Vlinderslag

Vlinderslag, also known as the butterfly stroke, is a swimming stroke used in competitive swimming. It is one of the four competitive strokes, alongside freestyle, backstroke, and breaststroke. The defining feature is that the arms move forward simultaneously in a wide arc while the legs perform a dolphin kick, producing a wave-like undulation that propels the swimmer forward. The body remains mostly horizontal and prone in the water, with the head in a neutral position. Breathing is coordinated with the arm recovery, typically by lifting the head briefly above the water for a quick breath.

Technique: The stroke begins with the hands entering the water in front of the shoulders. Both arms pull simultaneously in a broad, circular path toward the hips and recover over the water. The kick is a dolphin kick, driven by a coordinated movement of the hips and legs with the feet kept together. Timing and rhythm are essential, as the arm pull, kick, and breath must be synchronized to maintain speed and efficiency.

Training and pacing: Vlinderslag is physically demanding, requiring strength in the chest, shoulders, and core, as well as cardiovascular endurance. Common training focuses include technique drills, kick sets, and medium- to long-distance sets to develop rhythm, timing, and breath control. Swimmers may vary kick cadence to suit distance and individual style.

History: The butterfly stroke originated in the 1930s as a refinement of the breaststroke and was recognized as a separate stroke in the 1950s. It has been part of major competitive programs since the mid-20th century, including the Olympic program.

See also: freestyle, backstroke, breaststroke, individual medley.