Self-determined Engagement in Physical Activity and Sedentary Behaviors of US College Students.

Although the importance of promoting physical activity is well established, researchers have recently considered "sedentary behaviors" as another key risk factor for chronic disease. However, little is known about the motivational processes regulating sedentary behavior on a daily basis. A substantial amount of research has been based on the self-determination theory to examine the motivational processes regulating physical activity behaviors. However, only limited attention has been paid to sedentary behaviors from this theoretical perspective. This study aims to identify and understand motivational aspects related to sedentary behavior from a self-determination perspective. A convenience sample of undergraduate students (N=875) enrolled in a university required Lifetime Physical Activity and Fitness class completed an online survey which inquired about physical activity and sedentary behaviors as well as about motivational variables related to these behaviors. Physical activity variables were inversely and only slightly related to sedentary behavior (ρ = -.084 to -.146, < .05). Psychological needs and behavioral regulations together explained 14.3% of the variance in moderate-to-vigorous physical-activity ( < .001), but only 2.8% of the variance in sedentary behavior ( = .002). These findings suggest physical activity and sedentary behaviors are explained by unique motivational factors.