Ground reaction force (GRF)

What are ground reaction forces?

According to Newton's third law the so-called ground reaction force (GRF) is the force exerted by the ground on a body in contact with it. When a person is just standing, the GRF corresponds with the person’s weight. When the body is moving, the GRF increases due to acceleration forces. For example, while running, the GRF increases to up to two or three times the body weight.

How can I measure the ground reaction forces?

The most direct and effective way to measure ground reaction forces (GRF) is using a force plate. 

In biomechanics force plates are applied to:

• characterize walking
• characterize running
• characterize jumping

What is the benefit of measuring ground reaction forces?

GRFs are one of the most often analyzed biomechanical measures and help characterize human movements. Measuring GRFs plays an important role in the areas of:

• sports performance analysis
• rehabilitation
• products ergonomics
• clinical research