The kick in freestyle is one of the most misunderstood parts of the stroke. Most swimmers think it is the engine. It is not. At distance pace the kick contributes somewhere between 10 and 15 percent of total propulsion. The arms do the rest. This surprises most swimmers because the kick feels powerful and active, and the legs are working hard enough that they must surely be contributing more. But water is dense and the legs are not shaped like paddles. They generate relatively little forward thrust compared to the metabolic cost of moving them. What the kick actually does is stabilise and connect. It keeps the hips from sinking, maintains the body’s horizontal position, and provides the timing mechanism that links arm movement to body rotation. The downbeat on each side coincides with the opposite hand entering the water, creating the cross-body coordination that keeps the stroke balanced and connected. Without this timing the stroke splits into two independent movements, arms and legs running in parallel without mechanical relationship to each other. This changes how the kick should be trained. A kick that is developed purely for propulsion, big, deep, and powerful, is being trained for the wrong job. The kick that serves freestyle best is compact, rhythmic, and precisely timed. It costs relatively little energy, stays within the body’s profile to avoid drag, and keeps the stroke connected across every length. The swimmers who kick hardest in distance swimming are usually compensating for something. Sinking hips, poor body position, or a stroke that has lost its connection. A well-organised stroke needs very little from the kick. That is not a weakness. That is the point. Technical fact: Research on freestyle propulsion shows the kick contributes approximately 10 to 15 percent of forward thrust at distance pace, with the primary functional role being postural stabilisation and inter-limb timing. Excessive kick amplitude increases metabolic cost and drag without proportional propulsive return, making kick economy more valuable than kick power in distance freestyle. The kick is not the engine. It is what keeps the engine running smoothly. - @markus_marthaler