Thought I’d try a video blog for a change to show you how I’ve been using e-Verne to explore the kinematics of crouch gait with some counter-intuitive findings.
The first time I gave a series of lectures on normal gait was at the Melbourne Gait Course in 2009. I was looking to make the teaching and learning more interactive and I developed an articulated cardboard figure called Verne. He has little goniometers printed on his joints so that you can put him in any pose you want and see exactly what angle his joints are at. I then devised a series of exercises that involved moving Verne into a variety of different poses in order to explore how foot clearance and adequate step length are achieved during walking.
Each of the sixty delegates was issued with a Verne. Making them was quite an exercise taking three PhD students a full day to cut them our and rivet them together. The exercises went well and Verne was judged a success.
About a year ago I was surfing the net and came across this site which includes a Flash animation of a figure similar to Verne who’s joints can be moved by dragging with the mouse. I’ve spent a large part of that year looking for someone, possibly a student who could help me create e-Verne. Eventually I gave up and decided that maybe learning to programme in Flash myself was the best option so here is the result.
You can change the joint angles by dragging the different segments. Holding down the CTRL key while you drag allows you to change the angle at one joint without rotating all the segments at the same time. The figures superimposed on the graphs are the joint angles at any particular instant in time.
In “clearance” mode the coloured horizontal line shows the height of the lowest part of the foot. The horizontal grey line shows the height of the hip. The red and blue vertical arrows emphasize that whether you achieve clearance or not is essentially a matter of whether the swing limb is longer (in a vertical direction) than the stance limb.
In “step length” mode Verne’s pose is typical of that at foot contact. The vertical grey line represents normal step length and the coloured vertical line indicates what step length a particular pose of the body would achieve. You can thus explore the factors affecting step length. Investigate for example how flexion of the trailing limb affects step length.
Verne is named after Verne Inman the American orthopaedic surgeon who was responsible for setting up the Biomechanics Lab at the University of California Berkeley to study human walking with an ultimate aim of improving the design of artificial limbs in the aftermath of the Second World War. He developed physical models to try and better understand foot de and used imaginative illustrations as a basis teaching complex concepts.