“The true art of Gymnastics is in successfully manipulating the science” (Gerald, 2012)

The sport of Gymnastics encompasses a copious amount of movement skills all sequenced together to create an individualised routine on each of the four apparatus. In the words of Dr. George Gerald (2010) “to say success in gymnastics depends on the skills a performer can execute is but a story half-told.” The term “skill” implies both what is done and the way in which it is done (Gerald, 2010). As a sport that is driven by biomechanics, technical excellence in the execution of these skills is vital for success. The ‘giant circle’ is a fundamental skill of the uneven bars, used to form the basis of many high difficulty skills; much like a back-handspring is to the floor exercise. It is where a gymnast begins in a handstand position above the bar and fully rotates around the rail without releasing (Sevres et al, 2009). As coaches we are taught to focus on body shape when teaching a ‘giant circle’ to our gymnasts, however how much influence does body shape actually have? To answer this question we must first understand a few biomechanical principals and break down the ‘giant circle’ to see the connections.

Within his book ‘Championship Gymnastics: Biomechanical Techniques for Shaping Winners’ Dr Gerald identifies five training principles that refine Gymnastics. Here we are going to examine two of these principles and identify other biomechanical principles that correlate to the ‘giant circle.’

What is the Amplitude Principle?

The amplitude principle refers to the ‘range through which a performer’s body moves during execution of a skill or series of skills’ (Gerald, 2011. p. 27) This principle can be subdivided into two: external amplitude and internal amplitude. When studying the giant circle we focus only on internal amplitude as external amplitude relates to the body in relative to the ground/or apparatus (Gerald, 2011. p. 27).

            Internal Amplitude:

‘Internal amplitude refers to the range of motion through which one or more body segments move relative to each other’ (Gerald, 2011. p. 29). Within every gymnastics skill the complete range of motion within the appropriate joint ranges is required for maximum performance.

A ‘giant circle’ begins and ends with the skill that underpins gymnastics: THE HANDSTAND. In order to perform a handstand correctly, one must have reasonable amplitude within both the hip and shoulder joints in order to create a perfect vertical line with their body. The photo below depicts the difference in handstands when maximum internal amplitude is implied.

The following image was taken from George S. Gerald's book 'Championship Gymnastics' (2012)

Due to inadequate shoulder flexibility (internal amplitude), Gymnast number 1 has created an arched body shape. She must make this arch shape to keep her body mass directly over her base of support (her hands) to remain balanced (Knudson, 2007,). Gymnast number 2 has maximum amplitude in both joints and can therefore create perfect vertical line.

The second relevant training principle is the:

The Segmentation Principle

This principle claims that as a gymnast becomes more proficient with a skill, the number of body segments used in the execution decreases (Gerald, 2010). When executing a perfect handstand there is only one segment. For example, as shown in the image below, if a gymnast were to bend their knees in a handstand, this would then create two segments.



The following image was taken from George, S. Gerald's book 'Championship Gymnastics' (2012)



In specific to a ‘giant circle’ although the beginning and end uses one straight line segment, when rotating around the bar the gymnast creates a curved-line segmentation. Any diversion from this shape affects the acceleration and movement of the ‘giant circle’ and this will be further explained later on.

What affect does Gravity, Acceleration and Motion have in a Giant Circle?

Swing is a form of rotary or angular motion. It is a circular movement of an object about an axis of rotation (Gerald, 2010). In this situation, the gymnast does a complete swing to finish in the exact position they started in; with the axis of rotation being the bar they are on. This is called an Internal Swing.

When the gymnast begins a giant circle, she starts by balancing in a handstand position on the bar. This position can be balanced as her main body mass remains over her base of support (Blazevich, 2012). To initiate the ‘giant circle’ the gymnast must move her body mass outside of her base of support in the direction she wishes to travel, which in this situation is an anti-clockwise direction (Blazevich, 2012). With gravity’s downward pull the gymnast begins her descent swing. This continuous pull of gravity causes an increase in velocity with the greatest velocity being at the exact bottom of the swing (Gerald, 2012). Body shape definitely plays a role in the acceleration of the downward phase as the gymnast needs to be fully stretched out with maximum amplitude obtained within the shoulder and hip joints. Closed shoulder and hip joints (minimum amplitude) will create more segments which in turn will inhibit the flow of the swing and decrease the circle (Gerald, 2012).

Although gravity causes the acceleration of the decent phase, it also causes the deceleration in the ascent phase, as the gymnast will only accelerate until her body mass is directly under the axis of rotation (Sevres et al, 2009). The image below shows how if a gymnast maintains the same body shape throughout the entire swing she will not make it back to her initial starting point and the swing will stop at approximately 2 o’clock.



The following image was taken from George, S. Gerald's book 'Championship Gymnastics' (2012)

 The gravitational downwards pull plus the friction (the force that opposes the movement of two surfaces that are in contact with one another) (Blazevich, 2012. Pp. 125) created by the hands circling the bar decrease the velocity of the swing.   Therefore the gymnast must make a smooth but quick body shape change at the bottom of the swing to create a ‘tap’ like motion to create a balance between the angular momentum gained on the downwards swing and the angular momentum lost on the upwards swing (Yeadon and Hiley, 2000). This is further explained later in the discussion.

 

Is the Radius of Swing Rotation Relevant?

In order to understand how a gymnast completes the ascent phase of the ‘giant circle’ we need to understand both how body shape affects the radius of rotation and how lengthening and shortening the radius of rotation helps our ‘giant circle.’

When completing a giant circle ideally we want to the body to be as extended as possible. We want this as we know that when hitting a ball with a bat, we want to hold the bat as close to the end of the handle as possible to create a longer lever. This longer lever will generate more power when hitting the ball (as long as you hit the ball at the end of the bat) as the end of the bat will have travelled further in the same amount of time, therefore generating more speed (Blazevich, 2012, p. 21). When referring to the ‘giant circle’ by extending our bodies as much as possible we are creating the longest lever and therefore generating more speed.

Unfortunately, in gymnastics we tend to use the uneven rails. Therefore on the descent phase of the ‘giant circle’ we must pass by the lower bar. Any obstruction to this bar will not only mean deductions off the gymnasts score, but it hurts and will cause implications to the ‘giant circle’ itself. Therefore in order to pass by this lower bar safely but effectively, the gymnast must change her body shape (Gerald, 2010). This change in shape can be seen in the image below.



The following image was taken from George, S. Gerald's book 'Championship Gymnastics' (2012)



When referring to the radius of rotation, we are referring the distance between where the gymnast holds the rail and their hip angle. When completing the giant circle the aim is to maximise the descent swing whilst avoiding contact with the lower rail. In order to do this the gymnast needs to change her body shape whilst maintaining the longest possible radius of rotation to allow for even weight distribution (Gerald, 2010). In the image below we can see that the gymnast changes her body shape in two different ways. However gymnast number 2 does so in a way that creates the longer radius. Therefore bending at the hips is more beneficial than bending at the shoulders when passing through the lower rail.



The following image was taken from George, S. Gerald's book 'Championship Gymnastics' (2012)



Conversely on the upwards swing the gymnast is required to shorten her radius of rotation in order to complete a 360 degree circle. As mentioned above the gymnast creates a ‘scoop’ shape with her body whilst maintaining the longest radius of rotation (Busquets et al, 2007). After clearing the lower rail the gymnast extends her body to its fullest and then performs a ‘tap’ like motion at the bottom of the swing. We already know that at the bottom of the swing the velocity is at its peak, so using that momentum the gymnast opens her hip joint and then drives her feet forward, moving her body back into the intial ‘scoop’ like shape. On this upwards phase the gymnast needs to lead dramatically with her feet. In order to do this she must slightly close her shoulder angle, therefore creating a shorter radius of rotation to maintain the angular momentum (Busquets et al, 2007, p. 10). This then allows the feet to drive the body up to 12 o’clock and then the body can open itself and extend back into the initial handstand shape. The downwards phase can be seen two images above and ascent phase can be seen in the image below.

The follolwing image was taken was George, S. Gerald's book 'Championship Gymnastics' (2012)

How about the Kinetic Chain Sequence?

According the Dr Gerald (2012) “all gymnastics elements follow specific sequential movement patterns, and swing-orientated skills are no exception” (p. 159). When completing a ‘giant circle’ in the initial descent the gymnast closes her body shape using a 1-2-3 sequence (Gerald, 2012). The gymnast then opens her body shape in the mirroring 3-2-1 to take advantage of the increased velocity at the bottom of the swing. The gymnast then again closes her body shape with the 1-2-3 sequence to create a feet-driven force to assist with the ascent phase and then finally opens her body in a 3-2-1 sequence to finalise the ‘giant circle’ back in a handstand position (Gerald, 2012).

The following image was taken from George S. Gerald's book 'Championship Gymnastics' (2012)

Last but not Least - Newtons Laws

Newtons Laws of course play a role in the ‘giant circle’ and for any skill in gymnastics for that matter. The uneven bars themselves interplay with Newton’s Third Law. This law states:

            For every action, there is an equal and opposite reaction (Knudson, 2007, p. 133)

When looking at a giant circle; a force is applied when the gymnast pushes against the rail to hold her handstand. The rail then exerts an equal and opposite reaction force thus allowing the gymnast to remain in handstand on top of the rail. The same reaction occurs as the gymnast swings around the rail and pulls on the bar. The bar then exerts an equal and opposite reaction and in a sense pushes back allowing the gymnast the hang from the rail (Blazevich, 2012, p. 45).

 THE FINAL ANSWER

So now that we understand all the biomechanical principles involved in completing a ‘giant circle’ I think it’s fair to say that body shape plays a critical role. From the very beginning the gymnast must hold a tight, vertical body shape, with maximum internal amplitude in all relevant joints. The gymnast must then create a ‘scoop-like’ body position where the feet are leading the motion on the descent swing. This ‘scoop-like’ body shape comes from extension of the hip joint (Yeadon & Hiley, 2000). This allows the body to clear the lower rail but with the longest radius of rotation possible. As the gravitational downwards pull prevents the gymnast from completing the 360 degree circle with the same body shape, the gymnast must flex her hip joint to create an ‘arched’ shape and then drive her feet forward to lead the ascent phase (Yeadon & Hiley, 2000). This ‘tap’ phase of the giant circle allows the gymnast to use the increased velocity at the bottom of the swing to her advantage and drive her body up the ascent phase. Throughout this ascent phase the gymnast must shorten her radius of rotation by closing her shoulders to maintain the angular momentum and continue back up to handstand (Busquets et al, 2007, p. 10). Throughout all of this movement the body reflects the Kinetic chain sequence moving from a scoop position to straight shape, back to a scoop and finalising in a straight vertical handstand (Gerald, 2012).

Conversely if the body were to remain in the same shape during the entire swing, it would stop at approximately 2 o’clock and descent and shown in an image above, therefore the ‘giant circle’ would be deemed incomplete. 

How else can we use this information?

Body shape shares equal importance behind the biomechanics of any gymnastics skill. However does body shape have an influence in other sports?

Of course it does! When ten-pin bowling one must ensure their arm is completely straight. When doing a ‘giant circle’ keeping your body straight increases the acceleration and maximises the velocity at the very bottom of the swing. Similarly with bowling, having a straight arm increases the range of motion and creates a longer lever (Knudson, 2007, p. 218), thus the end of the arm has further to travel in the same amount of time. Therefore generating more speed as opposed to if you bent your arm and shortened your lever. This is also relevant to most batting sports as identified earlier in the discussion.

Additionally body shape and positioning plays another role in batting sports. The stance a batter needs to be in when hitting any kind of object is important. For example bending the knees in the initial stance lowers the batters centre of gravity and lowers the batters torso thus allowing the body to generate more force behind the hit.

References

Busquets, A., Marina, M., Irurtia, A., Ranz, D., & Angulo-Barroso, R. (2011). High bar swing performance in novice adults: Effects of practice and talent. Research Quarterly for Exercise and Sport, 82(1), 9-20

Blazevich, B. (2012) Sports Biomechanics, The Basics, Optimising Human Performance (2^nd Ed.). London, United Kingdom

Gerald, G.S. (2012) Championship Gymnastics: Biomechanical Techniques for Shaping Winners, California, America

Knudson, D. (2007) Fundamentals of Biomechanics (2nd Ed.).  California, America

Sevres, V., Berton, E., Rao, G. & Bootsma, R. J. (2009).  Regulation of pendulum length as a control mechanism in performing the backward giant circle in gymnastics, Human Movement Science, 28, 250-262

 

Yeadon, M. R., & Hiley, M. J. (2000) The Mechanics of the Backward Giant Circle on the High Bar. Human Movement Science, 19, 153-173