Fig. 1
From: The relationship between foot arch measurements and walking parameters in children
CSI and KI measurements. These are footprints from three individuals with similar CSI values, or even identical CSI measures (foot on far left and far right). Note that similar CSI values can originate from very different feet and that the KI captures some of those differences. For instance, even though the foot on the far left and far right have the same CSI values, the foot on the left exhibits more midfoot collapse and a lower KI value (similar to the middle foot), whereas the foot on the far right has a correspondingly higher KI value