The type of bridle worn by a horse in dressage competitions is not the only factor affecting their stress levels, a new study has revealed.

Scientists from Aberystwyth University and the University of Portsmouth studied the complex effect of using a two-bit double bridle versus a one-bit snaffle bridle.

The researchers’ analysis of 135 horses at a range of dressage events recorded signs of stress, as indicated by ‘conflict behaviours’ such as tail swishing, head tossing, and mouth opening.

They found that these conflict behaviours are common in dressage horses during competitions regardless of the type of bridle worn.

To get a more complete picture, they also looked at other factors, including the level and type of dressage competition, the horse’s head angle when ridden, and the use of different tack items, such as the noseband, cheekpiece type, spurs, and ear bonnets.

The new research comes at a time when equestrian sports are under increasing scrutiny for animal welfare standards.

Dr Sebastian McBride, co-author and senior lecturer in animal behaviour at Aberystwyth University, said: “This research challenges the simplistic narrative that double bridles are inherently more harmful. What we found is a much more nuanced picture - bridle type interacts with rider skill, horse training, and even the horse’s head position during performance. It’s not just about the tack, but how it’s used and the rider using it.”

The research also highlights the importance of behavioural observation to assess horses’ wellbeing.

By identifying patterns of behaviour that suggest stress, the study provides a framework for future studies into how equestrian competitions and riders can affect the horse’s state of mind.

Dr Sebastian McBride added: “Trying to assess horses’ mental wellbeing is complex and needs a focus on the evidence. Our study adds to a growing body of research that supports more informed, welfare-conscious decision-making in equestrian sport.”