Cross-training is significant in a fitness regimen as it combines various forms of exercise, reducing the risk of injuries associated with repetitive motions. This method enhances overall fitness by improving strength, flexibility, and endurance while keeping workouts varied and engaging. It allows muscles to recover by alternating stress on different muscle groups, preventing overuse injuries. Furthermore, cross-training can alleviate workout boredom, enhance motivation, and promote better overall performance by developing a well-rounded athletic capacity.