A look at the literature indicates that there is no statistically significant difference in the number of injuries sustained on turf versus grass. However, there is a slight difference in the types of injuries that predominate on the various surfaces. Muscle-tendon overload injuries (
e.g., ankle sprains and Achilles tendon tears) seem to be more common on turf, while musculoskeletal injuries (muscle tears, fractures) seem to be more common on grass. In one paper I looked at, injuries due to head duels in soccer were significantly more common on turf than on grass. I wonder if that is a reflection of players' ability to achieve greater speed and launching power on artificial surfaces.