Evaluation of the EMG activity of the long back muscle during induced back movements at stance

Abstract

Summary In this study we investigated the activity of the main back muscle (Musculus longissimus) by surface electromyography (EMG) during induced extension and lateral flexion at stance. Measurements were taken of 15 horses (age 5‐20 years, 450‐700 kg bwt) without signs of back pain. Reflecting markers were placed on the head, spinous processes of T5, T12, T16, L3 and on 2 of the sacral bones. The surface EMG electrodes were situated on the Musculus longissimus on both sides of the dorsal spinous processes of T12, T16 and L3. In all horses and all movements (extension, lateral flexion to the left and right), the EMG on both sides of the dorsal spinous process of T12 had the highest, and the EMG on both sides of the spinous process of L3, the lowest amplitude (30% of T12). At T16 the amplitude of the EMG signal was 60% of that at T12. There was no time shift between the EMG signals at the different locations (T12, T16, L3). There was a very high correlation between motion and amplitude of the EMG signal of extension, with correlation coefficients of 0.78 at L3, 0.80 at T16 and 0.75 at T12. The correlation of the lateral flexion between amplitude of the EMG and motion was lower, with 0.38 at L3, 0.43 at T16 and 0.39 at T12. This investigation showed that the EMG of the Musculus longissimus during spinal reflexes should be derived on both sides of T12, because this is important for the clinical use of surface EMG.

Core Training and Rehabilitation in Horses

“…Electromyographic studies have shown that m longissimus dorsi is activated during stimulated extension or lateral bending of the thoracolumbar spine with activity being greater at T12 than at T16 or L3. 39 It is likely that the deep stabilizing muscles are also recruited, though this has not yet been proven in horses. The position can be held for several seconds by maintaining the stimulus.…”

Electromyographic analysis of the gait cycle phases of boxer dogs

“…Systematic studies involving technologies such as surface electromyography (EMG) can provide veterinarians with important data that enable them to differentiate muscle, ligament, skeleton or neurological alterations that affect locomotion (Weigel et al, 2008). EMG has been employed in numerous studies to determine muscle function in equine athletes and in felines with secondary nutritional hyperparathyroidism (Colborne et al, 2001;Peham et al, 2001;Rahal et al, 2003;Wijnberg et al, 2003;Licka et al, 2004;Wijnberg et al, 2004). Therefore, the purpose of this work is to describe the phases of canine gait and the muscle activation of healthy Boxer dogs during the gait cycle by means of surface electromyography, proving information to improve veterinary diagnostic methods and the quality of treatments of orthopedic and neurological diseases in this canine breed.…”

A novel method to estimate the stiffness of the equine back

“…These spherical markers, consisting of a hollow hard plastic shell with a diameter of 4 cm, coated with reflective foil, were taped to the skin with textile adhesive tape. These reflective balls were placed on the dorsal median line on the skin above the spinous processes of thoracic vertebrae T16 and T12 according to Peham et al (2001). Fig.…”

“…The surface electrodes were fixed on the skin with special nonirritant adhesive. Measuring and preprocessing were done as described in Peham et al (2001).…”