Like humans, horses experience stress, are frequently startled and can develop chronically contracted muscles that produce consistent postural patterns across all breeds, disciplines and continents. These postural reflexes were first identified and named by Thomas Hanna for his work with humans, but both these characteristic postures and the reflexes that produce them can be observed across animal species, as observed by Eleanor Criswell when she created Equine and Canine Hanna Somatics®.

Once these patterns become habituated (aka learned), they become part of the horses 'new normal' baseline and can persist for years.

The Green Light Reflex creates the posture of flight or excitement

The Green Light Posture shows up when a horse is startled, afraid or excited, and is commonly known as "fight or flight."

Contractions above the vertebral column produce spinal extension with a high head carriage, bulging or tight brachiocephalic muscles and downward pressure on the thorax, commonly accompanied by a camped out and extended limb position with the ventral abdominal muscles forced into length, creating stretch weakness and a sway-back.

When the Green Light reflex is repeated enough to become habituated into the horses default posture, having their body in the flight position affects both their mental/emotional state and their movement and energy levels.

Horses stuck in the Green Light Reflex tend to be high-headed, hollow backed and 'strung out behind,' have difficulty tracking up, or lifting their back and withers, are predisposed to developing Kissing Spines and are often labeled as having a "weak" core or thoracic sling...

RESOURCES

Criswell, E. & Mayer, A. (2006-2025) Equine Hanna Somatics® Professional Training Program Manual

Hanna, T. (1988) Somatics - Reawakening the Mind’s Control of Movement, Flexibility and Health. Da Capo Press