Research Thesis (Phd): Uta Ulrike Von Borstel (2007). Fear In Horses and How It Is Effected By The Rider, Training and Genetics.

This study provides evidence that horses unaccustomed to being ridden in Rollkür prefer regular poll flexion rather than Rollkür. Horses were also more likely to exhibit behavior patterns indicative of discomfort or frustration when ridden in Rollkür than when ridden in normal poll flexion. This is supported with increased heart rates that reveal higher emotional arousal during Rollkür.  Fear reactions were also stronger after being ridden in Rollkür versus normal poll flexion. These results suggest that Rollkür may compromise the horses welfare and impact rider safety.