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Core Strengthening and Flexibility in the Equine Athlete

Updated: Mar 12, 2018

If we expect the horse to support the weight of a rider we first have to ensure that they can effectively support their own weight. The horses spine is supported by the fore-limbs and hind-limbs, however, the spine tends to drop in the middle due to the weight of the gut, leading to spinal extension. The addition of a saddle and a 75kg weight to a horses back has been reported to induce spinal extension during both standing and locomotion, commonly leading to tension in both the deep and superficial dorsal spinal muscles (1). Deep spinal muscles are difficult to influence passively and remedial exercises are therefore recruited to promote global core strengthening. Core strengthening exercises aim to promote active spinal flexion by muscular training and counteract the forces causing spinal extension.


Lowering of the head and neck and abdominal muscle contraction induces global spinal flexion, during which the distance between the dorsal spinous processes, the bony prominences extending from the vertebrae, is increased. Alternatively, a high head and neck position and dorsal spinal muscle contraction induces spinal extension and decreases the distance between the dorsal spinous processes. This motion is particularly important in the thoracic region where chronic muscle hypertension and kissing spines are most prevalent. Additionally, because the spine connects the forelimbs and hind limbs, spinal extension reduces tracking up and propulsion.


(Source: Van Weeren, 2016)


Core muscle strengthening involves both static and dynamic exercises, targeting muscle groups rather than specific muscles. Baited stretches, use of a Pessoa Training Aid and pole work are a good combination of exercises for promoting core strength and flexibility.


Baited Stretches


Stretching aims to improve flexibility, aid proprioception, relieve pain, prevent injury, improve symmetry and enhance performance (2). Soft tissue flexibility is one of the determining factors of joint range of motion, which significantly influences performance. Joint motion requires strength in the agonist (contracting) muscle and flexibility in the antagonist (stretched) muscle. Passive stretches only target the antagonist muscle whereas active stretches target both the antagonist and agonist muscles. Injuries most frequently occur at the muscle-tendon junction. Repetitive stretching regimes reduce the load at the muscle-tendon junction by improving compliance along the entire musculo-tendinous unit (2).


Signalment for core strengthening exercises:

  • Strengthening of core musculature in young horses in preparation for ridden work.

  • Maintenance throughout athletic career.

  • Maintenance on box rest.

  • Rehabilitation from colic surgery, commencing one month post-operative if post-operative complications are absent (3).


Factors inducing chronic hypertonicity of the epaxial musculature include; anxiety, management factors such as use of hay nets, inability to contract dorsal spinal musculature and back pain (4). Back pain causes rapid atrophy of the Multifidus muscle at the affected spinal level. The Multifidus muscles role is to stabilise the vertebral column and when it is incapable of performing this role the Longissimus dorsi muscle compensates. The Longissimus dorsi muscle is a mobilising, rather than stabilising, muscle and therefore will tonically contract, leading to global vertebral stiffness, micro-motion at the vertebral joints, vertebral column instability and a predisposition to degenerative disorders (Clayton, 2016). Additionally, a horse will be unable to elevate its vertebral column, produce lateral motion or support the weight of a rider while the Longissimus dorsi muscle is in chronic hypertonicity (4). Once the causal factor has been treated, baited stretches can be performed following exercise to release tension in the Longissimus dorsi muscle and re-activate the Multifidus muscle.


Flexion of the intervertebral joints through rounding of the neck and back enables dorsal spinous process separation. This stretches both the long mobilising and deep stabilising spinal muscles, difficult to achieve in a passive stretch (3). The baited stretches should be performed in a slow and controlled manner by guiding the head with the bait into the correct position and then maintaining this position for 5-15 seconds. Normal motion of the vertebral column is a smooth accumulation of small segmental movements and horses with normal neck range of motion should be able to touch their nose against any segment of the forelimb (5).


Baited rounding stretches are initially performed in a square stance, however, raising a leg, standing on an uneven surface or positioning alternate hind limbs in protraction increases the difficulty (3). These exercises should be performed equally bilaterally, observing for asymmetric range of motion between the two sides. The ears should remain at the same height and twisting of the neck should be discouraged, use of the therapists spare hand may prevent this (3). Standing the horse against a wall may prevent spinning. If the horse moves their feet during this exercise the therapist will need to stop, reposition the horse against the wall and start the stretch again (5).


(Source: adapted from Haussler 2016)


(Source: Wiki How, not dated)


Neck extension exercises can be performed as a warm down exercise following rounding and lateral bending exercises. The neck is stretched forward and low and placing the bait further from or closer to the ground will encourage extension at specific cervical regions (5). The horse may be placed behind a low barrier at chest height to prevent stepping forward (3).


Another active rounding exercise is the sternal elevation spinal reflex. With the horse positioned squarely the therapist should stand lateral to the thoracic limb facing the horse with their cranial hand on the chest to steady the horse and their caudal hand on the sternum. Upward pressure is then applied with the fingertips along the midline sternal groove, craniocaudally. The amount of pressure required will depend on the individual. This stimulus activates the Serratus Ventralis muscle causing active elevation of the withers and lowering of the head and neck (5).

(Source: Wiki How, not dated)


Repetitions:

Five repetitions of each exercise daily for five days per week for 12 weeks has been reported to significantly increase the cross sectional area (CSA) and significantly reduce asymmetry between left and right sides of the deep spinal muscles (T10-L5) (6). However, another study performed the same exercises three days per week for 12 weeks and also reported a significant increase in deep spinal muscle CSA (7). Additionally, no significant difference has been reporting using the same baited stretch regime over six weeks compared to 12 weeks, however, this study performed 10 repetitions of each stretch for five days per week (8). Therefore, five repetitions of each exercise for three days per week should be effective.



The Pessoa Training Aid:


The pessoa training aid has been marketed to improve core strengthening, engage the hind quarters, stretch the top-line and encourage correct movement through sensory input and gait re-education. The pessoa training aid consists of a pulley system, with a rope that goes around the hind quarters, through the roller, through the bit and then folds back on itself to re-attach to the roller. Additionally, the abdominal band provides sensory input and stimulates abdominal muscle recruitment (9).


(Source: Equishop, 2015)


The pessoa can pass through the roller low through the front legs, at shoulder height or at wither height. The lower level is indicated for young or less established horses whereas the highest level is indicated for advanced horses (10). The middle position encourages a low head and neck position with a wide atlanto-occipital angle and is the position most frequently used. In standing, the dorsal aspect of the head should be at vertical when at the end range of the pessoa length (11; 10). Care should be taken when applying a pessoa training aid to prevent excessive bit pressure as this may cause desensitisation of the mouth and potentially effect ridden work (10).


The exercise protocol should be adapted to the individual horse, however, a general guide is two minutes at medium walk and two minutes at working trot on each rein. Additionally, once the horse is familiar with the pessoa training aid a minute of canter on each rein can be introduced (10). It is vital that both reins are exercised as the muscles on the inside of the circle demonstrate more activity, for example the longissimus muscle on the inside of the circle exhibits 2-3 times more activity than the longissimus muscle on the outside of the circle (11). It is also recommended to warm the horse up for five minutes at walk and trot in both reins on a 16m diameter circle and on a soft surface prior to applying the pessoa training aid.


A recent report by Walker and colleagues (10) found the pessoa training aid to encourage a reduced head angle, lowered head and neck position, increased dorsoventral mid back displacement, increased lumbosacral flexion and increased grades for horses bend, over track, abdominal activity and tail swing (10). Many studies report that a low head and neck position, through contact at the bit, promotes hindlimb kinematics, however, to a lesser degree than it influences forelimb kinematics (11; 12; 13). The hindlimb band provides a sensory cue, aiding proprioception and stimulating the neuromuscular response of hindlimb engagement (14). The hindquarter band has also been suggested to activate spinal flexors, the Psoas major and minor, and Rectus Abdominis muscles, leading to strengthening of these muscle groups (4; 15). Hindlimb engagement has been reported to have a greater effect on thoracolumbar spinal motion than head and neck position (16).


Additionally, in Walker et al.'s (10) study only 1/16 horses exhibited negative behaviour association with pessoa training aid application, this conflicts with suggestions that training aids lead to confusion and negative behaviours (17; 18). Limb loading is not affected by use of a pessoa training aid, suggesting no ill effect of its use on horses recovering from limb injuries if they are already undertaking the same work without a pessoa training aid (10).


Alternatives to the pessoa include the Equiband, which has no connection to the horses mouth, is easily applied during ridden work and is reported to significantly reduce wither flexion, wither, thoracic and lumbar mediolateral movement and to have no effect on lumbo-sacral flexion or overall dorsoventral displacement, which could be due to the lack of contact at the mouth (9). Another alternative is draw reins, which have been shown to transfer the weight of the horse caudally, however draw reins do not stimulate hind limb engagement (13).


I hope you have found this blog post useful and informative. If you would like to read up on any of the research used please see the references below and please get in contact with any questions or recommendations.



References:


1. De Cocq, P., van Weeren, P. and Back, W. 2004. Effects of girth, saddle and weight on movements of the horse. Equine Veterinary Journal, 36, pp.758–763.


2. Frick, A. 2007. Fitness in Motion Keeping your Equine’s Zone at Peak Performance. Guilford: The Lyons Press.


3. Clayton, H. 2016. Core Training and Rehabilitation in Horses. In: King, M. and Davidson, E. ed. Rehabilitation of the Equine Athlete. Philadelphia: Elsevier. pp.49-72.


4. Paulekas, R. and Haussler, K.K. 2009. Principles and practice of therapeutic exercise for horses. Journal of Equine Veterinary Science, 29, 870–893.


5. Haussler, K. 2016. Soft tissue and joint mobilisation of the cervical region and cervicothoracic junction. American Association of Equine Practitioners 360 degree Pain in the Neck, pp.27-33.


6. Stubbs, N., Kaiser, L., Hauptman, J. and Clayton, H. 2011. Dynamic mobilisation exercises increase the cross sectional area of musculus multifidus. Equine Veterinary Journal, 43, pp.522-529.


7. De Oliveira, K., Soutello, R., Da Fonseca, R., Costa, C., Meirelles, P., Fachiolli, D. and Clayton, H. 2015. Gymnastic training and dynamic mobilisation exercises improve stride quality and epaxial muscle size in therapy horses. Journal of Equine Veterinary Science, 35, pp.888-893.


8. Tabor, G. 2015. The effect of dynamic mobilisation exercises on the equine multifidus muscle and thoracic profile: masters research project submitted in partial fulfilment of the requirement for MSc (Honours) degree in Equitation Science. Plymouth, UK: Plymouth University.


9. Pfau, T., Simons, V., Rombach, N., Stubbs, N. and Weller, R. 2017. Effect of a 4-week elastic resistance band training regimen on back kinematics in horses trotting in-hand and on the lunge. Equine Veterinary Journal, 49, pp.829-835.


10. Walker, V., Dyson, S. and Murray, R. 2013. Effect of a Pessoa training aid on temporal, linear and angular variables of the working trot. The Veterinary Journal, 198, pp.404-411.

11. Cottriall, S., Ritruechai, P. and Wakeling, J.M. 2009. The effects of training aids on the longissimus dorsi of the equine back. Comparative Exercise Physiology, 5, pp.111– 114.


12. Biau, S., Couve, O., Lemaire, S. and Barrey, E. 2002. The effect of reins on kinetic variables of locomotion. Equine Veterinary Journal, 34, pp.359-362.


13. Roepstorff, L., Johnston, C., Drevemo, S. and Gustås, P. 2002. Influence of draw reins on ground reaction forces at the trot. Equine Veterinary Journal, 34, pp.349-352.


14. Goff, L. and Stubbs, N, 2007. Equine therapy and rehabilitation. In: McGowan, C.M., Goff, L. and Stubbs, N. eds. Animal Physiotherapy; Assessment, Treatment and Rehabilitation of Animals. Oxford: Blackwell Publishing. pp. 239–250.


15. Denoix, J.M. and Pallioux, J.P. 2001. Physical Therapy and Massage for the Horse, 2nd ed. London: Manson Publishing.


16. Rhodin, M., Johnston, C., Roethlisberger, H., Wennerstrand, J. and Drevemo, S. 2005.The influence of head and neck position on kinematics of the back in riding horses at the walk and trot. Equine Veterinary Journal, 37 (1), pp.7-11.


17. Murphy, J., McLean, A., McGreevy, P., Sheridan, F. and Hanly, P. 2008. The use of training aids (gadgets) within equitation: Meritorious or detrimental? In: Proceedings of the International Society for Equitation Science, Dublin, Ireland, p.29.


18. McLean, A.N. and McGreevy, P.D. 2010. Horse training techniques that may defy the principles of learning theory and compromise welfare. Journal of Animal Behaviour, 5, pp.187–195.


Equishop. 2015. Lunging - Step By Step [Online photograph]. Equishop. Available from: https:// www.equishop.com/en/blog/lunging-step-by-step-n39 [Accessed 28 December 2017].


Van Weeren, R. 2016. Kinematics of the Equine Back and Pelvis [Online photograph]. Veterian Key. Available from: https://veteriankey.com/kinematics-of-the-equine-back-and-pelvis/ [Accessed 28 December 2017].


WikiHow. Not dated. How to Stretch a Horse [Online photograph]. WikiHow. Available from: https://www.wikihow.com/Stretch-a-Horse [Accessed 8 March 2018].

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