seal  Purdue News

November 13, 2003

Purdue teams with school to study how friends affect exercise

WEST LAFAYETTE, Ind. – Like their taste in fashion and music, teens' exercise habits may be influenced by their friends, says a Purdue University youth fitness expert.

Alan Smith, professor of health and kinesiology, is leading the Partnership for Youth Physical Activity at Lebanon Middle School. The project measures the attitudes, perceptions and participation levels of students' physical activity, as well as how friendships and classmates affect the teens' interest in exercising.

"There is an epidemic of obesity among this country's youth that can lead to chronic health problems, such as Type 2 diabetes and heart disease, at an earlier age," Smith said. "There always has been a sharp decline in physical activity for youth as they enter adolescence, and now that we are seeing more obese adolescents it is more important than ever to understand this trend. What makes them lose interest in being active during this impressionable time in their lives?"

Smith and graduate student Sarah Ullrich-French began tracking 164 sixth-graders (78 boys and 86 girls) in 2002-03. These students were surveyed four times throughout the year about their physical activity attitudes, perceptions and behaviors, and how their friends played a role in these characteristics. The students will be surveyed again this year as seventh-graders. Smith plans to survey the students twice a year through high school to observe how their friendships and classmates affect their level of physical activity.

"Overall, we saw relatively positive attitudes about physical activity," Smith said. "Our early research shows that when supportive friends were included in physical activities teens were more likely to enjoy being active, which led to a more positive self-image."

In comparison, students without supportive friends in physical activity reported they are more insecure about their bodies.

Smith and Ullrich-French will continue to measure how student interests and friendships affect their motivation in physical activity, and they also will evaluate how the students' perceptions of their bodies affect the way others react to them.

"Our goal is to help educators combat teenage obesity by using friends and classmates as a tool to promote healthy habits," Smith said. "We will be able to develop physical education curricula that better promote a lifetime of active living."

According to the American Obesity Association, the number of obese adolescents has tripled since the 1970s. More than 15 percent of adolescents are obese, which is defined as a child or adolescent who is at or above the 95th percentile of the body mass index, which shows body weight adjusted for height. For example, a teenager who is 5 feet tall and weighs 150 pounds would have a calculated body mass index of 29, which is between the 85 and 95th percentile. The 95th percentile starts at 30. Youth are at risk, meaning they are overweight, at the 85th percentile. Almost a third of the nation's adolescents, ages 12 to 19, are overweight.

"I have been in education for 28 years, and I have noticed children spending more time on computer games and e-mail and not playing outdoors," said Lebanon Middle School principal Mike Brown. "At the same time I have seen more health problems, such as obesity, affect our students. Now, more than ever, we are interested in strengthening our health and physical education department, and the information from this study can help us better educate our students."

Writer: Amy Patterson-Neubert, (765) 494-9723,

Sources: Alan Smith, (765) 496-6002,

Mike Brown, (765) 482-3400,

Purdue News Service: (765) 494-2096;

Related Web site:
Purdue Department of Health and Kinesiology

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