From April 1991 to Feburary 1995, 104 cases of stress fractures of lower extremities (8 cases involved femur; the other 96 cases, tibia) were treated in our hospital. The niechanism of this kind of fracture was explored by clinical observation, anatomic investigation and biomechanical analysis. It was found that the main cause of stress fracture of lower extremity was the bony intrinsic construction failed to adapt to the stress varying during the training course. When the destruction of bony structure was in excess of the remodeling capacity of the bone, the stress fracture was resulted.Owning to the anatomic characteristics, the distal one-third of femur and the middle medical aspect of tibia were the significant weak points in leg movement, and then they become the common site of stress fracture. For the prevention of these fracture, the remodeling capacity of the bone must be considered, instead of keeping the muscular adaption in the mind only in the training course arrangment. Sl...更多ow running will reduce the femoral inclination and then decrease the shearing force. 还原