Downhill work in horses strengthens which group of muscles?

The correct answer is that downhill work strengthens the pectoral, shoulder, and forearm muscles. When a horse works downhill, it shifts its weight forward, requiring more engagement from the muscles in the front of the body. This movement pattern increases the workload on the pectorals, which are crucial for forelimb movement and support. The shoulder muscles are also engaged, as they help stabilize the horse's movements and control the forelimbs while navigating the slope. Furthermore, the forearm muscles play a significant role in the coordination and propulsion of the legs as the horse adjusts to the terrain. This type of conditioning is beneficial for improving the overall strength and balance of the horse, particularly in the front half of the body.

Other muscle groups mentioned in the other options may be strengthened through different types of exercises or terrain, but they are not primarily targeted during downhill work.