Limb Strength Measurement Device (LSMD)
Technology description
Muscle strength measurement is a critical component of physical therapy, rehabilitation and sport science in general. Rehabilitation outcomes for many diseases, disorders and injuries, require assessment of muscle strength in a clinical environment.
Research in rehabilitation and sport science often use muscle strength as a primary outcome, and furthermore require measurement of "maximal voluntary isometric contraction" to normalize muscle electromyography assessments. Currently there is not a strength measurement device available to clinicians or researchers that is inexpensive and portable, and that requires no external support from the therapist or other supporting structure.
This invention presents an innovative and novel concept for obtaining measurement of elbow and knee joint strength using a wearable system of sensors and mechanical constraints. The limb strength measurement device (LSMD) is easily donned and doffed from the arm or leg, and can measure isometric strength of both flexor and extensor muscles of the joint, with the joint at a fixed angle of approximately 90 degrees.
Operating the LSMD is very simple. The basic design consists of linkages which are locked together in a fixed angle using a spring-loaded locking mechanism. Once locked, the LSMD uses the same principle as a three-point orthotic brace to prevent the joint from flexing. The subject simply applies a force against the distal pad. The distal pad assembly contains a load cell which measures the applied force. The same LSMD can be used to measure both flexion and extension. Changing from one direction to the other is done without the need to remove the device from the limb.
The geometric design of the framework and the selected locations of the padded contact points allow the device to be self-stabilizing and self-aligning with the subject's anatomical features when the subject is exerting force on the device. This self-contained measuring provides all the restraining force that opposes the subject's developed force and so requires no physical coupling, connection or restraining between the subject and the outside world through a floor, wall, chair or any other immovable objects.
Advantages
The novel features of the limb strength measurement device are:
- Portable - Compact and light weight for easy carrying;
- Stable - Self-stabilizing against the user’s own limb;
- Simple to use.
Stage of development
A prototype of the device was developed and was tested on human patients. Based on the test results, the design was altered and the new design is currently undergoing testing.
This device is intended to be commercialized as part of a suite of tools being developed in an AIF project entitled "BioTone - Clinician Tools for Neuromuscular Evaluation".
Intellectual property
- US Patent Pending
This technology is available for licensing.
Contact information
Office of Research Services, Industry-Government Services
University of New Brunswick
Phone: (506) 453-4674
partner@unb.ca
