Is it really necessary to incorporate interval training into a cycling routine to build strength and power, or can a well-structured endurance training program yield similar results, and if so, what specific circumstances would necessitate the use of interval training over endurance training, and conversely, when would endurance training be more beneficial than interval training, considering factors such as individual fitness goals, current fitness level, and available training time, and how do the benefits of interval training, such as increased anaerobic capacity and improved muscular endurance, compare to the benefits of endurance training, such as increased cardiovascular efficiency and enhanced fat metabolism, and can a combination of both interval and endurance training be used to achieve a more well-rounded fitness level, or would this approach lead to overtraining and decreased performance.