Quick Questions 1 Draw a FBD showing the

Quick Questions 1. Draw a FBD showing the 2 horizontal forces in a sporting action of your choice (2) 2. Draw a FBD showing the 2 vertical forces in a sporting action of your choice (2) 3. Describe Newton’s 3 Laws of motion (3)

Biomechanics Biomechanical Principles – Centre of Mass and Stability

Learning Objectives Learning Objective: Understand how centre of mass can affect stability. Learning Outcomes: All: Describe the relationship between Centre of Mass and stability Most: Apply your knowledge of centre of mass an stability to a variety of sporting examples Some: Explain how athletes can use their knowledge to maximise performance

Key Terms • stability = the ability of a body to return to equilibrium after being displaced. • centre of mass = the point at which the body is balanced in all directions. • equilibrium = a body is in equilibrium when the net force is 0 - all forces are equally balanced

Balance and Stability – how does it affect performance • https: //www. youtube. com/watch? v=9 R 74 g 1 I 4 UM (5 min video)

factors affecting stability • low centre of mass the lower the centre of mass, the higher the stability • increase size of base of support the larger the base of support, the higher the stability • line of gravity is central to base of support if the line of gravity is central to the base of support, stability is increased • increased body mass or inertia a performer with a larger inertia/mass will have a greater stability

Lets have a go • Take part in the following activities to see who can increase their balance and stability – 1 v 1 – who can push the other across from room – Headstand / handstand – Stork stand / dancers pose

Would these athletes want to increase or decrease their stability? Why? • • • Rugby player in a scrum Diver Sumo wrestler Sprinter out of the blocks High jumper Gymnast

Exam Questions • June 2014 - 4 b) Using examples, from sport, explain how performers maximise their stability. Using examples from sport, describe why a performer might want to minimise stability in sport. (5) • June 2011 - 4 a) What is meant by the terms ‘line of gravity’ and ‘base of support’? Use practical examples to show a performer can maximise their stability. (4) • Jan 2010 - 4 b) What is meant by the term centre of mass and how does this help to explain why the Fosbury Flop is the preferred technique for high jump? (4)