Swimming Evaluation

For many triathletes, the swimming portion of a race is often the most challenging and scary of the three disciplines. Many athletes seek the advice of coaches with a background in swimming to learn the basics and improve performance. Many of these coaches place emphasis on the metric of distance-per-stroke as a means of evaluating swimming efficiency. A minority of coaches and swimmers have alternative metrics. As an athlete, how do you sort out what is right for you?

As a former Division-1 swimmer in College, I can tell you what my metrics for efficiency are. But why would you care about how I feel about efficiency? You will just as easily find other coaches with the same passion for a different story, namely the importance of distance-per-stroke. The best way to settle the issue is to do an experiment to see if distance-per-stroke really makes a difference. The results of said experiment are contained in this article.

To perform the experiment, an experienced swimmer performed a series of laps in a random array of target times and techniques in a 50 meter pool. Some of the laps were swum using a Float technique: sharp angle of entry, no emphasis on stroke count. Other laps were swum using a Downhill technique: stretch at angle of entry and emphasis to reduce stroke count. Laps done with the Float technique required 6-7 more strokes on average compared to the Downhill method. Swim times, Heart Rate and stroke count attained immediately after each lap were recorded. In the analysis, the heart rate at various goal times per lap of Float and Downhill techniques was compared. The results are shown in Figure 01.

Figure 01 – Results

If one swim technique is more efficient than the other, then the red line and blue line would be distinct and not overlap in Figure 01. However, there is considerable overlap of the swim times between the Downhill and Float swim techniques. The result is that no difference in efficiency could be established between Downhill and Float swim techniques to a confidence of plus/minus 6 heart beats per minute.
In conclusion, stroke count over a set distance is an inappropriate metric for evaluating swimming efficiency. You will get just as tired with high turnover or low turnover. Something else is making an individual’s swim technique more or less efficient.

Does this mean that coaches should let their swimmers thrash in the pool with a high stroke count? Absolutely not! Any swim coach will tell you that deliberate swimming form is far more efficient than random and unbalanced swimming form. This experiment utilized an experienced swimmer to ensure that neither technique involved poor form.

Many coaches communicate good technique to athletes by telling them to slow their turnover down and lengthen the stroke. It is important that both coach and athlete know that this lengthening will NOT improve efficiency in and of itself. Efficiency must come from something else the athlete is doing in the process of attempting proper form. Altering an athlete’s distance per stroke (up or down) is a coaching tool to teach this alternative concept, whatever that concept might be.