The gait cycle can be divided into 2 parts, stance phase and swing phase (fig. 1). Stance phase is the period when the limb is in contact with the ground, this accounts for 60% of the gait cycle. Swing phase is when the limb is not in contact with the ground, this account for 40% of the gait cycle. There are 2 periods of double support, where both limbs are in contact with the ground, both of these last for 10-12% of the gait cycle. The 1st double support starts at initial contact and ends when the opposite foot leaves the ground at toe off. The 2nd double support begins as the opposite limb contacts the ground and ends when the limb in question leaves the ground at toe off.