Regular strength training sessions may be one strategy that overweight and obese teens can use to help reduce their risk of developing type 2 diabetes, researchers from Texas, California, and Alberta, Canada, say.

In this study, researchers divided 22 overweight Latino teen boys from Los Angeles into two groups: One group participated in a 16-week strength training program and the other group served as a comparison group. Twice a week for about an hour, the boys in the exercise group performed upper-body and lower-body exercises such as the leg press, bench press, dead lift, lat pull-down, biceps curl, triceps push-down, leg curl, leg extension, and shoulder press, using both weight machines and free weights (dumbbells and barbells). Throughout the study, trainers helped the teens change and/or increase the weight they lifted.

Before and after the study, all of the participants underwent physical exams to measure height, weight, body fat, and strength. They also had blood tests to measure insulin resistance, which occurs when the body doesn't respond as well to the insulin that the pancreas is making to help glucose leave the blood and enter the body's cells. Adolescents with insulin resistance may be at risk for developing type 2 diabetes.

The boys in the strength-training program experienced a variety of positive health benefits compared with those who didn't, including:

• significantly greater increases in upper- and lower-body strength
• greater decreases in body fat levels
• significant increases in insulin sensitivity over levels at the study's start

Ninety-one percent of the boys who strength trained had improved insulin sensitivity, whereas 60% of the boys in the comparison group experienced a drop in insulin sensitivity. Improving the body's response (or sensitivity) to insulin may be important in helping prevent metabolic diseases in people at higher risk for diabetes, such as Latino youth, the study's authors say.

What This Means to You. Previous research in adults has shown that regular exercise can improve insulin sensitivity, and the results of this study indicate that strength training may be an effective way to prevent diabetes and other overweight-related health problems. In addition to its metabolic benefits, strength training also builds healthier muscles, joints, and bones.

When kids and teens begin strength training, the goal shouldn't be to bulk up and add lots of muscle mass. Generally, training with a low amount of weight and a high number of repetitions is the best way to reap the benefits while minimizing the risk of injuries. For more information about getting your child started in strength training, talk to your doctor or an athletic trainer.

Source: Gabriel Q. Shaibi; Martha L. Cruz; Geoff D. C. Ball; Marc J. Weigensberg; George J. Salem; Noe C. Crespo; Michael I. Goran; Medicine & Science in Sports & Exercise, July 2006.

Reviewed by: Steven Dowshen, MD
Date reviewed: September 2006