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Foot Prosthesis
M1180 J-Foot L

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Activity Level and Body Weight Limits

Activity Level and Body Weight Limits
Activity Level Body Weight Limits
2~4 100kg

Achieve a powerful, smooth stride thanks to a laminated spring mechanism that stores repelling energy.

Product Features

The Laminated Spring Design of the J-Foot L

The Laminated Spring Design of the J-Foot L

The keel of the J-Foot uses a newly-designed "laminated spring structure," which is composed of five layered CFRP plates, with films between each plate for smooth movement. This structure allows the layered keel to gradually move forward from the first half of the stance phase, producing the maximum amount of travel at push-off. This works not only to store sufficient repulsion energy, but also to avoid the concentration of stress sustained by the heel. This produces greater deformation from loads exerted on the keel than with a one-piece keel, making it possible to provide a repulsion force suitable for walking as well as smooth ambulation.

Appropriate for Symes Prostheses

The J-Foot L is constructed with a low-profile design and a low connector mounting-point positioning, so it is usable even by those with long leg stumps.

Keel Displacement Characteristics

Displacement characteristic graph of Stepping return hardness

This graph shows displacement load characteristics of the J-Foot L and J-Foot, which are designed in such a way that displacement has difficulty occurring unless a larger load is exerted than that of the J-Foot (keel hardness: 'hard'). The J-Foot L is geared to those who enjoy having a foot prosthesis that is responsive during the stance phase, and to those who are active in doing light sports, such as jogging.

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The Concept

A Comment from the Developer

We took the J-Foot, which at the time was already being used and appreciated by many users, and created a new low-profile model that would be usable by a wider range of people as well as users with lower leg extenders.

Design Points

  1. Five layers of carbon fiber reinforced plastic in plate form stacked together, and release films sandwiched between each layer, form the means by which the user's every movement can be carried out smoothly.
  2. Foot prostheses with low-profile designs tend to have hard heels, so we designed it to contain a high volume of urethane in order to absorb the impact of heel-ground contact.


Our number-one objective in development was to create a foot prosthesis that would remove as many restrictions as possible regarding the movement of Japanese foot prosthesis users. By giving motions such as running and jumping secondary consideration, and by focusing purely on "walking like normal," we managed to create a foot that was appraised by most users as "a foot prosthesis that doesn't hinder me from walking."

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Product Specifications

M1180 Product specification table
Module Number M1180
Product Name J-Foot L
Size 22-26cm
Heel Height 10mm
Body Weight Limit 100kg

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The Origin of the Nickname

The J-Foot L went on sale three years after the J-Foot first went on sale. Rather than having a J-shaped carbon keel, it uses a newly-designed carbon keel that consists of a laminated spring, but to pass on the development concept that it was a "foot designed for the Japanese," and that it was a "low-profile" foot prostheses made for Japanese users, we gave it the name J-Foot L.

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