When people sprain an ankle, they tend to put all their weight on the other foot to compensate. Horses respond similarly to lameness, using sound muscles to compensate for the injury, according to a new study.

This means that lameness affects many muscles, not just those around the injury. This "functional adaptation" can result in secondary lameness in an otherwise sound limb, said Dr. Hafsa Zaneb, a graduate from the Veterinary Medicine University in Austria.

"Fixing a lameness-related issue early is the only thing that can help the health and future performance of your horse," she said.

Zaneb and her colleges studied the muscle effects of trotting and walking in sound and lame horses. Using surface electromyography, which measures the electrical activity of muscles, they identified differences in back and pelvic limb muscle function between lame and non-lame horses