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Hamstring and psoas length of crouch gait in cerebral palsy: a comparison with induced crouch gait in age- and sex-matched controls

Tae-Yon Rhie1, Ki Hyuk Sung2, Moon Seok Park3, Kyoung Min Lee3 and Chin Youb Chung3*

Author Affiliations

1 Department of Orthopedic Surgery, Nalgae Hospital, Seoul, South Korea

2 Department of Orthopedic Surgery, Kwandong University Myongji Hospital, Kyungki, South Korea

3 Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Kyungki, South Korea

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Journal of NeuroEngineering and Rehabilitation 2013, 10:10  doi:10.1186/1743-0003-10-10

Published: 30 January 2013



Previous studies have shown that hamstring lengths are often not short in patients with cerebral palsy, which raises concerns over the benefits of distal hamstring lengthening in patients with crouch gait. In this study, the authors measured lengths of hamstrings and psoas muscles in normal subjects mimicking crouch gait and compared these with lengths in cerebral palsy patients with crouch gait.


Thirty-six patients with cerebral palsy and crouch gait were included in this study, and in addition, 36 age- and sex-matched normal controls were recruited. Hamstring and psoas muscle lengths in patients were evaluated using gait analysis and interactive musculoskeletal modeling software. Muscle lengths were also measured in the normal control group during normal gait and while mimicking crouch gait, and these were compared with those of cerebral palsy patient with crouch gait.


No significant differences were observed between maximum hamstring (p=0.810) and maximum psoas (p=0.456) lengths of patients and controls mimicking crouch gait. However, patients showed significantly shorter excursions of hamstring (p=0.022) and psoas (p=0.036) muscles than controls, whereas no significant excursion differences were observed between controls during normal gait and mimicking crouch gait.


Normal controls mimicking crouch gait and cerebral palsy patients with crouch gait demonstrate similar muscle length patterns. However, mimicked crouch gait did not reproduce the excursion pattern shown by patients with crouch gait, which suggests that reduced hamstring and psoas excursion is an innate characteristic of pathologic crouch gait.