How tight should you girth a horse and how does girth tension effect performance?
Researchers at the University of Melbourne investigated this question through a series of studies. The first study measured the average tension applied to keep a saddle secure on Thoroughbred racehorses. This average was 13 kg.
To understand what a tension of 13kg feels like, lift a bucket with 13 litres of water. The downward force of the water is a good proxy for what the average girth tension feels like.
The second study set out to establish what the optimal tension range for a girth should be. That is what is the ideal girth tension in relation to the ability to breath and perform.
Using 8 former racehorses and a treadmill measurements were taken across various girth tensions namely 5, 10, 15 and 20 kg.
In sum, the was a relationship between girth tension and performance. If a girth was tightened to over 10kg performance was impaired. At the maximum tension of 20kg, for example, performance was reduced by around 19 percent.
The researchers postulated that tighter girths decrease blood flow and the ability of respiratory muscles to perform. And that a tight girth displaces bodily tissues which in turn affects performance.
Of course, there are limitations and cautions with this research. Including the small number of horses and that the findings may not generalise to other equine-related sports.
The final study compared elastic and non-elastic girths. Elastic girths reduced the tension however they did not improve performance.
The researchers are now working on a SMART girth that has elastic properties and can provide data on optimal tension and how this affects performance,
Bowers, J.R.; Slocombe, R.F. Influence of girth strap tensions on athletic performance of racehorses. Equine Exercise Physiology 5, Equine Veterinary Journal Supplement, 30, 52-56, 1999.
One hand width under a tightened girth equals about 10kg of tension.