Q&A: The Third Question – LSD PacingThe Benefit of Training Slow(er)

Thanks all for your congrats and supportive comments on my 10K PR race report. For your sake I’m going to stop questioning why I run these short races as I inexplicably do well even when I don’t specifically train for them. What I am going to do instead is answer more reader questions…

Over the weekend, I received a question from a reader on marathon training that intrigued me a bit because it addresses something I feel I need to work on in my next training cycle. She asks…So what’s your take on the whole idea behind the long slow distance (LSD) runs. Using all the calculators, etc, they always say to do long runs pretty slow, much slower than I do them. How do you approach your long runs? Do you run them at the prescribed slow pace (30-45+ sec slower than marathon pace) or do you just run by feel and effort? I am never sore after my long runs, and don't quite get down to marathon pace until the end of them, but am I losing the whole idea behind them since I am not getting as much time on my feet?

Well, I did a bit of research on this one because I KNOW I have made similar mistakes in the past. Unless I’m running with a friend who’s slower than me, I always find myself running a lot faster than the recommended pace when I’m out for a long run. Sometimes it’s because it just feels easier to run faster. Other times it’s because I just want to get the torture test over with as quickly as possible. Most of the time though, I have to admit, it’s simply due to laziness and lack of focus on keeping a relaxed pace. Again, I have this addiction to speed sometimes that’s ready hard to get a hold of!

So why is this bad? Why is it not good to do your 20 mile runs at 7:10 pace if your goal pace is 6:52 and your recommended LSD pace is between 7:22 and 8:00 miles? Well, first you have to understand the intended benefits of an LSD, which Pfitzinger outlines here. If I were to incorporate all of these objective into a single theme, it’d be to increase the body’s ability to sustain peak performance for an extended period of time. The key thing to realize is that the LSD is meant to be a constructive, rather than a destructive mechanism of training. What this means is that in the theoretical sense, you are supposed to have more muscle mass at the end of your LSD than at the beginning, which in essence means your body should be actively recovering while you’re running! So if you’re running your long runs at a pace that is faster than your muscle recovery pace, you’re engaging your aerobic system to bring down glycogen and destroying muscle fibers which essentially defeats the purpose of an LSD. Does this make sense? (This is not to be confused with marathon-pace training which is meant to be a hard race simulation type of workout that should be part of the race preparation phase of training and not the endurance building phase which an LSD is meant to be a part of.)

A second reason to keep the effort slow on your LSD is to decrease the necessary recovery time from this workout to the next. What is the point of running an LSD run hard (an oxymoron of sorts?) if it will take you a couple of days to recover and create a hiccup in your marathon training? Again, it goes back to the idea of keeping LSD as a constructive run rather than a destructive one (like intervals and tempo runs)

A third reason why it’s helpful to hold back your pace on LSDs, or so I’ve learned, is to simulate the situation on race day when you must similarly restrain your effort during the early miles even though you’re feeling so great and strong right after the long taper. It’s an opportunity to learn discipline and focus, which as I’ve come to learn, is so very important for success in a long distance race, such as a marathon. Finally, as the mileage increases, from 16 to 18 to 20 to 22 and perhaps 24 miles, the long run pace should feel appropriately hard by the end. If it isn’t, and you find yourself having to fight through the slow pace even after the 20 and 22 miles, your marathon race pace may need some adjusting.

Going forward, my recommendation and my plan for surviving the LSD, is to follow instructions and hold back the pace for the first half before gradually speeding up to about MP +10-20 seconds/mile in the second half. I will probably resort to running with others for the first half in order to keep my heart rate at a conversational pace and running the rest on my own if I want to finish somewhat faster. I can’t and I shouldn’t trust myself to run by effort and feel anymore for these LSD runs.

Thanks to the reader for her question. I hope this was somewhat informative. (For those who would like to know what their appropriate long run pace should be based on your marathon goal and/or a recent race performance, you can plug your numbers in the McMillan Calculator or the Training Calculator at Runners’ World.)