Quadriceps motor evoked torque is a reliable measure of corticospinal excitability in individuals with anterior cruciate ligament reconstruction.

This study comprehensively evaluated the test-retest reliability of raw and normalized quadriceps motor evoked responses elicited by transcranial magnetic stimulation (TMS) in individuals with anterior cruciate ligament (ACL) reconstruction. Fifteen participants were tested on three different days that were separated at least by 24 h. Motor evoked responses were collected during a small background contraction on the reconstructed leg across a range of TMS intensities using torque (MEP _TORQUE ) and electromyographic (MEP _EMG ) responses. MEP _TORQUE and MEP _EMG were evaluated using different normalization procedures (raw, normalized to maximum voluntary isometric contraction [MVIC], peak MEP, and background contraction). MEP _TORQUE was also normalized to the magnetically-evoked peripheral resting twitch torque. The area under the recruitment curve was computed for both raw and normalized MEPs. Intraclass correlation coefficients (ICCs) were determined to assess test-retest reliability. Results indicated that MEP _TORQUE generally showed greater reliability than MEP _EMG for all normalization procedures. Vastus medialis MEP _EMG generally showed greater reliability than rectus femoris MEP _EMG . Finally, both MEP _TORQUE and MEP _EMG exhibited good reliability, even when not normalized. These findings indicate that MEP _TORQUE and MEP _EMG offer reliable measures of corticospinal function and suggest that MEP _TORQUE is a suitable alternative to MEP _EMG for measuring quadriceps corticospinal excitability in individuals with ACL reconstruction.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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