Physical inactivity is an increasing problem among children and adolescents. The TAKE 10!® program, which integrates physical activity (PA) into academic subjects, was implemented in one elementary school in Magna, Utah to increase children's daily in-school PA. A three-study approach was used to examine: (a) effects of TAKE 10!® on elementary school students' PA and physical fitness levels, (b) effects of TAKE 10!® on elementary school students' on-task behavior, and (c) teachers' experiences in implementing TAKE 10!®. Two hundred thirteen students and 9 teachers from nine classes (3rd to 5th grades) participated in the project for 12 weeks (4 weeks baseline; 8 weeks intervention). Students wore pedometers and accelerometers for 4 days during week 1 (baseline), week 8 (mid-intervention), and week 12 (end-intervention) to examine their PA levels. Systematic observation was used to examine students' on-task behavior during weeks 1 to 4 (baseline) and weeks 8 to 12 (intervention). Teachers were interviewed regarding their experiences implementing TAKE 10!® at the end of the intervention and 5 months after the intervention. Results from the first study indicated that students' steps counts increased significantly by 672 steps from baseline to mid-intervention. Furthermore, students' average time spent in moderate to vigorous intensity PA and vigorous intensity PA increased significantly by approximately 2 minutes from baseline to end-intervention. Results from the second study showed that there was a significant decrease in mean percentage on-task behavior from pre-no TAKE 10!® (91.2 ± 3.4) to post-no TAKE 10!® (83.5 ± 4.0) during baseline, whereas there was a significant increase in mean percentage on-task behavior from pre-TAKE 10!® (82.3 ± 4.5) to post-TAKE 10!® (89.5 ± 2.7) during intervention. The five major themes identified from the third study were: (a) barriers, (b) benefits, (c) what worked, (d) personal attributes, and (e) doing it in the present and in the future. In conclusion, the TAKE 10!® program is effective in increasing students' in-school PA levels and on-task behavior. Despite experiencing barriers to implementing TAKE 10!®, teachers were generally positive about the benefits of the program, and a majority of them reported implementing the program after the study had ended. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]