While competing at the pro level, one of the biggest differences between racing at the age group level and the pro level is the importance of the swim. I’m far from the best swimmer out there, but with the help of Lakeside Seahawks and their coach, Nate, I’ve made some big improvements in my swim in the last year and half. One of the things they really worked with me on is developing a good catch. Something I would argue that most triathletes don’t actually have (I am still trying to make mine better too). What is a good catch? Basically, it’s anchoring your forearm and hand in the water and moving your body past it it. Getting a good catch takes time, drills, practice, more time, more practice, and more time! Breaking those bad habits can be rough. (I speak from experience!)
What I find interesting among triathletes and most triathlon coaches is how much they stress a good catch (and body position). This is a great place to start, but I rarely see people get past this. The stroke seems to be stuck at a very rigid, almost robotic, movement. In a sense, they have all the steps correct, but the smoothness and quickness of their arms is lacking. The rate at which your arms move through the water is called arm turnover. This is very important to efficient swimming, especially in open water.
To help make the connection to how important arm turnover is, let’s compare it cycling and the RPM of your legs. Pretty much everyone knows that the ideal cadence for people is somewhere around 90-100. Why is that? At higher RPM’s, you rely less on muscular endurance and glycogen stores and tax your cardiovascular system and fat stores more. A lower cadence, such as one in the low to mid 80’s, starts using more muscular strength and glycogen stores. (Those glycogen stores are crucial to a good run after biking.) The same holds true with with swimming. A faster arm turnover means you are using less muscular strength and relying more on cardiovascular fitness.
The second reason I believe a higher turnover in the swim is important is more crucial to open water swim success than pool swimming. Open water naturally has more chop in it from the waves and other athletes thrashing around you. If you have a larger time between strokes, the water slows you down and you have to accelerate back to your speed with each stroke. Just as it is with driving a car, the more you slow down and accelerate, the less miles per gallon you get due wasted energy. The human body is no different.
The next big question within this question is, “how do I know what my arm turnover should be?” Obviously someone swimming 1:10/100 meters is going to have a different arm turnover than someone swimming 2:00/100 meters. There are also other variables involved, such as the height of the athlete, arm length, and how efficient their stroke is, etc., but here is a graph to give you a range to shoot for:
Your goal should be to be somewhere in the white area based on your 100 meter time. If you only have a 25 yard pool at your disposal, the easiest way to convert to meters is to add about 10% of your time (convert to seconds and multiply by 1.1 to get your 100 meter time).
Faster arm turnover doesn’t mean you are allowed to start thrashing in the water again with no regard to form or technique. It just means that you need to cut out pauses in the stroke and have a faster recovery portion of your stroke (as in when your hand exits the water by your waist and re-enters past your head).
Here is a great example of fast arm turnover from some of the best swimming triathletes out there in the ITU circuit.