OVER-gliding is cited by some as a terrible problem in a swimmer’s stroke. UNDER-gliding is also a problem – a far more grave problem really, and unfortunately, left terribly under addressed in many coaching programs.

Have you ever felt or been criticized for having one of these problems?

Over-glide, in the sense of being an excessive glide, is a result of pausing in the stroke cycle at the moment the body reaches the most elongated passive streamline position.

Over-glide in its most common form is a timing problem. It is fixed by correcting the stroke timing. Initially, a coach may try to correct this problem by simply speeding up your stroke tempo. It touches on the right idea but does not completely arrive there. Simply increasing the tempo of the whole stroke cycle may solve one problem while cause another.  It all happens so fast, in microseconds in fact, but not all sections of the stroke cycle are equal in their value at various paces. In your most effective stroke the amount of time spent on each section of the stroke cycle (the distribution of micro seconds across that cycle) changes in proportion as the stroke tempo changes. Your optimal slow or medium tempo stroke distributes those micro seconds differently than an optimal fast tempo stroke does. The speed at which your arm travels through each section of the stroke cycle should vary according to the requirements of that particular pace (the optimal stroke length and tempo combination that you have chosen, tested and trained for). So when you need to correct an over-glide, we would not simply speed everything up to remove some dreaded pause. Instead, we would teach you how to speed up just a certain section of the stroke cycle while preserving a more effective steadiness in another. By this the deceleration and acceleration in your stroke is smoothed out, keeping a stronger pace that requires less power to maintain.

Over-glide in the context of drilling, however, is very beneficial. Over-glide is a test of balance and streamline. If you attempt to stroke into a glide but slow down quickly (as if drifting in mud) then it is obvious you have an excessive imbalance and/or drag issue. If you can stroke gently into a glide and keep gliding along a couple more meters with a very gradual deceleration then we see that you have relatively low drag in this passive streamline position. To envision this I like to think of how easily a sea kayak will glide along under the most gentle paddle pressure – because it is balanced and streamline. This is how I envision my own swimming.


You may also think of this like two sets of ball bearings in your bicycle wheel hub – one set allows your wheel to spin with a rough motion and grinding noise and the spin slows down quickly. The other set causes your wheel to hum quietly and seems to spin forever. Which one do you want on your bike? Swimming with poorly controlled shape is the same as riding a bike with rusty bearings. So, would you prefer to overcome the friction in your bike’s rusty bearings by hammering the pedals harder or by changing the hubs on your wheels?

By doing drills using gliding as a form of measurement you can receive instantaneous feedback about the drag in your body position, at least in the passive position that is being tested. In TI, when using glide in certain slow tempo drill work (like Slide And Glide, for instance), the swimmer is intentionally making time for detecting this direct feedback of drag, assessing what is causing it and make self-correction during the act of moving along, rather than waiting afterward to view a video or hear a coach’s external feedback then try to make the kinesthetic connection. Proprioception – your ability to control your body position and movement patterns without using your eyes – is improved by making correction while swimming not afterward.

Now let’s address UNDER-gliding.  And I dare say it is a far more serious and common problem than over-gliding. In pools around the world I rarely see anyone with an over-glide, while just about everyone I see suffers serious under-glide. While often treated as a problem of insufficient power under-glide is far more commonly a result of excessive drag – generating more power, before fixing the drag problem  just makes it worse.

Another analogy: it can be understood by common sense that if you take two boats with the same engine power but different hull shapes, send them propelling along at the same time then cut the engines, the boat which glides the farthest has the best (more efficient) hull shape. And it may be safely deducted that this particular vessel would also cruise along using less power than its competitor, or simply travel faster under the same amount of power. This is exactly the situation for human vessels in the water. Measuring a swimmer’s ability to easily over-glide is the most convenient test of whether this swimmer has achieved a superior hull shape or not.

So, how slick is the shape of your human hull?

I think the best swim programs have the same heart to help their competitive swimmers get FAST. But do they achieve this primarily by building power or by building shape? You can tell by how much attention is given to each in their programs and practice plans.

TI specifically guides a swimmer to FAST by first and foremost addressing this excessive drag problem. And to do this we must first slow everything down. The shape of the body at every section of the stroke cycle is formed and reformed within micro-seconds. In these terms we can see that fine tuning the streamline at every section of the stroke cycle is extremely difficult to make unless things are pieced out and slowed down at first. Hence, TI students learn drills that build the ability to over-glide at will  not as a rigid swimming habit. The over-glide is meant to give them time to feel, think, adjust. But as the brain catches on using this process it will be able to gradually speed things up, dialing in perfect timing as they go.

Here is something to keep in mind: Humans are so excessive in drag that it has been estimated that our best human swimmer converts, at best, only 7 or 8% of his power into forward motion while a dolphin converts up to 80%. The common swimmer converts maybe only 3 or 4%!!! That means at least 93% of the power you produce while swimming is being used for something other than moving forward in the water.

What do you think you are wasting your 97% on???

Is your preferred coaching program helping you move steadily from 97% wasteful to a mere 93%? I don’t know about yours, but that is exactly what TI coaching is focused upon. We are, in a very real sense, human hull engineers.

Because of this fact of humans-moving-in-water the TI method is obsessed with perfecting your human hull shape. And the great thing about being one of these complicated human vessels moving forward in water is that every human has endless opportunity to improve hull shape and gain more speed for less energy. This is the essence of efficiency. Get more done for less effort.

So, in the case of UNDER-glide power and fitness are rarely the real problem however convenient they are to focus coaching time on. When a coach doesn’t know how to reduce drag further he simply focuses on increasing power and stroke tempo. Historically, and today, the vast majority of swim programs are devoted to this approach, as you can readily see in how they design their practices and what they fill their teaching space with. But naval engineers, DARPA engineers, and TI Stroke Crafters do understand this reality, and work to continuously improve the shape of the hull, which reduces drag, which reduces energy waste. We make no apology for spending a great proportion of our attention on it.

So if you are worried, or have been criticized about having an over-glide in your stroke, I offer you this alternative perspective on your situation. Your first and highest and continuous priority is to find the ways to remove excess drag from your stroke and keep it away at every effort level, over every distance. And this will be your perpetual objective from your early swimming years, to your peak speed years, even as you cross over the threshold into middle age when your strength potential starts to wane. Obsessive drag reduction is, by a fact of physics, a far more effective approach to swimming fast and far.

Lastly, it is relatively easy to correct your stroke timing once you’ve developed a truly effortless over-glide – if that is even a ‘problem’ at all – than it is to reduce drag from an imbalanced and under-gliding stroke. In TI we can fix either one, but we will always address drag before power.  Learning to glide and then to read the critical feedback given in the glide is one of the first objectives for a student of basic TI.  I realize some people have gotten stuck there in that over-glide concept in your self-study and understandably drawn criticism for it. It’s actually not a problem unless you stay there ignorant of its training purpose. It just means you are ready for the next step.

PS- what I have not taken more space to explain here is how least drag shape can be discovered and preserved in each section of the stroke cycle, not just the longest passive streamline position. But that can wait for another post or for a nice coaching session with a TI Coach some day.

So now what problem do you think you have?

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