Table 5. Strength asymmetry thresholds used by the included articles (N = 53) and the evidence level of each threshold applied in the methodology of the study.
Article Strength Asymmetry Threshold Applied in methods? (Y/N) Evidence Tier
Bourne et al., (2015) Investigated asymmetries above and below 10%, 15% and 20% Y 1
Dos’Santos et al., (2017a) Threshold: mean + (0.2 SD of the mean)
Above the threshold = abnormal
Below the threshold = normal		 Y 1
Dos'Santos et al., (2018) Threshold: mean + (0.2 SD of the mean)
Above the threshold = abnormal
Below the threshold = normal		 Y 1
Lockie et al., (2014) Threshold: mean + (0.2 SD of the mean).
Above the threshold = greater asymmetry group
Below the threshold = lesser asymmetry group		 Y 1
Opar et al., (2015) Investigated asymmetries above and below 10%, 15% and 20% Y 1
Holsgaard-Larsen et al., (2014) Symmetry <85% and >115%=abnormal Y 2
Fältström et al., (2017) Symmetry <90% and >110% = abnormal Y 3
Guney-Deniz et al., (2020) Symmetry ≥90% = normal Y 3
Menzel et al., (2013) Asymmetry >15% = abnormal Y 3
Abourezk et al., (2017) Symmetry ≥90% = normal
Symmetry <85% = abnormal		 Y 4
Almeida et al., (2019) Symmetry >10% = abnormal Y 4
Ardern et al., (2015) Presence of deficits on at least 2 of the following criteria:

Bilateral concentric hamstring peak torque ratio of 0.86

Bilateral eccentric hamstring peak torque ratio of 0.86

Concentric hamstring-quadriceps ratio of 0.47

Mixed ratio of 0.80

 		Y 4
Batty et al., (2019) Symmetry ≥90% = normal Y 4
Clark &Mullally, (2019) Asymmetry >10% = abnormal Y 4
de Lira et al., (2017) Asymmetry >15% = abnormal Y 4
Hadzic et al., (2014) Asymmetry >15% = abnormal Y 4
Welling et al., (2019) Symmetry >90% normal Y 4
Zwolski et al., (2015) Symmetry ≥90% = High quadriceps strength group
Symmetry <90% = Low quadriceps strength group		 Y 4
Chmielewski et al., (2014) Symmetry ≥85-90% = normal N n/a
Costa Silva et al., (2015) Asymmetry <15% = normal N n/a
Dai et al., (2019) Asymmetry <10% = normal N n/a
Fort-Vanmeerhaeghe et al., (2015) Asymmetry >10-15% = abnormal N n/a
Fort-Vanmeerhaeghe et al., (2016) Asymmetry ≤10-15% = normal N n/a
Harput et al., (2018) Symmetry ≥90% = normal N n/a
Lisee et al., (2019) Symmetry ≥90% = normal N n/a
Lockie et al., (2012) Asymmetry ≥15% = abnormal N n/a
Lockie et al., (2016) Asymmetry >15% = abnormal N n/a
Miles et al., (2019) Asymmetry <10-15% = normal N n/a
Xergia et al., (2013) Symmetry ≥90% = normal N n/a
Zwolski et al., (2016) Symmetry >90% = normal N n/a
Ageberg & Roos, (2016) - n/a n/a
Benjanuvatra et al., (2013) - n/a n/a
Bishop et al., (2019c) - n/a n/a
Bishop et al., (2019d) - n/a n/a
Bookbinder et al., (2020) - n/a n/a
Carabello et al., (2010) - n/a n/a
Coratella et al., (2018) - n/a n/a
Hart et al., (2014) - n/a n/a
Hiemstra et al., (2008) - n/a n/a
Hubbard et al., (2007) - n/a n/a
Hughes et al., (2019) - n/a n/a
Kaminska et al., (2015) - n/a n/a
Lloyd et al., (2020) - n/a n/a
Lockie et al., (2013) - n/a n/a
Madruga-Parera et al., (2019) - n/a n/a
Madruga-Perera et al., (2020) - n/a n/a
Maloney et al., (2017) - n/a n/a
Peebles et al., (2019) - n/a n/a
Redden et al., (2018) - n/a n/a
Reid et al., (2007) - n/a n/a
Riemann & Davies, (2019) - n/a n/a
Suchomel et al., (2016) - n/a n/a
Vanderstukken et al., (2019) - n/a n/a
Y = Yes, N = No, n/a = not applicable, 1 = article provides the origin of the evidence for the threshold, 2 = article directly cites the origin of the evidence, 3 = article indirectly cites the origin of the evidence, 4 = article fails to provide or cite the origin of the evidence