THE THORACIC SLING
We’ve helped to mobilise our horse’s forehand and hindquarters, so the next step is to help them carry their weight equally on both forelimbs and then lift their back. But why is this important? Their ribcage is suspended between their scapulae with a set of muscles known as the thoracic sling (comprised of Serratus muscles and Pectorals) It’s these muscles that control the rotation of the horse’s trunk and its capability to lift. If their forelimbs are not weighted equally then their sling muscles develop asymmetrically – meaning the horse can never move truly straight- perpetuating the cycle of sub-optimal movement patterns.
STARTING WITH LUNGING
As with our example horse, some might think that it’d be suitable to start riding straight away – however his proprioceptive deficit means that lifting his back is exceptionally hard – adding the weight of a saddle and a rider will make this harder. Compounded with possible negative associations to the saddle, harder still. With this in mind, I like to start this element of retraining with lunging. We can then implement possible stressors (saddle and rider) when the horse is confidently travelling in good posture without them – see previous blog post which touches on setting the horse up for success.
I begin lunging on a square, starting close to the horse (eg 1.5m away whilst also walking the line of a square myself) at a walk. The reasons for this are that horses find it far easier to maintain equal weight on both forelimbs on a straight line than they do on a circle and you more readily help your horse with their body positioning closer than you can further away. At this point they should be familiar with hindquarter yields and I like to transition them from responding to pressure to responding to my hand pointing at their hindquarters. This means that as we come to the corner of the square, you can point to their hindquarters and they can begin to knit together stepping under with their inside hindleg on the turn. As they step under with their inside hindleg, they also begin to transfer a little bit of weight to their outside shoulder rather than their inside shoulder – meaning that as they are released to follow the next straight line, they are weighting their shoulders a little more equally. It’s also worth noting that stepping under with the inside hindleg will help them to achieve lateral flexion further down the line.
Tip: If you’re struggling to maintain the line of travel you can use poles or cones arranged in a square as a point of reference for you to follow. From experience, horses are a lot more confident with the exercise when the handler is paying attention to where they, themselves, are going!
HEAD AND NECK POSITION
When you’re certain the horse is understanding this, you can begin to lengthen the line and ask the horse to move further away from you. At this point, I start to pay attention to what the horse’s head/neck position are doing. As riders, there is a tendency to ask the horse to bend too much in the neck and get this confused with lateral flexion. Lateral flexion comes from movement in the horse’s core, not the neck. At this stage in training, their neck should be long and seeking forward-down, with the eye roughly in line with their tuber coxae (their hip bone) and the nose should be in front of the vertical as well as in front of their sternum or more preferably in front of their outside shoulder to help them weight the outside forelimb. This must not be compromised during the turn on the square – where you often see the horse collapsing through C7-T1 (the base of the neck).
Now for trot. From experience, once the horse understands the direction of travel, this exercise is much easier in trot as the horse’s vertebral column is more stable (the head should remain consistently forwards seeking, unlike the walk where it bobs forwards and down.) For those of us that like to conserve energy, you can make your line even longer and send the horse further away from you, but you do still have to move your feet! Alternatively, it may be necessary to wear some running shoes!
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