title: The muscle-bone interaction in Turner syndrome.
abstract: OBJECTIVE
  Turner syndrome (TS) is associated with an increased fracture rate due to reduced bone strength, which is mainly determined by skeletal muscle force. This study aimed to assess the muscle force-bone strength relationship in TS and to compare it with that of healthy controls.
  
  
  METHODS
  This study included 39 girls with TS and 67 healthy control girls. Maximum muscle force (Fmax) was assessed through multiple one-legged hopping with jumping mechanography. Peripheral quantitative computerized tomography assessed the bone strength index at the tibial metaphysis (BSI 4) and the polar strength-strain index at the diaphysis (SSI polar 66). The effect of TS on the muscle-bone unit was tested using multiple linear regression.
  
  
  RESULTS
  TS had no impact on Fmax (p=0.14); however, a negative effect on bone strength (p<0.001 for BSI 4 and p<0.01 for SSI polar 66) was observed compared with healthy controls. Bone strength was lower in the TS group (by 18%, p<0.01, for BSI 4 and by 7%, p=0.027, for SSI polar 66), even after correcting for Fmax.
  
  
  CONCLUSIONS
  Similar muscle force induces lower bone strength in TS compared with healthy controls, which suggests altered bone-loading sensitivity in TS.
authors: Department of Pediatrics, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Prague, Czech Republic.
authors: Ondrej
authors: O
authors: Soucek
authors: Department of Pediatrics, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Prague, Czech Republic.
authors: Jana
authors: J
authors: Matyskova
authors: Clinic for Sports Medicine, Lucerne Cantonal Hospital, Lucerne, Switzerland.
authors: Elmar
authors: E
authors: Anliker
authors: Exercise Physiology Lab, Institute of Human Movement Sciences, ETH Zurich, Zurich, Switzerland.
authors: Marco
authors: M
authors: Toigo
authors: Department of Statistics, Faculty of Mathematics and Physics, Charles University in Prague, Prague, Czech Republic.
authors: Zdenek
authors: Z
authors: Hlavka
authors: Department of Pediatrics, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Prague, Czech Republic.
authors: Jan
authors: J
authors: Lebl
authors: Department of Pediatrics, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Prague, Czech Republic. Electronic address: zdenek.sumnik@fmotol.cuni.cz.
authors: Zdenek
authors: Z
authors: Sumnik
mesh_terms: D000293:Adolescent; D000886:Anthropometry; D001696:Biomechanical Phenomena; D001842:Bone and Bones / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D009132:Muscles / Q000503:physiopathology*; D014424:Turner Syndrome / Q000503:physiopathology*
keywords: Bone strength indices; Muscle force; Muscle–bone unit; Ovarian function; Turner syndrome