With the goal of reducing catastrophic fractures in racehorses, researchers in Australia aimed to stop bone damage altogether. They found that intensive training suppresses bone remodeling, which is how bones repair microdamage before it develops into fractures. In contrast, normal exercise stimulates the growth of thicker bone that’s more fracture-resistant.

They developed a mathematical model to simulate how bone sensors naturally detect exercise stress and transmit signals for repair. The model also showed that high-speed running over long distances overwhelms this repair system and allows bone damage to accumulate.

To strike a balance for training, the researchers posited that high-speed training could be shortened in distance and duration, with rest periods of normal exercise offered more frequently.