Table 1.

Characteristics of cohort participants. The 141 participants consisted of 71 (50.4%) boys and 70 (49.6%) girls, and the average age was 29.6 (SD 4.3) months. A total of 2502 behavioral videos were collected, with 698 (23.9%) rated as “bad,” 581 (23.2%) rated as “good,” and 1321 (52.8%) rated as “perfect.” The distribution of the demographics of the population and the number of videos by label for each behavior are represented as the total number and its percentage.

Parameter and variable			Type of gross motor skill
			Climb up the stairs (N=141)	Go down the stairs (N=141)	Throw the ball (n=140)	Stand on 1 foot (N=141)	Total (N=141)
Demographics
	Age (months), mean (SD)		29.5 (4.3)	29.5 (4.3)	29.5 (4.3)	29.5 (4.3)	28.6 (4.3)
	Gender, n (%)
		Girls	70 (49.6)	70 (49.3)	69 (49.3)	70 (49.6)	70 (49.6)
		Boys	71 (50.4)	71 (50.7)	71 (50.4)	71 (50.4)	71 (50.4)
Number of videos by label, n (%)
	Bad		137 (21.9)	144 (23.1)	95 (15.0)	222 (35.9)	598 (23.9)
	Good		106 (16.9)	107 (17.2)	156 (24.7)	212 (34.2)	581 (23.2)
	Perfect		384 (61.2)	372 (59.7)	380 (60.2)	185 (29.9)	1321 (52.8)