Be 300 pounds and built low to the ground.
Have someone - anyone - push you with only one arm in the middle of the back.
First see if this lone arm has enough force to shove you headlong anywhere.
Second, See if your spinal column triggers a signal to both your arms to generate enough pushing force to push a 270-300 pound defensive lineman to the point where he almost falls over. That's a strong reflex if so.