It is the hope of every Thoroughbred racehorse trainer to have all of his or her charges put their best foot forward and win races with grace, finesse, and—most of all—without injury.

“Over the past several years, advances in the field of racehorse safety have focused on a number of variables, including the track surface-hoof interface,” explained Christie Mahaffey, PhD, of the Racing Surfaces Testing Laboratory in Orono, Maine. “We know that composition, cushion depth, moisture, temperature, and maintenance all can impact surface characteristics."

Some trainers try to optimize footing and control the track surface-hoof interface by using different kinds of shoes, such as those with toe grabs or heel calks or those with different weights and compositions. Some even choose different shoes based on track surface to manipulate traction.

To put some science behind trainers’ suppositions, Mahaffey and a team of racetrack surface researchers Mick Peterson, MS, PhD; C. Wayne McIlwraith, BVSc, PhD, DSc, FRCVS, Dipl. ACVS; and Jeff Thomason, PhD, created dirt and synthetic track surface plots in a laboratory. They then used those plots, along with the “Orono Biomechanical Surface Tester,” to measure various loading rates that represented primary and secondary impacts of the hoof in a galloping horse wearing different aluminum racing shoes: a flat racing plate, a shoe with a serrated V-grip, and a shoe with both a 6 mm toe grab and 10 mm heel calks.

“Our study found that in a laboratory setting, shoeing had little effect on loading during the primary and secondary gait phases when the hoof co