Influence of age on walking performance among adults with bilateral spastic cerebral palsy

PURPOSE: To examine age-related differences in walking performance and its physiological determinants in adults with bilateral spastic cerebral palsy (CP) compared with typically developed (TD) peers. METHODS: Thirty adults aged 18-50 years were included: younger (18-25 years; CPY, n = 7) and older (35-50 years; CPO, n = 8) ambulatory individuals with CP (GMFCS I-II), and age-matched TD controls (TDY, n = 7; TDO, n = 8). Assessments included maximal oxygen uptake (VO₂peak), walking performance (6-minute walk test, 10-m walk test, Timed Up-and-Go), energy cost of walking (CoW), lower-limb strength, balance, self-reported fatigue and quality of life, and actigraphy-derived activity levels. RESULTS: VO₂peak did not differ between groups. However, CPO walked approximately 30-35% shorter distance during the 6-minute walk test compared with CPY and TD peers, and showed similarly reduced performance in 10-m walk and Timed Up-and-Go tests. CPO also exhibited a higher CoW (approximately 8 vs. 4 J·kg⁻¹·m⁻¹). Lower-limb strength was consistently reduced in CPO compared with TD groups and was lower than CPY in most contraction modes. Self-reported fatigue was greater in CPO, whereas quality of life, daily step count, and sleep duration were similar across groups. CONCLUSION: Older adults with CP exhibit pronounced impairments in walking performance despite preserved aerobic capacity. These alterations are associated with increased walking cost, reduced strength, and impaired balance, suggesting accelerated mobility decline in adults with CP. Targeting neuromuscular function and walking economy may therefore represent key strategies to mitigate functional decline in adults with CP.