Preseason BFlh architectural characteristics (n=152), eccentric knee flexor strength during the Nordic hamstring exercise (n=131) and MVIC knee flexor strength (n=141) in elite Australian soccer players
| Uninjured group | Injured group | Compared to uninjured group average | ||||||
|---|---|---|---|---|---|---|---|---|
| Two-limb average | Between-limb imbalance (%) | Uninjured limb | Injured limb | Between-limb imbalance (%) | Uninjured group vs injured limb (95% CI) | p Value | Effect size (d) | |
| BFlh architecture | ||||||||
| Passive FL (cm) | 11.20±1.2 (n=125) | 11.2±8.2 | 10.90±0.9 (n=27) | 9.85±1.3## (n=27) | 13.8±1.3 | 1.35 (0.8 to 1.8) | 0.001** | 1.08 |
| 25% MVIC FL (cm) | 9.53±1.2 (n=116) | 11.7±9.2 | 9.16±1.2 (n=25) | 8.51±1.0## (n=25) | 11.3±1.0 | 1.02 (0.5 to 1.5) | 0.001** | 0.92 |
| Passive MT (cm) | 2.54±0.3 (n=125) | 8.0±6.1 | 2.58±0.2 (n=27) | 2.47±0.3 (n=27) | 7.8±6.2 | 0.07 (−0.1 to 0.2) | 0.357 | 0.23 |
| 25% MVIC MT (cm) | 2.66±0.3 (n=116) | 9.8±8.0 | 2.63 (0.3) (n=25) | 2.62±0.3 (n=25) | 6.4±5.8 | 0.04 (−0.1 to 0.2) | 0.671 | 0.13 |
| Knee flexor strength measures | ||||||||
| Eccentric force (N) | 309.5±73.4 (n=105) | 10.1±8.8 | 262.6±63.2 (n=26) | 260.6±82.9 (n=26) | 19.7±32.4 | 48.9 (16.2 to 81.5) | 0.004* | 0.62 |
| Eccentric torque (Nm) | 135.5±33.7 (n=105) | 116.2±28.7 (n=26) | 115.2±37.1 (n=26) | 20.3 (5.3 to 35.1) | 0.008* | 0.57 | ||
| Relative eccentric force (N/Kg) | 4.11±0.9 (n=105) | 3.47±0.9 (n=26) | 3.46±1.2 (n=26) | 0.65 (0.2 to 1.1) | 0.004* | 0.61 | ||
| Relative eccentric torque (Nm/Kg) | 1.79±0.4 (n=105) | 1.54±0.4 (n=26) | 1.53±0.5 (n=26) | 0.26 (0.1 to 0.5) | 0.007* | 0.57 | ||
| Isometric force (N) | 373.7±75.6 (n=116) | 10.4±7.56 | 365.2±73.9 (n=25) | 367.9±72.7 (n=25) | 12.1±13.7 | 5.8 (−26.1 to 39.4) | 0.690 | 0.08 |
| Isometric torque (Nm) | 163.2±34.2 (n=116) | 160.2±30.1 (n=25) | 161.4±34.2 (n=25) | 1.8 (−13.1 to 16.7) | 0.811 | 0.05 | ||
| Relative isometric force (N/Kg) | 4.99±1.0 (n=116) | 4.81±1.1 (n=25) | 4.81±1.1 (n=25) | 0.18 (−0.3 to 0.6) | 0.428 | 0.17 | ||
| Relative isometric torque (Nm/Kg) | 2.18±0.4 (n=116) | 2.10±0.4 (n=25) | 2.11±0.4 (n=25) | 0.07 (−0.1 to 0.3) | 0.495 | 0.18 | ||
All data represented as mean±SD unless otherwise stated.
**=p<0.01, *=p<0.05 versus average of uninjured group, ##=p<0.01 injured versus uninjured limb in the injured group.
BFlh, biceps femoris long head; Cm, centimetres; FL, fascicle length; MT, muscle thickness; MVIC, maximum voluntary isometric contraction; N/Kg, Newtons per kilogram of body weight; N, Newtons; Nm/kg, Newton metres per kilogram of body weight; Nm, Newton metres.