Seated Lower-Limb Strength Measurement With Patient-Weight Stabilization

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Solution Overview

Problem

Existing muscle strength measurement devices are bulky, impractical, and provide inaccurate or difficult-to-reproduce measurements, requiring patients to travel to specific locations and often necessitate complex setups that are not easily transportable.

Innovation Solution

A lightweight, portable device with a seat and lower limb support element that integrates a measuring instrument, allowing direct force measurement by leveraging the patient's weight for stability, ensuring accurate and reproducible readings without an operator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If isokinetic or isotonic apparatus are used to measure muscle strength, then measurement accuracy is improved, but device weight and bulk increase significantly

Engineering Contradiction:
Improvemuscle strength measurement accuracyVSAvoiddevice weight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The device is divided into separate components: a lightweight seat that can be placed on any stable surface, a lower limb support element, and a measuring instrument. This segmentation allows the measurement system to be portable while maintaining accuracy through proper mechanical coupling of components during use.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patient's body weight serves as the stabilizing force for the device. When the patient sits on the seat with their lower limb positioned on the support element, their weight naturally provides the necessary stability for accurate measurement without requiring heavy external stabilization structures.

Inventive Principle:
Principle #25Self-service

2Weight of moving object

If hand-held dynamometer is used with operator, then portability is improved, but measurement precision deteriorates due to operator dependency

Engineering Contradiction:
Improvedevice portabilityVSAvoidmeasurement accuracy
Core Design Contradiction:
Weight of moving objectVSMeasurement precision

Solution Approach 1:

The device eliminates operator dependency by using the patient's own body weight as the stabilizing force. The mechanical coupling between the seat, support element, and measuring instrument creates a self-stabilizing system that automatically ensures measurement accuracy without requiring operator strength or skill.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If complex positioning systems with straps are used to fix dynamometer to table, then measurement stability is improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement stabilityVSAvoidpositioning system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The device uses the patient's body weight to automatically stabilize the measurement system. The mechanical coupling through the seat and support element creates inherent stability without requiring complex strap positioning or attachment systems to tables or other external structures.

Inventive Principle:
Principle #25Self-service

4Reliability

If heavy frame structure is used to ensure device stability during measurement, then measurement reliability is improved, but ease of transport deteriorates

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidease of transport
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The device eliminates the need for heavy frame structures by using the patient's body weight as the stabilizing force. The lightweight seat and support element combine with the patient's weight to provide measurement reliability, making the entire system portable and easy to transport to any location with a stable surface.

Inventive Principle:
Principle #25Self-service

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The device provides precise, portable muscle strength measurements that can be taken at any location, ensuring stability and accuracy while simplifying the measurement process.

Implementation Method 1

the measuring device being configured so that it remains essentially immobile relative to the support during the application of a force by the patient's lower limb at the lower limb support element, thanks to the weight of the patient exerted at the seat

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP4216821B1Device and method for measuring a patient's muscle strength
Publication Date: 2025.08.13 MYOCENE
  • EP4216821B1 patent drawingFigure 1~2
  • EP4216821B1 patent drawingFigure 3~4
  • EP4216821B1 patent drawingFigure 5

AI summary

The invention relates to a measurement device (10) for measuring a muscular strength of a lower limb of a patient comprising a seat (12) for receiving the patient in seated position and suitable for being placed on a substantially horizontal mounting, an element (14) for supporting the lower limb so as to receive at least a portion of the patient's lower limb, mechanically coupled to the seat, and a measurement instrument (24) for measuring a force exerted by the lower limb at the element for supporting the lower limb, the measurement device (10) being configured so that it remains substantially immobile with respect to the support upon the application of a force by the patient's lower limb at the element (14) for supporting the lower limb, by virtue of the patient's weight exerted on the seat (12).