Both gait and cardiovascular dysfunction are primary factors limiting community ambulation for stroke individuals. Increased gait variability and asymmetry contributes to a higher risk of falls, leading to reduced physical activity, decreased cardiorespiratory endurance, and increased walking economy and sympathetic nervous system activity, thereby potentially triggering secondary strokes. Previous studies have primarily focused on the significant improvements in walking endurance and speed with high-intensity interval training (HIIT) on a treadmill, leaving a gap in understanding the effects of HIIT on oxygen uptake efficiency slope (OUES) and gait quality for stroke individuals using a stationary bicycle ergometer with exergaming. Therefore, this study aims to investigate the effects of HIIT using a stationary bicycle ergometer on improving cardiorespiratory fitness and gait quality in individuals with chronic stroke.