How Much Faster Do Swimmers Get In College?

By Kevin Hallman

One of the most fundamental aspects of a swimmer’s season is improvement – only one swimmer can win Olympic gold in each event, but every swimmer has the opportunity to measure success or not against their own best times. As swimmers, we put hours of work into getting stronger, building more endurance, and becoming more efficient. Yet for all the choices people make about swimming in college, which team to swim for, what events to concentrate on, which division of swimming to compete in, most swimmers have very little idea how much or little these things actually have to do with their getting faster. Using a couple of years worth of data on college swimmers, I hope to shed some light on some of these questions.

Measuring improvement is tricky since so much of a season’s performance depends upon on choosing which events and meets to peak at. These meets and events can vary year to year. To account for this, I chose to compare a swimmer’s top three events to their top three events the following year, using the measure of overall percentile rank in those events. I then took any top times that were swum in events that both years and compared these to the previous year, trying to only count tapered-swim to tapered-swim improvement. Unfortunately I didn’t have reliable data for high school swimmers, so I could only look at how people improved from their freshman years onward: admittedly a large omission.

This chart should give an overall baseline for how swimmers improve over their college careers. Shown below is the average percentage improvement of all swimmers, broken down by division and gender.

The first striking feature is that, on average, swimmers don’t improve much during their collegiate careers. To put a 0.3% improvement in perspective, a 50.00 second 100 yard freestyler who improved 0.3% would have swum a 49.85 the next season. The second is that men tend to improve about twice as much per year as women do.

The next graphic shows overall improvement data broken down by gender and year in school (well year of eligibility).

It is clear from this graphic that swimmers tend to improve less as they age. Note that I don’t include freshman improvement. This is mostly because I don’t have access to high school times the same way as college, but also because the comparison would be difficult since high school swimmers tend to swim different events college swimmers do. I would be highly surprised if swimmers didn’t improve the most during their freshmen seasons.

Next, I dove into the data by breaking out improvement results by event. I’ll just show a couple of events here to illustrate trends. First, the data showed that breaststrokers tended to improve more across their college careers than swimmers who swam the other strokes.

Secondly, the data showed that distance swimmers improve less than sprinters. You can see hints of this trend in the 100 and 200 breaststroke plots, but it becomes much more clear when looking at the 100 and 1650 freestyle events.

Exactly why this is the case is a bit unclear to me. As a distance swimmer myself, I can acknowledge that part of the issue is that distance events take longer to get in shape for. Year-round commitments to swimming became more difficult the older I got as the rest of life got in the way. Another explanation might be that sprinting is more technical than distance swimming, which makes it possible to improve even if your strength and endurance do not. This might explain why breaststrokers tend to improve more than swimmers in the other strokes, since breaststroke is usually thought of as the most technically complex stroke. However, other endurance sports like running and cross country skiing see many athletes peak late in life, so this probably isn’t a complete explanation.

Another trend, though small, emerges across the board: fast swimmers tend to improve less than slower ones, even when looking at improvement as a percentage of the time. The data here doesn’t explain why, but there are a couple different reasons for this that I could postulate: better swimmers are closer to their training peaks, regression to the mean i.e. fast swims tend to be outliers, and the fact that drag forces increase proportionate to the square of velocity in water (approximately). But without some more data, it is difficult to tell.

Another hypothesis I wanted to test was to see how improvement factored into building the top college teams. Since the best collegiate programs tend to attract the best coaches and the most dedicated swimmers, I would expect them to improve the most. Improving your swimmers is one of the keys to building a great program, in theory. Of course recruiting and retaining good swimmers probably has a stronger correlation ultimately, but recruits are supposed to make those decisions largely on how much they think they might improve in a given program.

Shown here are the average improvement percentages for the top 25 men’s and women’s programs at last year’s NCAA Championship meets plotted against a metric that shows their team strength on the national level in 2016.

These graphs show that team strength and improvement are probably correlated, but not in a way that I would have expected. I’m not entirely sure if the fact that better men’s college teams improve their swimmers more while top women’s teams do not is really a trend or its just due to the smallish data set. I would tend to think the latter since I don’t really have a good explanation why it might be the case.

Getting faster in college is difficult; even the fastest swimmers at the top programs won’t improve much. So if you’re a college swimmer at least take solace in the fact that averages aren’t everything and that getting better than your competition may not be quite as challenging as it used to be.