title: Amount of torque and duration of stretching affects correction of knee contracture in a rat model of spinal cord injury.
abstract: BACKGROUND
  Joint contractures are a common complication of many neurologic conditions, and stretching often is advocated to prevent and treat these contractures. However, the magnitude and duration of the stretching done in practice usually are guided by subjective clinical impressions.
  
  
  OBJECTIVE
  Using an established T8 spinal cord injury rat model of knee contracture, we sought to determine what combination of static or intermittent stretching, varied by magnitude (high or low) and duration (long or short), leads to the best (1) improvement in the limitation in ROM; (2) restoration of the muscular and articular factors leading to contractures; and (3) prevention and treatment of contracture-associated histologic alterations of joint capsule and articular cartilage.
  
  
  METHODS
  Using a rat animal model, the spinal cord was transected completely at the level of T8. The rats were randomly assigned to seven treatment groups (n = 4 per group), which were composed of static or intermittent stretching in combination with different amounts of applied torque magnitude and duration. We assessed the effect of stretching by measuring the ROM and evaluating the histologic alteration of the capsule and cartilage.
  
  
  RESULTS
  Contractures improved in all treated groups except for the low-torque and short-duration static stretching conditions. High-torque stretching was effective against shortening of the synovial membrane and adhesions in the posterosuperior regions. Collagen Type II and VEGF in the cartilage were increased by stretching.
  
  
  CONCLUSIONS
  High-torque and long-duration static stretching led to greater restoration of ROM than the other torque and duration treatment groups. Stretching was more effective in improving articular components of contractures compared with the muscular components. Stretching in this rat model prevented shortening and adhesion of the joint capsule, and affected biochemical composition, but did not change morphologic features of the cartilage.
  
  
  CONCLUSIONS
  This animal study tends to support the ideas that static stretching can influence joint ROM and histologic qualities of joint tissues, and that the way stretching is performed influences its efficacy. However, further studies are warranted to determine if our findings are clinically applicable.
authors.affiliation: Department of Rehabilitation Science, Graduate School of Health Sciences, Kobe University, Tomogaoka 7-10-2, Suma-ku, Kobe, Hyogo, 654-0142, Japan, morihide@harbor.kobe-u.ac.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Moriyama
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Tobimatsu
authors.forename: Junya
authors.initials: J
authors.lastname: Ozawa
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Kito
authors.forename: Ryo
authors.initials: R
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000473:pathology; D024043:Collagen Type II / Q000378:metabolism; D003286:Contracture / Q000209:etiology / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D004195:Disease Models, Animal; D017746:Joint Capsule / Q000473:pathology; D007719:Knee Joint / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D052580:Muscle Stretching Exercises / Q000379:methods*; D016059:Range of Motion, Articular; D051381:Rats; D017208:Rats, Wistar; D013119:Spinal Cord Injuries / Q000150:complications* / Q000503:physiopathology; D013997:Time Factors; D019415:Torque; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D024043:Collagen Type II; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat
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