In recent years, fitness concepts have continuously evolved, with many seeking to improve and enhance their physical condition through exercise to achieve better athletic performance. Aerobic exercise not only increases lipid utilization but also boosts athletic performance. Consequently, various aerobic exercise equipment has become increasingly popular in the market. Due to the pandemic's impact in recent years, people have rarely ventured outdoors, making indoor exercise equipment increasingly popular for home workouts. Spinning has emerged as a widely adopted new fitness activity, accessible to all genders and ages. Many gyms even offer specialized spinning classes with variations in speed and resistance. However, past literature has predominantly focused on continuous-intensity spinning interventions, which do not reflect the diverse training variations found in actual spinning classes. Therefore, this study aims to investigate the effects of incorporating high-intensity interval training (HIIT) into spinning on cardiorespiratory fitness.