title: Ground reaction forces, bone characteristics, and tibial stress fracture in male runners.
abstract: OBJECTIVE
  Tibial stress fracture is a common overuse running injury resulting from repetitive mechanical loading. This research project aimed to determine whether runners with a history of tibial stress fracture (TSF) differ in tibial bone geometry, tibial bone mass, and ground reaction force (GRF) parameters during running from those who have never sustained a stress fracture (NSF).
  
  
  METHODS
  Forty-six male running athletes (23 TSF; 23 NSF) ranging in age from 18 to 42 yr were recruited for this cross-sectional study. A force platform was used to measure selected GRF parameters (peak and time to peak for vertical impact force, vertical active force, and horizontal braking force) during running at 4.0 m x s(-1). Tibial bone geometry (cross-sectional dimensions and area) was calculated from a computerized tomography (CT) scan at the junction of the middle and distal thirds. Dual energy x-ray absorptiometry (DXA) provided measurements of tibial bone area, bone mineral content (BMC), and bone mineral density (BMD).
  
  
  RESULTS
  The TSF group had significantly smaller tibial cross-sectional area (P = 0.02) and DXA tibial bone area (P = 0.02), after adjusting for height and weight, than the NSF group. There were no significant differences between groups for GRF, tibial BMC, or tibial BMD.
  
  
  CONCLUSIONS
  These findings support the contention that bone geometry plays a role in stress fracture development and that male athletes with smaller bones in relation to body size are at greater risk for this bony injury.
authors.affiliation: School of Physiotherapy, The University of Melbourne, Parkville, Victoria, Australia. k.crossley@pgrad.unimelb.edu.au
authors.forename: K
authors.initials: K
authors.lastname: Crossley
authors.forename: K L
authors.initials: KL
authors.lastname: Bennell
authors.forename: T
authors.initials: T
authors.lastname: Wrigley
authors.forename: B W
authors.initials: BW
authors.lastname: Oakes
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D015519:Bone Density; D003430:Cross-Sectional Studies; D015775:Fractures, Stress / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D012420:Running / Q000293:injuries / Q000502:physiology; D013978:Tibial Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology*