Table 1.

Sample Characteristics

Characteristic	Groupa		P Value	t Value
	Concussed (n = 25)	Control (n = 15)
	Mean ± SD
Age, y	17.88 ± 1.74	18.27 ± 1.83	.51	−0.667
Height, cm	182.07 ± 8.08	180.01 ± 7.19	.42	0.815
Mass, kg	98.36 ± 21.70	93.83 ± 24.56	.55	0.608
Body mass index, kg/m2	30.15 ± 5.30	29.57 ± 7.36	.78	0.287
Years of football participationb	7.04 ± 2.90	8.33 ± 3.22	.20	−1.298
Wechsler Test of Adult Reading, standard score	94.72 ± 16.46	99.07 ± 13.00	.39	−0.871
Valid mobile application daysc (N = 14)	11.32 ± 1.95	12.20 ± 2.96	.26	−1.136
Valid Fitbitd days (N = 14)	10.68 ± 3.04	12.40 ± 3.27	.10	−1.685
	n (%)
Race			.43	0.615
White	18 (72)	9 (60)
Black or African American	7 (28)	6 (40)
Ethnicity			.60	1.893
Not Hispanic or Latino	22 (88)	12 (80)
Hispanic or Latino	1 (4)	1 (7)
Not reported or unknown	2 (8)	2 (13)
Competition level			>.99	0.000
College	20 (80)	12 (80)
High school	5 (20)	3 (20)
Previous history of concussion	15 (60)	3 (20)	.01	6.061
Attention-deficit/hyperactivity disorder	2 (8)	1 (7)	.88	0.024
Learning disability	0 (0)	0 (0)	>.99	NA
	n/N (%)			χ2 Value
Compliancee
Mobile application	283/327 (86.5)	183/225 (81.3)	.63	0.234
Fitbitd	267/327 (81.7)	186/225 (82.7)	.92	0.009
	Median (Interquartile Range)			U Value
Calculated Fitbitd wear time, h/df	19.4 (15.5–20.2)	19.6 (14.0–20.5)	.85	195.0

Abbreviation: NA, not applicable.

^aGroup comparisons of continuous data were calculated using 2-sided t tests. Observed versus expected frequency comparisons were calculated using Pearson χ² tests.

^bOne concussed participant was missing data for years of participation.

^cValid days is the number of days of valid data provided within the targeted 2-wk follow-up period.

^dFitbit Charge HR version 122; Fitbit, San Francisco, CA.

^eCompliance is reported as the proportion of participant days with data out of the total number of participant days for which data could have been provided.

^fEvaluated using the Mann-Whitney test.