The purpose of this study is to measure the ability of balance controlling and test the evaluation of clinical trials with different arch insoles. The investigators want to find out the difference and efficacy of arch insoles in the dynamic postural control for the elderly.

Inclusion Criteria:

• no cognition problem. (mini-mental state examination [MMSE] > 23)
• no sensory or motor problem
• no use drugs about balance control
• lower extremity without any traumatic injury

Exclusion Criteria:

• Cognition impairment
• with specific neurological deficits resulting from neuropathy, neuromuscular disorders or spinal stenosis
• use drugs about balance control
• total joint arthroplasty

the elders