Product Development Biomechanical Mobility Aid Adapts to the Healing Process

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Fachhochschule Pforzheim Hochschule f. Gestaltung Technik und Wirtschaft

FAULHABER Drive Systems

dataTec AG

Taiwan Machine Tool & Accessory Builders' Association (TMBA)

Traditional crutches are rigid and often involve ergonomic compromises. A student at the University of Pforzheim (Germany) has now unveiled a design for a crutch that can be adapted to a patient’s recovery thanks to carbon leaf springs used in sports prosthetics and a modular design.

People who rely on crutches often struggle with unnatural movement patterns and have to exert a great deal of effort. The concept “KinAid – more than just a crutch,” developed by Leon Kast as part of his bachelor’s thesis at Pforzheim University, addresses this problem. The design’s approach: a technology transfer from sports prosthetics and exoskeleton development to the field of everyday mobility aids.

Energy Recovery Through Adaptive Spring Characteristics

The technical centerpiece of this new development is the integration of carbon leaf springs into the crutch’s support structure. Similar to prosthetic legs used in competitive sports, the springs absorb kinetic energy when the user steps down and release it again during the push-off phase. This kinematic mechanism replicates the natural biomechanical movement of the human body and significantly reduces the effort required by the user.

A particular highlight from a design perspective is the ability to adjust the spring characteristics: The system is designed so that the number of springs used can be changed on a modular basis. 

A particular highlight from a design perspective is the variable adjustment of the spring characteristics: The system is designed so that the number of springs used can be adjusted in a modular fashion. In the early stages of rehabilitation, when maximum stability and weight-bearing relief are required, multiple springs provide high energy return. As the healing process progresses, the number of springs is reduced. The resulting softer spring characteristic encourages the patient to take a more active role in guiding their movements. The crutch thus adapts to the recovery process.

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Modular System Adapts to the Patient

To address the ergonomic shortcomings of conventional models, Kast relied on advanced 3D printing technologies during development. The result is a consistently modular system: Depending on the indication and the patient’s needs, the basic structure can be flexibly configured with an axillary support (for maximum stability) or a classic forearm support (for greater freedom of movement).

Designed for Circularity  

In addition to its hardware design, “KinAid” stands out for its integrated circular economy approach:   

• From the very beginning, the product design was focused on repairability and durability.
• All components are designed to be interchangeable. 
• Instead of disposing of the crutches after just a few weeks of use, the business model calls for a rental system through medical supply stores.
• Wear parts can be easily replaced, and the tools can be kept in use for multiple cycles, thereby conserving resources.

For this innovative and comprehensive development achievement, Leon Kast received two awards at the 2026 Pforzheim University Incentive Award Ceremony: He was awarded the Witzenmann GmbH Incentive Award as well as the Rolf Scheuermann Foundation’s Special Innovation Award.