- Knee injuries in football
- Knee injuries and artificial turf
- the effect that artificial turf has on knee injuries in the NFL
- Playing on grass instead of artificial turf fields will reduce the amount of knee injuries in the NFL
- Eliminating turf fields would reduce the amount of knee injuries suffered by NFL players in an NFL game
- Eliminating artificial turf fields with real grass fields would decrease the total amount of knee injuries in an NFL season