Biomechanics | cheerleadingscience

Scientific Advancements

Cheerleading Shoes

Cheerleading shoes first started out as the “normal saddle shoes” by keds. These shoes had soft leather on the top, had a durable rubber sole, and the collar of the shoe was padded for comfort. They were designed for the “typical cheerleaders” in the past. This means they were not designed for the jumps, tumbling or stunts cheerleaders do today. They were more designed for wearing while cheering on teams at the sideline, mainly for looks more than anything else. Then came the “keds champion sneakers” or “keds canvas shoes”. This shoe has a soft rubber sole, which made it easier for the cheerleaders to move around because of this lighter fabric. In modern days cheerleading shoes are made by several different athletic brands such as Nike, Adidas, Converse, Reebok, etc. There are also companies that make shoes specifically for cheerleading like Nfinity, Chasse, and Kaepa. These shoes that are made specifically for cheerleading have many advantages over the other brands or olden day cheerleading shoes. For example cheerleading shoes are now made of extremely light material in comparison to the older shoes, they weigh about 0.25 pounds. This lightweight material helps cheerleaders when jumping and tumbling throughout routines. Cheerleading shoes are also now made with finger grips. This is an aid for cheerleaders because it is now much easier to hold onto a flyers foot while you are stunting. These finger grips are the key spot to hold your flyers foot so they also serve as a guide or direction on where to place your fingers. Next, there is a smooth rubber sole on the shoes now which reduces uncomfortable friction while your top is in the air. This way while you are holding your flyer in the air the shoe is more comfortable in your hand. Cheerleading shoes also have padding in the inside of the shoe. This aids comfort for the cheerleader’s foot as they are constantly jumping, tumbling and moving around. Finally cheerleading shoes are made of breathable fabric. This is important while we practice and perform because it eliminates the opportunity for feet to heat up or swell.

Surfaces:

A second technological advancement would be the cheerleading surfaces. Since cheerleading first started at the sidelines of athletic events, they did not have any mats at all. This begun to be dangerous once they tried to add tumbling skills or stunts to their cheers. The hard ground began to become a safety hazard incase people landed on it. About 93% of cheerleading injuries were because of the hard surface. These fatal injuries caused a change in cheerleading. The first advancement they made was changing from hard surfaces to tatami puzzle mats. This did not make much of a difference because they were so thin, but was still better than the hard ground. They were inexpensive and were easy to store. They were made of foam and cushion and was able to somewhat help prevent strains or injuries from impact. As cheerleading advanced in difficulty they realized these mats were not of much help. Therefore, they advanced the surfaces by making it a carpet-bonded foam mat, also known as “dead mat”. These mats were placed onto of the gym floors and have a thickness of 1-2 inches. These floors are held together by Velcro strips that are about 2-4 inches wide. Usually there would be several mats side by side, mocking the normal size of a competition mat. The final technological advancement of cheerleading surfaces would be moving these “dead mats” onto a sprung floor. Beneath the mats there is a double layer of hardwood plywood, this plywood has a minimum thickness of 24mm. Under this plywood there are large metal springs and above it there is the carpet-bonded mats. All-star cheerleaders use this sprung floor, which is much different than sideline cheerleading. The purpose of these types of mats is to even further reduce the risk of injury as well as aid the athlete with a great initial impulse in their skills. This can be related to Newton’s third law of motion. “For every action there is an equal and opposite reaction” (Exercise science text). This is basically saying that the force you will put into the sprung floor will be equal to the force it gives back to you. When the springs under the mat react your body it will be propelled in an upward motion and you will be a projectile object.

Uniforms

The final technological advancement would be in uniforms. When cheerleading began many of the uniforms were made to be baggy and hot, they were made of a buttoned down cardigan, worn over a turtleneck with the school letter or symbol on the front. Women would wear long wool skirts with a sweater over a blouse or turtleneck. As cheerleading advanced and added harder skills into routines their uniforms begun to change as well. Cheerleading uniform then changed from bulky cardigans to lighter weight sweaters and long wool skirts to knee length skirts. These uniforms were still bulky in comparison to modern day uniforms but for that generation they were seen as a more form fitted and flattering uniform. As more cheerleading went from sideline to all-star the overall look completely changed. They had gone from bulky skirts and sweaters to complete form fitted outfits. These outfits were now made of a polyester-spandex bled. These uniforms are a pair of shorts, sometimes with a skirt over, and a form-fitted long or sleeveless shirt. This allows cheerleaders to have a comfortable fit that allows them to dance, jump, tumble and perform other difficult tricks.

Maximum Force Transfer

Principles of Biomechanics

Moment of Inertia: The moment of inertia is the body resisting rotation. In cheerleading this is demonstrated by back tucks and back layouts or a full twisting cradle and double twisting cradle. When in a tuck position you will flip faster than in a straight body position. In a straight body position there is more resistance to rotation, therefore you will flip slower. In a full twisting cradle the same concept applies. If when you twist you bring your arms in closer to your midline you will be able to twist faster than if they were further away. The rigidness of the body also depends on how fast the individual will spin. If the person is in a tight body position they will twist or flip faster, if they have a loose body with will flip or twist slower. When the individual twists or flips slower the length of the moment of inertia increases.
Friction: Cheerleading shoes have a rubber sole, which increases friction between the shoe and the bases hands. This friction is good because it helps prevent bases from dropping their flyers.
Centre of Gravity/Stability: In a double base or an extended position the centre of gravity is very important. It is critical that the bases remain directly under the flyers feet. This is the best way to ensure that the flyer can easily remain balanced. If the flyer is even a little outside their centre of gravity they may fall. Also the stability of the flyer is affected by the height of the stunt. The flyer is able to remain more stable within a double base position rather than in an extended position. This is because their centre of gravity is lower therefore they have more stability.
Newton's second law of motion: Newton's second law of motion states, "a force applied to a body causes an acceleration of that body of a magnitude proportional to the force, in the direction of the force, and inversely proportional to the body's mass. An easy example of this in cheerleading would be basket tosses. The bases start with the flyer in their hands and create a greater momentum for the flyer as they begin to throw her in the air. If the bases did not throw the flyer and she just tried to push off of their shoulders to get high in the air, she would not get too high. Therefore, with the extra force from the bases the flyer is able to get thrown higher in the air. Relating back to the law of motion, the force that is applied to the body (the bases throwing), causes and acceleration of that body in the direction of the force (the flyer to be thrown up into the air).
Newton's Third law of motion: Newton's third law states, "for every action there is an equal and opposite reaction." This can be related to tumbling in cheerleading. The cheerleader will push down into the ground when they take off (action) and then they will be propelled into the air (reaction of floor), becoming a projectile object. This can be demonstrated by front handsprings, back handsprings, backtucks, fronttucks, etc.
Below is a video demonstrating these biomechanical terms.

Basket Toss

Sequential Summation of Forces: To be able to generate maximum force every person within the stunt group must use their muscles in a sequential order. For example during a basket toss the bases first begin to generate power by straightening their legs, then they engage their torso by keeping a rigid body, following they will begin to lift up with their bicep, then extent their arms with their tricep, finally having a "flick" in the wrist.
General Motion: General motion is when you have both angular and linear motion. During a kick double basket toss you are using this general motion. The flyer is going in a linear motion upwards while being thrown. Then the flyer leans back and brings their arms in for a double twist, which is angular motion.
Kinetic Energy: The basses throwing the flyer she is gaining extra energy than what the top would normally have. If the top would try to just jump out of the bases hands without getting thrown by the bases, she would not get that high. But with the extra energy from the bases/ third they will be able to build kinetic energy and go higher.