Long slow distance

Long slow distance (LSD) training is a form of aerobic endurance training used in sports like running, cycling, and rowing. It involves continuous, low-to-moderate intensity workouts over extended distances or durations. Physiological benefits include improved cardiovascular function, thermoregulation, mitochondrial energy production, and increased fat utilization for fuel. Ernst van Aaken, a German physician, is credited with developing this method. While effective for undertrained individuals, elite athletes often combine LSD with other training methods, as it may not maximize performance on its own.

The concept of LSD was initially proposed by Arthur Newton in the early 20th century and popularized by Joe Henderson in 1969. Henderson advocated for LSD as a sustainable alternative to high-intensity training, emphasizing long runs at a conversational pace. His approach gained traction, with examples like the Honolulu Marathon Clinic adopting similar strategies. Other practitioners, such as Jeff Galloway, incorporated walk breaks into LSD routines, while Phil Maffetone developed Low Heart Rate Training, which aligns with LSD principles by focusing on aerobic zones.

Despite its popularity, LSD has limitations. Experts like Arthur Lydiard and Pete Pfitzinger argue that varied paces and higher intensities are necessary for advanced runners to achieve specific physiological adaptations. Additionally, high-intensity training is often more effective for building anaerobic capacity. Thus, while LSD remains a valuable tool for building endurance, it is most beneficial when integrated with other training methods.