Objective To study the general rule in the power spectrum percentage of balance when normal people standing and the differences of the power spectrum percentage between normal people and the stroke patients. Methods 30 normal people and 30 stroke patients was tested with Active Balancer EAB-100 (Sakai Iryo) open- and close-eye. The whole path length, circumference area and the percentages of power spectrum on the X, Y and Z axes were recorded. The correlation and the differences were analyzed. Results The percentages of power spectrum were not statistically correlated (P>0.05) with age, height, weight or gender. There was significant difference between two groups in the percentage of power spectrum (P<0.05). On the frequency spectrum, the ratio rised on the low and middle frequency part, especially within 0.2~2 Hz, but the ratio decreased on the high frequency part (2~10 Hz) (P<0.05). Conclusion The percentage of power spectrum can be an important reference in assessing the stroke patients' balancing functions.

Contracture and spasticity of ankle joints were major sources of disability in neurological impairment including stroke and cerebral palsy, etc. The manual stretching used in physical therapy might be laborious and time-consuming to the therapists and the outcome was dependent on the experience and the subjectiveend feelingof the therapists. A device was developed that could safely stretch the an-kle joint to its extreme positions with quantitative control of the resistance torque and stretching velocity. Furthermore, it could satisfy a strong need for quantitative and objective measures of the impairment and rehabilitation outcome. This was just the meaning intelligent stretching referred to. This article described the origin of the concept of intelligent stretching and its definition, operational principle, and su-periority and weakness, as well as its application in ankle joint spasticity and contracture in patients with stroke and cerebral palsy.