This is a continuation of Swimmer Speed Curve Part 1…
In this diagram we see two swimmer speed curves. The further to the right the curve, the faster the swimmer is going.
They both curve upward as the swimmer applies more power, and eventually reaches an ultimate Peak Speed limit at Node #3.
They both have an Easy Speed limit at Node #1.
But Swimmer B in GREEN is going faster than Swimmer A in RED. The two swimmers are applying the same amount of power but one goes faster than the other.
Why?
If all other things are equal between the two, Swimmer B’s faster curve is a result of having a better ‘hull shape’. In other words, the two swimmers are applying the same amount of power but have different technique for how that power is applied during the stroke. Shape is the most obvious reason why.
This explains how I can swim along side my student noticeably using a fraction of their power while swimming the same speed. I am not boasting, I am not an exceptional human specimen. I am teaching the student how to slide their curve closer to mine. Superior shape during each stroke allows me to travel along at the same speed with less power.
Superior body shaping (what we may also call a swimmer’s ‘form’) is one of the primary features of superior technique.
Look at the pairs of nodes on each curve this way:
- A1 is the speed you get with inferior technique with low power
- A2 is the speed you get with inferior technique with high power
- B1 is the speed you get with superior technique with low power
- B2 is the speed you get with superior technique with high power
And nodes A3 and B3 represent the speed limits for each curve, assuming this swimmer can hold superior shape under highest metabolic stress. All things equal, both apply the same power, but one will have a Peak Speed limit faster than the other.
Which curve do you want to swim on?
This first point is this: the swimmer who is understands that shape trumps power will be devoted to superior technique under all levels of intensity. She will have a higher speed potential than the swimmer who believes power trumps shape and is willing to compromise her shape when applying more power.
And the second point is this: power training will push you up your speed curve. Technique training will slide your curve to the right.
Note carefully – I am not saying power training is not good or useful. I am saying explicitly that power training has to be done always in respect to technique, never at the cost of it. The ability to increase power is critical if you want to compete and it must be done in the context of technique improvement. Power is delivered through technique. I repeat again – fitness is your ability to generate power and sustain it, while technique is your ability to deliver that power right where it is needed, when, and in the right amount to get the job done. Power has meaning only when delivered with precision.
And the third point is this (which I have said many times on this blog): to slide your curve to the right you must lower the power back down, rebuild the neuro-muscular circuits that improve your shape, then gradually power back up while maintaining loyalty to that improved shape. Hence, the Dual-State Swimming I described in Two Essential Measurements.
There is a reason why many of those hard working swimmers in the club next to you have a tremendous work ethic but little speed improvement. This may be it. They simply cannot work much harder, yet for a season they won’t lower the intensity enough to allow the body-reshaping process to slide their curve to the right.
Now look at this chart in a slightly different way – let’s say these two curves represent you in two different conditions – A is you with superior shape, and B is you with inferior shape. When you forsake the technique you’ve been working on in order to ‘just swim harder’, you stay on Curve A. But when you discipline yourself to develop speed always and only with superior shape that resists energy waste, you get on Curve B.
Want to go faster? First, use part of your season to slide your curve, then use the next part of your season to work your way up it.
There is more to say about this in the next part…
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Isaac sent me a message with more engineering thoughts on the speed curve…
The attached graph differs from yours only in aesthetics, not in content. However, you may find it interesting.
View Graph
The Wikipedia article you referenced, provides the correct formula. The graph reflects the formula using arbitrary constants. However, since I think of applying Power and getting Speed, I am used to reversing the axes (Power on the horizontal line).
In the graph you can visualize a poor swimmer (blue line, form factor=1) applying his utmost power (100%), and a getting a top speed of 1. Now he can choose between two options.
1. Work on fitness, and increase his aerobic capacity by 10% (110 on the horizontal axis). For swimmers in reasonable shape, this is a difficult undertaking, and the payoff is a speed increase (same blue line) of only 3%.
2. Work on technique/hull and improve his drag coefficient by 10% moving him to the red line (form factor 1.1). (I am not sure, but this may mean reducing his SPL from 24 to 21.5) In this case, his speed will improve by the corresponding 10%.
The story above is good for demonstration purpose. I think it may be unfair to assume that all these guys working hard in the pool, are only improving their fitness. Mindless repeated use, must improve efficiency, even if ever so slowly.
BTW, at any power level, a small increment in power input %, will result in only a third improvement in speed. That is due to the cube relationship in the equation.
ok I have read this blog when you first published it and was afraid of asking what probably is a dumb question. My knowledge of graphs is that they depict some measurable content. I know you can measure speed, but how do you measure power? I do understand what you are trying to get at, but to me, the graph is confusing.
Hi Sherry, definitely not a stupid question. It is actually a very difficult thing to do in swimming. Jane Cappaert has done it in the 1990’s for Olympic swimmers, for example, but as far as I know it is quite a tricky and disruptive thing to hook swimmers up to measuring devices and still allow them to swim naturally.
The diagrams are merely conceptual, but the increasingly vertical curve is meant to be an analogy to our land-mammal sense of effort involved in climbing up an increasingly steeper mountain-like curve. For now, we can use something like the Rate of Perceived Effort (RPE) to judge our level of effort, which (when healthy and under normal, consistent physical circumstances) corresponds roughly to our power output. RPE 1 = walking like effort, RPE 2 = jogging, RPE 3 = moderate running, RPE 4 = brisk running, RPE 5 = sprinting
It’s not an easy thing to describe and these articles are my way of practicing how to explain it better. I appreciate hearing that it didn’t make the connection for you so I can consider how to do it in a different way.