title: In vivo evaluations of morphologic changes of gastrocnemius muscle fascicles and achilles tendon in children with cerebral palsy.
abstract: OBJECTIVE
  The Achilles tendon plays an important role in soleus and gastrocnemius muscle functions, including proper muscle force transmission and movement generation. However, few studies have examined concurrent changes of tendon and muscle properties in neurologic disorders. The objective of this study was to investigate the morphologic characteristics of both the calf muscle fascicles and the Achilles tendon in children with cerebral palsy (CP).
  
  
  METHODS
  A cross-sectional study was planned, and 12 children with CP and 11 typically developing children participated in this study. For both groups, B-mode ultrasonography was used to evaluate the architecture of the medial gastrocnemius muscle, including fascicle length and pennation angle at various ankle (20, 10, and 0 degrees plantar flexion and 10 degrees dorsiflexion) and knee (full extension and 90 degrees flexion) positions. The length and cross-sectional area of the Achilles tendon were also evaluated using ultrasonography.
  
  
  RESULTS
  For both CP and control groups, muscle fascicle length, pennation angle, and Achilles tendon length and cross-sectional area varied with ankle and knee positions systematically. Compared with controls, children with CP had shorter muscle fascicles across the tested ankle range of motion (P ≤ 0.003), longer Achilles tendon (P = 0.001), and smaller cross-sectional area of the Achilles tendon (P = 0.003).
  
  
  CONCLUSIONS
  The changes in Achilles tendon properties could be a result of adaptation to calf muscle fascicle shortening and stiffening, which may affect performance of the muscles. A better understanding of the interactions between calf muscle fascicles and Achilles tendon in children with CP may help treat the pathologic changes more effectively.
authors.affiliation: Department of Health Care Sciences, the University of Texas Southwestern Medical Center at Dallas, TX, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: Gao
authors.forename: Heng
authors.initials: H
authors.lastname: Zhao
authors.forename: Deborah
authors.initials: D
authors.lastname: Gaebler-Spira
authors.forename: Li-Qun
authors.initials: LQ
authors.lastname: Zhang
mesh_terms: D000125:Achilles Tendon / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000502:physiology; D016022:Case-Control Studies; D002547:Cerebral Palsy / Q000503:physiopathology*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D009068:Movement / Q000502:physiology*; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000502:physiology; D016059:Range of Motion, Articular / Q000502:physiology; D014463:Ultrasonography