Table 2.

Examples: classification of contact as a mechanism for sudden-onset injury

Injury	Type of contact		Examples
Non-contact	None	No evidence of disruption or perturbation of the player’s movement pattern	ACL tear in a basketball player landing with knee valgus/rotation after a jump, with no contact with other players.
Contact	Indirect	Through another athlete	ACL tear in a handball player landing, out of balance after being pushed on her shoulder by an opponent while in the air.
	Indirect	Through an object	Downhill skier suffers a concussion from a crash, after being knocked off balance hitting the gate with his knee.
Contact	Direct	With another athlete	ACL tear in a football player from a direct tackle to the anterior aspect of the knee, forcing the knee into hyperextension.
	Direct	With an object	Volleyball player being hit in the face by a spiked ball, resulting in a concussion.