Gait analysis is very important for developing individualized rehabilitation techniques. Measuring ground reaction forces (GRFs) is essential for kinetic gait analysis. Usually, force plates embedded on the floor or instrumented treadmill is used in the labs and clinical settings. But, GRFs of only a few steps can be measured on a force plate and the walking style on a treadmill is different from overground walking. Also, measurement of GRFs in an unstructured environment such as walking on the uneven, uphill-downhill surface is not possible with the above tools. So, a wearable system is necessary for measuring GRFs for kinetic gait analysis.

GRFs has three components. Most of the available wearable systems - 

     - either predict all the three components of GRFs using kinematic gait analysis data and inverse dynamics 

     - or measure the vertical component using pressure sensors and estimate the other two shear components using various statistical methods or kinematic data

So, a three-axis force measuring sensor which can be embedded inside a shoe is necessary to measure all three components of GRFs directly.