Core muscles strengthening for balance and gait performance in individuals with chronic stroke

Participants will receive 6-weeks core muscle strengthening. Core muscle strengthening contains bracing exercise that is to activate the deeper core muscles particularly which is important components in core muscles strengthening exercises. Bracing exercise are performed by pushing the abdomen out externally. Participants should hold the breath and "brace" abdominal muscles. About the trial, bracing exercise includes bracing with heel slides, bracing with leg lifts, bracing with bridging, quadruped arm lifts with bracing, and quadruped leg lifts with bracing. Participants need to learn how to contract local muscle accurately in those different bracing exercise. If deeper core muscles have been activated, core muscles strengthening can be conducted continually. Exercises have some steps, as follow: (Gymnic Physio Ball will be used in the exercises) 1. Warm-up: participants step on Swiss ball in sitting position for 1 minutes 2. Bridge exercise: hold position for 5 seconds. Perform 10 repetitions for 1 set 3. Bridge exercise with legs crossed, Hold this position for 5 seconds. Perform 10 repetitions for 1 set 4. Bridge exercise with one leg. Hold this position for 3 seconds. Perform 10 repetitions for 1 sets 5. Curl-ups with straight reaching. Hold this position for 3 seconds. Perform 10 repetitions for 1 set 6. Curl-ups with diagonal reaching. Hold this position for 3 seconds. Perform 10 repetitions for 1 set 7. Patient sit on Swiss ball and combine with pelvis anterior tilt. Hold this position for 5 seconds. Perform 15 repetitions for 1 set. 8. Patient sit on Swiss ball and combine with pelvis posterior tilt. Hold this position for 5 seconds. Perform 15 repetitions for 1 set. 9. Supine on Swiss ball with feet on the floor. Hold this position for 10 seconds. Perform 10 repetitions for 1 sets. 10.Patient prone on Swiss ball and combine with trunk extension. Hold this position for 5 seconds. Perform 10 repetitions for 1 sets 11. Cool-down: patient sit on Swiss ball and step on the ball for 1 minutes Sessions will be delivered by a certificated physiotherapist. Training frequency will be core muscles strengthening for 20 min and treadmill walking training with comfortable speed for 10 min per session, 2 sessions per week for a total of 6 weeks. It will be individual one-on-one sessions taking place in Balance training center in Yang Ming university All participants will be supervised by certified physiotherapist in the exercises program. If participants don't know how to conduct, physiotherapist will use manual contact to teach them. And, demonstrate the repeated exercise.