 For the lower leg scan, the participant is seated on a chair in front of the pQCT unit. When the machine is at the start position, the participants lower leg is moved through the gantry and the foot is rested on the foot holder. With the foot holder positioned all the way to the front of the pQCT unit, the lower leg is centered and fixed into the concentric acrylic cylinder diameter 18 cm, which is located at the gantry opening. The foot is now fixed with the Velcro strap to the foot holder. Before the scan, the participant is asked to find a convenient and natural position to reduce movement artifacts during the 3-5 minute scan. 