Tag Archives: splenius

Researchers Study Head, Neck Positions’ Effects on Muscles

This is a terrific and ground breaking article by Alexandra Beckstett. Finally!:

The physiological effects of horses’ head and neck positions (HNP) while being ridden is a topic of fierce debate. And until now, there hasn’t been any data on head and neck position’s effect on muscle activity, especially that of the muscles controlling these positions.

Kathrin Kienapfel, MA, a doctoral student at Ruhr-University Bochum, in North Rhine-Westphalia, Germany, recently evaluated electromyography (EMG, a tool that allows researchers to read muscle activity through sensors attached to the skin) activity of three major head and neck muscles when horses performed three characteristic HNPs: free, gathered (competition frame with head high, neck flexed, and nose in front of the vertical), and hyperflexed (with the mouth pointing toward the chest, or behind the vertical). She presented her findings at the 9th Annual International Society for Equitation Science, held July 18-20 at the University of Delaware, in Newark.

The three muscles Kienapfel and colleagues evaluated were the splenius muscles on each side of the neck that attach the neck and upper back vertebrae to the skull; the brachiocephalicus muscles that run from the upper limb to the back of the skull; and the trapezius muscles that attach the neck and mid back vertebrae to the shoulder blade.

In the study they used EMG to measure five healthy Warmbloods’ HNPs in both directions at the walk, trot, and canter, with and without a rider (positions without a rider were achieved using draw reins). Each horse performed, on average, 10 cycles (or 10 steps at each gait) in each position. The researchers compared HNPs between left and right directions, left and right sides of the muscle, with and without a rider, and between gaits. They found that:

  • There were no significant differences between ridden and unridden conditions.
  • At all gaits, the splenius muscle was significantly less active (e.g., working less) in the hyperflexed position than in the free position; it was most active in the free position.
  • At all gaits, the brachiocephalicus muscle was significantly more active in the hyperflexed position than the other positions.
  • At the walk, the trapezius muscle was significantly less active in the hyperflexed position than the other positions; its highest activity was during the free position. At the trot, muscle activity in gathered and hyperflexed positions did not differ significantly, and at the canter the muscle showed no differences between any position.
  • Only the brachiocephalicus displayed a difference between sides, with the right being more active than the left.
  • “In HNPs with the nose line in front of the vertical, the topline muscles of the neck (the splenius and trapezius) are activated/trained,” Kienapfel summarized. “In contrast, in the hyperflexed position a main muscle of the lower neck (brachiocephalicus) is activated/trained.”

    She explained that this is important because riders and trainers typically desire a muscular topline in their horses as opposed to a muscular lower neck. “The brachiocephalicus is also a muscle of the foreleg—it swings the leg forward,” she said. “In hyperflexion, because of the activation of the brachiocephalicus, you get a more pronounced, unnatural movement of the foreleg.

    “These results should be considered by riders and judges as an undesired result of an HNP,” Kienapfel concluded.

Case Study of a 9 Year Old Holsteiner

I had an interesting case today: an upper level warm blood dressage and event horse. This horse is stunning and balanced, but quite large. He is over 17 hands, has a long neck and back, and big bones. His owner sent me video of a recent dressage lesson and pointed out that he was a bit stiff behind and not coming through over his back. I watched the video several times. The ride was lovely, but the horse seemed uncomfortable. I saw slight twisting of the head, occasional gaping of his mouth: just little signs that something was not quite right.

When I started working on the horse, I noticed one side of his neck was more hollow than the other. I also found big spasms in the rhomboid and brachiocephalicus. These muscles are in the neck, and even though the owner felt that jumping had left the horse stiff in the hind end, I thought that if I could release the spasms in the front end, the hind end would be able to connect and the back would come through. The brachiocephalicus muscle needs to contract properly for jumping and collected work. With the spasm on the left side of his neck, this horse appeared stiff behind because he wasn’t working through his back as well as he could. The big spasms in the rhomboid muscle also were preventing him from reaching and arching his neck.

I also worked on the splenius, a muscle that attaches at the poll, the atlas, and three vertebrae in the neck. As I worked, the hollow looking space in the neck started to match the fuller side. The splenius muscle must be functioning properly to have the flexion necessary in the upper levels. I then did some myofascial release on either side of the neck and there were audible snap,crackle, and pops!

This wonderful horse seemed very relaxed and happy by the end of the session. He will be competing this weekend and I expect to see more connection, balance, flexibility, and freedom of movement.

Send me a message if you would like to know how he places in his championship division!

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