Table 2.

Athlete characteristics

a		# Included athletes		Age (years)
	Male	104		25.4 ± 7.9
	Female	5		25.2 ± 2.2
	Total	109		25.4 ± 7.8
b	Injury grade	Number of injuries (percentage)		RTP time (days) (number of injuries)
	0	7	(6.4%)	9.0 ± 6.5	(5)
	1	22	(20.0%)	28.2 ± 19.5	(17)
	2	81	(73.6%)	50.9 ± 32.4	(65)
	Total	110		44.1 ± 31.8	(87)

Characteristics of the included athletes with acute hamstring injury (a) and injury figures (b) including injury grading based on a modified Peetrons’ classification, number (and percentage) of injuries per grade, and return-to-play times for the athletes where RTP time was known. For 23 injuries, the RTP times were not known. The definition of the modified Peetrons’ classification was as follows: grade 0 = no abnormality; grade 1 = edema without architectural distortion; grade 2 = edema with architectural disruption; grade 3 = complete tear (exclusion criteria in this study). Data for age and RTP are given as mean ± standard deviation

RTP Return-to-play