Sixty-seven parents ( 97.0 % mothers ; mean age 38.7 7.1 years ) of children ( 64.2 % boys ; mean age 5.3 3.0 years ) with CP ( Gross Motor Function Classification System = 15 , 22 % ; II = 18 , 27 % ; III = 12 , 18 % ; IV = 18 , 27 % ; V = 4 , 6 % ) participated and were randomly assigned to SSTP , SSTP + ACT , or waitlist .