Table 1: Principal component analysis of the items in the parental questionnaire assessing parental and friends’ influence on children’s physical activity.

General parental supportNeighborhood play with friendsParental PAParental PA with child

I pay for my child to attend a sports club (e.g. soccer, swimming).893
I transport my child to a sports club in the after school period.847
I buy sports clothes and other sports equipment related to the sports that my child engages in.763
My child attends a sports club with a friend.671
I talk to my child about the benefits of physical activity.607

My child meets some friends in the afternoon to play outside in the neighborhood.860
There are children of the same age of my child in the neighborhood for him/her to go out and play.841
Near our house there are houses of my child’s friends where my child can walk on his/her own to meet friends.829
My child visits the houses of some friends for play.369

During weekdays, how much time do you spend being physically active (e.g. walking, gym)?.909
During weekends, how much time do you spend being physically active (e.g. walking, gym)?.889

I take part in physical activity with my child during weekdays (e.g. walking, cycling).849
I take part in physical activity with my child during weekends (e.g., walking, cycling).844

Eigenvalues3.0252.3941.7081.545
Percentage of variance explained by each factor23.27118.41413.13811.882
Cronbach’s alpha of each factor0.8280.7680.7670.650