Alexander Frey died tragically on Monday, 16th October 2000, a great loss to all friends, colleagues and coworkers at the locomotion research group. This work would not have been possible without his effort and his enthusiasm. This article is dedicated to the memory of Alexander.
Evaluation of the EMG activity of the long back muscle during induced back movements at stance
Article first published online: 10 JUN 2010
© 2001 EVJ Ltd
Equine Veterinary Journal
Volume 33, Issue S33, pages 165–168, April 2001
How to Cite
PEHAM, C., FREY, A., LICKA, T. and SCHEIDL, M. (2001), Evaluation of the EMG activity of the long back muscle during induced back movements at stance. Equine Veterinary Journal, 33: 165–168. doi: 10.1111/j.2042-3306.2001.tb05382.x
- Issue published online: 10 JUN 2010
- Article first published online: 10 JUN 2010
- motion analysis
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.