Movement analysis in Sports, Exercise, and Health Science (SEHS) involves understanding how and why the body moves. This includes examining the mechanics of movement, the factors that influence it, and the principles that govern it. This study note will break down the key concepts of movement analysis into digestible sections, with examples and tips to help you grasp the material effectively.
Biomechanics is the study of the mechanical laws relating to the movement or structure of living organisms. It helps us understand how forces interact with the body to produce movement.
Kinematics deals with the description of motion without considering its causes. Key parameters include:
Example
If a sprinter covers 100 meters in 10 seconds, their average velocity is: $$ v = \frac{100 , \text{m}}{10 , \text{s}} = 10 , \text{m/s} $$
Kinetics deals with the forces causing or resulting from motion, including:
Example
If a gymnast applies a force of 50 N at a distance of 2 meters from the pivot point at an angle of 90 degrees, the torque is: $$ T = 50 , \text{N} \times 2 , \text{m} \times \sin(90^\circ) = 100 , \text{Nm} $$
A body at rest will stay at rest, and a body in motion will stay in motion unless acted upon by an external force.
Note
This law explains why athletes need to apply force to start moving or to stop.
The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Given by $F = ma$.
Example
If a soccer player kicks a ball with a force of 100 N, and the ball has a mass of 0.5 kg, the acceleration is: $$ a = \frac{F}{m} = \frac{100 , \text{N}}{0.5 , \text{kg}} = 200 , \text{m/s}^2 $$
For every action, there is an equal and opposite reaction.
Tip
In sports, understanding this law helps in optimizing performance. For example, swimmers push against the water to propel themselves forward.
Note
Most muscles in the human body operate as third-class levers.
Mechanical advantage is the ratio of the output force to the input force. Given by: $$ \text{Mechanical Advantage} = \frac{\text{Load}}{\text{Effort}} $$
Example
If a lever system allows a person to lift a 200 N load with 50 N of effort, the mechanical advantage is: $$ \text{Mechanical Advantage} = \frac{200 , \text{N}}{50 , \text{N}} = 4 $$
Linear motion occurs when all parts of an object move the same distance in the same direction at the same time.
Example
Sprinters exhibit linear motion when running in a straight line.
Angular motion occurs when an object moves in a circular path around an axis of rotation.
Example
A gymnast performing a somersault exhibits angular motion.
Projectile motion is the motion of an object thrown or projected into the air, subject to only the acceleration of gravity.
Note
Key factors include the angle of release, speed of release, and height of release.
Example
In basketball, the optimal angle for a free throw is around 45 degrees to maximize the chances of scoring.
Video analysis is a common method used to study movement. By recording and analyzing footage, coaches and athletes can identify areas for improvement.
Tip
Use slow-motion playback to observe details that are not visible at normal speed.
Force plates measure the forces exerted by the feet on the ground. They are used to analyze aspects like balance, gait, and jump performance.
Common Mistake
Ignoring the importance of calibration and proper setup can lead to inaccurate data.
Understanding movement analysis is crucial for optimizing athletic performance and preventing injuries. By breaking down the components of biomechanics, Newton's laws, lever systems, and specific types of motion, we can gain a deeper appreciation of how and why the body moves. Utilizing tools like video analysis and force plates further enhances our ability to study and improve human movement.
