Long Slow Distance (LSD) for Endurance

by Jeff Godin, Phd.D., CSCS

Director of Spartan Coaching

In recent years there has been a focus on High Intensity Interval Training (or HIIT) to improve anaerobic and aerobic capacity concomitantly. One of the earliest studies to show this was conducted in 1996 by researchers at The National Institute for Fitness and Sports in Japan.  This study showed that moderate-intensity aerobic training improved maximal aerobic power but did not change anaerobic capacity and that high-intensity intermittent training improved both anaerobic and aerobic energy systems significantly. This change was most likely due to imposing intensive stimuli on both systems. A year later, research out of McMasters University in Canada corroborated these findings and showed that HIIT improved aerobic enzyme activity. Since then much more research has come out confirming early findings with other populations including women and trained athletes.

Although the method is proven and it is a time efficient method of training, I think we have lost our appreciation for Long Slow Distance (LSD) aerobic training. CrossFit nation has just let out a collective sigh. But wait… I haven’t finished, I think we can all get along.

The idea for this blog came about during the Ultra Beast and Beast race a few weeks ago in Killington, VT. As I was trucking up the last big climb, I came across a number of very fit appearing athletes who were clearly exhausted by 5-6 hours of continuous exercise. They had the power to barrel through obstacles, but lacked the endurance to keep up the intensity for more than a few hours. The Super Spartan and Beast requires athletes to go long at a submaximal pace.

Those studies that show HIIT improves aerobic capacity focus on VO2max as the variable of interest. Although this is an important parameter for predicting aerobic performance, it isn’t the only one, and in fact aerobic efficiency may be more important. By aerobic efficiency we mean consuming less oxygen or expending less energy for a given amount of work. The best way to develop efficiency is through LSD training. If you look at the training plans of some elite endurance athletes, the majority of their training (80%) is made up of this type of training.


I am not suggesting that we follow this path, rather suggesting that most Spartan racers would see huge gains in their performance if they would include some more LSD training into their programs. For most people, an hour of steady state submaximal running twice per week would satisfy this need. For athletes racing in the Beast, at least once a week they should build up their running time to 3 hours. For the well trained athlete, they could even do a HIIT workout followed by a LSD run.

I think the biggest complaint against LSD training is boredom. I cure this problem by running the trails, or by hiking mountains. The change in scenery and constant undulations in the terrain seem to make time go by faster. Buy a headlamp and try running the trails at night or early morning. The darkness and low visibility force you to go slower, and being in the woods in the dark adds an element of excitement. Don’t go alone though, and make sure you know your way around. I love HIIT training, but it needs to be accompanied by LSD training in order to promote long distance endurance. Rock hard abs won’t get you to the top of the mountain. Get at it!

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8 Responses

  1. avatar

    Great article!

  2. avatar

    During first Spartan race in Ottawa 2 years ago we ran up the ski hill. Five times. It was +30 at 10am. Good to read about LSD training. For winter trainers… great time to practise crawling, as the snow provides both resistance and cushioning!

  3. avatar

    I couldn’t agree more. I did the beast in Vermont. I’m exactly what you are talking about when you talk about a fit looking guy running out of gas . Although I hadn’t slept in 2 days due to a family emergency, I still realize that my half hour crossfit workouts were just probably appropriate for a sprint distance only. I also did two five milers a week while training. Defiantly not enough. I plowed through the obstacles, except for the Tarzan swing under the bridge,with ease. It was the total time and distance that wre me out. No my training for next years sounds a lot like your recommending. I’m at three long runs a week, adding a mile and a lb to my pack every week for now, plus a lot more lightweight met ones such as filthy fifty and fight gone bad. Perhaps everyone needs to work on something different. But I can’t not stress the need for LSD cardio and hills hills hills. Next year I plan to run every bit of that race uphill and down!

  4. avatar

    If we do our LSD as fast as we can but still for a long duration (hour and more) are we helping our aerobic endurance? Or does it absolutely need to be slow…? I ask because at the moment I am replacing my runs with cross-country ski runs and I find its too cold to go slowly.

    • avatar

      Ideally it should be completely aerobic. With skiing the action of the arms will increase heart rate above the aerobic zone, but the muscles will still be aerobic. Keep it at a pace where you aren’t out of breath

  5. avatar

    Great article. The Beast in Killington was my first ever obstacle race, and though I was too intimidated to sign up for the Elite race, I was fourth in the competitive race and beat all but 13 of the folks in the Elite race. I am a runner and almost everything I do is LSD (though interested in being more well rounded, hence my attraction to this race). Runners will always dominate these longer races (not me, too old to dominate), and it might be more fair to have a championship event be a more neutral distance to level the field between the runner warriors and the beefy warriors. We’re all warriors, just with different specialties. Now I am getting ready for something way harder than the Beast, the Vermont snowshoe marathon dreamed up by the same sickos who started the spartan series.

  6. avatar

    I’m glad you wrote this. I’ve been training for my next race and I’m doing this and have seen huge improvements in my endurance.

  7. avatar

    I agree 100%….LSD is as much about training your mind as it is about training your body. Your mind will fail you long before your legs… LSD is the only way to win the mental battle… the “what the hell am I going to think about for 3-5 hours” battle… LSD is the glue that binds your training together.

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