Efforts to enforce “straightness” in the training of horses should be abandoned, according to researchers.
That is not to say that straightness cannot be achieved, Konstanze Krueger and her fellow researchers noted in the journal Animals, but it should be encouraged through training focused on balance exercises, coordination and developing equal strength on both sides.
For centuries, straightening a horse has been considered a key element in achieving responsiveness and suppleness, and has been a traditional training goal.
However, body asymmetry (natural crookedness), motor laterality (the preference for limbs on one side) and sensory laterality (the preference for sensory organs on one side) are natural phenomena.
“In humans, the forced correction of these imbalances, for example, forcing left-handed children to write with their right hands, has been shown to lead to psychological imbalance.
“In view of this, lateral asymmetries in horses should be accepted, and training should focus on psychological and physical balance, coordination and equal strength on both sides, instead of enforcing ‘straightness’,” they said.
Krueger, Sophie Schwarz, Isabell Marr and Kate Farmer carried out a scientific review on the function and causes of motor and sensory laterality in horses, especially in horses when trained on the ground or under a rider.
Published studies reveal that body asymmetry is innate but does not prevent horses from performing at a high level under a rider.
The review team said the evidence suggests that enforcing straightness may be stressful and may even be counterproductive by causing psychological and physical imbalance, making horses tense and uncooperative.
“In general, body asymmetry has been shown to have little impact on performance,” they said. However, a pronounced preference for the use of left sensory organs or limbs indicate that the horse is experiencing increased emotionality or stress, likely relating to long-term problems with welfare, housing or training.
“We therefore propose that laterality should be recognized as a welfare indicator and that straightness in a horse should be achieved by conducting training focused on balance, coordination and equal strength on both sides,” they wrote.
Just as in human athletes, a sport horse has to be able to use both sides of its body, even when these sides are not symmetrical.
“However, it remains debatable whether many riders confuse straightening the horse by reducing body asymmetry with increased straightness through counterbalancing, because body asymmetry and motor laterality assessments by riders have been shown to mismatch measurements taken from the ground.”
Under the weight of a rider, a horse’s motor laterality tends to increase to its preferred side, either to the left or to the right.
The harmonious use of both sides is believed to be a prerequisite for success in sport and the long-term maintenance of the horse’s health. To achieve this, the horse needs appropriate training to build equal strength on both sides, as suggested by many trainers.
True “balance” is not only lateral; it is also longitudinal, they said. “The horse has to be balanced between hindquarters and forehand, as well as between left and right, and often ‘straightening’ only becomes an issue when riders and trainers try to deal with the longitudinal balance too soon or too severely.
“If the horse’s head and neck are pulled back and downward to bring the forehand back over the balance point, rather than bringing the hindquarters forward and under the horse’s balance point, horses may displace laterally to ‘escape’, because the hindquarters are not yet strong enough to carry the horse in true balance.”
This calls for using a variety of exercises to strengthen the hindquarters, as well as bilateral exercises to strengthen each side of the horse, in order to help it find its balance, while accepting its natural laterality.
“In view of recent research, the goal of straightening the horse should perhaps be reconsidered,” they argued. “Body asymmetry is innate, but it does not prevent the horse from performing at a high level under a rider.”
The researchers, who cited 80 scientific papers in their review, noted that many methods have been proposed to achieve straightness, such as additional equipment and forced training on the weaker side. These may prove stressful to the horse and may even be counterproductive by causing the horse to become tense and uncooperative.
“In the worst-case scenario, this can lead to a loss of sensitivity and learned helplessness.”
There should, they said, be a rethinking of current training methods aimed at straightening the horse, with an emphasis on balance rather than straightness.
“If the horse is truly balanced and moves its hindquarters under its balance point, it will be straight, but if it is simply straight, it is not necessarily truly balanced.”
There will always be a degree of body asymmetry as well as motor laterality, they said, but these can be minimised with correct training and muscle development.
“Considering the goal of a relaxed and responsive horse, training that focuses on the longitudinal balance, as well as the lateral balance, should be applied while accepting the horse’s natural laterality.”
Krueger and Marr are with the Department Equine Economics at Nuertingen-Geislingen University in Germany; Schwarz is with University of Hohenheim, also in Germany; and Farmer is with the University of St Andrews in Scotland.
Krueger, K.; Schwarz, S.; Marr, I.; Farmer, K. Laterality in Horse Training: Psychological and Physical Balance and Coordination and Strength Rather Than Straightness. Animals 2022, 12, 1042. https://doi.org/10.3390/ani12081042