MR-Compatible Knee Ergometer

MR-Compatible Knee and Full Leg Extension Ergometer

This project aims to enable the study of the biochemical and physical dynamics of the quadriceps femoris muscles at high levels of muscle tension and fast contraction speeds. This is done using a magnetic resonance (MR) compatible ergometer designed to apply loads in two main forms; radially where the load is applied as a torque of up to 400 Nm acting against knee extension at speeds as high as 4.7 rad/s and linearly where the load is applied as a force of up to 1200 N acting against full leg extension at a maximum speed of 1.67 m/s. A spectroscopy coil placed on the thigh will be used to get the biochemical data through nuclear magnetic resonance spectroscopy (NMR), and MR imaging will be used to study the physical activation of the muscles during constant static (isometric) contraction, constant load, variable speed (isotonic) contraction, constant speed, variable loading (isokinetic) contraction, and constant power contraction.

Due to the electromagnetic limitations of having the device operate inside the MRI machine, the design was split into two parts. |A passive part designed to fit inside a 70 cm bore 3.0 Tesla Siemens Skyra MRI machine and is made out of materials exhibiting a minimal level of magnetic interference. The active part is located outside the MRI room actuating the passive part via a cable passing through the waveguide – a hole in the wall of the room.

This project is collaboration with Dr. Jane Kent in the Department of Kinesiology at UMass-Amherst.