Objective: We investigate the influence that inguinal fat has on maximal quadriceps response to femoral nerve magnetic stimulation.
Methods: Vastus lateralis M-wave amplitude and quadriceps twitch peak torque were measured (i) in lean and overweight subjects and (ii) when slices of pig fat ranging from 2 to 18 mm in thickness were placed between the coil and the nerve.
Results: In overweight group, the maximal response could not be elicited when intensity was ≤90% and ≤85% of maximal power for twitch torque and M-wave amplitude, respectively. The maximal response was obtained at 80% of maximal power in the lean group. Negative correlations between relative twitch torque changes and inguinal thickness were observed. Fat thickness altered quadriceps response at 14 mm and 8 mm in the lean and overweight groups, respectively.
Conclusions: The capacity of femoral nerve magnetic stimulation to deliver supramaximal stimulation is altered when fat thickness below the coil increases.
Significance: Special caution should be taken by clinicians when overweight or obese subjects are tested using femoral nerve magnetic stimulation.
Copyright © 2010 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.