Table 1.

Summary of game exposure and contact incidence by age

Age group	Exposure		All contacts				Contacts on play			Head contact
	Games	Plays	Plays	Contacts	IR per 1000 AP	IR per 100 PH	1	2	3	Plays	Contacts	IR per 1000 AP	IR per 100 PH
12U	4	126	16	27	15.3	145	7	7	2	4	4	2.3	21.4
14U	6	198	34	63	22.7	225	8	23	3	9	9	3.3	32.1
HS	38	1318	202	366	19.8	165	72	96	34	66	67	3.6	30.2
All	48	1643	252	456	19.8	170	87	126	39	79	80	3.5	29.8

AP, athlete-plays; HS, high school; IR, incidence rate; PH, player-hours (computed assuming 20 min games for 12U and 14U and 25 min games for HS); 12U, under 12; 14U, under 14.