Does adding weight to a person affect the time taken for a person to run 20 metres? I am doing a science experiment to see if adding weight to a person affects the time taken for a person to run 20 metres. I am needing to write some background information (1 page) and I am not too sure what I should write about this so I was looking for some help. Thank you!
 A: Of course adding weight to a person affects the time taken for the person to run a particular distance, because if the person takes the same amount of time then they are running at the same velocity, and if they are running at the same velocity then they need more energy (since their total mass increases).
You can see this in effect yourself by timing yourself running 20 meters, and then running 20 meters again while carrying a heavy backpack.
A: Humans do not run or walk at constant accelerations rather we walk with alternative periods of acceleration and deceleration. The same friction which helps us walk slows us down .
I don't think air drag has much effect on our top velocities (we run no where near the terminal velocity) it is  the friction from our feet that limits our top velocities.
Why did I say all this? It was to make the point that we need to  accelerate again and again while running and added weight makes us do extra work in every step we take and also  a greater mass means a lower acceleration (for the same force) which means added weight inevitably slows us down .
There's a lot more that can be
added .With  Added weight our abdominal and back mulscles Will have  work extra hard  to maintain our posture at the same time time our legs are working harder, which results in increased oxygen  and energy demand , greater heat generation and thus early muscular fatigue .
Also while running a hundred meter race , runners utilize the stored energy in their muscles. In a 20 m race it will be the same , while running 20m you would hardly breathe.
