Why do swimmers peak at such a young age?

Question

Why do swimmers reach their peak performance at a relatively young age compared with track and field athletes? Particularly female swimmers seem to produce their best results in their late teens to early twenties. This seems to be true for both sprint and longer distances.

By contrast, track sprinters peak at an older age than swimmers, and endurance runners even older. Is there perhaps a buoyancy issue? Do younger swimmers who are not fully developed physically have an advantage because they have built up the muscles they need through training, but have an overall physique that isn't fully bulked out, meaning less dead weight? Compared with track athletes, a streamlined body is more important since water drag is much greater than air. I would be interested in an answer that addressed the physiology involved.

Edit: Here is a study using the career performance of thousands of athletes. http://www.springerlink.com/content/g338206j72233hq5/fulltext.html Statistically, swimmers peak at 21 and runners at 26. That's what the data says, but the study doesn't go deeply into the physiology of why that might be the case. However, swimmers are still peaking a good 5 years before runners.

Answer 1

My hypothesis: Swimmers peak at a younger age than track and field runners because of metrics such as explosive and dynamic strength, reaction time, and speed of limb movement. Ages of winners in strength and speed events have historically peaked earlier than endurance events (see below).

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The first table shows what psychomotor and physical factors are utilized during a given sport/event. Swimming and short distance events utilize explosive and dynamic strength, reaction time, and speed of limb movement, unlike medium and long distance running events. In comparison (the second table shows the mean ages of gold medal winners in given sports/events between 1896-1980), the mean age of gold medal winners in medium and long distance running events have generally and consistently been higher than gold medal winners in swimming and short distance events.

Keep in mind, water is 773 times denser and 55 times more viscous than air₍₁₎. One could argue that more energy is spent in swimming than running due to resistance. An article states the following:

"What makes swimming different? Simply put, running is a natural activity, while swimming is a 'natural struggle.'"

To put the two sports in perspective, in world record time, a 1500m freestyle swimming event (men: ~ 14:30 min.) takes 10+ minutes more to complete than a 1500m run (men: ~ 3:30 min).

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Characteristics of strength and speed events include reaction time, speed of limb movement, flexibility, explosive strength, and gross body coordination. Characteristics of endurance events include control precision, rate control, arm-hand steadiness, aiming, and stamina.

Human strength peaks at age 25₍₂₎. Human reaction time also peaks in the 20s₍₃₎. From a neural standpoint: As we age, humans lose brain connections₍₄₎, which contribute to slower reaction times.

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I used this study to answer your question. _{For the purposes of this question, I did not include outliers or exceptions to said research.}

Answer 2

I have to say that this is a fantastic question, though quite hard to address rigorously. So take my answer with a pinch of salt and keep in mind that it's mostly an idea than a well-posed theory or product of thorough research.

Around late teens early 20s the vertical growth of the body is more or less complete and most people usually "bulk up" as you have mentioned. In this period it's not uncommon to gain weight without getting physically much bigger, since the body will mass up in the bigger bones (like femur) and muscle structure.

This could (as you have also pointed out) be a bigger issue with swimmers than with track runners. Especially short distance runners are usually very muscular in order to get the "explosivity" they need, which builds on a very different type of muscle structure than "endurance" which swimmers perhaps need more often. That however does not explain the variation between swimmers and long-distance runners.

Answer 3

There are a few reasons. First, between 10-15 years after initial onset of puberty, the body goes through a "settling" phase; growth and sexual maturation is completed, so some of the hormones are dialed back. Metabolism slows, calories consumed more easily turn to fat, and the body generally "bulks". All of these are counterproductive to maintaining a peak level of performance in athletics. Phelps, when training, eats 11,000 calories a day, mostly complex carbs. Before the big slowdown, a lot of that is readily available as blood glycogen, but after the metabolism drops insulin more readily turns those blood sugars to fat. That makes between about 25 and 28 years of age a critical dropout range beyond which it is extremely difficult to maintain a high level of performance and nigh impossible to keep up with the younger whippersnappers coming in behind you.

Second, swimming takes a LOT of time and effort. When training for the buildup to the Olympics, you're in the pool pretty much all day, cycling between endurance-building (long swims in a particular stroke; 1000m fly is a common torture technique), muscle development (sprint lengths; 50/100/200m going all-out), skills drills (starts, turns, arm/leg isolation of various strokes), and practice meets (some more "practice" than others). And this is year-round; you're still training in the winter months, usually working around school schedules, which in most US climates requires an indoor heated pool just to be possible. At some point, usually very soon after college age, it becomes impractical to keep up this pace from a time and money perspective.

Third, competitive swimming in the United States is one of those sports we pay attention to once every four years, and even then only the real standouts become household names (and not for long). After you've won a few gold medals in the Olympics and the World Championships, and maybe set a world record or two, you've pretty much done all you can do in the sport, and it's time to go off and find something else to do with the rest of your life. Contrasting that, in the popular US spectator sports like football, basketball, even hockey, you can make millions of dollars years beyond your performance peak as a "franchise player", a household name that puts butts in seats to see you.