She is referring to the subject of this article;
https://www.equitopiacenter.com/the-price-we-pay-for-spectacular-horses/#:~:text=Hypermobility%20results%20in%20the%20possibility,is%20a%20downside%20to%20this.&text=All%20the%20joints%20in%20the%20body%20of%20the%20horse%20are,joints%20and%20the%20entire%20spine.
Sorry it’s so long.
This is usually the case in horses like Totilas or Blue Horse Matine, but not normally in chunky cobby types !
