Sport specific rehabilitation of the dressage horse: straightness: a case study

Hannah Nash ACPAT Cat A

History

Frisbee is an 8 yr old warmblood gelding who was purchased from Holland following a full 5 stage pre purchase veterinary examination for low level dressage in his 7th year. Conformationally, he is long in the body with high set neck typical of Dutch carriage horses. His full history is unknown. At the time of purchase he was working at basic preliminary dressage level and despite his conformation, showed no significant difficulty with progressive schooling towards elementary level over the next eight months. He was always reluctant to lower his head and neck and relax the topline when ridden or lunged and showed less suppleness on the left rein.

Eight months following purchase, he developed a sudden onset shortened stance phase on the left hind leg when ridden which was graded 1/10. Full lameness work up with nerve blocks revealed a resolution of the lameness with a tarsometatarsal (TMT) block to the left hock. Radiographs indicated possible minor degenerative changes to both distal TMT joints which was felt to be borderline significant.

Veterinary treatment consisted of bilateral Depo Medrone injections to the TMT joint space and a Tildren infusion. After ten days, a progressive walking programme was started in hand and under saddle. Six weeks post medication; there remained an intermittent uneven stride on the left hind on a left circle. Secondary referral to a specialist referral centre for Gamma Scintigraphy to the hind quarters showed no abnormality and a gradable lameness was not able to be reproduced on trot up, lunge or under saddle. A return to full work was advised.

In this case study, the horse was shod with a standard shoe on all four feet and remedial alterations to support the veterinary treatment were not added.

Physiotherapy Assessment

The main issue we noted with Frisbee’s movement was an intermittent irregular stride pattern. On close assessment we noted poor muscular development of the hind quarters relative to the shoulder and he carried his head in an elevated outline but was unwilling to stretch his neck down and forward when lunged or ridden.

On a right 10 m lunge circle, the right hind limb had a shortened cranial swing phase – possibly due to the extended stance phase and increased weight bearing on the right fore limb. The left hind had a shortened stance phase with marked medial rotation through to the end of the caudal phase. The hind limbs travelled laterally left to the forelimbs with the right hind crossing under the body therefore travelling on four tracks. There was a lack of lower cervical side flexion and over activity of splenius during gait (not evident in stance).

We hypothesised that the sudden onset of left hind limb lameness was due to the repetitive shearing and rotational forces through the tarsal and stifle joints as a result of the asymmetrical movement pattern. We proposed that the shearing forces would have been increased as ridden work progressed at increased paces and more complex schooling patterns, a possible factor in the sudden onset of lameness. The author proposes that the initial sudden onset of gradable lameness and a positive block suggested that hock pain was the initial problem. The symptoms remaining post medication were suggestive of an underlying mechanical dysfunction that would require rehabilitation.

On palpatory assessment, there was a moderate range of cervical side flexion and flexion equal bilaterally and spinal range of movement was within normal expectations. Left sided caudal longissimus spasm was elicited with pressure into resistance and mild increased tone in the lumbar insertion of the left middle gluteal. The middle gluteal and biceps femoris bulk was reduced on the left.

Treatment 0-4 weeks

The secondary lumbar and gluteal muscle spasm was addressed with reflex inhibition techniques and myofascial release. Reflex Inhibition Techniques have been demonstrated to temporarily reduce spasm in longissumus (Wakeling et al., 2006) which may be utilised to restore normal movement patters. In cases of long standing back pain it is suggested that the multifidus in the horse is inhibited (Clayton, Stubbs, 2010). Baited stretches have been proposed to help in the recruitment and hypertrophy of the multifidus in the horse (Clayton, 2010).

In this case we used daily lateral spinal flexion exercises biased to the lower cervical, thoracic and lumbar spines. We added a combination of weight transfer and pelvic stability exercises to increase recruitment of the biceps femoris, particularly on the left. It is proposed that Biceps femoris is active throughout the stance phase of gait (Robert et al., 1999) and the deep fibres contain a higher percentage of type 1 fibres (Karlstrom et al 1994). It has an important stabilising role in controlling the forces transmitted through the hock and stifle (Clayton, 2010). The stability exercises were started immediately and continued daily for 4 weeks along side a walking programme. The stability exercises

Rehabilitation of a movement dysfunction of a horse using theraband and proprioceptive taping

are continued long term but we felt it was valuable to introduce a baseline level of control before progressing dynamic stability work.

Dynamic Control 2-6 weeks

The goals of the dynamic exercise programme was to increase spinal stability and ability to relax over the topline, increase pelvic and hind limb stability, control and proprioception, improve and even out stride length and limb loading. Progress this to ridden work and competition dressage if possible.

Work began walking in hand in straight lines with no side reins. We used proprioceptive taping (kinesiotape) over the left biceps femoris and bilaterally for transverse abdominis and the external obliques. There are a significant number of papers suggesting the benefit of taping techniques for lower limb ligament injuries in humans but a lack of a satisfactory physiological explanation for its effect. Stubbs (2007) suggests that the tape provides sensory feedback to modulate performance via a closed loop feedback system. Facilitation the abdominal muscles was reasoned to aid an increase in stride length and control of spinal rotation. Facilitation of Biceps femoris was to aid pelvic stability and try to reduce shear and rotational forces travelling through the hock. Short periods of trot work were added, avoiding tight turns and small diameter circles to begin with.

Proprioceptive rehabilitation was enhanced by varying the terrain the horse was walked over from sand to grass to gravel, deep and firm surfaces. At one stage we added a proprioceptive pastern chain but for this horse, the effect was evident for no more that two strides.

4-6 weeks

Dynamic work progressed to pole exercises in variations of patterns. Initially starting with individual poles and incorporating bend and raising one end of the pole. Different sequences were used to address abdominal recruitment, stride height and length and proprioception in walk and progressing to trot as the exercises were consistently well achieved in walk. Proprioceptive effects were not limited to the school work but walk hacking over varied terrain was consciously added to maximise the development of strength, coordination and balance. Periods of trot were introduced on hacks.

6-12 weeks

Through this early work developed improved range of movement, even stride length, reduced rotation at the hock and the horse was able to consistently work on two tracks. (For this case study we did not have access to objective measures to show any improvements made. This could be a potential role for field based gait analysis systems). From 6 weeks we progressed the exercises over poles, increased hacking and added gentle slopes and short periods of canter (as this was potentially the most physically stressing gait, it was kept in short periods and only on straight lines). From the 6 week stage we introduced a specific ridden

Discipline Specific Training

Progressing to the ridden school work provides a good opportunity to link with a trainer with a good understanding of equine biomechanics and training. I worked with classically trained dressage trainer Simon Battram who has a deep technical knowledge of dressage training and its evolution. He has introduced the ridden exercises analysed below. It has been very interesting to apply the classical exercises and principles of dressage training to progression of sport specific rehabilitation. All the ridden exercises were first started in hand and then ridden in walk. The exercises on each rein were specifically tailored to address the straightness and suppleness issues individual to each rein. All angles were introduced gradually.

Ridden Exercises Long and Low:

When progressing to ridden work, the functional goal was for the horse to develop into a riding horse and to specifically compete in dressage. The aim of this type of training is for the horse to push evenly from his hind legs into an even rein contact. At this stage, the training should become functional and working towards a technically correct outline and contact for dressage is required if the rehabilitation is to be discipline specific.

The outline chosen to commence ridden work was a ‘long and low’ frame. The head carriage is low and the nose in front of the vertical. Studies into the benefits of different head positions in the ridden horse are not fully conclusive and are not directly transferrable to all training scenarios for example; a study by Rodin et al (2009) omits the ‘long and low’ (nose in front of the vertical) head position and uses high level trained dressage horses as the subjects. Comments on the training of dressage horses by Dr Gerd Heuschmann (2007) support the use of the long and low frame in the novice horse and are based on an analysis of anatomy but are not supported by controlled studies. The debate between dressage trainers is unresolved with a variety of experiences and hypotheses. In this case, long and low was chosen to encourage the horse to reach into a soft contact and relax over the epaxial muscles. This has been suggested to allow a greater cranial stride length and more even (straight) placement of the hind limbs. The horse is not held in this frame and periodic changes in head carriage are encouraged as the ridden exercises progress.

Ridden exercises were initially aimed at biasing the propulsive role of the left hind leg. As increased symmetry was noted in the work on straight lines and circles, the exercises were introduced on both reins and degree of difficulty progressed.

Proposed Exercises for Developing Left Hind Leg Carrying Capacity: Left Rein ‘Giravolta’

The giravolta is an exercise whereby the horse is brought onto a 10m circle. The horse is then asked to bend towards the middle of the circle, the forelegs stay on the 10m path and the inside hind leg is asked to move forwards and under the horses mass. This exercise was initially done in hand and progressed to under saddle. The left hind steps under the trunk of the horse and through stance phase the limb moves through extension, abduction and a degree of lateral rotation. The muscle activity involves the middle gluteal, biceps femoris, illiopsoas and tensor fascia latae (Denoix, 2001). The deep and cranial parts of biceps femoris have a greater percentage of type 1 fibres (Karlstrom et al., 1994) and so we can suggest one function of this exercise is to promote global pelvic stability.

This exercise does not fully address the transfer of weight onto the right shoulder so it is possible for the horse to escape the full potential of the exercise. In order to progress, the control of the right shoulder needs to be incorporated. Left rein riding a square, enables the rider to gain a better control of the right shoulder which then in turn allows a better placement of the forehand in front of the hind quarters. The shoulder-in as a continuation of this work places a larger work load to the left hind leg. The shoulder in has similar activity analysis to the giravolta and may increase or decrease the load on the left hind depending on the angle used.

Right Rein Leg Yield to Travers

We started off with some leg yield head to wall, encouraging the left hind, now on the outside, to swing forwards and through under the trunk of the horse. The leg yield does not require lateral bend and can be done at varying angles to increase or decrease the load on the hind legs. At a later stage, the exercise was progressed by adding lateral cervical and thoracic flexion to the right. This will prevent the excess weight transfer to the right fore, increasing the requirements for the horse to stabilise through the pelvis and spine effectively. Active force through the rein to move the neck into side flexion was avoided as this had the effect on reducing stride length and creating a strong muscle contraction in splenius. The process of working gradually into side flexion created a greater release through the right side of the neck.

Long Term Management

More recently, we have progressed lateral exercises to work on both reins evenly and incorporated working on different terrains and slopes. The horse is working through a variety of hacking and schooling at elementary level at home and has successfully competed in dressage at novice level. The long term plan is for the horse to progress up the levels in dressage but the progression will be gradual in order to successfully achieve the suppleness and strength required at each level. High level dressage may not be achievable due to the increased loading placed on the hind limbs with collection.

A Chartered Physiotherapist takes a holistic approach assessing both horse and rider

on the hind limbs with collection. This will need to be monitored throughout the schooling programme and a wide variety of supplementary activities such as hacking and turn out would be advisable.

There are many thoughts and arguments about the correct training and rehabilitation of horses with little objective data available. This case study attempts to relate some of the pertinent literature in equine kinematics and rehabilitation to a specific case. However, the case itself lacks objective measures. This may be a future role for GPS based gait analysis systems in clinical practice.

References

Clayton H., (2010).Posture Strength and Balance in Horse and Rider. Proceedings of the ACPAT Seminar. Unpublished data.

Denoix, J.M.,Pailloux, J.M. (2001), Physical Therapy and Massage for the Horse: Biomechanics, Exercise and Treatment. 2nd edn. Manson Publishing. Heuschmann, G. (2007) Tug of War: Classical versus Modern Dressage pg 71-73 JA Allen

Karlstrom K., Essen-Gustavasson B., Lindholm A. (1994) Fiber type distribution, capilliarization and enzymatic profile of locomotor and nonlocomotor muscles of horses and steers. Acta Anat 151, 2:97-106.

McGowan C., Goff L., Stubbs N. (2007), Animal Physiotherapy: Assessment, treatment and Rehabilitation of Animals. Pg 243 Blackwell Publishing.

Robert C., Valette J.P., Deguerce C., Denoix J.M. (1999) Correlation between Surface Electromyography and Kinematics of the Hind limb of Horses at Trot on a Treadmill. Cells Tissues Organs 1999;165:113-122

Rodin,M.,Gomez Alvarez, CB.,Bystrom, A. ,Johnston, C.,van Weeren, P.R., Roepstorff, L.,Weishaupt, MA. (2009) The effect of different head and neck positions on the caudal back and hindlimb kinematics in the elite dressage horse at trot. Equine Vet. J. 41(3) 274-279

Wakeling J.M., Barnett K., Price S., Nankervis K. (2006) Effects of Manipulative Therapy on the longissimus dorsa in the equine back. Equine and Comparative Exercise Physiology 3:153-160.

A Neuromuscular Stimulator can be used to reduce muscle atrophy