How motion, energy, and force combine to power peak athleticism
We all love sports, don’t we?
It does not require an IQ of 200+ to know that athletes wants to improve their performance, prevent injuries, and gain an edge over their opponents. In that case, a good knowledge of science can be of great help in understanding various aspects of physiology and the physics related to force, matter, energy and motion. It helps in understanding how things work — from the smallest finer movement to the largest or gross movement patterns.
Physics can also help athletes master their respective sports, be it cricket or Formula One. In that parlance, we will explore some of the physics concepts that are applicable to sports, and how you can use them to your advantage.
The power of force
One of the most important physics concepts in sports is force. Force is a push or a pull that causes an object to change its speed, shape, or direction. It can be applied in various ways — through muscles, gravity, air resistance, and friction. It can also be measured by its magnitude (how strong it is) and its direction (which way it points).
In sports, force affects the speed of movement, farthest distance thrown, height of jumps, and intensity of impact.
According to the Third Law of Motion, when you run, you apply a force to the ground with your feet, and the ground applies an equal and opposite force back to you. This ground reaction force propels you forward and upward, allowing you to run faster and longer. However, if the ground is too soft or slippery, the force is diminished, and you lose speed and stability. A simple example is running on grass as compared to running on a beach.
Similarly, when you throw a ball, you apply a force to the ball with your arm and hand, and the ball applies an equal and opposite force back to you. The ball’s force pushes you slightly backwards, while it flies forward with a certain speed and direction. However, if the ball is too heavy or too light, the force will vary, and the ball will not go as far or as fast as you want.
To use force effectively in sports, you need to know how much force to apply, in which direction, and for how long. You also need to consider the effects of other forces acting on you or the object you are moving — such as gravity, air resistance, friction or wind direction. These forces will always be present to varying degrees. By adjusting your technique and training accordingly, you can optimise your performance and avoid injuries.
The art of work and energy
Another key physics concept in sports is work and energy.
In physics, work is defined as the energy transferred to or from an object by a force acting upon it as it is displaced. It is done when a force causes a displacement of an object. Energy, however, is the ability to do work. Some forms of energy are specific to sports and closely related in their transfers:
Kinetic energy: Energy of motion
Potential energy: Stored energy that has the potential to do work (e.g., a stretched rubber band, a ball held above the ground)
Thermal energy: Energy associated with temperature and heat
In sports, work and energy are involved in every movement and action. To explain in simple physics: in fast bowling, you transform chemical energy from your food into kinetic energy of your body while running up, creating momentum. The muscles store elastic potential energy to be converted into kinetic energy at the right moment. Part of this kinetic energy becomes elastic potential energy as the body positions itself, and gravitational potential energy as you rise above the ground. Then, this potential energy becomes kinetic energy while releasing the ball. The bowler aims to maximise the impulse (force multiplied by time) at the point of release.
The law of conservation of energy helps in efficiently conserving, transferring, and converting energy from one form to another, while accounting for energy lost due to friction, air resistance, heat and sound. This allows you to do more work and have more energy in sports. For example, when you swing a golf club, you want to uncork your wrists at the right angle so that the clubhead hits the ball with the greatest speed possible.
By understanding work and energy concepts in sports, one can improve speed, endurance, power, and accuracy while also preventing fatigue and injuries by managing energy levels and avoiding overexertion.
The science of motion
Another indispensable physics concept in sports is motion. Motion is the change of position or orientation of an object over time. It can be described by various quantities, such as speed, velocity, acceleration, momentum, and angular momentum. These quantities help you analyse and predict the behaviour of moving objects in sports across different frames of reference.
An example of the synergy between angular momentum and rotational inertia is skating. When you skate, you use angular momentum to spin faster or slower. Angular momentum is the product of rotational speed and rotational inertia. It is sustained in an isolated system, which means it stays uniform unless acted upon by an external force.
This means: if you decrease your rotational inertia by pulling your arms and legs closer to your body, you will increase your rotational speed and spin faster. Conversely, if you increase your rotational inertia by extending your arms and legs, you will decrease your rotational speed and spin slower.
By mastering motion in sports, you can control and manipulate your own movement and that of other objects. You can also anticipate and react to the movement of your opponents and the environment. This gives you an advantage in reflex, speed, agility, stability, balance, and coordination.
The magnificence of the physics and sports combo
Physics and sports are intimately linked. Physics helps you understand how things work and why they happen in sport.
It also helps improve your performance, prevent injuries, and gain an edge over your opponents. It does not mean one has to be a scientist to understand human movement, angles and forces. A simple understanding of it can pave the way for excellence.
But physics is not only useful for sports but also understanding oneself, especially through the lens of quantum mechanics.
