Author: Sian Townson

  • Dressage and the Equine Back


    The equine back is gaining popularity as research topic, but it has a long way to go. It’s difficult to research, diagnose and treat because it’s so inaccessible and so complex. The most popular current model of the back is the bow and string introduced in ’46 by Slijper. In this theory the vertebral column (spine) is a bow held in tension by the ventral abdominal wall – the part we call the stomach. Contraction of the abdominal (stomach) muscles, particularly the rectus abdominus, will tense the bow flexing/rounding the back, as will the engagement of the legs underneath the horse (retraction of the forelimbs and particularly protraction of the hind limbs). The string will be tensed (i.e. the back extended/hollowed) by protraction of the forelimbs and retraction of the hind limbs – when the forelimbs flash out in front or the hind legs trail behind. The string is also tensed by the weight of the abdominal organs, hence the many old brood mares with their often sunken backs.

    The Bow and String Model, Slijper 1946

    The bow and string theory puts a lot of emphasis on head and neck movement, a subject that people already get very excited about. Theoretically, if the head is lowered, the nuchodorsal ligament will pull on the withers and flex/round the spinal column. Vice versa, lifting of the head will extend/hollow the back.

    The nuchal ligament, and its action on the withers. Adapted from Denoix 2001

    In dressage the desired position of the head and neck is described by the Fédération Equestre Internationale (FEI) as: “The neck should be raised, the poll high and the head slightly in front of the vertical”, implying a much more upright position than in the natural situation. Both in academia and on forums across the internet the welfare implications of training techniques using neck positions strongly diverging from the natural position are always a popular topic. Studies carried out by an international group have established that there is a significant influence of head/neck position on spine movement. Positions with an elevated neck tend to induce extension (hollowing) in the thoracic region and flexion (rounding) in the lumbar region. Lower neck positions produce the opposite. High neck positions generally lead to reduced movement of vertebrae, especially in the lumbar area, but low-neck positions increase motion. A very high neck position seems to greatly disturb normal motion, much more than a strongly flexed position (Gómez Álvarez et al., 2006; Weishaupt, 2010, Rhodin et al. 2005). The 2006 workshop organized by the FEI in Lausanne discussed the acceptability of the Rollkür or hyper-flexion training technique, in which the horse is ridden with a strongly flexed mid-cervical region that brings the head almost down between the front limbs. The preliminary outcome was that “there was clearly no evidence at the present time that any structural damage is caused by this training exercise, when used appropriately by expert riders” (Jeffcott 2006). The effects on vision, respiration and psychology, I’ll leave to another post…

    The great majority of the muscles that attach to bony elements of neck or back run from one part of this skeleton to the other, not attaching to the limbs, prioritising active, internal stabilisation to compliment the passive, internal stabilisation provided by the ligaments. The back will try to compensate abnormal or one-sided loading of it (e.g. by lameness or rider) by increased muscle tension. As a result, painful muscle spasms are common and early clinical signs of back problems even though they are generally secondary in nature.

    The different gaits have characteristically different movements of the spine and muscle activity. The walk is largely under the influence of passive mechanisms, where movement of the head, neck and limbs affect the spine kinematics. At the walk the back does not experience the twisting of the thoracolumbar junction seen in the trot and canter. The trot shows a very stable back with a reduced range of movement, and with major restraining influence of the muscles. At the canter, the back is influenced by passive mechanisms as in the walk and is restrained by the muscles in the total range of movement as in the trot. Muscle activity has a restraining function instead of an initiating function. Diagonal support of the trot and canter sees extension and twisting of the spine in the areas where pathologies are often found. Abdominal muscle strength, as well as hip extensors, are important in stabilising the back and preventing these injuries. There are clear relationships between back conformation and movement that are likely to be important to the orthopaedic health of the horse. Another topic for a future post…

    Carl Hester and Uthopia in competition 2011

  • Students! Read this first

    It’s that time of year, you’re a student clutching your new dissertation or thesis title, trying to get your teeth into biomechanics and motion capture so naturally you turned to the internet and Google sent you here. Here are some answers:

    1) Will you help me?

    Absolutely. However I will not do it for you or do anything that might constitute cheating. I’m happy to help you grasp, plan, analyse and even conclude. So is your supervisor, who needs to know that you’ve contacted me.

    2) Can you tell me about motion capture?

    Absolutely. Ask a more specific question though: I’ve supervised eight PhDs on motion capture, and none of them overlapped.

    3) Will you tell me what data to collect?

    First you need to work out what your question is. Also what kit you have to work with and whether you’re an engineer, medic, vet, sports scientist or a biologist.

    4) Will you come to my Uni?

    Sure, my time is £200/hr, plus expenses. However I’ve been known to coach riding for as little as £20/hr because, you know, I really like horses. If the project is interesting and the people are nice, I’ll even work for free. Good luck, and be nice.

  • Biomechanics clinic before & after shots Monday lunchtime sessions.

  • Biomechanics Clinic before and after shots Monday afternoon/ evening sessions.

  • An early video of some of the Dressage calmer trial work. Will get around to updating this soon!

  • Biomechanics Calmer Trial FAQ

    What is the calmer being tested?

    Science Supplements ProKalm. It’s not magnesium based, and unusually for a calmer seems to actually work. Details about it can be found here: https://equinemechanics.com/Prokalm

    Do you make the calmer?

    No, I’m just interested in whether it affects the gait quality.

    What will you be measuring?

    Stride length and regularity (rhythm and temp), engagement (hock and fetlock joint angles, step length, overtrack, protraction and retraction angles, spine and pelvic angles, centre of gravity displacement), and responsiveness (transition quality). In addition a List One Judge will also score the “tests”.

    How will you do that?

    I’ll come and film you in your home environment. I won’t anything to the horse so as not to put you, the horse or the judge off.

    Who and where are the other trial members?

    All trial members are in BD Northern Region. Feel free to out yourself on http://www.facebook.com/EquineMechanics

    Can I take part from Scotland?

    At the moment it’s restricted to BD Northern region, but I’m currently looking at opening it up to Scottish BD members. UPDATE: we have now included a Scottish member or two.

    Does my horse need to be currently competing?

    No, it’s training level that counts.

    Will you include my competition?

    Maybe, but probably not.

    What if my horse is too tense or unreliable or performs badly?

    You can’t do badly or be too tense. Each horse is being compared only with itself to see if there’s an improvement in quality and regularity. We’ll be using a high number of strides and comparing averages, so it won’t matter if they vary or you make mistakes.

    What if I’m more relaxed thinking the horse is on a calmer? Won’t the calmer have a placebo effect on me?

    No doubt, that’s why you’ll also test a placebo. I’m afraid that neither you nor the judge will know which is the calmer until the end.

    Why hasn’t the trial started yet?

    We had to narrow people down from a lot of volunteers, and then get hold of enough calmer! UPDATE: Trial now starting!

    Why can’t I find the Facebook page?

    It’s case sensitive: EquineMechanics http://www.facebook.com/EquineMechanics

  • Recruiting for Biomechanics Trial

    David Marlin and I are recruiting for a trial to look at the effects of Science Supplements ProKalm on dressage horses’ way of going. I’ve used it on my horses and think it improves the quality of the trot (quick and dirty test showed a 20% increase in stride length & 50% improvement in tempo consistency in my anxious, green gelding and a 10% increase in stride length in laid-back stallion). So we’re now doing a full trial so I’m looking for people in the BD Northern region who’d be interested in being involved. The horses will all get free ProKalm, a full biomechanical analysis and be assessed by a List 1 judge on three occasions once with and twice without the calmer. We’d be looking for people who can show collected, working and medium trot, although extended would be a bonus.

    On a side note, I’m biased but the calmer is ace. It’s BD and BS legal, not magnesium based, doesn’t knock any of the sparkle out of them but just helps focus – I had a loose horse canter into my ring during my test at Richmond last Monday and stallion stood like a rock until it was caught! Similarly talented but homicidal gelding hasn’t tried to kill me for ages…

    Anyone who’d like to know more (or just order the calmer!) should contact sian@equinemechanics.com.

  • Hand in glove: can wearing gloves make you a better rider?

    I like gloves because I like my hands, and I particularly like my hands with the skin on – not ripped off by some leadrope or lunge rein. Also I hate the cold and I live in the U.K. so I have expensive gloves and I use them. However this evening I started to think about their effect on my riding, when little stallion had a few rather unkind things to say about my hands and then I realised I had forgotten to put them on.

    Why do gloves improve your riding?

    (Good) gloves increase the friction between your hand and the reins. That means that you can keep a more relaxed hand and still have the reins secure. In turn this relaxed hand means a more relaxed forearm, as like horses we keep the muscles further up the limb, away from the digits. If your forearm is relaxed you have softer more responsive hands and your stallion stops whinging (or whining and complaining in American). Everyone’s a winner. My gelding also tells tales on me, but apparently I wore gloves to ride him.

    I have ambitions, Sox merely likes grass and doesn’t see why he has to put up with fools.

  • Engaging the hindquarters and lengthening the stride


    Photo from BritishDressage.co.uk

    BD Convention supported by The National Saddle Centre

    The recent BD convention featured the training talents of the Academy Bartels. It was covered by an informative write-up in the most recent British Dressage magazine. There was some very refreshing talk of responsiveness and relaxation – a horse that waits for, not predicts, the commands and once asked to go forward continues in these longer strides until given an aid to change without continual nagging from the legs. Similarly a half pass ends in a new set of commands not in the removal of the aid. The removal of any aid has already occurred as soon as the horse complied. This strict philosophy gives a strong foundation, and shows how the Bartels achieve such relaxed, engaged horses.

    The classic changes of stride length and tempo exercises are used to reinforce this. However I found these two types of exercises a little confused in the report. The report appears to refer to longer strides being faster strides, and this being part of the tempo exercise. The accepted wisdom in dressage, entirely supported by the scientific literature, is that in order to maintain the same tempo, longer strides should in fact feel a little slower. Tempo exercises changing the stride timing are very useful in creating engagement and responsiveness, as are exercises changing the stride length, but these are not normally seen as the same thing. As early as ’94 we knew academically that in high-level horses stride duration is maintained (canter) or extended (trot) with increases in stride length (Clayton, 1994a; Clayton, 1994b). Biomechanically-speaking speed is the product of stride length and stride frequency, so it is entirely possible for speed to increase, as a result of longer strides, whilst the horse’s stride frequency (tempo) slows. However the article refers to faster strides rather than faster speeds. Was the journalist making an error here, or do the Bartels really change the stride frequency as well as the stride length when in training? Anyone?

    Interesting the research also shows that in order to achieve increased stride length, the footfall rhythm in canter is altered by increasing the time spent in suspension and hence the distance covered between leading front leg and the next hind leg placement. The timing of the hoof-falls within the hind leg-diagonal pair-front leg part of the pattern is proportionally quicker, with longer spent in suspension. Perhaps this is why lengthened strides, which have the same duration and in fact feel slower to ride, are often described as faster.

    In trot, stride length is increased by increasing over-reach distance, and stride duration increases (tempo slows) with increasing stride length. In other words medium and extended trots do have a higher speed, but a slower stride frequency. So in fact in both gaits higher engagement of the hindquarters is needed for lengthened strides, and this would be undermined if the strides were faster rather than longer.

    I wish I had attended the convention and will try to make the next one. The report was a great read, and I particularly liked the following points, which fit well with my last post on the equine back:

    On straightness: “The hind legs must step into the same tracks as the forelegs, whether on the straight line or a curve. Tineke used the helpful image of the horse having to be like a train that stays on the railway lines…..The aim frequently spoken was to ride into the two reins.”

    On roundness: “..they put great emphasis on getting the muscles from the tail, under the hindquarters, under the saddle, into the area in front of the wither and up the neck, soft and malleable. Being round and soft on a connection helped soften these muscles and remove blockages. Any blocks of tension in the upper line would mean there is no connection from the hindquarters to the bit….. Until the horse took the rein down there was no work on the movements.”

  • Be your own Biomechanist: What to look for in your photos

    If you can afford regular lessons with a good instructor you’re laughing. If not eyes on the ground or at least a video can be a real help. Even if all you have is the odd photo you can still plan and make progress.

    So, without further ado, here is why Carl Hester is better than me, from a biomechanics perspective.

    Here’s that photo from the previous post, of Carl and Uthopia in competition (right) and me slobbing about on the left:

    Carl’s horse is obvious happier, it’s more uphill, it’s more engaged and swinging through. All this is easy to see when you have a comparative photo opposite. But let’s assume you don’t. Here’s a few basic biomechanics things you can look at in any picture, with or without a gold standard.

    1) Would it make a statue?
    Even though Uthopia (right) is on one leg, you could imagine it as an ambitious statue. If my photo was made into a statue, little horse would fall on his nose. In biomechanics terms, what you’re looking at is whether the horse and rider’s centre of gravity is over the base of support. Imagining the statue helps you do this, without the maths, and in my case makes it obvious that he’s not that well-balanced. I find thinking about this helps when I’m riding too.

    2) Check your verticals (pictures below)
    Carl’s horse’s nose is slightly in front of the vertical, as is correct for a dressage test. He is sitting slightly behind the vertical (the line of his back is more or less parallel with his horse’s nose). My horse is behind the vertical and I need to straighten up and get my shoulders back too.

    3) Check your horizontals – is the horse uphill? 
    Badly timed or angled photos can easily hide how uphill a horse actually is, so if you compare your horse’s back to the fence line look at the whole horse -. If we look at the top of my horse’s back it doesn’t looks so bad, but if we look at the whole horse and check for lowered (engaged) quarters and raised shoulders the illusion is shattered. Compare the little guy to Carl’s horse.

    Moving on….

    4) Is the horse tracking up and symmetrical?
    For the horse to use its back effectively (see previous posts) the hind legs should be stepping well underneath it. Check whether the hind hoof is landing in the print of the fore hoof. In walk your horse should over-track – the hind hoof should land well in front of where the front hoof left the ground. My horse, on the left, is trotting so we can also check for symmetry – are the diagonal pairs synchronised? It’s pretty common to start to spot problems in extended or very collected work. My horse is looking nicely symmetrical and similarly Uthopia is clearly in the midst of a clear three beat canter, with the diagonal pair well matched.

    5) Is the horse happy and relaxed?
    Yes, this is a biomechanics thing! Muscle tension is the enemy of athletic performance and my little stallion is not just giving his grumpiest just-been-told-off face and tail twitch but you can see the muscle tension in his neck, shoulders and back. Carl’s horse, Uthopia, on the other hand.. oh, you get the idea…..

    6) Is the rider secure? Dancing with the horse or fighting against it?
    Ok, first let’s all concede that my photo is taken from a very unflattering angle! Ok. So if you look at Carl’s seat and leg, ignoring the lower leg, you can see his security comes from the seat and length of thigh. Even if his leg ended where his boot started, you can see he’s staying on. Look how ineffective my seat and thigh look in comparison. Admittedly my legs are shorter than Carl’s but I’m not using what I’ve got. My security is coming from the lower leg, a show jumping habit, whereas it should be coming from higher up.

    People are intuitively good at maths. You use it every time you catch a ball – having successfully predicted it’s path and timing, allowing for gravity, momentum, and air drag. Horse riders tend to be doubly so. Carry on using it.