Table 1:

Frequency and percent of the entire sample of participants of each position and lineup designation, as well as average age at each practice timepoint

	Practice Number	PRE 1	PRE 2	PRE 3	POST 1	POST 2	POST 3
Participants (n)		13	12	17	14	14	13
Average age		20	20	20	20	20	20
Position (n)
	OL	3 (23.08%)	2 (15.38%)	2 (11.76%)	2 (14.28%)	3 (21.43%)	3 (23.08%)
	DL	2 (15.38%)	1 (8.33%)	2 (11.76%)	1 (7.14%)	2 (14.28%)	2 (15.38%)
	RB	2 (15.38%)	1 (8.33%)	3 (17.65%)	3 (21.43%)	3 (21.43%)	2 (15.38%)
	TE	3 (23.08%)	2 (15.38%)	3 (17.65%)	2 (14.28%)	1 (7.14%)	3 (23.08%)
	LB	3 (23.08%)	6 (50%)	7 (41.78%)	6 (42.86%)	5 (35.71%)	3 (23.08%)
Starters (n)
	Starter (S)	2 (15.38%)	0 (0%)	1 (5.88%)	0 (0%)	1 (7.14%)	2 (15.38%)
	Rotational (R)	3 (23.08%)	3 (25.0%)	3 (17.65%)	3 (21.43%)	3 (21.43%)	3 (23.08%)
	Non-Starter (N)	7 (53.85%)	6 (50.0%)	9 (52.94%)	8 (57.14%)	6 (42.86%)	7 (53.85%)

Note: PLA = peak linear acceleration, PAA = peak angular acceleration, PRE = 3 practice sessions without the guardian cap and POST = 3 practice sessions with the guardian cap, OL = offensive lineman, DL = defensive lineman, RB = running back, TE = tight end, LB = linebacker