Muscle activation patterns displayed during landing
| Condition | |||||
|---|---|---|---|---|---|
| Variable | Muscle | Normal | Repeat | Knee instruction | Muscle instruction |
| Values are mean (SD). | |||||
| *A negative value indicates that muscle burst onset occurred before IC time. | |||||
| †Negative value indicates that peak muscle activity occurred before IC time. | |||||
| ‡Significantly different from other three conditions (p<0.05). | |||||
| §Significantly different from other three conditions (p<0.05). | |||||
| ¶Significantly different from knee instruction condition (p=0.013). | |||||
| IC, Initial contact time of the test foot with the force platform during landing; RF, rectus femoris; VL, vastus lateralis; BF, biceps femoris; SM, semimembranosus. | |||||
| Muscle burst duration (ms) | RF | 447 (67) | 435 (45) | 527 (59)‡ | 461 (98) |
| VL | 366 (65) | 372 (56) | 459 (54)‡ | 383 (88) | |
| SM | 312 (85) | 302 (80) | 327 (101) | 330 (111) | |
| BF | 447 (126) | 430 (128) | 457 (114) | 475 (134) | |
| Muscle burst onset time to IC (ms)* | RF | −83 (33) | −77 (27) | −72 (34) | −110 (53)§ |
| VL | −86 (37) | −82 (28) | −81 (39) | −97 (51) | |
| SM | −183 (39) | −185 (35) | −189 (42) | −194 (70) | |
| BF | −216 (54) | −209 (34) | −203 (42) | −220 (66) | |
| Muscle burst peak time to IC (ms)† | RF | 82 (29) | 81 (26) | 93 (41) | 72 (26)¶ |
| VL | 66 (44) | 74 (23) | 81 (23) | 68 (25) | |
| SM | −54 (24) | −59 (19) | −60 (23) | −68 (47) | |
| BF | −46 (59) | −51 (43) | −38 (50) | −51 (66) | |