SACH-SAWCH

POLAR GRAPHS Periodic data can be (& often is) polar graphed in engineering. The knee curves from three conditions are seen on the left with their polar graphs on right. The polar graphs colors mark out equal time segments. The 'harmonics' that are active in each data set are easily seen in polar graph format. Also notice that an ellipse is a circle of two centers. Hip and knee cooperating can generate functional elliptical paths and do. The knee graph has changes that come from the hip (toe on ground) , rarely from the knee, from the heel and forefoot by ground reaction on the linkages. Looking at the standard graphs on the left gives us little clue as to what is contributing what to what. Polar graphs have each harmonic quite obvious in contribution size and when active.