Physics KS3/GCSE: Why can't I run fast?

Greg Foot investigates whether humans will be able to run faster and continue to break world records, or if there is a limit to human performance.

Greg explains that running involves exerting a force against the ground which in turn exerts a counter-force on the human body. The greater the force exerted by the leg muscles, the faster a sprinter can run.

He demonstrates the force exerted by running over a pressure pad and explains the force is measured in Newtons. A top athlete can exert a force of four times their body weight but this force is limited by our genes.

Greg explains the difference between slow-twitch and fast-twitch muscle fibres and why sprinters need genes that ensure they have more fast-twitch fibres than most other people.

He then explains why four legs are better than two legs and investigates if having longer legs would enable us to run faster.

Teacher Notes

This short film could be useful for students when looking at human biology, the genetics of inheritance and how muscles work.

Students could investigate force and counter-force when a force is applied to an object in relation to Newton’s laws.

Curriculum Notes

These short films will be relevant for teaching physics and chemistry at both KS3 and KS4 in England, Wales and Northern Ireland and National 4/5 in Scotland.

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