Breaststroke Coupling Technique: A Tale of Two Breaststrokers

Breaststroke Coupling Technique: A Tale of Two Breaststrokers

I have two female clients who are good breaststrokers. Both are 16 years old. One lives in New Jersey and the other in California. Both have excellent anatomical tools for breaststroke (10/10 in hip internal rotation and 7-8/10 in pronation). Both kick a 50 breast in 38-39 seconds. Both swimmers have relatively fast kick cycle times at 5.1 seconds. Yet one swims 1:02 and other swims 1:06 in the 100 yd breast, even though they both train very hard. The question is why the difference?

Using our new Race Club app, I was able to answer that question easily, something I couldn’t do from the standing on the deck.

As I have described before, there are four metrics that really matter in analyzing breaststroke:
⦁ Kick Propulsion
⦁ Kick Cycle Time
⦁ Loss of velocity after the peak from the kick
⦁ Pull propulsion

When it comes to kick propulsion, the two girls are similar, as determined by their 50 kick times. Yet, when looking at their peak velocities achieved after the kick during the swim, the 1:02 breaststroker reached a velocity of 2.48 m/sec, while the 1:06 breaststroker reached a peak velocity of 1.85 m/sec. That is a huge difference. So, if it wasn’t because of the kick propulsion, why the difference? It wasn’t pulling propulsion, and the slower swimmer streamlines better and loses less speed after the kick. She doesn’t get nearly enough speed to begin with.

The answer has to do with what I call the spurt technique. Great breaststrokers spurt forward at the critical moment. Others do not. Both the timing and the magnitude of coupling energy were better with the faster breaststroker. Here is how she did that.

With the slower breaststroker, the descent from the highest shoulder position is a steady climb downwards, with the short axis rotational speed peaking as she hits the water. Unfortunately, that occurs .159 seconds ahead of her peak kick propulsion (K1). By the time she reaches peak kick propulsion, the kinetic energy of her upper body is near zero. She misses the coupling timing.

The faster breaststroker, on the other hand, during her descent downward, as her hands are lifting for the strike phase forward, she slows the descent of her upper body. Then, she spurts forward and downward aggressively, timed perfectly with her peak kick propulsion. The result is an incredible increase in her swimming speed.

The slower breaststroker peaks her upper body rotational speed (182 degrees/sec) when she strikes the water (pink curve on left image), .159 seconds before she reaches peak propulsion from her kick (K1) (orange curve on right image).

The result is that she misses the timing and reaches a peak velocity of just 1.85 m/sec

The faster breaststroker starts her upper body descent at the same time as the slower breaststroker, but before she strikes forward, she slows the descent of her upper body, then spurts forward and downward again, peaking at a greater rotational speed (291 degrees/sec pink curve above). The delay and slowing of her fast downward body motion results in her peak rotational speed (pink curve) and her peak kick propulsion (orange curve) coinciding.

The result of the increase in coupling energy from the forward spurt, and the perfect timing of the peak coupling motion is to reach a peak velocity of 2.48 m/sec

For years, I have observed the great breaststrokers of the world spurting forward with their upper bodies at the key propulsion timing from their kicks. Some thought it was the swimmer riding the wave from their own body or an undulating motion that resulted in the extra speed. It is neither. It is the power of effective coupling: timing and energy. Now I get it.

Yours in Swimming,
Gary Sr.