It is possible to adjust the distance between the elbow and the central point of the head by taking the elbow’s height into consideration (pic. 1 to 4).
This will have an impact on the recovery of the over water arm. In fact, the recovery of the over water arm is dependent to the distance between the elbow and its own hight as well as to the distance between the elbow and the central point of the head. Let’s use the cartesian plan to visualise better the distance between x and y from the central point (0). The forearm position changes too. It is visible that if the elbow gets lower, the wrist gets further from the shoulder. Nevertheless, if the elbow is high, the wrist will get closer to the shoulder. This is always true, but during the straight/half-straight arm over water.
Now that we are aware of this process, how can we improve the movement? Having the elbow and the shoulder in a lower position induce a lower rotation of the shoulders which results in a higher resistance to the body while it is moving forward. Elbow and shoulder having a higher position facilitate a bigger rotation which will sustain the body to float on the water. Although this seems positive, it results in a worse legs’ movement which will lead them to move on aside, following the movement of the shoulders. This is to say that legs’ movement needs also to be taken into consideration since it depends on the inclination of the shoulders.
Another peculiarity of the high shoulder involves the other shoulder which is in frontal stretching and it could go too deep and take the rest of the body under water. This will compromise the principle of floating, as known from the Archimedes’ fluid mechanics principle. Lateral respiration changes too: high elbow means high shoulder. This helps head lateral rotation to breathe but could also mean having an over lateral rotation, which will take down both body and arm in the water during the pushing . This will have an impact on the body axe and on the stroke, itself. Having a lower elbow means that the lateral rotation of the head is harder. In fact the length between the head and the shoulder is reduced since the shoulder is totally under the water. The engagement of shoulder and arm’s muscles When the arm is over water, there is a recovery phase where strengths are back and the muscle later utilise in the peak of the push is now relaxed. The straight arm overwater has an optimal rotation at shoulder griddle level but it might over stress the deltoid and the tendons of the triceps. An over bended arm tends to over stress the deltoids and trapezius, especially in case it tries to get close to the head: elbow goes up and that involves hard work for the rotator cuff and bicep. The bicep will tend to shorten since the forearm gets closer to the arm. Agonist and antagonist muscles need to be properly trained in a balanced way. Arms need to get back strength in the best way and a tailored training for each swimmer is needed.
My suggestion as international coach is to start training the straight arm in both situation: over water and under water. This will help the rotation of the shoulders and give stability to the swimming style. Finally, training a young swimmer to push water until the end of the underwater stroke. Pushing the water with the hand near the knee is the best way. There is also a need to work on the recovery over water with the half bend arm.
Muscles involved in this action: biceps brachialis triceps brachialis deltoid
Anterior deltoid, middle deltoid, posterior deltoid, rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis), triceps brachii, latissimus dorsi, teres major.