Hamstring strength and flexibility after hamstring strain injury: A systematic review and meta-analysis

Maniar, Nirav, Shield, Anthony, Williams, Morgan, Timmins, Ryan, & Opar, David A. (2016) Hamstring strength and flexibility after hamstring strain injury: A systematic review and meta-analysis. British Journal of Sports Medicine, 50(15), pp. 909-920.

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  • To systematically review the evidence base related to hamstring strength and flexibility in previously injured hamstrings. Which variables, if any, should be monitored during hamstring rehabilitation?


  • Systematic review and meta-analysis.

Data sources

  • A systematic literature search was conducted of PubMed, CINAHL, SPORTDiscus, Cochrane library, Web of Science, and EMBASE from inception to August 2015.

Inclusion Criteria

  • Full text English articles which included studies which assessed at least one measure of hamstring strength or flexibility in men and women with prior hamstring strain injury within 24 months of the testing date. Studies were required to have an uninjured comparison group (contralateral leg or uninjured control group).


  • Twenty eight studies were included in the review, which in total included 898 participants. Previously injured legs demonstrated deficits across several variables. Lower isometric strength was found <7 days post injury (effect size, -1.72, 95%CI, -3.43 to 0.00), but this did not persist beyond 7 days after injury. The passive straight leg raise was restricted at multiple time points after injury (<10 days, effect size, -1.12, 95%CI, -1.76 to -0.48; 10-20 days, effect size, -0.74, 95%CI, -1.38 to -0.09; 20-30 days, effect size, -0.40, 95%CI, --0.78 to -0.03), but not at 40-50 days post injury. We report deficits that remained after return to play in isokinetically measured concentric (60o/sec , effect size, -0.33, 95%CI, -0.53 to -0.13) and Nordic eccentric knee flexor strength (effect size, -0.39, 95%CI, -0.77 to 0.00). The conventional hamstring to quadricep strength ratios were also reduced well after return to play (60:60o/sec , effect size, -0.32, 95%CI, -0.54 to -0.11; 240:240°/sec , effect size, -0.43, 95%CI, -0.83 to -0.03) and functional (30:240o/sec, effect size, -0.88, 95%CI, -1.27 to -0.48) but these effects were inconsistent across measurement velocities/method.


  • After hamstring strain, acute isometric and passive straight leg raise deficits resolve within 20-50 days. Deficits in eccentric and concentric strength and strength ratios persist after return to play, but this effect was inconsistent across measurement velocities/methods. Flexibility and isometric strength should be monitored throughout rehabilitation, but dynamic strength should be assessed at and following return to play.

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ID Code: 96793
Item Type: Journal Article
Refereed: Yes
Keywords: Hamstring, injury, strength, flexibility
DOI: 10.1136/bjsports-2015-095311
ISSN: 0306-3674
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Current > Schools > School of Exercise & Nutrition Sciences
Copyright Owner: Copyright 2016 BMJ Publishing Group
Deposited On: 12 Jul 2016 22:47
Last Modified: 10 Oct 2016 01:10

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