Table 1.

Selected Exemplar Comments fromChild Interviews by Age

Question	Example Responses
What does being physically active mean to you? [Word Association]	Responses from 14 – 17 year olds: Sports, running, all kinds of different sports like track, soccer, football, lacrosse Physical activity is something that you do that's physical, something that helps you move around, get your body strong. I'd say 'you play basketball, that's one form of physical activity. Physical activity is exercising and eating healthy. I can feel that my arms and legs are getting stronger, 'cause that's what you use the most. And after I know that my muscles are really tightened up.
	Responses from 8 – 11 year olds: You get to do kinds of activities, games; sometimes I do physical activities in school. [probe: when do you use that word?] like for writing and for talking to my teacher. [probe: do other people talk to you about Physical Activity?] Yes, my gym teacher Exercise; Being out of the house more, playing basketball, football, lets go play some sports, ride some bikes
What are some ways that you are active or could try to be more active?	Responses from 14 – 17 year olds: Go out, go on vacations, play games, have fun with family, have cook-outs, do good things, get attention, do things with friends, go to school, listen to parents, likes what he/she likes doing, enjoys her activities, make their friends laugh
	Responses from 8 – 11 year olds: Chase each other, play tag, go outside, play tag Go outside more, run around more. Chasing my dog or my brother. [probe: what about something that's physically active at home but outside?] running around. [probe: what about parks and fields?] I do monkey bars. [probe: is there another place that's not home or school that you spend a lot of time in?] Yes, my cousin's house.
Describe a time when you were extremely physically active and moving around. What were you doing? Why did you stop?	Responses from a 17 year old: When we hiked up the mountain, we went to Hawk mountain. I didn't make it all the way up, but I made it far. [probe: did you like it?] Yeah, it was ok; I just wish I didn't get as tired as fast as I did. [probe: do you know why you think you got so tired?] Because I'm overweight. [probe: can you think of anything that would make it easier?] I think if I was smaller. [probe: did it seem like that activity flew by or was it dragging on forever?] It was flying by and once I got tired it was going slow. [probe: how did your body feel?] My heart was beating real fast and my legs weren't really tired but it was an incline so I could feel the burning, I was breathing heavy. [probe: is that why you stopped?] Yes. [probe: how did you feel after you did that hike?] Exhausted, my feet were hurting, I guess I wasn't wearing the right sneakers, I just felt tired. [probe: how long did it take for you to feel back to normal?] The next day.
	Responses from an 8 year old: I was at my cousin's house and we're playing kickball in their basement. [probe: how long were you playing for?] An hour. [probe: was it hard to keep track of time? Did it seem like time was passing quickly?] No. [probe: were there other people there with you besides your cousins?] My aunt, my uncle and my mom. [probe: when's the last time you played kickball like this?] Not that long ago, we were there in September or something. [probe: what do you notice about your body?] My feet move, sometimes I had to catch the ball. [probe: did your body feel different than normal?] Yes, it felt tingly then funny a little. [probe: when do you get the tingly feeling?] When I run. [probe: how long did it take for your body to get back to normal?] A couple days. [probe: what happened to your energy after you were really physically active?] It got a little stronger
Describe being physically inactive	Responses from a 14 – 17 year olds: [probe: how describe inactive feeling to someone?] felt like going to sleep, feel tired [probe: how often do you do that?] maybe every two months; [probe: other words to describe how this feels?] no, not really. [p: what are some things you like to do that are inactive?] watching tv, getting on facebook, go on youtube, watch videos and stuff [probe: how much time did you spend being inactive yesterday?] maybe about 4 hours watching tv and an hour on the computer, andi did read my book watch TV, coloring w/ my nephew, [probe: how does your body feel when you're sitting around watching TV?] its like nothing. knitting, I started that 2 years ago. My mom knits and I was always interested so I asked her to teach me. [p: how long do you knit for?] A long time, if I have the time. This past summer. [p: do you think you have more or less energy after you're knitting?] I get tired so I think I get less energy [p: how do you feel when you're sitting around?] I was feeling tired, lazy and fat
	Response from 8- 12 year old on a Saturday, when it was raining, we just sat in the house and watched TV. I played some of my video games, some board games. [probe: how did you feel?] I'm used to going outside a lot but now the school year started and its cut. So now I usually just come home from school, go home, do my homework, sit down and relax. [probe: if I was to ask another kid, what would be a better word than you felt like a big blob?] Lazy. [probe: what does that do to your energy?] It went down. [p: how would you fix it?] Moving around, getting up, stretching. [probe: How does somebody look when they have a lot of energy?] Not tired, not looking lazy. [probe: what part of the body do you look at when you're deciding if they have a lot of energy?] Mostly their legs. [probe: how do tired legs look?] Just dragging.
Describe a time you worked out getting your muscles stronger	Responses from 14 – 17 year olds: I can feel that my arms and legs are getting stronger, 'cos that's what you use the most. And after I know that my muscles are really tightened up Lifting weights, push-ups, sit-ups, jumping jacks, bench pressing, and I ran around my house a couple times too. [probe: what were the things that let you know you were exercising hard?] Sweat, my muscles were getting bigger, and I was feeling a little bit tired.
	Responses from 8 – 11 year olds: When my uncle took me to the gym for the first time about a year ago. We were there from 6:00 to 8:00. We jumped rope, push-ups, sit-ups, treadmill. [probe” how'd you feel, how'd you know you were working really hard?] well I can't really do push-ups, that was really difficult for me. Something hurt, my arms and legs. You're sweating, your body is sore. [probe: why did you stop? did you have enough?] I had enough. [probe: how'd you feel the next day?] Sore. [probe: would you do it again?] Not really, because it hurt