WBV therapy might be an interesting technique to achieve this in JIA patients. It is able to improve muscle function very efficiently with relatively short training times and at the same time confers loads to the lower limbs which are only 30% of body weight. The WBV device consists of a plate going up and down along a fulcrum at a high frequency. The patient stands on the WBV device and the vibration will induce muscle stretch reflexes producing muscle contractions. These muscle contractions are similar to muscle activity during exercise and are not perceived as painful or unpleasant. The technique has been used in children with several conditions impairing muscle function.