Review of Long Slow Distance Runs for Endurance

In the age of flashy interval sessions and high-tech gadgets, the humble long slow distance (LSD) run might seem old-fashioned. Yet ask any marathoner, ultra-runner, or seasoned coach, and you’ll hear the same advice: the long run is the cornerstone of endurance training. But what exactly makes these slow, often tedious runs so powerful?

What Are LSD Runs?

LSD runs are extended efforts at a conversational pace — usually 60–90 seconds slower per mile than marathon pace. They typically make up one run per week and grow longer as training progresses.

Benefits of LSD Runs

Aerobic Development: Long runs train the heart, lungs, and blood vessels to deliver oxygen efficiently.
Fat Utilization: Teaches the body to burn fat as fuel, sparing glycogen for later stages of races.
Musculoskeletal Adaptation: Strengthens bones, tendons, and ligaments to handle distance.
Mental Endurance: Builds patience, pacing discipline, and resilience against fatigue.
Race Prep: For marathons and ultras, they’re essential to simulate time on feet.

Challenges of LSD Runs

Time Commitment: A 20-mile run can take 3+ hours.
Risk of Overuse: Jumping distance too quickly can lead to stress fractures or tendon injuries.
Monotony: Running slow for hours can be mentally draining.

How to Do Them Right

Build Gradually: Increase distance by no more than 10% per week.
Keep the Pace Easy: If you can’t hold a conversation, you’re going too fast.
Fuel and Hydrate: Practice your race-day nutrition during these runs.
Mix Terrain: Trails can reduce pounding and add variety.

Verdict

The LSD run is an indispensable tool for endurance athletes. While it may lack the thrill of fast intervals, its physiological and psychological benefits can’t be matched. Recreational runners also gain resilience and aerobic base from long runs. Whether you’re aiming for your first half marathon or your tenth ultra, LSD runs are your secret weapon.

- Edward

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