Best of the TI Discussion Forums: How Does Stroke Length Affect Speed?

On November 3rd, Deborah Georges posted the following question: “Does SPL increase with arm turnover?”

This inspired a lengthy and stimulating discussion that lasted nearly a week. On November 9th, TI Coach Bob McAdams posted the following highly practical suggestion for turning Deborah’s question into personal insight.

Topic: Faster turnover & SPL (13 of 13)
Conf: Freestyle
From: Robert McAdams (rwm@fambright.com)
Date: Wednesday, November 09, 2005 05:25 AM

If you're playing with stroke rate, you might find it beneficial to try the following:

1) Swim a lap, counting your strokes and timing yourself. Don't strive for any particular stroke count - just do whatever comes naturally.

2) Swim another lap, again counting your strokes and timing yourself. This time, try to reduce your stroke count by 1.

3) Repeat step 2, again trying to reduce your stroke count by 1.

4) Swim another lap (counting your strokes and timing yourself), but this time increase your stroke count by 1. If you've followed the directions correctly, you should swim this lap with the same stroke count you used in step 2.

5) Swim another lap (counting your stroke and timing yourself), and try to increase your stroke count by 1 again. This should bring you back to your original stroke count.

So, in summary, you began with a stroke count, which we'll call n, and you swam:

lap 1: n
lap 2: n-1
lap 3: n-2
lap 4: n-1
lap 5: n

It takes some practice to do this drill successfully, but people almost invariably find when they do is that they get a faster time on lap 4 than on lap 2, and a faster time on lap 5 than on lap 1.

The reason is that, as they decreased their stroke count on laps 2 and 3, they were increasing their Stroke Length (SL). But then, as they increased their stroke count on laps 4 and 5, they increased their Stroke Rate (SR) while maintaining some of the increased SL they had achieved on lap 3. The result is that, while their SL was the same on lap 4 as it was on lap 2, and the same on lap 5 as it was on lap 1, their SRs were higher on laps 4 and 5 than they were on laps 2 and 1, which translated into more Velocity, or a faster time.

The beauty of Bob’s post is that it takes a topic that can be intimidatingly technical and makes it relevant via a simple exercise that any swimmer can do, and thereby gain a feel for how to swim faster efficiently.

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