Knee flexor strength and bicep femoris electromyographical activity is lower in previously strained hamstrings
Journal article
Opar, David A., Williams, Morgan D., Timmins, Ryan G., Dear, Nuala M. and Shield, Anthony J. (2013). Knee flexor strength and bicep femoris electromyographical activity is lower in previously strained hamstrings. Journal of Electromyography and Kinesiology. 23(3), pp. 696-703. https://doi.org/10.1016/j.jelekin.2012.11.004
Authors | Opar, David A., Williams, Morgan D., Timmins, Ryan G., Dear, Nuala M. and Shield, Anthony J |
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Abstract | The aim of this study was to determine if athletes with a history of hamstring strain injury display lower levels of surface EMG (sEMG) activity and median power frequency in the previously injured hamstring muscle during maximal voluntary contractions. Recreational athletes were recruited, 13 with a history of unilateral hamstring strain injury and 15 without prior injury. All athletes undertook isokinetic dynamometry testing of the knee flexors and sEMG assessment of the biceps femoris long head (BF) and medial hamstrings (MHs) during concentric and eccentric contractions at ±180 and ±60° s−1. The knee flexors on the previously injured limb were weaker at all contraction speeds compared to the uninjured limb (+180° s−1 p = 0.0036; +60° s−1p = 0.0013; −60° s−1 p = 0.0007; −180° s−1 p = 0.0007) whilst sEMG activity was only lower in the BF during eccentric contractions (−60° s−1 p = 0.0025; −180° s−1 p = 0.0003). There were no between limb differences in MH sEMG activity or median power frequency from either BF or MH in the injured group. The uninjured group showed no between limb differences in any of the tested variables. Secondary analysis comparing the between limb difference in the injured and the uninjured groups, confirmed that previously injured hamstrings were mostly weaker (+180° s−1 p = 0.2208; +60° s−1 p = 0.0379; −60° −1p = 0.0312; −180° s−1 p = 0.0110) and that deficits in sEMG were confined to the BF during eccentric contractions (−60° s−1 p = 0.0542; −180° s−1p = 0.0473). Previously injured hamstrings were weaker and BF sEMG activity was lower than the contralateral uninjured hamstring. This has implications for hamstring strain injury prevention and rehabilitation which should consider altered neural function following hamstring strain injury. |
Keywords | muscle; strain injury; surface electromyography; maladaptation; neuromuscular |
Year | 2013 |
Journal | Journal of Electromyography and Kinesiology |
Journal citation | 23 (3), pp. 696-703 |
Publisher | Elsevier Ltd |
ISSN | 1050-6411 |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.jelekin.2012.11.004 |
Scopus EID | 2-s2.0-84876998176 |
Open access | Published as green open access |
Research or scholarly | Research |
Page range | 696-703 |
Research Group | School of Behavioural and Health Sciences |
Author's accepted manuscript | License File Access Level Open |
Publisher's version | License All rights reserved File Access Level Controlled |
Output status | Published |
Publication dates | |
04 Jan 2013 | |
Publication process dates | |
Accepted | 06 Nov 2012 |
ARC Funded Research | This output has not been funded, wholly or partially, under the Australian Research Council Act 2001 |
https://acuresearchbank.acu.edu.au/item/860x5/knee-flexor-strength-and-bicep-femoris-electromyographical-activity-is-lower-in-previously-strained-hamstrings
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Author's accepted manuscript
AM_Opar_2013_Knee_flexor_strength_and_bicep_femoris.pdf | |
License: CC BY-NC-ND | |
File access level: Open |
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