Can a wearable strain sensor based on a carbon nanotube network be an alternative to an isokinetic dynamometer for the measurement of knee-extensor muscle strength?

This study aimed to find out whether a wearable strain sensor including thermoplastic polyurethane composite with a multi-walled carbon nanotube network could be a viable alternative to an isokinetic dynamometer for the measurement of knee-extensor muscle strength. For the first time, the voltage-torque and angle-time relations of the sensor were determined to allow a comparison between the angle-dependent torque changes of the dynamometer and the sensor. This comparison suggested that the torque-angle relations of the dynamometer and the sensor did not have the same characteristics. In this regard, the sensor may be used in the torque measurements due to the moderate correlation between the torque values determined via the isokinetic dynamometer and the sensor and due to the significant difference between low and high torque values of the sensor. By the same token, the torque-angle graph of the sensor may be more informative than that of the dynamometer in evaluation of knee problems.