Introduction: Improve the Toad Anti-Gravity Foot Brace ("TAG" Brace)
The Toad Anti-Gravity Foot Brace (or Tag Brace) is an orthotic device made by Toad Medical Corporation. It is advertised to "completely [unload] the foot and ankle complex". It accomplishes this by taking the pressure normally occurring on the sole of the foot and distributing it over the the lower leg.
Our group found the brace very effective at removing pressure from the rear of the foot but largely ineffective at removing pressure from the forefoot.
This project comes as a result of a Capstone project at Brigham Young University. The project was co-sponsored by the university and Pachyonychia Congenita Project, a non-profit that promotes research, advocacy and support for persons with Pachyonychia Congenita (PC), a rare genetic disorder that often involves extremely painful blisters and callouses forming on the soles of the feet. You can learn more abut PC here.
Step 1: Results From Brace Testing
The brace reduces pressure peaks by 33% compared to a no The brace combined with foam cushions reduces pressure peaks by 77%.
The brace alone leaves little pressure on the foot. The pressure that is experienced is on the forefoot and is about the peak values of this pressure are reduced by about 33% compared to a normal shoe with an insole. The foam insert succeeds in lowering pressure peaks by about 77% by distributing the remaining pressure over the entire plantar surface.
Step 2: Foam Insert
The foam insert is shaped like a wedge to redistribute the force on the fore foot over the entire foot. The top, wedge-shaped layer is memory foam and conforms to the surface of the foot. The lower layers provides a springy support as the user walks.
A more detailed analysis can be found in Appendix B of our formal report.
Step 3: Cutting the Foam
The foam we recommend using (available from McMaster-Carr) is the
Super-Cushioning Polyurethane Foam 8643K515 $12.96 (12" x 12" x 2") Firmness rating 1 (to be used in place of the green foam pictured here)
Slow-Recovery Super-Cushioning Polyurethane Foam 86195K39 $31.99 (12" x 12" x 2") Softness rating 1 (yellow)
The foam should be cut into blocks of the length and width defined in the drawings.You can make the angular pieces by cutting along the diagonal. We found a band saw to be most effective at cutting the foam. Since these are often not readily available we recommend using a bread knife, an electric kitchen knife or a box cutting tool. The memory foam (yellow) can be especially difficult to cut. You can place it in the freezer (or other cold environment) to make it stiff for the short time it takes to cut.
The width of the rectangular piece should 3.5 inches and it should be 1 inch thick. The thickest part of the triangular piece should be 2 inches.
The length of the rectangle and the base of the triangle should be one of three sizes
Small, 8.5 inches (shoe sizes up to US Mens 9)
Medium, 9.5 inches (shoe sizes up to US Mens 12)
Large, 10.5 inches (shoe sizes up to US Men's 14)
Step 4: Download Templates
You can download one of the templates attached below to cut out the fabric pattern to cover the foam.
Step 5: Cutting and Folding the Fabric
Download and print one of the templates for the fabric. You can cut out the pattern in paper and then tranfer the pattern to the fabric of you choice using a fine-tip marker or tailor's chalk.
We recommend using a a light fabric that can conform to your feet and won't irritate them by rubbing.
Sticky-back velcro is available at any arts and crafts store. A good one with low profile is "Ultra-mate" by Velcro (pictured below).
Cut the corners of the velcro to get it to fit in the tabs of the pattern. The long rectangular piece should have one side of velcro (e.g. hooks) and the trapezoidal tabs should have the other side (e.g. loops). The velcro on the tabs and on the rectangular piece also needs to be on opposite sides of the fabric. Note how the rectangular piece in the picture is folded over to show the under side.
After you have folded up the sides and fastened them with velcro, you can insert the flaps to keep the foam from being exposed.
Step 6: Fixing the Foam to the Brace
If you don't want the foam insert to slide around in the brace, we recommend adding a strip of velcro to foam foot bed and on the bottom of the fabric surrounding the foam.