Three-Dimensional Gait Analysis Can Shed New Light on Walking in Patients with Haemophilia

Figure 1

The infrared cameras (a) are positioned so that at least two visualize each reflective marker at any given time. From the reflective markers movements we can calculate the 3D trajectories of the body segments (b). The images are then processed to derive the graphs of the kinematics, that is, the joint range of movement of each lower limb joint (c). A force platform located under the treadmill (b) records the patient’s ground reaction forces. The joint moments and powers, that is, kinetic data, (d) are derived from force platform measurements and kinematic data. Energy expenditure is measured indirectly based on the rate of oxygen consumption by the patient using an ergospirometer (e). Finally, the mechanical work is calculated as the work performed by muscles to raise and accelerate the center of body mass (external mechanical work) and to move the body segments relative to the center of body mass (internal mechanical work) (f).