What is the science behind strength testing?

Question

What is the science behind HUMAN Strength testing

Answer 1

When designing something, it's important to know how much stress it can sustain without breaking.  Stress in these tests is the force divided by the cross-sectional area over which it is applied:

Stress = Force / Area

Depending on how you load the material, it may respond differently.  For example, if you try to pull the material apart, it will fail at its tensile strength.  If you try to crush the material, it will fail at its compressive strength.  If you try to slide two parts of the material in opposite directions past each other, it will fail at its shear strength.