Surface Electromyography Repeatability of the Vastus Lateralis, Biceps Femoris and Gastrocnemius Muscles at a Trot in Normal Dogs: A Pilot Study

Introduction: The objective of this study was to document the repeatability of surface electromyography (sEMG) activity of the vastus lateralis (VL), biceps femoris (BF) and gastrocnemius (GN) muscles bilaterally in healthy dogs at a trot over two time periods. We hypothesized that the sEMG data from these muscles would be accurate and repeatable over time.

Materials and Methods: Five client-owned normal dogs were selected for the study. sEMG surface electrodes were bilaterally placed on the VL, BF and GN muscles. sEMG data were recorded while simultaneously collecting ground reaction force measurements at a trot on day 0 (T1) and 14 days later (T2). sEMG data were processed for comparative analysis and to normalize the data to 100% of the maximum amplitude (maximum–minimum = %MM). The maximum %MM of each muscle during a gait cycle was assessed for repeatability using repeated measures ANOVA for parametric data or a Friedman’s test for non-parametric data. Significance was set at p < 0.05.

Results: There was no statistical difference between T1 and T2 for sEMG data for VL (p = 0.16), BF (p = 0.22), and GN (p = 0.65). Waveforms generated for VL, BF and GN were consistent in morphology over time.

Discussion/Conclusion: The sEMG activity observed in this study for the VL, BF and GN was accurate, consistent and repeatable, supporting our hypothesis. The repeatability of sEMG data will provide additional diagnostic features for current and future therapeutic modalities for hip and stifle joint-related diseases.

Acknowledgement: Funding for this study was provided by the Comparative Orthopedic Research Laboratory, Washington State University and a grant from Dechra.