Lecture 6 Flashcards
What is Centre of Mass?
The point around which body’s mass is equally distributed in all directions.
How can you determine COM in a stationary human?
You can use a balance of reaction board. The COM is the point at which board levels out. This also means you can also only know the COM in the horizontal direction.
What is important to remember when determining the COM of a moving individual?
Must consider each body’s segments and its own mass and mass distribution.
Why are relative anthropometric measures not exactly the same between all individuals?
Differences depending on if individual is a child, athlete, or based on what biological sex they are.
What are the steps to calculating COM in the human body?
- Determine number of segments.
- Identify joint centres and connect with straight lines.
- Draw an x-y coordinate system.
- Determine COM of each segment.
- For each segment, multiply its x and y coordinates by its mass.
- Sum the x and y products and divide by the total body mass.
What is a Base of Support?
Area that is in contact with the support surface.
Why do humans have a worse BOS than animals?
Due to our bipedal stance, we have a higher centre of mass meaning it is easier to topple over and a reduced base of support.
Why does a cane help older individuals who may be a fall risk?
Provides them with another point of contact and widens their base of support.
To remain stable what do you want?
COM to not exceed BOS (but this constantly occurs when you’re moving!!)
