What does the science say about the grass vs. turf debate in sports?

Which playing surface is safer for athletes: natural grass or artificial turf?

The question is important not just in football, but also for soccer, recreational sports and high school and college athletics — anywhere athletes make sudden shifts in direction that can twist joints and tear ligaments.

Scientists continue to study the question, but there are challenges to getting the answer right. There are variables to take into account: the player’s age and physical shape, weather and surface conditions, the type of shoes and whether the injuries involved contact with other players. And surfaces have changed over the years with new technology.

The debate was revived when Aaron Rodgers tore his Achilles’ tendon during an NFL game on artificial turf. Although Rodgers’ injury may have been just as likely on grass because of the circumstances, that hasn’t stopped the wrangling.