Why you should care about power balance and what to do about it

Posted Chris Articles, Vasa Swim

One feature of the Vasa SwimErg that I have been playing around with is power balance.

For those of you not familiar with the SwimErg, it is a swim bench similar to a rowing ergometer. Instead of sitting and rowing, you lie down on a bench and swim with two paddles.

Since the paddles and cords work independently, you can get a power reading for your left and right sides individually.  

With the help of the cycling app called Rouvy and TrainingPeaks, I am able to see if one arm is pulling harder and by how much. Interestingly, my right arm pulls harder than my left arm.

On average, 47% of my power came from my left and 53% came from my right. This is particularly noticeable at higher, race pace intensities.

This might not seem like a major difference. But over the course of 4000 m or a 1:15 long workout, it does add up. After long workouts and sets over 500 m both on the SwimErg and in the water, my left shoulder, lat, and pec would be much sorer and fatigued than my right.

So what was causing this power imbalance?

My swim coach looked at my stroke and my left arm was entering the water wider than my right. My hand was also entering straight down rather than out and extended.

This flaw was putting more strain on my left shoulder and causing me to lose power. Not surprisingly, it was also slowing me down.

To fix this, my coach had me focus on hand placement through three drills:

  1. 6/3/6: 6 kicks on my left side, 3 strokes, and 6 kicks on my right side. Repeat. Here I focus on keeping my left hand glued to my cheek and my hand right at the surface of the water so that I could become accustomed to what that position feels like.
  2. The tarzan or heads up drill where I swim with my head above water focusing on proper hand position.
  3. Catch-up drill with a kickboard in front so that I slow down my stroke. And I can get used to where my hand should go after the recovery phase and beginning the catch and pull phase.

In addition to these drills, I did bilateral breathing. Many triathletes and swim coaches say it does not matter which side you breathe on as long as you are exhaling underwater enough. However, if you have a power/asymmetrical swim stroke, bilateral breathing can help fix this.

After two weeks of focusing on hand position, my times in the water were five seconds faster per 100 m and I felt more relaxed doing it.

My power on the Vasa SwimErg also began to balance out with it now being 49%/51%. It is not essential  to have the power balance at exactly 50/50. But  it is important to check that this power imbalance is not a symptom of a larger swim stroke imbalance.  An imbalance can slow you down and may lead to a shoulder injury.

Even if you do not look at swim power, a symmetrical, balanced stroke is important.

Especially if you unilaterally breathe (breathe to one side only), it is worth getting your swim analyzed to be sure that one of your hands is not entering wider or more narrowly relative to your other hand. If it does, try the above drills and bilateral breathing to help correct the issue.

Your shoulders and swim splits will be thankful that you balanced out.

Chris Hague
Tri Swim Coach

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