Impact of exercise selection on hamstring muscle activation

Bourne, Matthew N., Williams, Morgan D., Opar, David A., Najjar, Aiman Al, Kerr, Graham K. and Shield, Anthony J. (2016) Impact of exercise selection on hamstring muscle activation. British Journal of Sports Medicine, . doi:10.1136/bjsports-2015-095739


Author Bourne, Matthew N.
Williams, Morgan D.
Opar, David A.
Najjar, Aiman Al
Kerr, Graham K.
Shield, Anthony J.
Title Impact of exercise selection on hamstring muscle activation
Journal name British Journal of Sports Medicine   Check publisher's open access policy
ISSN 1473-0480
0306-3674
Publication date 2016-05-13
Year available 2016
Sub-type Article (original research)
DOI 10.1136/bjsports-2015-095739
Open Access Status Not Open Access
Total pages 10
Place of publication London, United Kingdom
Publisher B M J Group
Collection year 2017
Language eng
Formatted abstract
Objective: To determine which strength training exercises selectively activate the biceps femoris long head (BFLongHead) muscle.

Methods: We recruited 24 recreationally active men for this two-part observational study. Part 1: We explored the amplitudes and the ratios of lateral (BF) to medial hamstring (MH) normalised electromyography (nEMG) during the concentric and eccentric phases of 10 common strength training exercises. Part 2: We used functional MRI (fMRI) to determine the spatial patterns of hamstring activation during two exercises which (1) most selectively and (2) least selectively activated the BF in part 1.

Results: Eccentrically, the largest BF/MH nEMG ratio occurred in the 45° hip-extension exercise; the lowest was in the Nordic hamstring (Nordic) and bent-knee bridge exercises. Concentrically, the highest BF/MH nEMG ratio occurred during the lunge and 45° hip extension; the lowest was during the leg curl and bentknee bridge. fMRI revealed a greater BF(LongHead) to semitendinosus activation ratio in the 45° hip extension than the Nordic (p<0.001). The T2 increase after hip extension for BFLongHead, semitendinosus and semimembranosus muscles was greater than that for BFShortHead (p<0.001). During the Nordic, the T2 increase was greater for the semitendinosus than for the other hamstring muscles (p=0.002).

Summary: We highlight the heterogeneity of hamstring activation patterns in different tasks. Hip-extension exercise selectively activates the long hamstrings, and the Nordic exercise preferentially recruits the semitendinosus. These findings have implications for strategies to prevent hamstring injury as well as potentially for clinicians targeting specific hamstring components for treatment (mechanotherapy).
Keyword Biceps femoris long head (BFLongHead) muscle
Strength training exercises
Hamstring strain injuries (HSIs)
Future strain injury
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
Centre for Advanced Imaging Publications
 
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