When running, the acceleration forces on a shoelace knot are higher than that experienced by the human body on the most extreme rollercoaster
1
2
3
Running
motion
Foot hits ground
Leg swing
A running foot strikes the ground at seven times the force of gravity, causing the free end of the laces to stretch and then relax ...
Free
end
Loop
... as the knot loosens, the swinging leg applies an inertial force on the free ends of the laces ...
Inertial
forces
... which rapidly leads to a failure of the knot in as few as two strides after inertia acts on the laces
Knot loosens
under forces
When running, the acceleration forces on a shoelace knot are higher than that experienced by the human body on the most extreme rollercoaster
1
2
3
Running motion
Leg
swing
Foot hits
ground
A running foot strikes the ground at seven times the force of gravity, causing the free end of the laces to stretch and then relax ...
... as the knot loosens, the swinging leg applies an inertial force on the free ends of the laces ...
... which rapidly leads to a failure of the knot in as few as two strides after inertia acts on the laces
Knot loosens
under forces
Inertial
forces
Free
end
Loop