The technical explanation of why you should recover your arms a certain way during the freestyle stroke.
There are a wide variety of recovery arm positions in freestyle. Some athletes bend the elbow, with the hand sweeping just above the water line in the more traditional way. Others keep the arm straight or nearly straight as it leaves the water and moves back to the front for another stroke. Which is better and why?
Each type of recovery has its advantages and disadvantages. Though one may more frequently see a straight-arm recovery used with pool sprinters, some pretty amazing distance swimmers and triathletes use a straight arm. Bottom line, one can use either recovery in distance freestyle.
Let’s get technical
While considering the benefits of the two types of recovery, the Law of Conservation of Energy comes into play. This universal law states that the total energy within an isolated system is constant. The energy is conserved over time. While the arm recovering over the top of the water is not an isolated system, since the shoulder is connected to the body, for this analytical purpose, we can consider it so.
The freestyle arm recovery is a rotating system, pivoting at the shoulder. The total amount of energy in the arm recovery is proportional to the square of the angular velocity (speed of the hand) and what is called the moment of inertia. The moment of inertia is proportional to the mass of the arm and the square of the length of the arm (radius). What this means is that if we shorten the length of our arm, we should see a resultant increase in speed in the arm recovery. A good example of this is a figure skater starting a twirl with arms extended. Then, when the hands are brought in tight to the body, the result is an extraordinary increase in the angular speed of the skater.
That is not what we see in swimming. The sprinters with a straight-arm recovery are swimming with the fastest stroke rates; some at as high as 140 strokes per minute. Janet Evans swam the mile with a stroke rate of 100 all the way. According to the Law of Conservation of Energy that must mean that there is more kinetic energy in the straight-arm recovery than in the bent-arm recovery of the same angular velocity. That also means it takes more work to recover with the straight arm than with a bent arm, which one can easily confirm by doing these two motions on land.
So why swim with a straight-arm recovery?
If the straight-arm recovery requires more work to do, why do it? That is where the concept of coupling motions comes in. A coupling motion is defined as a motion of some part of our body that, by itself, creates no propulsive force, yet, when coupled with a propulsive force, augments the effect of that force. For swimmers, coupling motions lead to increased distance per stroke. The two most notable coupling motions in the freestyle are body rotation along the axis of motion and the recovering motion of the arm. The more energy we put into those coupling motions, the more we can augment the forces of our hands and feet propelling us through the water. The timing of those motions is critical. In order to work, they must take place either while the propulsive force is taking place or while the motion from the propulsion is still taking place. Therefore, the freestyle technique and stroke rate being used end up determining whether a straight-arm recovery will have any benefit at all.
Which recovery style is best for you
For those swimmers using a hip-driven freestyle, with stroke rates typically in the 50–70 range (learn how to check your stroke rate below), it makes no sense to recover with a straight arm. With this technique, the hand that enters the water usually delays by pushing forward prior to initiating the propulsive phase (where it moves backward in the water). By this time, the other hand has already entered the water, the angular velocity is now zero, and the kinetic energy in the recovering arm had no opportunity to couple with the pulling arm during its propulsion. In this case, you would want to recover the arm with the least amount of energy possible, with a bent elbow.
Once the stroke rates reach 80 and above, where the freestyle technique becomes shoulder-driven or a hybrid (one arm shoulder and one arm hip), coupling between the pulling arm and the recovering arm can take place. Then, it may make more sense to use a straight-arm recovery, though it requires a greater level of fitness to do so. A hybrid freestyler might benefit from one arm recovering straight and the other bent, as is not uncommonly seen.
There are also biomechanical considerations. In order to do a straight-arm recovery, the body must be rotated backward enough to unlock the shoulder joint for this recovery motion. Not all shoulders are equipped to do so well and many swimmers don’t have the core strength to achieve this extra body rotation over and over again.
How to check your stroke rate
The best way to check your stroke rate is by using a Finis Tempo Trainer, a small device that fits under your cap behind the ear and, when set to mode 3, makes a nice audible beep each time your hand should be entering in the water. Set it to whatever rate you desire or can handle, depending on your technique and fitness level. You can also use it for cycle times (mode 1) or lap split times (mode 2) if you desire. It is the most valuable tool in your swim bag.
Pros and cons of each type of recovery
- More coupling energy when done with fast stroke rate
- Forces more body rotation, which means even more coupling energy
- Requires more work and strength to do
- Only benefits those with a high stroke rate
- May be challenging with tight shoulder joints
- Easier to perform
- Can be done with less body rotation
- Works for any stroke rate
- Less coupling energy with high stroke rate freestyle
- May encourage a lazier, slower freestyle with less body rotation