Methods
Thirty-four participants aged 6.0 to 12.6 years with CP acted as their own controls and underwent two consecutive study periods: a 12-week lead-in (control) period prior to the intervention period of 20-week side-alternating VT (9 min/session, 4 days/week), with the frequency either 20 Hz or 25 Hz, determined by randomisation. Participants had 4 assessment visits: baseline, after the control period, after 12-week VT (12VT), and after further 8 weeks of VT (20VT). Assessments included 6-minute walk test (6MWT); dual-energy x-ray absorptiometry; gross motor function; muscle function testing on the Leonardo mechanography plate and by hand-held dynamometry, and a quality-of-life questionnaire (CP QOL). Analysis was carried out using linear mixed models based on repeated measures.