Results of best evidence synthesis
| Strength variable | n | Univariate | Multivariate | Association with risk (↑\↓\=) | Best evidence synthesis | |||
| Low risk of bias | High risk of bias | Low risk of bias | High risk of bias | Association | Level of evidence | |||
| A. Hamstring | ||||||||
| Concentric 60°/s | 1533 | (8, 14, 15, 19, 32, 33) | (16, 17, 18, 30) | (14, 15, 31) | (16, 18, 30) | ↑(17) =(8, 14, 15, 16, 18, 19, 30, 32, 33) | No | Strong |
| Concentric 180°/s | 265 | (15, 32, 33) | (16, 17, 18) | (15, 32) | (16, 18, 30) | =(15, 16, 17, 18, 32, 33) | No | Strong |
| Concentric 240°/s | 506 | (19, 32) | (19, 32) | =(19, 32) | No | Strong | ||
| Concentric 300°/s | 905 | (8, 14, 15, 33) | (17, 18) | (14, 15) | (18) | =(8, 14, 15, 17, 18, 33) | No | Strong |
| Eccentric 30°/s | 462 | (19) | (19) | =(19) | No | Limited | ||
| Eccentric 60°/s | 890 | (14, 32, 33) | (16, 18) | (14) | (18) | ↑(14) =(16, 18, 32, 33) | No | Strong |
| Eccentric 120°/s | 462 | (19) | (19) | =(19) | No | Limited | ||
| Eccentric 180°/s | 276 | (32, 33) | (16, 18) | (18) | =(16, 18, 32, 33) | No | Strong | |
| Eccentric 240°/s | 44 | (32) | = (32) | No | Limited | |||
| Eccentric 300°/s | 130 | (33) | (18) | (18) | =(18, 33) | No | Moderate | |
| B. Quadriceps | ||||||||
| Concentric 60°/s | 2697 | (8, 14, 15, 19, 32, 33) | (16, 17, 18, 30, 31) | (14, 15, 19) | (30) |
↑(14, 30) =(8, 15, 16, 17, 18, 19, 32, 33) | No | Strong |
| Concentric 180°/s | 349 | (15, 32, 33) | (16, 17, 18) | (15) | (18) | =(15, 16, 17, 18, 32, 33) | No | Strong |
| Concentric 240°/s | 506 | (19, 32) | (19) | = (19, 32) | No | Strong | ||
| Concentric 300°/s | 2069 | (8, 14, 15, 33) | (17, 18) | (14) | (18) | =(8, 14, 15, 17, 18, 33) | No | Strong |
| Eccentric 60°/s | 232 | (33) | (16, 18) | (18) | =(16, 18, 33) | No | Moderate | |
| Eccentric 180°/s | 232 | (33) | (16, 18) | (18) | =(16, 18, 33) | No | Moderate | |
| Eccentric 300°/s | 130 | (33) | (18) | (18) | =(18, 33) | No | Moderate | |
| C. Hamstrings:quadriceps ratio | ||||||||
| Conventional 60°/s | 1974 | (8, 15, 19, 32) | (16, 17, 20, 30, 31) | (8, 15, 19, 32) | (17, 29, 31) |
↑(17, 30) =(8, 15, 16, 19, 20, 31, 32) | No | Strong |
| Conventional 180°/s | 240 | (15, 32) | (16, 17, 31) | (15, 32) | (31) | ↑(32) =(15, 16, 17, 31) | No | Moderate |
| Conventional 240°/s | 506 | (19, 32) | (19, 32) | =(19, 32) | No | Strong | ||
| Conventional 300°/s | 1325 | (8, 15) | (17) | (8, 15) | =(8, 15, 17) | No | Strong | |
| Functional 60°/s | 176 | (32, 33) | (16) | (32) | ↑(33) =(16, 32) | Unknown | Conflicting | |
| Functional 180°/s | 246 | (32) | (16, 18) | (32) | (18) | ↑(16) =(18, 32) | Unknown | Conflicting |
| Functional 240°/s | 44 | (32) | (32) | =(32) | No | Limited | ||
| D. Hamstring:opposite hamstring ratio | ||||||||
| Concentric 60°/s | 377 | (32) | (16, 17, 20) | (32) | (17) |
↑(
17) =(16, 20, 32) | No | Moderate |
| Concentric 180°/s | 183 | (32) | (16, 17) | (32) | =(16, 17, 32) | No | Moderate | |
| Concentric 240°/s | 44 | (32) | (32) | =(32) | No | Limited | ||
| Concentric 300°/s | 37 | (17) | =(17) | No | Limited | |||
| Eccentric 30°/s | 194 | (20) | =(20) | No | Limited | |||
| Eccentric 60°/s | 102 | (16) | =(16) | No | Limited | |||
| Eccentric 180°/s | 102 | (16) | =(16) | No | Limited | |||
| E. Other mixed ratios | ||||||||
| Croisier ‘strength imbalance’ | 462 | (19) | (20) | (19) | ↑(19) =(20) | Unknown | Conflicting | |
| QuConc 60°/s:HSConc60°/s | 614 | (14) | (14) | =(14) | No | Limited | ||
| QuConc 300°/s:HSConc300°/s | 614 | (14) | (14) | =(14) | No | Limited | ||
| QuConc 300°/s:HSEcc60°/s | 614 | (14) | (14) | =(14) | No | Limited | ||
| F. Hip extensors | ||||||||
| Concentric 60°/s | 30 | (33) | ↑(33) | Yes | Limited | |||
| Concentric 180°/s | 30 | (33) | =(33) | No | Limited | |||
| Concentric 300°/s | 30 | (33) | =(33) | No | Limited | |||
↑, Association with future hamstring muscle strain; ↓, association with lower risk of future hamstring muscle strain; =, no significant association with future hamstring muscle strain.
HS, hamstrings; Qu, quadriceps.