Table 1. Values of concentric H/Q ratio used in professional soccer players with and without hamstring injury (mean±SD) at 60 deg/s of isokinetic velocity during concentric knee flexion–extension movement.

Authors	Mean age of players (range) [years]	Injured		Non-injured		Type of study	Comments
		n	Mean ± SD (range)	n	Mean ± SD (range)
Paton et al. 1989 [24]	19.9	14	0.7 (0.5–1.0)	29	0.7 (0.5–1.0)	Cross-sectional	With retrospective injury register, number of injured or uninjured legs
Mangine et al. 1990 [25]				31	0.56±0.17(R)	Cross-sectional	Cross-sectional assessment repeated for 5 years, leg right(R), left(L)
					0.56±0.17(L)
Zakas et al. 1995 [26]	21.0–26.6			51	0.68±0.09(I)	Cross-sectional	Four different divisions (I,II,III,IV)
					0.71±0.09(II)
					0.72±0.10(III)
					0.67±0.06 (IV)
Tourny-Chollet et al. 2000 [27]	22			21	0.64(NP)	Cross-sectional	H/Q values calculated indirectly, preferred(P), non-preferred(NP) leg
					0.66(P)
Dauty et al. 2003 [8]	23	11	62.2 ± 12.5	17	66.8±9.0	Prospective	Number of injured and uninjured players
Dauty et al. 2003 [18]	23	15		17	0.67±0.07 (UI)	Prospective	Uninjured legs (U) of injured (I) and uninjured (UN) players
					0.66±0.09 (UUN)
Lehance et al. 2008 [23]	26			19	0.62±0.07(P) vs.	Cross-sectional	Three groups of professional players: PRO, U-21 and U-17; preferred(P) vs. non-preferred(NP) leg
					0.59±0.07 (NP) (PRO)
	19.5			20	0.60±0.07(P) vs.
					0.61±0.08 (NP) (U-21)
	15.7			18	0.63±0.07(P) vs
					0.61±0.08 (NP) (U-17)
Fousekis et al. 2011 [6]	24			100	0.56±0.80(YR)	Cross-sectional	Number of injured and uninjured players; H/Q values are provided depending on professional years of playing: young(Y)5-7 yrs, medium(M)8-10yrs, old(O)more or equal to 11 yrs, and testd leg: right(R) vs. left(L)
					0.55±0.10(YL)
					0.56±0.80(M)
					0.58±0.70(M)
					0.58±0.80(OR)
					0.59±0.10(OL)
Henderson et al. 2010 [28]	23	10	0.60±0.09	25	0.62±0.12	Prospective	All results are presented for preferred leg(P)
da Fonseca et al. 2007 [29]	24			117	0.83±0.19(P)	Cross-sectional	preferred(P), non-preferred(NP) leg
					0.51 ± 0.09(NP)
Zabka et al. 2011 [30]	24			39	57.8±0.08(R)	Cross-sectional	right(R) vs. left(L), number of uninjured players
					57.7±0.07(L)
Ruas et al. 2015 [31]	26			102	0.60±0.07(GP)	Cross-sectional	Depending on players position: goalkeepers(G), side backs(SB), central backs(CB), central defender midfielders(CDM), central attacking midfielders(CAM), forwards(F) and tested leg preffered(P) vs. non-preffered(N)
					0.55±0.08(GN)
					0.63±0.16(SBP)
					0.61±0.10(SBN)
					0.64±0.13(CBP)
					0.61±0.12(CBN)
					0.60±0.13(CDMP)
					0.62±0.09(CDMN)
					0.62±0.12(CAMP)
					0.60±0.08(CAMN)
					0.59±0.11(FP)
					0.58±0.12(FN)
Carvalho et al. 2016 [4]	25.5			159	0.62 ± 0.10 (IR)	Cross-sectional	Depending on the level of league (I vs. II) and tested leg right(R) vs. left(L)
					0.61 ± 0.11 (IL)
					0.59 ± 0.10 (IIR)
					0.58 ± 0.09 (IIL)
Dauty et al. 2016 [9]	22.5(U); 25.2(I)	64	0.66 ± 0.11	620	0.66 ± 0.10	Case-control	Number of injured and uninjured legs