Back-to-Back Long Training Runs: Friend or Foe?


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!


About Author

Pam Smith ran her first trail race in 1992 and started ultra-distance races in 2002, with more than 70 finishes. She was the 2013 Western States champion and holds the Angeles Crest course record. She has been on a total of seven national teams for both the 100km and 24-hour events. Pam is running her seventh Western States 100 in 2018 under the Active Joe sponsorship. She lives in Salem with her husband and two children and she works as a pathologist. More of Pam’s writing can be found on her blog, “The Turtle Path.”


  1. Great article, Pam. I would add only one pro, and go a little more in-depth about the con of making runners more susceptible injury. Pro: back-to-back longs runs are necessary when you are training for a back-to-back long run race, like 3 Days of Syllamo — but only then. Con/injury: Back-to-backs leave you out of balance on the 2nd day, with cardiovascular recovered, and legs still trashed. This is a recipe for catastrophic injury, much as you risk in driving your car on the highway with under-inflated tires. Greater potential for not picking your feet up, because of tired legs; while moving briskly because of recovered cardio, and thus taking a ruinous face-plant at speed. Otherwise, excellent article.

  2. This is really helpful, thank you! I thought I had to run back-to-back long runs but I’ve been struggling with injuries for the past year and something has gone off the rails in my training. I haven’t been able to complete my target distance of 100 miles so have been concerned that I have not had sufficient training, but am open to the suggestion that I’ve been over-training or doing more damage than good with back-to-back long runs (I have put in many long weekends!). Thanks for this very helpful article!

  3. If you are looking to do one day of long training per weekend, then that works for you. But if a runner cannot handle back-to-back long runs without getting injured, that is a great indicator that they are not ready for their longer, more demanding race. Huge fan of back-to-back long runs over here.

    • Good article, and good replies to make one think about their particular situation, or to allow one to rationalize what they may prefer to do rather than what is going to get them the finish they want. The last comment by LB makes a very strong point when it is said that if a runner can’t handle back to back runs, it is an indication that they may not be ready to endure a longer, harder race. All comes down to goals, time allowed, injury and such I know.
      I would rather suffer through one longer day, but my limited experience is showing that the back to back may make me pay for it the next week (which should often be a cycle down/recovery week anyway), I gain more mental and physical strength from it.
      We all have to learn to figure out what works for us to obtain the results we want for ourselves.

  4. Back -to-back long runs were disastrous for me, leading to the hip pain that caused me to limp, and ultimately led me to take several months off of running to recover with strength training and cross training (bike and XC skiing). In the scheme of things, the back-to-back long runs make no sense from a training perspective when considering modulation of training bouts – provide a certain type of stress – and then recover, rather than stress and ‘don’t recover.’