Takahashi Yuji, Mukai Kazutaka, Ohmura Hajime, Takahashi Toshiyuki
Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.
Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Tochigi, Japan.
J Equine Vet Sci. 2020 Mar;86:102901. doi: 10.1016/j.jevs.2019.102901. Epub 2019 Dec 25.
Muscle activities of the major hindlimb muscles have been reported to decrease with fatigue in horses. However, those in other muscles have been scarcely reported. We aimed to quantify fatigue-induced electromyographic changes in head and neck muscles and muscles around the shoulder joints in horses. Surface electromyographic recording of the splenius, brachiocephalicus, infraspinatus, and deltoid muscles was performed on a total of nine healthy Thoroughbred horses. Horses galloped on a treadmill inclined to 3% at a constant speed (12.7-14.6 m/second) to make them fatigued after approximately 5 minutes. They trotted at 3.5 m/second before and after this exercise. Stride frequency, integrated electromyographic values for a stride, and median frequency of the muscle discharge were calculated every 30 seconds. These parameters were compared at the start and end of the gallop exercise for the lead and trailing limbs and while trotting before and after the exercise using a paired t-test. The stride frequency significantly decreased at the end of the gallop (P < .001), whereas it did not change while trotting. Integrated electromyographic values of the splenius and brachiocephalicus muscles in both lead and trailing limbs at the gallop and those of both left and right sides at the trot significantly decreased with fatigue (P < .05), whereas those of infraspinatus and deltoid muscles did not change at either gallop or trot. No changes were observed in median frequency in any muscles with fatigue. These results suggest that splenius and brachiocephalicus muscle activities can be associated with stride frequency and speed.
据报道，马后肢主要肌肉的活动会随着疲劳而减少。然而，其他肌肉的情况鲜有报道。我们旨在量化马匹头部和颈部肌肉以及肩关节周围肌肉因疲劳引起的肌电图变化。对总共9匹健康的纯种马进行了斜方肌、臂头肌、冈下肌和三角肌的表面肌电图记录。马匹在倾斜3%的跑步机上以恒定速度（12.7 - 14.6米/秒）飞奔，约5分钟后使其疲劳。在此运动前后，它们以3.5米/秒的速度小跑。每30秒计算步频、一个步幅的肌电图积分值以及肌肉放电的中位频率。使用配对t检验比较飞奔运动开始和结束时前肢和后肢以及运动前后小跑时的这些参数。飞奔结束时步频显著降低（P <.001），而小跑时步频没有变化。飞奔时前肢和后肢的斜方肌和臂头肌的肌电图积分值以及小跑时左右两侧的肌电图积分值均随疲劳显著降低（P <.05），而冈下肌和三角肌在飞奔或小跑时均无变化。任何肌肉的中位频率均未随疲劳而改变。这些结果表明，斜方肌和臂头肌的肌肉活动可能与步频和速度有关。
