So, let’s talk about the variables that actually affect outcome, and examine each one as they relate to Simone’s vault and gymnastics skills overall.
The Brain
Prefrontal cortex, cerebellum and parietal cortex are the parts of the brain that contribute to processing. The cerebellum, specifically, does smoothness of motion and the timing of when things come before others, or in sequence.
Timing of performance is key. As we noted about Biles’ vault, the whole process takes the same amount of time as the average adult’s single reaction time (which is 0.15 to 0.2 to one stimulus alone). This means that they receive stimulus from hearing, seeing, or feeling, and then create a response.
In contrast to Single reaction time, Complex reaction time, is for certain not welcome in high level gymnastics. This is where you have many incoming stimuli to choose from, and you have to make educated decisions on which to respond to. Though more appropriate for gymnastics as a sport (with multiple stimuli), there is just no time for multiple choice answers.
Hick’s Law essentially says that the more choices you have, the more likely you are to have a slower response time due to funneling through options. If one knows that the “block” before flipping happens to be off, there are quick choices to be made. Maybe their wrists were too flexed on the vault. Maybe the block sounded more like hands sliding and not a pop. Do they, then, turn it into a single, do a layout, pull hard if high enough, etc.? In hundredths of a second, how realistic is making that decision?
The Body Position
So many variables go into the amazing feat of creating the space and time in the air to be able to perform the unimaginable. The run and steps have to be just right. The position of the body on the springboard needs to be exactly where the athlete needs it – not too vertical, not too hip flexed, feet exactly on the part of the springboard to give the most back to the athlete. The placement of the body, and the angle of impact, the openness of the shoulders and torso, the placement of the hands, the angle of the wrists all directly affect the transition of force, and whether an athlete will block enough to complete the skill and not land short.
Coaches give feedback and instruction during conditioning to stay “tight” in the body, so that there is no give. This means, no bend in the shoulders, no slow-absorb in the elbows (small pushups), no buckle in the back or “arch,” prevented by keeping abdominals tight. This is because one wants there to be energy lost, if you will, and the force put into the vault to be given back to the athlete to make them go higher or transition this into rotational force. You get less height if you aren’t tight. If you go “slower” from the board to the vault table, you will most likely not go as high, either, because there is no force in to create force out.
Proprioception, or knowing where your body is in space, is a key part of the feedback that automatically happens up the chain, or from body parts to the brain. The ankle usually responds, for example, to the outer ligaments feeling “stretching” or length, by saying, “uh oh, we may roll in or sprain.” With this new information, the muscles on the outside kick in to respond and prevent this from going any further. The reaction time depends on many things, including these variables: amount of repetitions practiced, basic strength, makeup of fast and slow twitch muscles, brain response training (speed of reaction time), hand-eye coordination, proprioception, etc.
The elite-level athlete, therefore, should be able to respond faster, more accurately. For Biles’ vault, again as an example, how her wrists are flexed, or pressure on her shoulders, may give her suggestive feedback as to how high she will be and how to adjust if possible. They also know sooner if the environment is off. Examples of this are: my hands slipped or are slipping; I came on to the vault too high; I did not block high enough. Recognizing this should allow the athlete to safely adjust what comes next (pull harder) or pull “out” of a skill, doing a timer, or purposely balking.
Friction
Let’s assume the preflight goes well. The contact with the board is perfect. The hands hit the vault, and there is a slip. Maybe a quarter of an inch, maybe a millimeter. How much is too much? Physics will tell you that any contact alteration will directly influence the quality of force that is lost. In this split second, the athlete has to decide whether to continue the pre-planned path or not. At times, there is more risk in balking that there is in pulling harder, pending many things. The keen sense that the experienced, elite athlete has to know, exactly how high they are off of the table and the speed of flip or rotation, is fine-tuned and is different in magnitude for each athlete.
FIG has equipment mandates, or apparatus norms, for the surface make-up of each surface an athlete comes in contact with. This includes the covering on the vault table, balance beam, the rebound rating of the foam and springs in the floor. Friction, however, is a product of what comes in contact with it. Chalk, honey, spit (I know, but it happens), sugar water, the makeup of the leather of the grip, all are ways the athlete adjusts their “stickability” to a surface. Increasing the coefficient of friction will allow for more energy transition.
Doubt
Young and inexperienced athletes often experience phases of fear in the sport, which often result in doubt or a lack of confidence going into learning or performing a skill. Even the best gymnasts in the world have experienced this phenomenon. At times, this is because of a lack of preparation, mentally and physically, a lack of lead-up skills, numbers performed, watching another athlete fall or get injured, or just even a lack of confidence in one’s self. The elite athlete trains with such numbers, and such past success, that their confidence should be based in part because of a history of repetitive success.
The trust in one’s coach and the respect for their opinion (i.e. you are ready to take this to high beam, let’s flip today, you can do this without spot or matting, etc.) plays into the level of confidence the athlete has. This has to be present in order to perform some of the world’s most difficult skills in any sport. A developmental gymnast can say “split, then step down, lift arms, square hips” for a simple handstand step-down. An elite cannot wait to flip, or initiate flipping, when planning a Yurchenko pike single let alone a double. The more flipping and twisting, the harder the skill, the higher the velocity or rotational velocity, the less room there can be for doubt, mistakes, or even equipment malfunction.
Physics
Now for the best part! Let’s nerd out on a concept called Linear Kinematics which is the culmination of the pattern, the form and the sequence of movement over time. This is important as we look at the risk of the skill in relation to what observers see as speed, how much actually happens over a period of time, on top of the concept of sequencing that we have already touched on.
The speed that is applicable in gymnastics is called velocity, which has a direction and a magnitude. We look at horizontal (side to side) and vertical (up and down) velocities. The speed of the run creates horizontal velocity. It can be changed vertically, by means of an object changing its path (hands hitting the vault for example). This turns into angular velocity, depending on the contribution of each, and their ratio. And, thus, you have the Pythagorean Theorem. Remember that?
Of course, all of this is complicated (or made more interesting, depending upon your point of view) by things like friction, energy transfer (if the body is loose, elbows bent, shoulders soft, etc.). There are forces inside and outside of the body, or internal and external forces. External forces are, truly, what make gymnastics different now than years ago- springs that can store and give more energy, the density of the foam, spring in a bar, rebound of the vault table, etc. The difference between gymnastics when Natalia Yurchenko originally performed the namesake vault in 1982 (a single flip) is a mountain of advances in equipment. Even she is in awe of adding a second flip.
There is a “flight path,” or curve, that the athlete takes after they leave the object that changes their direction, for example to make running velocity and springs in the vault turn into a curve that goes up and then comes down. Add in rotation, and we refer to it as angular movement (speed or velocity). We can consider the vault block that will potentially be affected by Newton’s Law (the first) as well (objects keep moving unless something makes that different).
With good friction, as we spoke of earlier, motion can be changed, and the energy lost minimized. If hands slide or slip, motion stays in that direction (i.e. linear with some vertical and a touch of rotation in vault pre-flight and at impact of hands to the vault table) then less motion will be transferred to vertical. Thus, not enough height to make a double pike.
Jade Carey, Senior National Team Member and Tokyo contender, is also tempting physics this week in Fort Worth by planning to perform a triple twisting laid out double backflip on floor, from a roundoff back handspring takeoff, after a few simple steps of a run.
Ah-maz-ing‼️RT @timdaggettnbc: And here it is!!!@jadeacarey TRIPLE DLO. @Simone_Biles WALKED BY AND SAID CONGRATS AND THATS CRAZY! pic.twitter.com/37Lw3gmZei
— Inside Gymnastics (@InsideGym) June 2, 2021
The position of the back handspring when she takes off is purposeful. For a triple twist with a single flip, the athlete wants to take horizontal velocity and change that into vertical velocity. The more twists there are, the higher the degree of angle on takeoff. One flip, three twists. They will take off at a negative angle relative to vertical. For Jade, she has the nearly impossible charge of flipping two times, twisting three times, and not doing too much of either. This would result in over-flipping (missing her feet and falling to back or even more) or over or under-twisting (knee and ankle purgatory). She is close to vertical upon setting as she needs the height, and time to flip.
The craziest part are the athletes who are trained so highly that they can perform a triple twist, a double layout, a double-double and a triple-double – all skills that require such fine tuning. Changes between each are so minute that confusion is a concern. The angular momentum (direction) and the angular velocity may be in different planes of motion. All with such subtle changes in angular and rotational velocity, take off angle and organization of the order of magnitude of each, that hundredths of a second make a difference. Twisting at a certain velocity versus flipping at a different one. Again, with such marginal room for error.
At the end of the day, the respect due to the athletes and the coaches who guide them through these feats is astonishing. The hours of preparation and repetition are unfathomable. When the art and science of sport come together, anything is possible.
