The butterfly is, without a shadow of a doubt, the most energy-sapping stroke. You consume twice as many (kilo)calories swimming the butterfly than swimming freestyle. For this reason and because of the symmetry of arm movement required when performing this stroke and the large muscle groups involved, the butterfly is often used for developing strength, [...]

The butterfly is, without a shadow of a doubt, the most energy-sapping stroke. You consume twice as many (kilo)calories swimming the butterfly than swimming freestyle. For this reason and because of the symmetry of arm movement required when performing this stroke and the large muscle groups involved, the butterfly is often used for developing strength, [...]

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