BOSS, the ultimate cross-training, a revelation

“Never again would I look at a hiker with a backpack and think, meh, that is just walking!”

That’s what I wrote in a post I’d published after my 2023 BOSS (Boulder Outdoor Survival School) 14-Day Field Expedition course in southern Utah. In preparing for the course, being a long-distance runner, I’d thought I had both the physical and mental parts of the course covered. It turned out the mental part was fine. But, the physical part was definitely not! It was a lesson-learned that should not have been one. Because of course I knew about the importance of training specificity: to prepare for a lot of hiking with a loaded backpack, I need to train by hiking a lot with a loaded backpack. Duh!

The “revelation” in the title of this current post came in the training for my 2024 BOSS 14-Day Primitive Living Intensive course. (This post is the latest in the “BOSS, the ultimate cross-training” series that I’d begun after my first BOSS course, a 7-Day Field Expedition, in 2015. See part 1, part 2 (physical), part 3 (mental), part 4 (spiritual), and a community.) With the 2023 BOSS experience still etched in my mind, I scheduled several training hikes with a loaded backpack in the weeks before the 2024 course. For the first morning hike, it was yet another lesson-learned that should not have been one: I went out too fast and I went too far. And I barely made it back home. For the rest of the day, I could hardly walk, even on flat surfaces. Stairs were painfully slow. It was like nothing I’d ever felt after marathons. And I had a 5-mile run scheduled for the next morning.

With the legs still very fatigued in the morning, I decided to try doing my run anyway. I did my usual indoor warm-up routine, went to the bathroom, donned my running gear, hobbled to the end of my driveway by the street, and waited for my heart rate to drop below the usual threshold. All this time, I was thinking that I would just run a few steps, and, mostly likely, the legs would complain so much that I’d have to turn around and go back home. I started my watch and began running and, whoa! What?! Nothing--I felt practically nothing! My legs felt almost completely normal! There was none of the fatigue I was just feeling while walking down the driveway. Astonished, fascinated, and puzzled, I did the entire run with a big grin on my face. But, that’s not the end of the story. I finished the five miles, jogged a few steps, slowed down to a walk, and, bang, I was hobbling again … Huh?!

So, at least from my personal experience, it seems the usage of the leg muscles is very different between running and walking. I’ve just started looking into the literature about the underlying physiological reasons for this difference. So far, I’ve not come across any study that clearly confirms my experience. Here’s one, on “Differences in muscle function during walking and running at the same speed” (in Journal of Biomechanics). Except for the soleus (back part of the calf), “[a]ll other muscle groups distributed mechanical power among the body segments and provided support and forward propulsion in a qualitatively similar manner in both walking and running.” For me, though, the main fatigue was not in the soleus.

Whatever the reason for my experiencing a much greater difference between running and walking, this difference is directly relevant to cross training, especially for endurance running on trails with large vertical elevation differences. Training for one strengthens performance in the other. And, this difference reinforces why training specificity is so important. For that 7-Day course, I got away with relying on just my running. For that 14-Day course, not so much. And, for a 28-Day course, the “standard” BOSS field expedition course, no freaking way!

I’m currently tapering in my training for the upcoming 28-Day course.  I adapted my favorite marathon training plan, the one that helped me run my PR and first BQ. Basically, I replaced two of the weekly runs with hikes of increasing distances and backpack weights, and of varying elevations and terrain surface types (of trails and cross-country).

Because hiking with a loaded backpack is definitely not just walking!