PURPOSE: This study examined whether a community-based progressive resistance strength training programme could improve muscle strength and functional activity in a group of adults with cerebral palsy with high support needs. METHOD: Using a single group pre-post clinical design, 10 adults (7 males, 3 females; mean age 47.8 SD 5.7 years) with cerebral palsy and high support needs completed 4 weeks of introduction and familiarization, followed by a 10-week progressive resistance strength training programme in a community gymnasium. Participants were measured for muscle strength, locomotion speed and timed sit-to-stand. RESULTS: After establishment of a stable baseline from weeks 2 to 5 with no systematic change and a high degree of association (r>0.86), participants increased leg strength by 22.0\% (p=0.02), arm strength by 17.2\% (p=0.01) and improved performance of sit-to-stand (p=0.02) during the 10-week strength training intervention. CONCLUSIONS: This study adds to the accumulating evidence that strength training can be beneficial for people with cerebral palsy by demonstrating benefits for adults with cerebral palsy and high support needs who are subject to decline in physical function associated with the ageing process.