By Kathryn Doyle NEW YORK (Reuters Health) – Exercise can help overweight kids slim down, but a new study suggests they might be at risk for leg, ankle and foot injuries in the process. The finding makes sense intuitively, but there had not been conclusive, thorough studies done among children before, lead author Eva Jespersen said. Jespersen is a physiotherapist and doctoral student at the Centre for Research in Childhood Health at the University of Southern Denmark in Odense. They measured the kids’ body fat percentage and body mass index (BMI), a ratio of weight in relation to height, then followed them for the next two and a half years.