Effective walking and balance require not only lower limb muscle strength but also coordinated movement. For individuals with Spinocerebellar Ataxia (SCA), rehabilitation strategies targeting coordination are essential to improving mobility and reducing the burden on caregivers. However, evidence-based rehabilitation approaches for ataxia remain limited. Recent studies suggest that improvements in motor learning are often accompanied by changes in cortical excitability. Abnormal cortical excitability in SCA patients may hinder rehabilitation efforts, yet priming strategies-such as exercise or specific stimuli-have been shown to enhance motor learning by modulating cortical excitability. Cycling exercise, in particular, has demonstrated the potential to improve coordination and influence cortical plasticity in individuals with SCA, making it a promising priming strategy for coordination training. This clinical trial aims to: 1. Investigate the priming effect and neural mechanisms of acute cycling exercise on coordination training in patients with SCA. 2. Explore the long-term impact of priming cycling training on cortical plasticity and functional mobility in individuals with SCA. This study seeks to provide insights into optimized rehabilitation interventions that could enhance the quality of life and independence for people with SCA.