What should you do if your legs keep kicking involuntarily while swimming freestyle? The root cause is often applying too much force when kicking.

Some swimming enthusiasts notice that, while performing the flutter kick in freestyle, their other leg tends to unconsciously wobble along with it. While this habit isn’t ideal, it’s not easy to correct overnight—so they ask me how they can improve their freestyle kick. Based on my swimming experience, that "wobbling" leg isn’t actually trembling; rather, it’s executing a subtle, mini version of the kick itself. Swimmers who exhibit this behavior often have previously struggled with an awkward or uneven kicking pattern, or perhaps they’ve focused too heavily on practicing the freestyle kick without mastering the proper technique. In some cases, it could also stem from poor coordination between the arm strokes and the leg movements, leading to an imbalance in timing.

1. To master the flutter kick in freestyle, start by practicing hip rotation.

For young children who may not yet have strong comprehension skills but possess remarkable physical flexibility and strength, performing direct kicking exercises is the preferred learning approach for mastering freestyle swimming. However, for adults who excel in understanding but lack sufficient body flexibility, attempting to focus solely on kicking can often feel like trying to achieve twice the effort for half the result. Struggling relentlessly with a kickboard to master that "whipping" leg action—only to then move on to other freestyle techniques—typically leads to less-than-ideal learning outcomes. In contrast, the Full Immersion Swimming System emphasizes first grasping the fundamental concepts behind freestyle movements, followed by practicing unilateral swimming, incorporating proper body rotation and secondary kicks. This method prioritizes solving the core challenge of learning how to swim correctly before gradually refining technique and improving overall body coordination during full-length practice sessions. Ultimately, this approach enables swimmers to glide effortlessly through the water—efficiently, comfortably, and with maximum effectiveness.