Increased incidence of stress fracture has been reported for amenorrheic runners, while some studies have reported decreased spinal bone mass in amenorrheic runners. Based on results from these studies, one tends to associate decreased spinal bone mass with an increased risk of stress fracture. The present study compared regional bone mass and external loads during running between six female runners reporting a history of stress fracture (seven tibial and three femoral neck) and eight female runners with no history of stress fracture. Dual photon absorptiometry measures indicated significantly greater spinal (L2-L4) and femoral neck bone mineral density in stress fracture subjects (p<0.05) but no differences between groups for tibial bone density. Normalized forces recorded from Kistler force plates indicated significantly greater vertical propulsive, maximal medial, lateral, and posterior forces for stress fracture subjects during running (p<0.05).
The authors are with the University of Calgary, Calgary, Alberta, Canada T2N 1N4. S.K. Grimston and J.R. Engsberg are with the Human Performance Lab, Faculty of Physical Education. R. Kloiber is with the Dept. of Nuclear Medicine and D.A. Hanley is with the Div. of Endocrinology and Metabolism, Faculty of Medicine.