New Model Shows Importance of Feet, Toes in Body Balance
By Jessica Orwig
Hooshang Hemami, a professor of electrical and computer engineering who built the model, says many studies concerning human balance have emphasized the legs and upper body while ignoring the feet.
“In order to reduce the complexity of the problem, the feet are often either neglected or modeled using simple shapes that don’t really give full credit to the importance of feet,” says Hemami, one of a handful of researchers nationwide who are analyzing how toe strength can affect human balance.
Hemami and a former doctoral student, Laura Humphrey, designed a computer model that allowed them to focus primarily on the pressure of the feet and toes and to manipulate toe strength as they performed simulations of balance and forward leaning.
Results indicated that in a healthy person, toes became increasingly important as the person leans forward. As the computer-modeled body leaned forward, the pressure underneath the toes increased significantly, and the pressure underneath the heel decreased in a similar fashion.
When the same tests were performed on the computer-modeled body with diminished toe strength, the pressure underneath the toes remained at zero. Initially, the pressure underneath the heel was significantly higher than in the healthy subject, and as the body leaned forward, the pressure underneath the heel only decreased by half the amount that it did in the healthy subject.
The maximum angle that a healthy computer-modeled body could lean forward from the waist without its heels lifting off the ground was nearly 12 degrees from vertical. The model with diminished toe strength could only lean forward nearly 10 degrees.
The computer model supports past studies on real people, Hemami explains.
“Now that we have a reasonable computer model, we hope to explore the sensory apparatus and other functions of the toes in diverse human activities,” Hemami says, adding that he will collaborate with Ian Alexander, an Ohio State physician and professor of orthopaedics, to model other body parts, such as the spinal cord.
“My hope is that my work will inspire construction of robotic models of various body parts that can move similarly to the human body. If you can make a robot or computer model kick a soccer ball like a soccer player, we will have a better understanding of how various parts of the body work during movement,” says Hemami, himself a soccer player. “Then, perhaps, you can build an artificial spinal cord that could help the handicapped. Attaching a robotic spinal cord to the outside of someone who is handicapped could help muscle development.”
“We try to model what muscles do,” Hemami explains, “which may help to develop more advanced prosthetics, so we have something better to offer people who need them.”
