Accuracy of a portable lower-limb muscle strength measuring device with a training function

Area of Science:

• Biomechanics
• Kinesiology
• Rehabilitation Engineering

Background:

• Quadriceps muscle strength is crucial for functional mobility and daily activities.
• Accurate and accessible measurement tools are needed for clinical assessment.
• Existing methods may lack simplicity or portability.

Purpose of the Study:

• To evaluate the LocomoScan (LCS), a novel device for measuring lower limb muscle strength.
• To compare the LCS device with established instruments (e.g., Cybex) for simplicity, reproducibility, and accuracy.
• To assess the correlation between knee extension force, torque, and lower leg muscle mass.

Main Methods:

• One hundred and four healthy university students participated.
• Knee extension force was measured using LCS.
• Knee extension torque was measured using Cybex; lower leg muscle mass was assessed via body composition meter.
• Reproducibility of LCS and correlations were analyzed.

Main Results:

• LCS demonstrated significantly higher measurement reproducibility compared to other devices.
• LCS knee extension force measurements showed proportional relative reliability with Cybex knee extension torque.
• A relationship was found between knee extension force and muscle mass, but muscle mass does not directly estimate muscle strength.

Conclusions:

• The LocomoScan (LCS) exhibits high reproducibility for knee extension force measurement.
• LCS is a simple, effective, and portable tool for assessing muscle strength.
• It holds potential as a valuable alternative instrument in clinical practice for muscle strength evaluation.