The butterfly stroke is the most difficult for many swimmers to master because it involves more muscles to activate at the same time. To accomplish an effective and smooth butterfly, swimmers must be incredibly powerful in numerous parts of their bodies. Specifically, they must have strong legs and flexible hips to pull themselves through the water with their arms alone. Butterfly swimming is not as inefficient as it may seem at first glance. Although it requires more energy than other strokes, a swimmer using this stroke can cover much greater distances before reaching shore or a boat. This is because the butterfly stroke uses all the principal muscle groups in your body, including your shoulders, back, and chest. These are the same muscles that power other types of strokes such as front crawl or backstroke. Thus, by engaging these muscles throughout the movement, a swimmer using the butterfly stroke gains strength and flexibility. Butterfly swimming is also less fatiguing than other strokes due to its minimal-repetition, maximum-effort nature. Since this is a one-time use of your muscles, you will not get exhausted as quickly when performing it regularly. Finally, butterfly swimming is very accessible. Even beginning swimmers can learn this stroke because there is hardly any technique involved. You simply need to know how to breathe out while pulling yourself forward with your arms and then breathe in while pushing off with your feet.