Surface Electromyography of the Gluteus Medius, Vastus Lateralis, and Gastrocnemius Muscles During Sit-to-Stand and Stand-to-Sit Motions in Normal Beagles

Abstract

Rehabilitation exercises play a crucial role in veterinary medicine by facilitating recovery from musculoskeletal and neurological injuries. Among these exercises, sit-to-stand and stand-to-sit movements are fundamental tasks frequently incorporated into rehabilitation programs. However, the specific activation patterns of hindlimb muscles during these motions remain inadequately characterized. This study was carried out to evaluate the activity patterns of key hindlimb extensors—the gluteus medius (GM), vastus lateralis (VL), and gastrocnemius (GC)—in six healthy Beagle dogs. After treadmill acclimatization at 0.7 m/s, each dog performed 10 valid gait cycles followed by five repetitions each of sit-to-stand and stand-to-sit motions. Surface electromyography (sEMG) recordings were normalized to the maximum amplitude observed during gait cycles. Statistical analysis using the Wilcoxon signed-rank test revealed that the VL exhibited significantly greater activation during the sit-to-stand motion than during the stand-to-sit motion (p < 0.05), while the GC showed the opposite pattern, with significantly higher activation during the stand-to-sit motion. Additionally, all three extensor muscles functioned in a coordinated manner during the controlled descent of the stand-to-sit motion. These findings highlight the critical role of the VL in generating stifle extension during the early phase of sit-to-stand, which is particularly relevant for rehabilitation strategies targeting stifle joint function. Conversely, the cooperative activation of the three extensor muscles during stand-to-sit suggests that this movement may serve as an effective rehabilitation exercise for improving coordinated hindlimb control. This novel insight provides objective data to refine targeted rehabilitation protocols and optimize functional recovery in canine patients.

Keywords: dog, Surface Electromyography, Kinematics, rehabilitation, Sit-to-stand, Stand-to-sit