Part III: Coupling Motions, The Arm Recovery
The most powerful coupling motion of the dive is with the arms. The coupling energy of the arms is not only proportional to the square of the speed of the arm motion, but also to the square of the radius or length of the arm. A swimmer has the ability to change the speed and the length of the arm on the start and, because of the exponential relationship of both factors with kinetic energy, each has the ability to significantly change the outcome of the start. The following are the most common motions seen with the arms on the start.
- Arm swing forward. This motion is most commonly seen on the weight forward start. With this technique, the arms swing forward from the front of the block, either straight or with a slight bend, while the head is lifted to reach the streamline position. This technique provides the least amount of coupling energy.
- Arm/hand elevation. This technique can be used with either the weight forward or backward start. Rather than simply moving forward, the arms and hands move upward at the start, with greater bend in the elbow. Because the path of the hands and arms is longer with this technique, there is more velocity and therefore, more coupling energy with this motion, even though the length of the arm is reduced from the first motion.
- Arms pulled to the swimmer’s side. This technique is not seen often at the elite level, but more commonly among younger swimmers. It is effective only with the weight back start. With this technique, the swimmer pulls on the front of the block with the arms and quickly moves the fully extended arm to his side, while the head is lifted. Once at the side, the arms swing more slowly back out front into the streamline position. Although this technique creates a lot of kinetic energy with the arms at the beginning of the start, stopping the motion of the arms at the side reduces that energy to zero.
- Butterfly recovery on the start. This technique is the most powerful of all on the start because there is nearly a continuous fast motion of the arms from the starter’s beep until the swimmer’s entry into the water. It can only be done effectively with a weight back start. With this technique, the swimmer pulls on the front of the block (or bar) and, with the back arched, elevates the hands and arms above the head as they move forward into the streamline, very similar to a butterfly recovery motion. This circuitous motion can be done with either a slightly bent arm or a straight arm, with the longer straight arm creating even more coupling energy. The risk of this start technique is that the arms are coming together in front with such speed and energy that one can easily overshoot the hands, particularly with the straight arm, and end up with the arms crossed at entry, a disastrous complication. This technique also requires that the swimmer has extraordinary shoulder flexibility (extension backward).
Brad Tandy in the lane 8 in the finals of the 50 Freestyle in the Rio Olympics uses an over extended butterfly arm recovery on start, maximizing all coupling motion energy with head lift, arm swing and back leg lift. Which arm recovery do you use on your swimming start?
Yours in Swimming,