How significant is the impact of weight on cycling performance, and are there any specific areas of the body where excess weight has a more detrimental effect on efficiency and speed? For example, does carrying extra weight in the legs and core have a greater impact on pedaling efficiency and power output compared to carrying it in the upper body? Are there any studies or data that suggest a certain amount of weight loss can lead to a corresponding increase in speed or endurance? Additionally, how do factors like body composition and muscle distribution influence the relationship between weight and cycling performance?