< Go Back MSc Veterinary Physiotherapy Research Project Posted: Oct 21, 2017THE EFFECT OF THE PESSOA TRAINING AID ON WORKLOAD OF THE RECTUS ABDOMINIS IN HORSES AT WALK AND TROT Charlotte Betchley and Jessica Meager
This research was gratefully supported by Hartpury College and Delsys.
We would like to express our sincerest gratitude to our supervisors, Dr Jane Williams and Gillian Tabor.
Rationale The Pessoa Training Aid (PTA) is a piece of equipment consisting of ropes and pulleys that run along the side and around the hindquarters of the horse (1).
(Odendaal, 2009) The PTA can be put into three different positions: low which attaches in between the forelimbs (position 1), middle which attaches at shoulder level (position 2) and high which attaches in level with the withers (position 3). Position one would lead
to a low head and neck position (HNP), position two would create an elevated HNP, and position three would promote and extremely elevated HNP (2).
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(Gomez-Alvarez et al., 2006)
The PTA is commonly used in equine practice to create a shift in weight-bearing from the forelimb to the hindlimb, with the aim to create spinal flexion and engagement of the hindquarters to strengthen the spinal and abdominal muscles (2-6). The rectus
abdominis muscle (RA) is thought to play an essential role in stabilisation and flexion of the spine (7). The relationship between the PTA and RA workload has not yet been investigated.
The studies compared the workload of the RA in horses wearing the PTA in the middle and low position, to no training aid. It was hypothesised that the highest muscle activity for RA would occur in the middle position, and the lowest with no PTA.
Methodology: Ten horses were walked and trotted on a treadmill and surface electromyography (EMG) was used to measure muscular workload of the RA across the three conditions (control, low, middle). HNP and stride parameters were measured using reflective markers
and a 2-dimensional video camera.
Results: No significant differences in workload occurred between conditions for right and left RA at walk and trot. Workload of the RA was greater for the left than the right at both walk and trot, however significance was only observed at trot. For walk and
trot, there was a significant reduction in stride length and increase in stance duration with the PTA compared to no PTA. No significant differences occurred in HNP between the conditions at walk and trot.
Limitations: A treadmill was used to standardise speed, however may have negated the true effect of the PTA when used overground in normal equine practice. The mechanical effect of the treadmill may influence HNP and limb movement and reduce workload of the RA
(6-8). Intervention from the handler may effect HNP and subsequent activity of the RA (9). Although the RA has been proven to aid in spinal flexion, other muscles may more accurately highlight the role that the PTA has on posture of the spine (10).
Conclusion: Muscular workload of the RA and HNP were not changed on application of the PTA, however stride kinematics were. Based on this research, recommendations for the use of the PTA for strengthening of the RA during rehabilitation cannot be made. However,
the research does provide support for the fact that the PTA does not achieve its reported actions unless fitted and used correctly. Further investigation into the effect of the PTA on other postural muscles with horses walking and trotting over-ground
may lead to more representative results. This may enable extrapolation of findings into rehabilitation of equines, thus increasing evidence based practice.
References: Odendaal, T. (2009) Training aids and gadgets: part 2. SA Horseman: pp 31-35. Gomez-Alvarez, C., Rhodin, M., Bobbert, M., Meyer, H., Weishaupt, M., Johnston, C. and Van Weeren, P. (2006) The effect of head and neck position on the thoracolumbar kinematics of the unridden horse. Equine Veterinary Journal. 38 (S36), pp. 445-51. Roepstorff, L., Johnston, C., Drevemo, S. and Gustas, P. (2002) Influence of draw reins on ground reaction forces at the trot. Equine Veterinary Journal. 34 (S34), pp. 349-52. Bystrom, A., Roepstorff, L. and Johnston, C. (2006) Effect of draw reins on limb kinematics. Equine Veterinary Journal. 38 (S36), pp. 452-6. Cottriall, S., Pattama, R. and Wakeling, J.M. (2008) The effects of training aids on the longissimus dorsi in the equine back. Comparative Exercise Physiology. 5 (3-4), pp. 111-4. Walker, V., Dyson, S. and Murray, R. (2013) Effect of Pessoa Training Aid on temporal, linear and angular variables of the working trot. The Veterinary Journal. 198 (2), pp. 404-11. Zsoldos, R., Kotschwar, A., Kotschwar, B., Groesel, M., Licka, T. and Peham, C. (2010) Electromyography activity of the equine splenius muscle and neck kinematics during walk and trot on the treadmill. Equine Veterinary Journal. 42 (38), pp. 455-61. Buchner, H., Savelberg, H., Schamhardt, H., Merkens, H. and Barneveld, A. (1994) Kinematics of treadmill versus overground locomotion in horses. Veterinary Quarterly. 16 (2), pp 87-90. Wennerstrand, J., Johnston, C., Roethlisberger-Holm, K., Erichsen, C., Eksell, P. and Drevemo, S. (2004) Kinematic evaluation of the back in the sport horse with back pain. Equine Veterinary Journal. 36 (8), pp.707-11. Williams, J. (2015) The use of surface electromyography within equine performance analysis. DPhil, University of the West of England. Available from: http://eprints.uwe.ac.uk/25786. Accessed on 21.11.2017.
