The Physics of Sports - Essay Example for Your Academic Purposes

The athletic footwear is a fundamental piece in the race since the shoe is the element fundamental that connects the locomotor apparatus with the ground. Much of the injuries suffered by the runner are determined by an incorrect choice of sports footwear or by bad use of it. The podiatrist is obliged to understand this aspect, both to seek the best adaptation of his foot supports, as to make a good recommendation to the runner. The podiatrist therefore not only has to have an extraordinary knowledge of the biomechanics of the locomotor and foot apparatus, but also the container element thereof, which is none other than the sports footwear, since our orthopedic treatments are not going to act on the ground, but on the sole of the sports shoe, therefore our foot supports will have to contemplate this aspect but want to be doomed to failure.

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Order now

The three main causes for which the broker is injured are:

• Structural errors of the locomotor system
• Error in the technique of training and competition
• Error in the choice and condition of the shoe

Sports shoes have evolved in an extraordinary way and more and more thousands of citizens who decide to run for running, aware of the benefit that this entails to improve their level of well-being and healthiness and for the simplicity and comfort that this involves.

However, and the fruit of that benevolent and straightforward a priori fashion of "going for a run", hides the ghost of the injury and that's where podiatrists have a lot to say and what to do thanks to our orthopaedic treatments applied to sports.

The Marks have come to understand that to run properly; a good cushioning, stability was needed in the tread and little by little they have been introducing elements in the designs of your shoes to promote that stability. Today we find ourselves with Sneakers for "almost" all types of runners and almost for all uses. 4 decades ago Bill Bowerman, precursor of Nike, had the idea of melting wheel rubber of a truck on the grill in which his wife cooked the famous sausages, to obtain a sole with tacos that he later sewed on his runners' shoes, with this he tried to improve the grip, traction and cushioning of shoes, today the North American firm offers a line of footwear type running in honor of this character.

The physical goals of the running shoe are:

• Offer to cushion to the locomotor system
• Stabilize the tread
• Improve traction
• Technical considerations of a good training shoe:
• The height of the midsole will be greater than 15 mm
• The density less than 35o Shore
• Will contemplate inserts in the midsole
• The cutting material will be adjustable
• It must allow the adaptation of the footwear to the personalized plantar support

Sports shoe functions:

• Decrease the effort during movement
• Avoid impact forces on the locomotor system
• Protect the foot during the race
• Optimize sports performance
• Facilitate biomechanical needs
• Avoid injuries
• Favour the sporting gesture

Anatomy and structure of the shoe:

• Back or heel. It is the heel container
• Midfoot. It contains the instep of the foot
• Forefoot or toe. It contains the fingers

Motion control

Running is characterized by the repetition of a large number of cyclical movements, with very few variations (Galili, 2003).

The arrangement of the talus bone concerning the calcaneus indicates perfectly where must turn the foot in the moment of full support or medium support, towards pronation. Therefore it is important to maintain and allow these physiological degrees of pronation, between 6 and 8 degrees approximately. The problem comes when that pronation is increased, hyperpronation or overpronation and also now we know and have found in various studies carried out on runners with neutral or physiological tread, end up pronando or hiperpronando when they reach the finish line, due to joint muscle fatigue, hence the importance that footwear intended for this type of tests have good movement control, especially good pronation control.It is often activated when the runner's foot starts to turn inward.The shoe with motion control is usually rough, straight or semi-curved, offers little flexibility and its weight ranges between 350 and 450 grams.

Newton's third law states that there is an equal and opposite reaction force for each force. When you run on a surface, you exert a force onto the surface, and it exerts a force back on you. Friction is necessary for anyone to walk or run. When walking on a surface, an individual's foot applies a force that pushes backwards on the surface. The friction between the person's foot and the surface produces an equal and opposite force back on foot, causing the person to move forward. Without friction, the foot pushes backwards against a surface and slips.

A demonstration experiment is presented that illustrates the behaviour of the forces of static friction and kinetic friction in the sliding movement of a rigid body. It is also illustrated that these forces are not constant, in general. The objectives are achieved with a bar or an object that has a straight part, like a broom. The bar in horizontal position is placed on each finger 'index of both hands; the fingers are slid until they meet below the centre of mass of the bar or separate until one of them arrives at one end of the bar.

Friction

Whenever an object moves on a surface or in a viscous medium, there is a resistance to movement due to the interaction of the object with its surroundings. This resistance is called friction force.

Friction forces are important in everyday life. They allow us to walk and run. Every force of friction is opposed to the direction of relative movement. Empirically it has been established that the force of kinetic friction is proportional to the normal force N, where k is the constant of proportionality, that is,

f = N.

Dry Friction

To illustrate the forces of friction, suppose you try to move a heavy piece of furniture on the floor. You push harder and harder until the furniture seems "free" to immediately move with relative ease.

Let's call f the force of friction, F to the force that is applied to the piece of furniture, mg to its weight and N to the normal force (that the floor exerts on the piece of furniture). The relation between the force F that is applied and the force of friction can be represented by the following graph:

Coefficient of friction

Some of the forces involved in running can be understood from the concepts:

Kinematics: (from the Greek kinema, movement) that studies the movement itself same without worrying about the cause that produces it. But instead, there are some concepts or a part of the kinematics that helps study the movement or immobility in the bodies.

Dynamics: (from the Greek dynamic, force) which deals with the causes that originate the movement, that is to say, that at the latest we will call the forces of nature.

Static: (from Greek, status, immobile) is the one that deals with studying the state of balance or rest of the bodies. Another important point that will help us in the study is Newton's second law what does it say: "The acceleration of a body is directly proportional to the external force resulting that acts on the body, and has the same direction and meaning acceleration of gravity, g, whose value is 9.8 m / s2 and is always directed towards the soil.

When a body is resting on a surface, it exerts a force on it whose direction is perpendicular to that of the surface. According to the

Newton's third law, the surface must exert on the body a force of same magnitude and direction, but in the opposite direction. This force is what is called Normal, and we represent with N.

Friction Force

Friction is defined as a resistant force acting on a body, which prevents or retards the sliding of this respect to another or on the surface that this in contact. This force is always tangential to the surface at the points of contact with the body and has such a sense that it is opposed to movement possible or existing body concerning those points. On the other hand, these forces of friction are limited in magnitude and will not impede movement if they are applied forces big enough to the said force. "Since it states that when the resultant force is not null, the body moves with accelerated movement. The acceleration, for a given force, depends on a property of the body called mass.

The main forces involved with the movement of a body while running

The weight: is the force of gravitational attraction that exerts the Earth on the bodies that are on it. In most cases, it can be assumed that it has a constant value equal to the product of the mass, m, of the body. This force is the cause, for example, that we can walk (it costs a lot more to walk on a surface with little friction, ice, for example, that a surface with friction, such as a rough floor).

Experience shows us that:

The force of friction between two bodies does not depend on the size of the contact surface between the two bodies, but it does depend on which one the nature of that contact surface, that is, of what materials the form and if it is more or less rough.

The magnitude of the frictional force between two bodies in contact is proportional to the normal between the two bodies, that is:

Fr = m N

Where m is what is known as the coefficient of Friction

There is friction even when there is no relative movement between the two bodies that are in contact. We are talking about FRICTION Force static, For example; if we want to push a very large closet and we do a small force, the cabinet will not move. This is due to the strength of static friction that opposes the movement. If we increase strength with liquid we push, there will come a time when we overcome this force of friction, and it will be then when the cabinet can move. Once he Body begins to move, we speak of dynamic friction force. This Dynamic friction force is less than the static friction force. We can thus establish that there are two coefficients of friction: the static, me, and the kinetic, mc, the first being greater than the second:

Static friction force

There is a frictional force between two objects that are not moving relative. Such force is called static friction force. In the following figure, we apply a force F that increases gradually, but the block remains in position. As in all these cases the acceleration is zero, the force F applied is equal and opposite to the static friction force Fe, exerted by the surface.

The maximum static friction force Fe max corresponds to the instant in which the block is about to slide. Experiments show that:

Fe max = m eNWhere the proportionality constant is called the coefficient of friction static, Therefore, the static friction force varies, up to a certain limit to preventing one surface from sliding on another:

Fe max <= meNKinetic friction force

In the following figure, we show a block of mass m that slides through a horizontal surface with constant speed. Three forces act on the block: the mg weight, the normal force N, and the friction force Fk between the block and the surface. If the block slides with constant speed, the applied force F will be equal to the friction force Fk.

We can see that if we double the mass m, the normal force N, the force F with which we pull the block is doubled and therefore Fk is doubled. So the kinetic friction force Fk is proportional to the normal force N.

Fk = m k N

The proportionality constant m k is a number without dimensions that is called the coefficient of kinetic friction.