Swim butterfly using only your arms
Swim the butterfly using your arms only: keep your legs still (use a pullbuoy or pullkick as an aid). Swimming the butterfly with your arms only can be rather tiring, but it will produce great results! Place the pullbuoy between your thighs and, if you are struggling with the arm stroke, kick gently with your legs to make it easier. Focus on the catch phase and on pulling relatively hard with your hands and arms. Make sure your body is not too stiff or tense, let your legs float naturally (an unnatural position is likely to give you cramp in your calves).