A new simple foot designed with materials used in the aerospace industry provides a flexible alternative to more traditionally designed feet.

“We hired our engineering team from the aerospace industry and took a real outsider’s point of view [when looking] at the needs of amputees, specifically their needs in regards to prosthetic feet,” J. Blount Swain, president and chief executive officer of Ability Dynamics, told O&P Business News. “The result was that the RUSH foot was developed with materials that have never been used in prosthetic feet prior to this time.”


The RUSH foot is made out of Flexeon, a glass-reinforced composite material. The material is durable yet flexible.



J. Blount Swain


“One of the most important aspects of this foot is the flexibility, which is a direct result of the materials and design we are using,” Rich Sainz, MA, CP, national clinical manager for Ability Dynamics, said.

Sainz is a lifelong amputee, and one of his main complaints about prosthetic feet, is how easily they can break.

“I have been a prosthetic foot user for 45 years and have been a high level performer. Quality of life was, and still is, the most important aspect for me, and I never wanted to be limited,” Sainz said. “So another nice aspect of our foot is the durability factor.”

According to Sainz, the RUSH foot is the first foot he has worn that he has not broken.



Rich Sainz


“I have broken countless feet throughout my life, which is frustrating and disappointing because it tends to interrupt your flow of life and activity,” Sainz said. “This foot is designed and built with the moderate to highly active amputee in mind.”

The RUSH foot, which had been under development for 2 years, was officially released in September 2012, and so far, the feedback has been 

“We’ve got plenty of high-end amputees on the product who demand durability and flexibility,” Sainz said. “And the feedback that we’ve received is that it’s flexible, comfortable, smooth and ground-compliant.”


The foot consists of an upper and lower strut that creates the rocker sole. The struts propel the user forward and enable the foot to flex in a natural and organic way, imitating the feel of an ankle.

“The material afforded us the ability to have a unique design,” Swain said. “We wanted to not only change the material, but also eliminate a lot of the hardware that you might find on other feet.”

The RUSH foot has three holes at the top for the pyramid attachment, but the rest of the foot is held together with aerospace adhesives and rubber compounds.

“One thing that we were intent on was not having bolts and brackets and things that could be subjected to breakage,” Swain said. “Every time you drill a hole or cut a slot in a carbon fiber foot, it increases the potential for breakage.”


Image: Andrea Martone


The RUSH foot is available with a full rocker sole for transfemoral amputees and a half rocker sole for transtibial amputees.

“Our design is very simplistic, and we have found that it virtually eliminates failures and breakdowns,” Swain said. “We consider amputees to be our customers, because they are the end users who will be wearing these products. It is a real passion for us to provide a superior outcome for our amputee community.” — by Megan Gilbride

Disclosure: Swain and Sainz are both employed by Ability Dynamics, the maker of the RUSH foot.

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