Long term consistency and location specificity of equine gluteus medius muscle activity during locomotion on the treadmill

Abstract

BackgroundThe equine m. gluteus medius (GM) is the largest muscle of the horse, its main movement function is the extension of the hip joint. The objective of the present study was to measure equine GM activity in three adjacent locations on GM during walk and trot on a treadmill, in order to document potential differences. Fourteen Haflinger mares were measured using surface electromyography and kinematic markers to identify the motion cycles on three occasions over 16 weeks. The electrodes were placed on left and right gluteus medius muscle over the middle of its widest part and 5 cm lateral and medial of it. For data processing, electrical activity was normalised to its maximum value and timing was normalised to the motion cycle. A Gaussian distribution approach was used to determine up to 10 modes of focussed activity, and results were analysed separately for stance and swing phase of the ipsilateral hindlimb.ResultsFair reliability was found for mean mode values (Cronbach’s alpha = 0.66) and good reliability was found for mean mode locations (Cronbach’s alpha = 0.71) over the three data collection days. The magnitude of muscle activity identified as mean mode value was much larger at trot than at walk, and mean mode value was significantly different between stance phases of walk and trot for all electrode positions (p < 0.01). The pattern of muscle activity identified as mean mode location was significantly different for walk and trot at all electrode positions, both during stance and swing phases (p < 0.001). This indicates the different timing pattern between the gaits. Results of the three electrode positions on the same muscle during each gait were not significantly different when comparing the same measurement.ConclusionsThe middle of the equine GM does not show any indication of functional differentiation during walk and trot on a treadmill; this might be due to lack of segmentation as such, or due to lack of need for segmented use for these very basic main tasks of the muscle. The reliability of the sEMG measurements over several weeks was fair to good, an indication for the robustness of the methodology.

Reliability of surface electromyographic (sEMG) measures of equine axial and appendicular muscles during overground trot

“…To our knowledge, only a few equine gait studies have described the reliability or variation observed for sEMG data, collected during treadmill locomotion [5][6][7]31]. As such, the reliability of sEMG profiles from a healthy population of horses remains largely unknown during over-ground trot.…”

Comparison of Shifts in Skeletal Muscle Plasticity Parameters in Horses in Three Different Muscles, in Answer to 8 Weeks of Harness Training

“…Many training studies have been combining two or three out of the four aforementioned muscle plasticity parameters ( 5 – 7 ), most of them, focusing on the m. gluteus medius, known as an archetype locomotion-function type of muscle group ( 55 , 56 ).…”

“…However, to our knowledge, at this point, no training studies are available involving longitudinal follow-up of all four muscle plasticity parameters in multiple muscles with differing main mechanical function (muscles mainly involved in postural stability vs. muscles involved in locomotion). It can be expected that each type of training modulates a different core set of muscles ( 55 , 56 ). By involving both “main posture vs. main locomotion directed muscle groups” at the same time, a much more integrative and subtle physiological insight is obtained into how the muscular compartment adapts in response to a certain training type.…”

Descriptive electromyography signals analysis of equine longissimus dorsi, rectus abdominis and gluteus medius muscles during maneuvers used to activate the core

“…Dysfunction of gluteus medius (GM)may cause reduction of steps and make lateral movements or changes in directions harder. It happens because it is the main extensor muscle of the lumbosacral joint and contributes to abduction and flexion of hind limbs (Williams and Mckenna, 2016;Zsoldos et al, 2018).…”