Wikipedia
In orthopedics, weight-bearing is the amount of weight a patient puts on the leg on which surgery has been performed. In general, it is described as a percentage of the body weight, because each leg of a healthy person carries the full body weight when walking, in an alternating fashion.
After surgery of the hip, or of the bones of the leg, ankle, or foot, it is of the utmost importance for recovery to get the right amount of weight-bearing when moving around with crutches or frames.
The grades of weight bearing for each phase of recovery will be determined by the surgeon. The Anti-Gravity Treadmill can allow testing of weight bearing by lowering effective body weight in 1% increments from 100-20% of body weight.