Trunk Forward Ability in Patients With Lumbar Fusion

The hypotheses of this study are as follows: 1. There is no significant muscle activity difference of each muscle in patients between pre and post operation. 2. There is no significant forward reach distance/average velocity difference in patients between pre and post operation. 3. There is no significant standard deviation of center of pressure (COP) along x axis, speed of COP along y axis during the task and COP path during the 3-sec holding phase difference in patients between pre and post operation. 4. There is no significant muscle activity difference between muscles on both sides at post operation.