The articles for the approach, hurdle and take off, plus the back press and take off on this site are basic descriptions of getting to the end of the board and applying force to load the board with energy. As the title suggests, this will delve further into this process.
Divers should try to load the board with as much energy as possible. That means bending the diving board as much as possible. That should be the focused objective as one descends from the hurdle or begins the back press. In order to do this effectively the diver must stay balanced over the feet to apply maximum loading. If there is too much lean, it is almost impossible to bend the board to the maximum. Maximum refers to the individual diver’s strength and ability to bend the board.
When the board is fully loaded, the diver must get into a position to best initiate their intended dive. A question arises as to, "When is the optimum moment for that to begin?" The answer to that question will seem vague because "it will depend on how much rotation is needed to complete the dive successfully". It should be noted here that all rotation must be initiated while the feet are still in contact with the diving board. Conversely, rotation can not be initiated after the feet leave the board. Example: A person jumps from a high place and intends to land foot first. On the way down he changes his mind and wants to dive. He bends over in an attempt to start a dive. What he finds is that his feet and legs move forward to block that effort. This is the action-reaction affect that many divers don't understand. Newton's 3rd Law of Motion explains the reason aptly. "For every action there is an equal and opposite reaction. When air born, this basic law of movement comes into play and it is different from our idea of what should happen. When this diver decides to bend over, that is the action. The equal and opposite reaction is that the legs move in front of the body blocking the effort to dive. The original intended jump will maintain the initial lack of rotation and therefore enter feet first into the water. Changing one's mind in the middle will not change the amount of rotation once the feet leave the board. For the safety of the diver, no dive should be initiated while the diving board is depressed to its maximum. By doing so the diver may not be propelled up and/or out, which is where safety lies for all dives.
The answer to the question above is that all dives will be initiated somewhere between the time the board begins to unload its stored energy and that moment before the diver’s feet leave the board. As a rule of thumb the less rotation desired, the later it is initiated. (It begins closer to that moment when the feet leave the board.) Conversely, the more rotation desired, the earlier it is initiated. (It will be initiated closer to maximum depressed state.) The diver must remember that all rotation is initiated as the board is rising and while the feet are still in contact with the board.
Complex motor skills are most efficient/dynamic when one part of the body is moving at its quickest before another part becomes involved. This idea has been presented in both Kenesiology and Bio-mechanical studies. Using that premise on the recoiling diving board, it would seem that the most effective rotation would occur when the board is recoiling at its quickest point. That point appears to be just below horizontal.
As divers practice they should be experimenting with the "timing" for this process (Finding that moment which produces the desired affect). Example: If the diver is establishing too much rotation to complete a forward dive successfully, then he/she has to wait longer for the board to unload its energy before initiating the dive in order for it not to sail over at entry. Each dive must be initiated at a slightly different moment in time to get the desired affect. If this same diver finds that he/she is stuck and has to bend the knees on a forward dive pike just to land head first upon entry, then he/she must initiate the action a little sooner so the knees don’t have to bend. Timing is crucial for every dive. If a diver’s timing is slightly off, many of their dives will feel and look awkward or out of control. When the timing is correct, the dive is easier for them to do, looks smooth and is under control. Practice affords them the opportunity to gain this timing consistently.
The positioning referred to in the second paragraph (which I have called the "magic position") is nothing earth shattering. When the board is no longer bending downward, the diver should be standing tall with the arms extended directly overhead. That position is critical for numerous reasons. The following are the more important ones.
Observations
I have noticed the following when some divers are executing tuck somersaults and then change them to pike. Generally when performing tuck somersaults, they bend the knees earlier than is necessary at the start of a front 1 ½ somersault tuck. By doing this they do not receive all of the energy from the recoiling board. The somersault doesn’t go high in the air and can be slow in rotating. In essence it’s like holding a wet noodle on a fingertip and trying to push it up in the air. Because the noodle is not rigid the lifting force is neutralized by the collapsing noodle. Instead of going up, the noodle collapses and sticks to the end of the finger.
It is interesting to observe that when these same divers change to the position to pike, the dive goes higher and spins better. The reason seems easy to explain. Because the knees don’t bend in a pike, the board is allowed to impart all of its stored energy through the legs and hips giving the diver this increase in height and rotation. The difference is the energy from the board is allowed to act longer on the body in the pike than the tuck. This can be attributed to anticipating the action for the tuck position which, is too early. If these divers would continue extending through the legs a moment longer, the tuck dive would be just as high as the pike but would spin faster because of its smaller radius.
Many divers have been observed jumping a mile in the air only to find that after finishing multiple somersaults that they barely are able to complete their intended dive. What good is it to jump that high if the rotation is insufficient to complete the dive successfully? All dives will follow a parabolic arc, which is a predetermined path a dive will travel once the feet leave the board. The divers described above seem only to use half of that arc to perform their dive. The part being described is from the top of the arc down. To complete the more difficult dives, divers must begin to utilize the other half of the arc. That is the upward portion of the arc. Care must be take here because there is a point where height will be sacrificed for rotation. It is up to the diver and coach to find that moment which produces the most desirable affect.
Height and direction while initiating rotation are established by a line of force that passes through the body as the board unloads its energy. In the pike position, the line of force that this energy travels is through the legs and hips. As the upper part of the body is bending beyond the end of the board rotation is established. The energy of the rising board assists in popping the hips up while the upper body bending over causes rotation.
I am not in full agreement with the "C" position referred to by many coaches on forward and inward somersaults. Many divers exaggerate that position which seems to hinder the hip action described above. This exaggeration is an unusual curvature of the upper spine. Divers observed doing this appear to roll off the end of the board and have difficulty getting into a compact position. If forward and inward somersaults are the result of a double lever action, then the "C" position emphasized seems to ignore the importance of those levers.
Points To Emphasize