Why don’t the legs sink during the full-body streamline swim? A detailed analysis of the full-body streamline concept

•5 min read
Why don’t the legs sink during the full-body streamline swim? A detailed analysis of the full-body streamline concept
How can you swim freestyle with ease? It becomes effortless when you focus on two key techniques: First, master your breathing—practice it until it feels natural, ensuring your body always has a steady supply of oxygen. Second, keep your body completely streamlined, floating horizontally on the water like a flat board; even a gentle push will send you gliding smoothly and far.
Some swimmers might feel self-conscious about their belly fat or weight gain—don’t worry, though; even a massive 10,000-ton ship can still float on water. And believe it or not, the reason humans can swim isn’t because we’re particularly strong—it’s all thanks to the buoyancy of the water!
The Total Immersion freestyle method features a specially designed practice system tailored for adults learning to swim, helping them effortlessly discover the natural, relaxed feel of freestyle. Many viewers of Total Immersion freestyle videos will notice that swimmers maintain a more streamlined, horizontal body position compared to traditional freestyle—despite minimal kicking, their legs seem to stay buoyant and avoid sinking. This is precisely what makes Total Immersion freestyle so easy and comfortable to swim.
1. First, we need to figure out why the leg is sinking?
There are three main reasons why the leg sinks: first, the leg's own weight; second, lifting the upper body; and third, having the support point positioned too far forward or becoming ineffective.
When swimming, your body has two key points of support: one is the arm extended forward, and the other is your hip as you twist your body sideways. Think back to when your body lies flat in the water—your upper body is broad, creating a large surface area in contact with the water and generating significant buoyancy. Meanwhile, your lower body consists of just your two legs, which have a much smaller surface area in contact with the water—and naturally, less buoyancy. As the saying goes, "A rope breaks at its weakest point"—and that’s exactly why your lower body tends to sink first.
So, to prevent the legs from sinking, you need to achieve balance between the upper and lower body—either by letting the entire body sink together or by making it rise as a whole. There are two ways to achieve this balance: either by increasing buoyancy in the lower body, or by increasing the gravitational pull on the upper body. Traditional freestyle swimming typically opts for the former approach—focusing on practicing leg kicks—while the full-body immersion technique chooses the latter, shifting the center of gravity forward.
2. Why doesn’t the full-body freestyle kick easily cause you to sink?
The application of the center of gravity. Since full-body immersion swimming focuses on the center of gravity, it’s essential to emphasize how the body’s own weight is utilized during the swim—after all, gravity affects the entire body. As a result, compared to leg-kicking techniques, full-body immersion embodies a more holistic approach to swimming philosophy.
In the full-body streamline freestyle stroke, you swim using your entire body—naturally making it easier and more efficient than relying solely on arm strokes and leg kicks. As your body moves through the water, its center of gravity shifts continuously, and the full-body streamline technique effectively leverages these dynamic changes.
Gravity-assisted arm recovery. In the full-body immersion freestyle stroke, greater emphasis is placed on fully relaxing the arms during the recovery phase compared to traditional freestyle. As a result, swimmers avoid the sweeping arm motion typically used in conventional styles, instead opting for an elbow-lift technique—lifting the elbow out of the water and then performing a high-elbow recovery. The arm is brought upward until it’s positioned directly above the head, with the entire limb now suspended entirely above the water, relying solely on gravity rather than buoyancy. This approach significantly increases the gravitational pull on the upper body, naturally making it harder for the lower body to sink downward.
Highlighting the reason for deeper entry into the water. Additionally, in full-immersion freestyle, the entry action is emphasized more than in traditional freestyle—specifically, entering the water at a deeper angle. This approach is primarily aimed at preventing the palm from pushing downward after entry, which could generate upward buoyancy and cause the upper body to rise while the lower body sinks accordingly.
Considerations of trade-offs. In the latest full-body immersion swimming technique, the requirement for water entry depth has been reduced—after all, there’s no clear correlation between how deep a swimmer enters the water and the subsequent downward pressure applied with the palm. Instead, most swimmers tend to unconsciously press their palms downward as they extend their arms forward. Personally, I suspect that emphasizing deeper water entry in full-immersion techniques might simply help beginners focus more on achieving the right depth, leaving them less aware—or even distracted—from performing the downward-pressure action altogether.
Two-beat kick: Beyond the arm recovery motion on the water's surface, the underwater two-beat kick is also a defining feature of the full-body immersion freestyle technique. It’s widely recognized that kicking plays a crucial role in boosting swimming speed—but for most adults, stiff ankles are quite common. Pushing too hard to master the whip-like kick, as traditionally emphasized in conventional freestyle, can actually hinder instruction and fail to meet swimmers’ urgent need to start moving through the water quickly. Instead of attempting an unsteady six-beat kick, full-body immersion advocates focusing intently on perfecting the efficient, two-beat kick. Moreover, even if beginners struggle with the two-beat kick initially, its impact on the upper-body stroking technique remains far less detrimental compared to the six-beat kick.

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