Variation of hamstrings lengths and velocities with walking speed

Kiran J. Agarwal-Harding, Michael H. Schwartz, Scott L. Delp

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Crouch gait, one of the most prevalent movement abnormalities among children with cerebral palsy, is frequently treated with surgical lengthening of the hamstrings. To assist in surgical planning many clinical centers use musculoskeletal modeling to help determine if a patient's hamstrings are shorter or lengthen more slowly than during unimpaired gait. However, some subjects with crouch gait walk slowly, and gait speed may affect peak hamstring lengths and lengthening velocities. The purpose of this study was to evaluate the effects of walking speed on hamstrings lengths and velocities in a group of unimpaired subjects over a large range of speeds and to determine if evaluating subjects with crouch gait using speed matched controls alters subjects' characterization as having "short" or "slow" hamstrings. We examined 39 unimpaired subjects who walked at five different speeds. These subjects served as speed-matched controls for comparison to 74 subjects with cerebral palsy who walked in crouch gait. Our analysis revealed that peak hamstrings length and peak lengthening velocity in unimpaired subjects increased significantly with increasing walking speed. Fewer subjects with cerebral palsy were categorized as having hamstrings that were "short" (31/74) or "slow" (38/74) using a speed-matched control protocol compared to a non-speed-matched protocol (35/74 "short", 47/74 "slow"). Evaluation of patients with cerebral palsy using speed-matched controls alters and may improve selection of patients for hamstrings lengthening procedures.

Original languageEnglish (US)
Pages (from-to)1522-1526
Number of pages5
JournalJournal of Biomechanics
Issue number8
StatePublished - May 2010

Bibliographical note

Funding Information:
We are grateful to May Liu for help with data analysis. This work was supported by the National Institutes of Health through the Roadmap for Medical Research U54 GM072970 and NIH R01 HD046814 .


  • Cerebral palsy
  • Gait
  • Hamstrings
  • Speed-matched assessment
  • Walking speed


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