The aim of the work was to show that the fatigue load of bone tissue causes permanent structural changes in it.On the basis of the movie recording of gait, the time courses of angular changes in the joints of the lower limb were determined. Using the method of transforming Denavit-Hartenberg coordinate systems, the course of force loading the hip joint and, after that, the course of normal contact reaction of the femoral head of the knee joint during gait for the support phase were determined. On the basis of the Hertz formula, the course of contact stresses in the femoral joint head and the damage coefficient were determined according to the Palmgren-Miner damage accumulation hypothesis.A calculation example was made using own software. The course of the obtained damage factor was compared to the image fixed in the X-ray image after its appropriate processing. The thesis of the work has been confirmed to a satisfactory degree.The nature of the lesions is similar to the image of structural changes in the head of the joint. It should be assumed that the image fixed in the bone is the result of the stored history of loads. Analysis of the obtained image can be used to determine the state of bone strength.