All sports activities at the competitive level have a risk of injury. Repetitive physical loading of tendons, ligaments, muscles, and bones is especially problematic. There are reports of elite athletes who have trained for many years developing low back pain and degenerative disc disease (DDD).
Each sport has its own specific associated postures and motions. But the ones with frequent rotations of the trunk, frequent jumps, repetitive flexion and extension of the spine, and frequent kick motions seem to have the highest incidence of back problems. This seems to include baseball, gymnasts basketball, soccer, high-load swimmers, and kick boxers most often.
Athletes involved in activities such as running and low-load swimming had the lowest rate of degenerative disc disease.
Given the high rate of obesity and increasing incidence of diabetes among young children today, encouraging physical activity and exercise of any and all kinds seems to be the way to go. For those children who may eventually become elite athletes, a careful training program and prevention techniques may help reduce the risk of injury. More studies will be done and results reported on that will guide athletes and their trainers.