What the Black Canyon 100k taught me about Pacing, Pride and Rhabdo

Last February (2025) I ran the Black Canyon 100k and ended up in the hospital after finishing the race with rhabdomyolysis.

If you’re not familiar with rhabdo, it’s caused by the breakdown of muscles to such an extent the muscles release a substance called myoglobin into the bloodstream, which is something kidneys struggle to filter. In severe cases, it can lead to permanent damage and even organ failure.

To back up a bit, the Black Canyon 100k had been a bucket-list race for me for years. What drew me to the race was the competitive field with it being a Golden Ticket race for the Western States 100 Mile (the oldest 100 mile race in the world), the adventurous point-to-point desert course, and how runnable the trails are.

Despite how poorly this race went, I still believe Black Canyon suits me as a runner. It is runnable, not overly technical, and not a mountain race with massive elevation. With the right training build and better execution, I think I could run a strong 100k there.

Of course my training leading into Black Canyon and how I raced it are exactly why I ended up in the hospital. Training had been going well until about four and a half weeks from race day. I got ahead of myself and stacked several big volume weeks, including multiple 100+ kilometre weeks and one 140 kilometre week. That was my first mistake: increasing mileage too quickly and pretty predictably it led to my usual Achilles flare-up.

My Achilles is always the first thing to show up when I’m doing too much or neglecting regular strength work. And I know from experience this injury is not a “take a couple days off” type of injury. It’s a multi-week problem that usually means not running at all.

The year before I’d bought a used elliptical, which was always been my go-to cross-training back in University. Once I knew I had to take some time off of running, I shifted most of my training to the elliptical. I did a couple of longer sessions that were at least two and a half hours while watching Black Canyon livestream replays to pass the time. For four weeks, the elliptical replaced running almost entirely, and it wasn’t until the day we left for Arizona that my Achilles finally felt okay to run again.

I managed a few short runs on the Black Canyon trails the week leading into the race, but they weren’t going to meaningfully improve my fitness. At best, they just confirmed I could run.

Race morning, I felt surprisingly confident. Before the injury, I’d strung together some of the best training weeks I’d had in years, and I believed I’d held onto most of that fitness aerobically. I thought that on a perfect day, maybe I could run around 8 hours and 20 minutes—roughly five-minute-per-kilometre pace. In hindsight, that was very naive after barely running through January. I also had looser goals in mind: breaking nine hours, breaking ten, and simply completing the distance.

My race plan was to sit near the back of the lead group early and see how I felt. Based on past years, I expected the front to go out in the higher four-minute-per-kilometre range, which should have felt reasonable and controlled. The course also trends downhill the first half of the race, so I expected to be under five-minute pace through 50 km.

What I didn’t expect was how fast the race actually started.

The race begins with a lap around a gravel high school track, and it was chaotic. I didn’t line up aggressively close to the front (I’m not a pro chasing a Golden Ticket) but everyone was jockeying for position like it was a 5k. When we exited the track and hit the road toward the trail, I looked at my watch and saw sub-four-minute pace. I kept getting passed. Less than a kilometre in, I was somewhere around 50th position and wondering what the hell was going on.

I knew the pace was too fast, but I let myself get pulled along anyway. That was one of my biggest mistakes of the day.

Around 9 km in, a long downhill section begins and continues for roughly the next 10 km. It was flowy, fast, and honestly a lot of fun. At one point I was running just behind the lead woman, which was pretty cool. Even though I was running low four-minute pace, I kept telling myself to stay controlled and not hammer the downhills to save my quads for later in the race.

But the damage was happening quicker than I realized. By around 25 km, my quads started to feel fatigued. As the course levelled out, I hoped slowing my pace would allow them to recover. Instead, things continued to deteriorate. By 40 km, I knew I was in trouble. By 45 km, I was fairly certain I’d be dropping at 50k.

I walk-ran into the 50 km aid station and told Emily and Ben, my crew, that I didn’t think I could finish. They didn’t entertain the idea. They reminded me that my final goal was to just finish the damn race. I took in fluids, electrolytes, a gel, stocked up and eventually walked back out of the aid station.

Leaving that aid station was daunting knowing I still had 50 km to go. After about a kilometre of walking, my legs loosened just enough that I could jog again. For about the next 16 km, I managed to mostly keep moving between six and seven minute pace. At the following aid station, several runners were sitting down, clearly struggling and looking like they were going to drop out. I did my best not to look at them. As I headed back out, I heard Ben and Emily cheering (at a no-crew aid station)… they’d gone there because they thought I might be dropping.

By 70 km, I could no longer run downhill at all. Uphills actually hurt less, so I found myself jogging climbs and walking descents. I started setting tiny goals—run for 200 metres, then walk. Sometimes I couldn’t even make the 200m “jog”.

The mental battle for most of the second half of the race became about continuing to move forward and don’t stop. Watching my pace slip toward ten-minute kilometres was almost scarier than the distance remaining. The slower I moved, the longer I knew I’d be out there suffering. Doing mental math in an ultra while completely wrecked is a dangerous place to be mentally.

Hydration and fueling, at least, went mostly according to plan. I ran with two 500 ml handheld bottles, took gels consistently, and was close to my 90 grams of carbs goal per hour through the first half. Even late in the race, when everything had fallen apart, I was still able to get fluids, electrolytes, and calories down. I never felt nauseous and never struggled to eat or drink.

Looking back, I don’t believe hydration or fueling was the primary reason I ended up with rhabdomyolysis. I think the reason I ended up with rhabdomyolysis is because I wasn’t able to actually run for more than 4 weeks before the race to prepare my legs for the pounding of running. Especially for that distance and that much downhill running. On top of that my naive confident running and lack of willingness to run my own pace in the early kilometres of the race did not help.

So I finished the race in 11 hours and 9 minutes. After the race I sat at a picnic table with Emily and Ben and I think I talked about how f*%^!@# hard that was. I somehow got on some warmer clothes and straight leg shuffled my way to the shuttle bus back to our AirBnB.

I think I went to shower pretty soon after getting back to our place and that was the first time in many hours that I kind of felt like peeing. So I went pee and shocked myself when I saw how black my pee was. I actually said out loud something like “uh oh” (probably “oh shit”) which I remember Emily overhearing me from the hall and asking if something was wrong. At that moment I didn’t say anything. I flushed the toilet after taking a moment to stare at my black pee and then asked for Emily to help me into the shower. It was a tub shower and I absolutely could not get into that shower on my own. I couldn’t lift my legs up even the slightest to get over the tub edge and Emily had to help me sit down. In the shower I was definitely questioning my life decisions to get to that point of suffering. 

The next time I peed that night it was quite yellow but normal looking so I felt (wrongly) relieved that I hadn't really hurt myself and didn’t need to rush to a hospital. Somewhere between peeing and showering I started to feel nauseous, which was the beginning of not being able to keep any food or water down for a few days. Emily and I planned to check out Tucson for a few days after the race. We made the drive to Tucson but I spent most of the next few days laying in bed and trying to get any amount of food and water down. I felt bad because Emily really couldn’t do very much and also had to take care of our son Austin with me feeling so crummy.  Each day I kept thinking I would turn a corner and start to devour food and water. That didn’t happen.

We made the flight home the Wednesday after the race. Thursday morning I went to the Strathroy emergency room as I still wasn’t able to keep much food or water down. A nurse took a blood test and pretty quickly they hooked me up to IV fluids. Going to the hospital I knew I probably needed to get on IV fluids, but I thought once I had a bag or two of fluids I’d start to feel much better and be on my way. Obviously not the case, the doctor came to see me not too long after I was on fluids. He asked me if I was familiar with Rhabdomyllosis, which I told him I was aware of it but that I didn’t know much about it. He explained that I was dehydrated and my kidneys were really struggling (my creatinine level was over 1200 and normal for my age is ~50) and my liver was even having a hard time. He turned the IV pump basically to the highest it can go to pump me full of fluids with the goal of flushing out my kidneys. He also told me there was potential for permanent damage, but it was a waiting game to see how much my creatinine levels would come down.

For the next few days I went through bags and bags of IV fluids and my blood was taken regularly to check my kidneys and liver function and my electrolyte balance. My liver responded to fluids pretty quickly, but my kidneys were quite slow to start seeing the numbers go down, which is why I stayed 6 days in the hospital. With all the IV fluids my body swelled up everywhere, which actually became quite uncomfortable and didn’t help with trying to sleep in a hospital room. My creatinine levels were trending down and in the 600s before they let me go home and it took about 4 more weeks visiting my family doctor before my levels were below 100 again. This luckily means I made a full recovery and I didn’t do any permanent damage.

It was a pretty scary experience being in the hospital and not knowing if my kidneys were going to fully recover. I really didn’t think this was something that could happen to me. I had thought with my running background getting rhabdo was pretty unlikely. Obviously I was wrong about that.

The rest of the year running felt different. I wanted to get out for runs, but I really had no motivation or desire to race or train towards anything. I was quite motivated training towards Black Canyon, but I lost that kind of motivation for the rest of the year.

Until recently I had no interest in consuming any sort of trail running content, but it is coming around again. I wasn’t sure if I would ever want to do an Ultra marathon again, but it has become clear to me that I want my revenge. I don’t know what year it will be, but Black Canyon is back on my bucket list. For now though, I’m signed up for Around the Bay 30km in April.

I hope sharing my experience with rhabdomyolysis can help spread some more awareness of what it is and how you can get it. Here are some quick takeaways and pieces of advice from my experience:

• Getting your legs accustomed to the pounding of running is incredibly important for ultramarathons.

• Don’t start an ultramarathon if you’ve been injured for a few weeks before the race. It just won’t be worth it. Pay the extra money if available to cancel your registration and get most of your money back if you can’t get to the start line.

• Stick to your own race plan and be willing to make changes in the race if things don’t go according to plan.

• If your legs are completely trashed half way through a race, you should probably drop out. I’m a competitive person and understand there is a time to push your body to its limits…. But it shouldn’t be for multiple consecutive hours. There is a difference between tired and fatigued legs and muscularly trashed legs.

• Everyone's nutrition and hydration strategies and needs are different, but you probably need more water and electrolytes than you think and you should probably eat some real food. I really only did gels and I should have started eating real food at 50km when my race plan drastically changed

Thanks for reading!

Aaron Hendrikx