Question

A 70kg person jumps from 3m and does not roll (impact time of 0.1sec), does he break his tibia or fibula?

Answer 1

He breaks none, both are strong enough to absorb the impact.

Answer 2

Neither. But for the sake of an argument I would say tibia. Tibia being the weaker of two bones.

Answer 3

do you have the numbers to see if it is within the amount of force the bones can take?

I want to know if he would be injured by the jump/fall.

Answer 4

this is really not a physics question but a strength of materials question along with several variables. barefoot or work boots or nike shoxkz or reebok
old or young person (size does matter because mass matters)
extremely overweight person or underweight person or average
bone density
number of time the person has fallen or jumped from this height or others (stress/microfractures)
I can keep going but I hope you get the picture