Sixteen children with CP, eight boys and eight girls, aged 9.2 (2.1) years with diagnoses of either spastic diplegia (N = 11)
or spastic quadriplegia (N = 5) were recruited from a local hospital and a special education school. The inclusion criteria
were: (1) add-up MAS scores of bilateral lower extremity greater than two; (2) ability to walk for at least 6 min with or
without walking aids; and (3) ability to comprehend commands. Criteria which would affect their muscle tone and
ambulatory performance were excluded. The exclusion criteria were: (1) the presence of any progressive disorder or a severe
concurrent illness not typically associated with CP; (2) lower extremity surgery within the past 6 months; (3) nerve block or
botulinum toxin injection within the past 3 months; (4) a limitation of knee joint range-of-motion over 108;(5) epilepsy. One
of the authors performed the selection process. Most participants walked independently without walking aids except four,
who used 4-wheeled walkers for ambulation. The Institutional Review Board for Human Studies of Chang Gung Memorial
Hospital approved this protocol. Written informed consents were obtained from all participants and their legal guardians.