The final phase of the underwater pull is the release, when the hand moves from 9 o’clock back to 12 o’clock, precisely where it started this .85-second, almost circular journey.
Since the hand/arm are now moving in the forward direction again, the objective of this phase is to slip the hand and arm out of the water with the least amount of frontal drag possible. To achieve this, the swimmer draws the elbow up and forward first with the forearm and hand following. The hand then rotates internally with the palm facing toward the swimmers body in order to reduce drag as it leave the water.
The duration of this final phase of the pull is about .15 seconds, slightly longer than the previous phase, but not much. Since the motion of the hand and arm are now forward and up, there is neither propulsion nor lift to be gained from this final phase of the pull. Once the hand leaves the water and begins the recovery above water, the sooner one can get the arm and hand back in the water for another pull cycle, the better.
The recovery of the arm above water takes only about .27 seconds. It is important to realize that while the pulling arm is in the fourth phase of the pull cycle, the other arm is already in the water and initiating the first lift phase of its new cycle. However, neither the release nor lift phase contributes to propulsion, so all of the propulsive power for this brief time must come from the legs.
The frontal drag forces of the human body in water, even in the most streamlined position we can manage, are so imposing that without some source of propulsive power happening, the body will begin to decelerate quickly. This is one reason why the kick is so important; to sustain some propulsive power during this brief ‘down time’ of the underwater pull.
For the record, this analysis of my underwater pull was done without any kick (pull buoy was strapped to my ankles) in order to isolate the effects of the pulling motion. My entire stroke cycle, including the recovery, took 1.1 seconds. This equates to a stroke rate of 110 strokes per minute or a cycle rate (rpm) of 55 cycles per minute. (Normally coaches consider stroke rates not cycle rates). In other words, I was sprinting using a shoulder-driven freestyle.
One can slow the stroke rate by holding longer in front (hip-driven technique), but the rest of the pull cycle (phases II through IV) as well as the recovery, should be just as fast as with the shoulder driven technique. By holding the hand in front longer, one effectively lengthens the propulsive ‘down time’ of the pull. However, because there is more time to rotate the hip, this type of pull will generate more power each time it goes through the propulsive phases because of the greater hip rotation creating a greater force to pull against. In order to use hip-driven freestyle effectively, however, one must also have a strong propulsive kick to sustain the body speed and help create more lift during the down time.
Virtually all of the fastest sprinters in the world use a high stroke rate, shoulder-driven technique. Where I live in the Florida Keys, instead of catch-and-release fishing, I call this catch-and-release swimming; quick catch (no hold out front) to get into the propulsive phase soon and quick release to get ready for another pull. Stroke rates for world-class swimmers vary from 110 to 140 in the 50 sprint and 85 to 110 for the 100 meters. For distance swimmers doing the mile, stroke rates will vary from 60 strokes per minute for hip-driven freestylers to nearly 100 strokes per minute for some shoulder-driven freestylers.
For distance swims, both hip-driven and shoulder-driven techniques can be effective, depending on the strength of the kick. In the former, one uses more of Bernoulli’s principle taking advantage of lift, so long as there is a good kick behind. In the latter, one uses the arms more like a propeller, trying to keep a more constant propulsive force applied by the arms. The technique that works best for you will depend on how strong a kicker you are and how aerobically fit you can become in order to sustain a higher stroke rate.
Yours in swimming,