Improve your elbow and shoulder with a parabolic motion—avoid letting the stroke and body rotation disrupt your balance.

•4 min read
Improve your elbow and shoulder with a parabolic motion—avoid letting the stroke and body rotation disrupt your balance.
When first learning freestyle, the biggest concern is often sinking underwater. Typically, people tackle this by focusing on perfecting their kick—but in reality, all it takes is shifting your center of gravity slightly forward and keeping your body streamlined. While kicking effectively to prevent sinking is a solid long-term strategy, for beginners eager to start swimming as soon as possible, it can feel like "trying to fetch water from a distant well when you’re already thirsty."

The swimming motion in freestyle involves a constantly shifting center of gravity—especially during the arm strokes and body rotations. Even the up-and-down movement of the head directly affects the body’s balance, disrupting equilibrium and often leading to sinking. So, why do many swimmers manage to float smoothly on the surface yet still sink when they start moving? This article shares insights and practical tips on this very issue.
1. A New Perspective on the Freestyle Swimming Stroke
Analyzing a single issue from multiple angles helps achieve a comprehensive understanding of the subject—and the same holds true for swimming. Viewing freestyle as a combination of arm strokes and leg kicks breaks down the swim’s propulsion into distinct upper and lower components, allowing swimmers to focus on refining their individual stroke and kick techniques. Alternatively, if freestyle is seen as an alternating rhythm of propulsion between the left and right sides of the body, it offers a more holistic perspective on the swim. In this case, the emphasis shifts to maintaining a seamless, continuous power chain involving the arms, legs, and core muscles.

The recovery phase of the arm movement in the "pulling" action can be visualized as reaching into your pants pocket to grab something—and then tossing it forward, right in front of your body. Meanwhile, the push phase feels more like pulling a lever backward: steady yet surprisingly swift. As for the kicking motion, imagine a kite’s streamer gently fluttering up and down with the wind. From a power-generation standpoint, the arm pull resembles throwing the muscles from your back forward, only to pull them back again, while the kick mimics swinging your hip muscles forcefully toward your feet.
2. Formation of a Single Power Chain
Looking at the propulsion system from one side, the arm stroke generates a backward, vertically aligned thrust against the water; the kicking motion pushes downward, and thanks to the angled slope of the foot, this creates a backward component that contributes to the overall propulsive force. Meanwhile, core strength acts as a stabilizing brace, ensuring the torso remains rigid and upright throughout the movement.
Overall, both the sculling and kicking motions on the same side generate thrust. Ideally, this thrust should remain consistently strong and stable—but unlike pushing a box, where the force doesn’t diminish as you push it backward, pushing water actually results in the force becoming weaker the farther you go.

Therefore, to maintain stable propulsion, the arm pull-through must begin with a catch phase and continuously accelerate, counteracting the gradual loss of water that weakens the thrust. Meanwhile, for consistent propulsion during the kick phase, continuous kicking is essential—after all, the key factor in generating forward momentum through kicking lies in its seamless, uninterrupted rhythm.
3. The Relationship Between the Power Chain and the Support Line
No matter how strong the force applied to the power chain may be, its effectiveness ultimately depends on a solid supporting structure. As Archimedes famously said, give me a lever long enough, and I shall move the Earth. But before you can exert any force, you must first establish a robust foundation of support—otherwise, your effort will either fail entirely or even risk damaging the very part from which you’re applying it.
Swimming is exactly the same: whether you’re generating power with your arms or your kicks, establishing solid body support is absolutely essential—it’s the fundamental prerequisite for improving both your stroke efficiency and kicking technique. Unfortunately, some swimmers overlook this critical aspect during practice, instead relying on brute force. As a result, they end up overexerting their arms, leading to shoulder instability; pushing too hard with their kicks, which causes excessive hip movement; or even applying too much rotational force, causing their bodies to lose control and become unsteady.

To put it another way: if the power chain is like a "creeping fig," then the supporting lines are like "wooden poles." The body’s stability relies on core strength—if your core isn’t strong enough, or if it’s weaker compared to your arm and leg movements, your body won’t stay rigid or well-supported. In this scenario, the stronger your arm and leg movements become, the worse your swimming performance will actually be.


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