9%), and (3) "Controlled motivational profile toward PA" (10.8%). The results of the chi-square test showed that a statistically significantly higher percentage of males were represented in cluster 1 (p <.001). The results of the one-way analysis of variance showed that students from cluster 1 had statistically significantly lower levels of SB, and higher levels of light PA, moderate-to-vigorous PA and total PA than those from cluster 2 (p <.05; |d| = 0.40–0.61). Conclusions: In line with the Self-Determination Theory, the students within the self-determined motivational profile had lower SB and higher PA. This preliminary evidence could inform and guide future policy regarding students' PA promotion. [ABSTRACT FROM AUTHOR]