The head and neck of the horse weighs up to 10% of a horses total body weight and so its unsurprising that the position of the head and neck plays such an important part in how the horse moves. Obviously the position of the horses neck will vary throughout the disciplines, due to the different demands and aesthetics desired, and with conformation.
I am not going to discuss these different head positions as there are pros/ cons and controversies about the effect on equine behaviour and physiology with an overly flexed necks or highly held necks. What I do want you to think about is your horses head and neck position and what you do which effects the position.
If we consider a horses natural position when moving it is nice and relaxed with deep muscles stabilizing the vertebrae with the larger and superficial muscles flexing, extending, side flexing and rotating. What I feel happens a lot of the time is that people try and force the horses and neck position via different methods (both intentional and unintentional). This is rather than allowing the horse to actively stabilize the position having gradually built up the strength to maintain that position over time.
Some methods include increased tension through the reins, different leverage bits, side reins and Pessoa which also put the head in a certain forced position. This is then going to increase tension and activation of certain muscles and alter the balance and coordination of the deep and superficial muscles. If the horse is then repeatedly schooled in this position, stabled (so unable to graze) and then fed from a hay net then it is unlikely the neck will relax out if this position and stretch. Remember if they don't stretch at rest then they are unlikely to suddenly stretch when moving.
Now I am not critising any of the above things as they are all common practices with equine management and on their own are not problematic. But when added together can lead to some of the complaints which will prompt a call for physiotherapy. Common complinants include decreased performance, stiffness and lack of suppleness when being ridden. Physiotherapy and the right stretches can make a bit difference as can giving you and your horse a break from the same schooling routine...
Can you go for a hack or to the beach etc and let them relax there head without having to worry about being balanced on circles? Can you make sure you warm up and warm down after schooling to allow for a gradual increase in the muscle activation?
Consider why you are using the tools to achieve the shape – could you do exercises such as pole work to help achieve the same strengthening results. Could you feed food from the floor or a lowered head rack? Look at what happens to your horses neck muscles as it pulls hay out of a net. If you want to use side reins or a Pessoa think about why you are using and what you want to achieve?
During an equine physiotherapy assessment I want to look at how the horse holds their head and neck at rest and also when moving. This can give me information about which muscles are normally used (looking for an increase in muscle size) and its frequent range of movement taking into account its environment (amount of time turned out, how it's fed etc). Using treats we can assess their active movement to find any restrictions within the neck, we can also assess the movement at each vertebrae using mobilizations and assess the tension and feel of the muscles. Treatment will normally then involve manual therapy to help with any joint restrictions or muscle tightness found or techniques to aid relaxation. Home exercises that you can then do daily with your horse will help maintain this movement and allow them to constantly stretch out there neck. That along with the previous examples of changes you can make in your horse management can make a huge difference.
Carrot (baited) stretches are brilliant to do for horses – they help with core stability and with general mobility. You can do side flexion stretches where you try to get the head to turn towards the hip (ideally not tilting or rotating the head to get there).
You can also do to the floor in between feet or on to the outside of hooves. But one of my favorite exercises is getting them to stretch forward which really opens out the area between the jaw and neck and you can vary it by how high or low you do the stretch.
Here are some examples of the benefits of Physiotherapy on neck position at rest: