In her book Dressage with mind, body & soul: A 21st-century approach to the science and spirituality of riding and horse-and-rider well-being Linda Tellington-Jones discusses some of the negative effects of riding a horse in rollkur including blue tongues, bloody foam, and that many scientists and veterinarians argue that the horse’s airway is compromised when ridden in this over flexed position and that this position can limit a horse’s ability to see their surroundings, which according to Jones can cause extreme stress to a flight animal (like a horse) which is significant and damaging. Jones continues on discussing possible long-term effects of this position including, neurologic issues, career ending injury, onset of early arthritis, pain