What should be increased in long, slow distance (LSD) work as a horse's fitness improves?

As a horse's fitness improves, the duration of long, slow distance (LSD) work should be increased. This type of conditioning focuses on building endurance gradually and allows the horse to adapt to longer periods of work over time without the stress of increased speed or intensity. By extending the duration, the horse's cardiovascular capacity and muscle stamina develop effectively, promoting overall fitness without risking injury that could arise from suddenly increasing speed or intensity.

Increasing duration encourages the horse to maintain a steady pace over a longer time, solidifying its endurance base, which is crucial for more advanced levels of training and performance. This method aligns with the principles of conditioning, where the goal is to enhance fitness progressively and safely, making it an essential component of a horse's overall training program.