THE MYSTERY OF TWISTING ( GEORGE HERY )
AUGUST 16, 2015
Twisting is indeed a mystery for many people; and mainly because we do not really understand three very important principles for analyzing movements. In addition, there are many different types of twisting movements; some beginning from a static position on the ground or on the apparatus, some while up in the air, and some while flipping.
For many years coaches and athletes have asked “what is the secret to twisting?” You probably know by now that there are no secrets; only the laws of physics that we must learn to utilize.
Let’s begin with a definition of twisting. For the purposes of this presentation, we will define twisting as movement around our longitudinal axis; the long axis running from our head to our toes and through our c.g. This means that pirouettes on floor, balance beam, bars and ice are twists; a jump in the air with 360 degrees of rotation around the longitudinal axis is a twist; and twists can be added to flips, double flips and dismounts off the apparatus, the diving board and the ski jump.
In this presentation we will explore four different twisting movements: the simple twist, the action-reaction twist, the cat twist, and twisting while flipping.
Earlier I mentioned that there are three very important principles for analyzing movements that we must understand and use in order to “learn the secrets” and “unravel the mystery.” These three important principles are: (1) the initiation of movement; (2) the control of that movement; and (3) the efficiency or perfection of that movement.
The initiation of any movement requires some kind of force or forces acting on the body that is to be moved.
Forces – pushes, pulls and resistances. There are external forces such as the force of gravity, contact with another object, collisions, friction forces, wind resistance, etc. There are also internal forces such as muscular contractions, coefficients of restitution (the ability of an object to return to its original shape after it has been deformed) in high bar rails, uneven bar rails, parallel bar rails, vault boards, trampoline springs, etc.
Force through the center of gravity – a force or combination of forces directed through the center of gravity of a body in free space produces only linear movement for that body.
Eccentric forces – forces not directed through the center of gravity produce angular movement (rotation) around an axis or axes.1244241_10201961044932941_1470537808_o
Control of Movement
Once the body is moving, the second phase, Control, must be understood and utilized. Since most of our movements involve rotation, the laws that control angular movements will be covered here.
We know from our Second Law of Movement, that the angular momentum established at take-off will remain constant. So a gymnast who is twisting in free space will continue to twist with the same angular momentum until he/she lands on the mat or catches a bar, etc. Note that even though angular momentum cannot change, angular velocity can.
Angular momentum is given by the formula: M (angular momentum) = mass x angular velocity x (radius of rotation squared). We know that mass will remain constant so we can see that by reducing the radius of rotation we will increase the angular velocity). So pulling the arms in close to the body increases the rate or velocity of the twist and conversely; widening the arms will slow the twisting velocity. Spread eagle?
Perfection is simply the most efficient use of the “Laws of Movement” and is the necessary ingredient for progression from easier skills to the more difficult.
Usually takes many repetitions, much practice and a good coach. The correct body positions and shapes, strength, timing and speed of movement all play an important role in perfection.
The natural twist direction
Before beginning to teach twisting movements, I test each student to try to determine his/her natural twist direction. Below is an example of a profile on several of my advanced trampoline students.
Notice that we check the direction of twist for the jump with full twist (360), the swivel hips, the airplane, the back drop with half twist to feet and if they all go the same way that is their natural twist direction (N Tw). I also check the roundoff as it twists the opposite direction most of the time. This is very useful knowledge as we begin to teach the barani and twisting front flips. It is almost impossible to learn front full, rudi, etc. if the barani twists opposite the natural twist direction.
Below is an example of the “profile” I kept on several of my advanced trampoline athletes. Notice that Nick and Anika both barani like their roundoff and neither can learn the front full or rudi.
Name 360 SH Air B1/2 NTw RO Br Full Rudi Jump Comp Opt
Tyler R. L L L L L R L L L 19.5 16.9 16.3
Jake J. L L L L L R L L L 17.3 15.8 14.8
Kyle P. L L L L L L L L L 14.4 13.7 13.3
Alex H. L L L L L R L L L 13.8 12.9 12.3
Nick L. L L L L L R *R* L 15.5 15.1 14.6
Brenten R R R R R L R R R 16.7 16.4 15.6
Alyssa O. R R R R R L R R R 17.7 16.2 15.8
Brittney L L L L L R L L L 17.1 16.6 15.9
Jessica H. R R R R R L R R R 16.2 13.8 13.7
Taylor G. R R L R A L R R R 15.4 14.7 14.4
Bailey M. L L L L L R L L L 17.2 15.4 15.2
Amy L. R R R R R L R R R 15.5 14.9 14.3
Taylor G. R R L R A L R R R 16.6 15.6 14.9
Anika M. L L L L L R *R* L 13.7 13.1 12.7
Simple Twisting – rotating only around our long or longitudinal axis
(no flipping action). Initiation is usually accomplished by an eccentric thrust or a couple to produce twisting momentum. Examples are pirouette on one foot while on beam or floor, jumps with twists and twists initiated while on bars or the apparatus.
While in the air, twisting momentum will remain constant, and the twisting velocity can be increased or decreased by shortening or lengthening the radius of rotation (bring the arms in/out). Control of the twisting velocity explained above.
Understand that this simple twisting momentum cannot be initiated up in the air. It must be initiated while in contact with an apparatus.
Action – Reaction: It is possible, though, to move the body through a twisting movement without attaining twisting momentum by using action-reaction techniques while up in the air. There will be no momentum created and the movement will stop as soon as the action stops. Action-reaction techniques are mainly used for correcting body positions and for landings.
The cat twist is accomplished by piking (or arching) the body, thereby establishing two nearly perpendicular leverages which can be turned (twisted) in the same direction against each other without causing large reactions.When the body is straightened from this pike (or arch), the entire body will turned to the extent of the twist that is in the two separate body parts. Half twists are easily achieved with one catting action. The cat twist is used for “swivel hips”, flips with late twist, kips and headsprings with half twists, certain vaults, hechts with twists off bars, etc. (story-Crystal Palace). Every gymnast should learn and master the cat twists; It will be of great use later.
Twisting while flipping – from simple twisting, we see that we can initiate twisting movement by two techniques; the cat twist which produces no momentum and by starting the twist before we leave the apparatus which does produce twisting momentum. There is an additional method of initiating twisting while we are in the air, but only if we have already established flipping rotation. We know that if we begin our back (S) with arms overhead and body straight we establish a certain angular momentum (rotation). We can increase our rotation while up in the air by dropping our arms which shortens our radius of rotation and decreases our moment of inertia. If we were to just drop our left arm we would decrease our moment of inertia on the left side of our body and that side would try to speed up and go ahead of (precede) the other side thereby producing a twist to the left. Another way of understanding this is that dropping the left arm to the side will cause the body to react by tilting to the right thereby decreasing the radius of rotation. Since the total momentum must remain constant the increase in angular velocity will become twisting momentum to the left. Please note carefully that dropping the left arm during forward flipping rotation will produce a twist to the right, so be certain to understand this completely. Examples of this type of twisting can be seen during the full twisting back on trampoline, the full twisting handspring vault, during double flips with the twist in the second flip, etc.
The straight body twists best
Earlier I mentioned that perfection requires correct body positions and shapes. Our bodies twist most efficiently when perfectly straight so the athletes must be able to get into this position/shape whenever they wish to twist, especially if only doing one flip with a twist. There are occasions during multiple twisting double and triple flips when a slight tuck is used so that the flips can be completed. A fun proof of the straight body necessity is to have the athlete hang on only one of the rings, spread his/her legs and then you give them a spin. When they close their legs (assume straight body) their spin greatly increases. Then have them pike; they slow down, straighten and they speed up again. Then have them arch and they slow down again and when they straighten they speed up. Soon they realize the importance of the straight body position/shape.
Teaching the straight body during front flips is best done with front pike with kick out (opening to straight body) at 12 o’clock and at top of flight.
During back flips use the magic position; straighten and tighten the body from 10 o’clock till 2 o’clock.
Twisting during forward rotations (flips).
So now let’s teach the athletes to twist. We will begin with the forward flips with twists. Beginning with the half twist, we find that the necessary first step is to master a front pike with early opening to straight body (at 12 o’clock). Then we add a bounce with half turn in the natural twist direction after landing. Next is to put the half turn in just before the landing. Finally we can turn as we open allowing us to see the trampoline, landing mat or water during the entire descent.
Now you can add another bounce with half turn to this barani (P); repeat the entire process and we have a front with full twist. This can go on through rudolf, randolf, adolf and beyond.
As you start to perfect the rudi the pike will be less and the opening will be earlier so that you see the landing from takeoff till about 10 o’clock; do not try to see it during the twist; and again see the landing from about 2 o’clock until landing.
A front with half twist can be accomplished by using only the cat twist, but as the twists increase all of the initiation techniques will become necessary.
Twisting during backward rotations (flip)
Here it is imperative to master the back straight with the magic position spotting forward at takeoff (Millman and Hery spotted the ceiling) and seeing the landing from 2 o’clock until the actual landing. I often have the student clap their hands when sighting the trampoline so that I know they know that timing. Then I have them bounce with half twist after landing, then add the half twist where they clap their hands (back straight with late half twist). When this is secure add another bounce with half twist and soon you have a late full twisting back. This is where the magic position comes in. The twist must start at 10 o’clock, not 2 o’clock, so now if the magic position is perfected, it will be easier to begin the twist at the correct time. Once this is mastered, it is easy to add the bounce with half twist up through quad and quint twists (Marco Canistrelli did seven). Again as the twists increase, using all the initiation techniques will be necessary.
What are the twisties? Who gets them? What is the cause? How do you fix them?
The “twisties” is a phenomonen that only happens to a few gymnasts, trampolinists and tumblers. It happens when the athlete is attempting a non-twisting salto or double salto and the “twisty” happens most often when he/she is in the straight position. The athlete is attempting to do a back straight, a whipback or a double layout and he/she suddenly twists without meaning to. This is frightening to both performer and coach and can be quite dangerous as the athlete can be seriously injured.
The athletes most likely to get the “twisties” are those who have progressed very quickly and perhaps have not completely mastered all of the possible progressions for that particular skill, and may not have developed a good sense of body shape, body awareness and proprioperception.
It takes only a very slight deviation from total symmetry to produce a twist during a flipping rotation in the straight body shape. An arm, leg, head or body not in the symmetrical plane will cause the twist.
You must go back to the very beginning and carefully go through all the progressions taking care to ensure that the athlete understands and masters the concepts of symmetry during the flipping rotation. Start with 1/4 flips and progress until you reach the trick in question.
Similar but opposite the twisties are the flippies, which happen mostly to very advanced performers who suddenly cannot seem to twist when desired and go right on past the skill into another flip or portion of a flip. Again this is a very scary and dangerous situation. Examples are not being able to barani or rudi on the second flip of the fliffus or the third flip of the triffis. Usually this results from the performer not opening early enough to “see” the trampoline and execute the twist. You must return to early opening drills to fix this.