Equine Biomechanics: The influence of water on lumbosacral symmetry and range of motion

Q4E Case Study 36 – Equine Biomechanics: The influence of water on lumbosacral symmetry and range of motion

Introduction

Biomechanics of the equine back are effected by a multitude of factors, including the movement on the limbs effecting specifically the thoracolumbosacral region of the spine.

Most movement in the back occurs at the lumbosacral junction and variations of the lumbosacral spine can affect the mobility of this region.

Poor saddle fit, rider impact, back pain and inability of muscle growth can cause asymmetries of the spine (Greve and Dyson, 2015).

The presence of a water when exercising in a water-treadmill alters the biomechanics of the back, varying with depth of the water (Mooij et al., 2013).

It is commonly seen that horses have a lateral preference with many of the owner’s commenting on horse’s lack of symmetry.

Methodology

A group of 7 horses was used to investigate the influence of water on lumbosacral symmetry and range of motion (ROM) over a period of two weeks (10 sessions) when using the aqua treadmill for 10 minutes at 10% water depths (fetlock height).

Horses were marked with reflective markers placed via palpation on anatomical locations T18, lumbosacral junction, sacrococcygeal junction to track the symmetry of the lumbosacral region of the back. Quintic high – speed 2D motion capture camera system (300Hz) was used to record 15-second-long clips every 2 minutes. Three strides of data from each session were analysed using the Quintic intelligent tracking 3 point template as seen in the image below. Quintic Software is able to smooth each variable independently in the X and Y axis to ensure that ‘Optimum’ smoothing occurs and data is not over or under smoothed.

Statistical Analysis and Results

There was no significant difference between ROM across sessions, (f(2,20)=0.45,p=0.65). A significant difference was identified between left ROM and right ROM for horses 1-7 in session 1, 5, 6 and 10, (f(1,47)=28.16,p=0.003). However no significant decrease in left ROM and right ROM between the two weeks (f(3,47)=0.13,p=0.94). Left side ROM was consistently greater across session 1, 5, 6 and 10.

Discussion

It is of interest that the left and right side ROM was of a statistically significant difference from each other, with left side ROM being consistently greater than that of the right side. Despite the lack of statistical difference in symmetry, riders commented on the horse’s improvement in straightness under saddle and although this was said to improve over 2 weeks, there was no statistical change to support these comments. However, the ability to monitor and track these details supported the individual owners in adapting their training programmes and use of hydrotherapy to support their performance, based on biomechanical analysis of their horse

References

Greve, L. and Dyson, S. (2015) ‘A longitudinal study of back dimension changes over 1 year in sports horses’. The Veterinary Journal, 203(1), pp.65-73.

Mooij, M., Jans, W., den Heijer, G., de Pater, M. and Back, W. (2013) ‘Biomechanical responses of the back of riding horses to water treadmill exercise’. The Veterinary Journal, 198, pp.120-123.