The term ‘sports biomechanics’ refers to the science which deals with an athlete’s movement while also considering the internal as well as external forces that are in effect while performing any physical movement.
Sport biomechanics studies the effects of forces on sport performance. By making use of laws as well as principles that are grounded in physics – which apply to human movement – athletes and sports coaches can make sound decisions to develop efficient sport techniques.
When sports coaches understand how forces work in sports, and how athletes can leverage these forces, they have a distinct advantage over those who lack these tools. Coaches and personal trainers with a command of both mental training tools and sports training principles can make amazing things happen on the field.
The link between biomechanics and kinesiology
Biomechanics and kinesiology, which are areas of study about human movement, can help coaches to:
- Analyse sport movements,
- Select the best training exercises,
- Reduce or prevent injuries,
- Design or choose the sport equipment that best matches athletes’ personal needs.
- Maximise economy and efficiency of movements.
Kinematics is a branch of biomechanics which looks at the study of movement referring to the amount of time which is taken in order to carry out the activity:
- Distance as well as displacement
Distance (in other words, the length of the path that a body follows) and displacement (in other words, the length of a straight line that join the start and finish points) are quantities used in order to describe a body’s motion. For example, in a 400m race on a 400m track, the distance is 400 metres but the displacement will be zero metres (start as well as finish at the same point).
- Speed in addition to velocity
The terms ‘speed’ and ‘velocity’ describe the rate at which a body is transferred from one location to another. The average speed of a body is achieved by dividing the distance by the time taken.
Average velocity is acquired by dividing the displacement by the time taken, for example for a swimmer in a 50m race, in a 25m-length pool, who completes the race in 71 seconds the distance is 50m and displacement is 0m (the swimmer is back where they started). This means that speed is 50/71= 0.70m/s and velocity is 0/71=0 m/s.
What is linear kinetics?
Kinetics is about what causes a body to move, in other words momentum, inertia, mass, weight as well as force:
This is calculated with the following equation; mass x velocity.
This refers to the reluctance of a body to change whatever it is doing/
Mass is the amount of matter that a body is composed of. This measurement is not affected by gravity and is measured in kilograms (kg) or pounds (lb).
Weight is the force owing to gravity -9.81m/s².
Force is a pushing or, alternatively, a pulling action which causes a change of state (rest/motion) of a body. This is proportional to mass x acceleration and is measured in Newtons (N). One Newton is the force which generates an acceleration of 1 m/s² in a body of 1kg mass.
The categorisation of external or internal forces will depend on the definition of the ‘system’. In biomechanics terms, the body is seen as the ‘system’. This means that any force which is exerted by one part of the system on another part of the same system is known as an internal force. All other forces are external.
What is meant by ‘kinetic energy’ and ‘power’?
The term ‘kinetic energy’ refers to the mechanical energy that is possessed by a moving object. The equation to work out kinetic energy is the following:
- Kinetic Energy = ½ x mass x velocity² (joules)
‘Power’ is defined as the rate at which energy is used or created from other forms. There are a number of equations for power:
- Power = energy used ÷ time taken,
- Power = (force x distance) ÷ time taken, and
- Power = force x velocity.
A force which acts through the centre of a body results in movement . A force where the line of action, which does not pass through the body’s centre of gravity, is called an eccentric force. This force results in movement and rotation. For example, if one pushes through the centre of an object it will move forward into the direction of the force. If you push to the one side of the object (eccentric force) it will move forward as well as rotate.
Biomechanics in sports applies the laws of mechanics as well as physics to human performance. This is done in order to gain a better understanding of performance in athletic events by the use of modelling, simulation as well as measurement. You must also have a good understanding of the application of physics to sport an fitness because physical principles such as motion, resistance, momentum and friction play a part in the majority of sporting events.