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Updated: Apr 4, 2026
A Novel Application of Musculoskeletal Ultrasound Imaging
Published on: September 17, 2013
Entrainment of vastus medialis complex activity differs between genders
Matthew S Tenan1,2, Anthony C Hackney3, Lisa Griffin1
1Department of Kinesiology and Health Education, University of Texas at Austin, Austin, Texas, USA.
Introduction:
That the vastus medialis oblique (VMO) is a functional unit of the vastus medialis (VM) is disputed. Delayed VMO activation predicts patellofemoral pain, which has higher rates in women.
Methods:
Single MUs and surface electromyogram (EMG) were collected from the VMO and VM of 9 men and 9 women. Men were tested once; women were tested during 5 menstrual phases. Coherence was assessed for motor unit (MU) firings within and between the VM and VMO using multilevel logistic models to determine statistical significance.
Results:
Compared with women, men have 741% (MU pairs) and 256% (MU-EMG pairs) greater odds of common drive (0-5 Hz) coherent oscillations. MU pairs from the VMO and the dual VM/VMO complex have 228% and 212% greater odds of coherent oscillations in the beta band (15-35 Hz) compared with VM pairs.
Conclusions:
The VM and VMO are neurologically different muscles; control of the VM complex is sexually dimorphic.
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