Gearing up for a longer ultra, such as a 100k or a 100-miler requires a dedicated training plan with particular focus on getting more miles and more time on feet. One way to accomplish this is with back-to-back long runs. Back-to-back long runs refers to doing long runs on two consecutive days, typically Saturday and Sunday for those with full-time jobs. Back-to-back long runs are a common practice in ultra training, but are they really necessary for success? That’s up for debate in this month’s column!
Heads (Pros): When it comes to high mileage and lots of time on feet, nothing checks the box faster than back-to-back long runs. These runs give ultrarunners a chance to test nutrition and gear to help figure out what is going to work for the long haul on race day. But the real goal of these runs is to teach people to run on tired legs. After the first day of running, one is understandably tired yet must find the physical and mental strength to make it through another long run on the next day. This feeling of fatigue is meant to mimic the late stages of a race and help you get through those final tough miles before the finish. Beyond the physical training, these back-to-back runs impart a good deal of mental training, too, requiring one to find an extra dose of grit to finish the intended distance the second day. Successfully completing a hard back-to-back effort instills a good deal of confidence, which is another mental component that will serve you well come race day.
Tails (Cons): Back-to-back long runs are quite stressful and can take a major toll on the body. This type of effort takes longer to recover from not to mention running while fatigued puts you at risk for injury. If only running long one day a week, that long run can be somewhat longer than either of the two individual runs in a back-to-back, which is more similar to race day conditions. And the longer a run gets, the more problems are likely to arise, requiring you to work on your troubleshooting skills in training. This is especially true for GI issues which tend to exacerbate the longer you go. Two back-to-back 18-milers may not cause any GI issues or be short enough that you can “cheat” your eating and drinking plan and still finish strong each day, but this is less likely to be the case in a single 30-mile run, meaning you really have to practice those race day nutrition strategies. More practical reasons to stick to a single long run include lifestyle and overall enjoyment. If you’ve got a family or any interests outside of running, it is nice to not sacrifice your entire weekend for ultra training! And running while fatigued may be good mental training but it can certainly suck the joy right out of running and leave you feeling less enthusiastic about the rest of your training.
My Two Cents: While back-to-back long runs can pay physical and mental dividends, the overall emotional and physical toll is also quite high. As a mom with two kids and a husband, I always felt it was important to have one of my weekend days that wasn’t completely consumed by running to spend time with the family and to give my husband a chance to pursue his own activities. I never felt like I was scrimping on my training because I always felt I could get everything I needed out of one longer run; mileage, time on feet, nutrition practice and gear testing can all be addressed with a single weekly long run. And as much as I love running, I think I would’ve burned out pretty fast if I were doing a lot of back-to-backs. Certainly, the rest of my weekly training would’ve suffered if I was already in a deep hole come Monday morning!
I don’t think it is ever necessary to add back-to-back long runs into a successful training program. I would particularly advise against back-to-backs for those who have trouble with GI issues; one long run forces you to be more diligent with nutrition and is a better test of how your stomach will hold up. I also think anyone struggling with injury or low motivation should avoid the back-to-backs.
However, for those who have weathered a few ultra training cycles successfully and want to take their training to the next level, back-to-back long runs – used sparingly and with plenty of scheduled recovery – may be just the thing to do the trick!