Sports-And-Fitness

The biomechanical principles

introduction

In general, the term biomechanical principles is understood to mean the use of mechanical principles for optimizing athletic performance.

It should be noted that the biomechanical principles are not used to develop technology, but only to improve technology.

HOCHMUTH developed six biomechanical principles for utilizing mechanical laws for sporting loads.

Biomechanical principles according to Hochmuth

Hochmuth developed five biomechanical principles:

The principle of the initial force states that a body movement that is to be carried out at a maximum speed must be initiated by a movement that runs exactly in the opposite direction. The correct relationship between introductory movement and target movement must be optimally designed for the individual.
The principle of the optimal acceleration path is based on the assumption that the acceleration path must be optimally long if the goal is a high final speed. In the case of straight movements, one speaks of a translation and in the case of evenly curved movements of a rotation.
In order to follow the principle of the temporal coordination of individual impulses, individual movements must optimally mesh with one another and be perfectly timed. Depending on the goal of the movement, a temporal optimization of the individual movements can be more important than a phased start of the individual movements.
This can just as well be the other way around. The principle of counteraction relates to Newton's third axiom (Actio equals reaction) and states that for every movement there is a countermovement. Human equilibrium, for example, is an interplay of movements and counter-movements.
The principle of momentum transfer is based on the fact that it is possible, with the help of the law of conservation of angular momentum, to take impulses with you by shifting the body's center of gravity into another movement.

Principle of the initial force

definition

The biomechanical principle of the initial force plays an important role, especially in throwing and jumping movements, in which a maximum final speed of the body or a piece of sports equipment is to be achieved.
This principle states that an introductory movement opposite to the main direction of movement results in a performance advantage. The term used in the older literature as the principle of maximum initial force is no longer used in more recent sports science, since this initial force is not a maximum but an optimal power impulse.

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How does this initial force arise?

If the main movement is preceded by a movement opposite to the actual direction, this movement must be slowed down. This braking creates a force surge (braking force surge). This can then be used to accelerate the body or the sports equipment if the main movement immediately follows this "backward movement".

Explanation of the principle of initial force

The figure illustrates the principle of the maximum initial force using an example on a force plate.

An athlete throws up a medicine ball with his arms straight. Initially, the athlete is in a calm stance on the measuring platform. The scales show the body weight [G] at (The weight of the mediball is neglected. At the time [A] the subject goes into the knee. The measuring plate shows a lower value. The area [X] shows the negative impulse that corresponds to the braking impulse [y] corresponds. The acceleration force surge occurs immediately after this braking force surge. The power [F] acts on the mediball. A larger measured value can be seen on the measuring platform. For optimal power delivery, the ratio of braking force to acceleration force should be about one to three.

Principle of the optimal acceleration path

acceleration

The acceleration is defined as the change in speed per unit of time. It can occur in both a positive and a negative form.
In sport, however, only positive acceleration is important. The acceleration depends on the ratio of force [F] to mass [m]. consequently: If a higher force acts on a lower mass, the acceleration increases.

Explanation

The principle of the optimal acceleration path, as one of the biomechanical principles, aims to give the body, partial body or sports equipment a maximum final speed. However, since biomechanics are physical laws in relation to the human organism, the acceleration path is not maximal, but optimal due to muscle-physiological conditions and leverage.
Example: The acceleration path when throwing a hammer could be extended many times over by additional rotary movements, but this is uneconomical. Crouching down too deep during the straight jump leads to an increase in the acceleration path, but causes unfavorable leverage and is therefore not practical.

In modern sports science, this law is called the principle of the tendency towards the optimal acceleration path (HOCHMUTH). The focus is not on reaching a maximum final speed, but on optimizing the acceleration-time curve. With the shot put, the duration of the acceleration does not matter, it is only about reaching the top speed, in boxing, however, it is more important to accelerate the arm as quickly as possible in order to prevent evasive actions by the opponent. In this way, the start of the acceleration can be kept low during the shot put and a high acceleration only occurs towards the end of the movement.

Principle of the coordination of partial pulses

Definition of impulse

An impulse is the state of motion in direction and speed [p = m * v].

Explanation

With this principle, it is important to distinguish between coordination of the entire body mass (high jump) or the coordination of partial bodies (javelin throw).
In close connection with the coordinative skills (especially coupling skills), all partial body movements / partial impulses must be coordinated in terms of time, space and dynamics. This can be clearly seen in the example of a serve in tennis. The tennis ball can only reach a high top speed (230 km / h) if all of the partial impulses follow one another immediately. The result of the high impact movement on the impact begins with the stretching of the legs, followed by a rotation of the upper body and the actual impact movement of the arm. The individual partial impulses are added up in the economic version.
It should also be noted that the directions of the individual partial pulses are in the same direction. Here again, a compromise has to be found between anatomical and mechanical principles.

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Principle of counteraction

Explanation

The principle of counteraction as one of the biomechanical principles is based on Newton's third law of counteraction.
It says that a force that has arisen always creates an opposite force of the same magnitude in the opposite direction. The forces that are transmitted to the earth can be neglected due to the mass of the earth.
When walking, the right foot and the left arm are brought forward at the same time, as humans cannot transfer forces to the earth in the horizontal position. Something similar can be observed in the long jump. By bringing the upper body forward, the athlete simultaneously lifts the lower extremities and thus gains advantages in jumping distance. Other examples are the punch in handball or forehand in tennis. The principle of rotary recoil is based on this principle. As an example, imagine standing in front of a slope. If the upper body is supported, the arms begin to circle forward in order to generate an impulse on the upper body. Since the mass of the arms is less than that of the upper body, they must be done in the form of fast circles.

Principle of conservation of momentum

To explain this principle, we analyze a somersault with a straight and crouched posture. The axis around which the gymnast jumps a somersault is called the body width axis. When the body is stretched out, there is a lot of body mass away from this axis of rotation. This slows down the turning movement (angular speed) and the somersault is difficult to perform. If body parts are brought to the axis of rotation by crouching, the angular speed increases and the execution of the somersault is simplified. The same principle applies to pirouettes in figure skating. In this case, the axis of rotation is the longitudinal axis of the body. As the arms and legs approach this axis of rotation, the speed of rotation increases.

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The biomechanical principles in the individual disciplines

Biomechanical principles in high jump

During the high jump, the individual movement sequences can be brought into harmony with the biomechanical principles.
The principle of the optimal acceleration path can be found again in the approach, which has to curve forward in order to hit an optimal jump point. The principle of the temporal coordination of individual pulses also plays an important role. The caulking step is extremely important and determines the trajectory after the jump. The principles of impulse transmission and initial force play an important role here. They ensure that the athlete brings the optimal power when jumping on the ground and takes the momentum from the run-up.

When crossing the crossbar, a rotation takes place which is due to the principle of counteraction and rotary recoil. When jumping, the body is turned sideways over the bar and then caught on the back.

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Biomechanical principles in gymnastics

In gymnastics and gymnastics exercises, several biomechanical principles also come into play. Turning movements and swings are of particular importance. These follow the principles of the optimal acceleration path.Different jumps are also frequently performed movements in gymnastics. Here we find the principle of the maximum initial force, as well as that of the optimal acceleration path. Finally, the individual sub-movements must be combined into a fluid sequence, which corresponds to the principle of the coordination of sub-impulses.

Biomechanical principles in badminton

The principles can also be applied when the badminton is served. The backward movement follows the principle of the optimal acceleration path and the principle of the initial force. The principle of conservation of momentum is important so that the momentum can also be transferred to the ball. The principle of temporal coordination of individual pulses also helps here. When the blow is complete, the movement is intercepted using the principle of counteraction and rotary recoil.

The biomechanical principles in tennis

The tennis serve is very similar to that of the badminton. Many of the biomechanical principles interlock and thus ensure optimal execution of the movement. In tennis it is particularly important to pay attention to optimal movement sequences, as mistakes can cost a lot of energy due to the speed of the game. Therefore, these principles are very important in training and can make the difference between winning and losing in competition.

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Biomechanical principles in sprinting

The sprint is primarily about the principles of initial force, the optimal acceleration path, the temporal coordination of individual impulses and the principle of conservation of impulses. The principle of counteraction and rotary recoil is hardly used here.
The start must be powerful and focused. The sequence of movements of the legs must be adhered to in an optimal frequency and step length as far as possible until the goal.
This example nicely illustrates how important biomechanical principles can be for movement.

Biomechanical principles in swimming

In swimming, the biomechanical principles can be applied slightly differently to the different swimming styles.
The breaststroke example is presented here because it is the most popular type of swimming. The principle of the temporal coordination of individual impulses corresponds to the cyclical movement of arms and legs with simultaneous breathing (Head above and below the water).
The principle of impulse transmission is reflected in the fact that good swimmers can learn the swing from the individual strokes (Crossbow strike and leg strike) and use the propulsion for the next train.

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Biomechanical principles in long jump

The long jump is similar to the high jump. The type of approach is different. It is not arranged in a curve as in the high jump, but linearly on the jump pit. The principle of the optimal acceleration path plays a major role here. In addition, the principle of impulse transmission is used as well as the principle of initial force, without which the start would not even be possible.

At the end of the run-up, the jumper takes a caulking step and uses the principle of counteraction and impulse transmission and pushes himself into the trajectory towards the jump pit. In flight, the jumper throws his legs and arms forward, using the principle of impulse transmission to fly even further.

Biomechanical principles in the shot put

Various biomechanical principles play a role in the shot put. In order to achieve a large distance when pushing, it is crucial to transfer as much force as possible to the ball in order to achieve a high throwing speed. We call this the principle of maximum initial force. A higher push-off speed is also achieved by backing out and thereby lengthening the acceleration path. This is the principle of the optimal acceleration path. Finally, an optimal coordination of the partial phases of the movement in the shot put is important; an unclean transition, for example, has a negative effect on the stroke distance. We know this as the principle of the coordination of partial impulses.

Biomechanical principles in volleyball

Volleyball is a dynamic sport with a wide variety of elements, including hitting, jumping and running elements. In principle, all biomechanical principles can be found in volleyball. The principle of the initial force and the optimal acceleration path can be found, for example, when serving. The principle of the coordination of partial impulses defines, for example, the clean jump and clean hit with a smack ball. The impact of the ball results in the rebound from the hands with the principle of counteraction. The principle of impulse transmission comes into play in the passing game.

Biomechanical principles in hurdles

The biomechanical principles are also of great importance in hurdles. The principle of maximum initial force describes, for example, the push off in front of the hurdle, which maximizes the jump height. In order to optimize the start of a hurdler, the principle of the optimal acceleration path comes into play, the weight shift and the force effect when pulling off the block play a major role. The partial movements in the hurdles must be optimally coordinated to guarantee success. This follows the principle of optimal coordination of partial pulses. The principle of counteraction comes into play as soon as the runner lands on the leg again after jumping and the balance is maintained by stretching the upper body.