An all-boys summer camp in Winslow, Maine, Camp Caribou has been managed by three generations of the Lerman family. With a range of land and water sports, Camp Caribou also recently added a new 10,000-square-foot indoor gym with cardio and strength-training equipment.

Often performed with free weights, exercise machines, or the body’s own weight, strength training helps people to increase bone density, lower body fat, and even reduce their chances of sports injuries because of stronger muscle and bone. According to research published in The Journal of Pediatrics, a moderate level of supervised strength training is a healthy form of exercise for teens and children.

The researchers assessed results from 42 past studies that included more than 1,700 children and teenagers who had been randomly assigned to either a strength-training or a control group. The study found that working with weights improved physical fortitude, particularly in children older than 10. While better results were seen in youth who engaged in frequent or longer sessions, the majority of the children increased their strength by at least 20 to 40 percent of their prior level.