Where to start with the incredible Junko Kazukawa? This two-time breast cancer survivor is an ultrarunning legend with twenty-one 100-mile ultras in the bank, multiple 50-mile finishes and a road marathon PB of 3:20 – and at 59 years old, she’s not stopping yet!

In 2015, at the age of 52, Japanese-born Junko was the first person to complete both America’s ultrarunning Grand Slam and the full Leadville race Series in one season. To break this incredible achievement down, within a four-month period, Junko completed the Western States 100 Run, Vermont 100 Run, Wasatch Front 100 Run, and the Leadville 100, alongside the Leadville Marathon, 50-mile run, 10K run and the Leadville 50-mile and 100-mile Mountain Bike events. Amazing. 

Junko’s running CV is vast, but notable mentions include her finishes at the UTMB, Ultra Trail Mount Fuji, and the Ultra Fiord Patagonia, where she was the second woman to cross the line. Thankfully for the American ultrarunning community, Junko shows no signs of stopping anytime soon. In fact, check out her 2023/24 plans in our interview below. Junko also shares how her second breast cancer diagnosis led her to take on her first 100-mile event, and we cover her training, race strategies, and her endurance running coaching business, which she runs from her home in Denver, Colorado.

You were a keen road marathon runner before you moved into ultra-trail and even completed the NYC marathon five weeks after finishing chemotherapy. What made you sign up for your first 100-mile race, the Leadville 100, in 2011?
I was diagnosed with breast cancer in 2005 and was lucky it was detected early. The treatment was a lumpectomy and radiation treatment. I recovered fairly quickly and returned to running. However, in 2009, I found another lump. The resulting mastectomy and chemotherapy, which made me sick, took a long time from which to recover.  

I could not believe that I had been diagnosed with breast cancer twice, as I thought I had been a healthy and fit person all my life. The second episode of cancer made me think that anything can happen in life and that life can be short, so I should try the things I want to do while I can. At that point, I decided to challenge myself to run the Leadville 100, and to make this race special and meaningful for me, I raised money for the Susan G. Women Foundation (a breast cancer foundation in the US). This was my first 100 miler story in 2011.

How did you find your first 100-mile event?
I live in Denver, Colorado and always enjoyed hiking up the many mountain trails, including those in Leadville, before I began running on the trails. While I was training for the Leadville 100 mountain bike race back in the day, I learned there is a 100-mile foot race running through the mountain trail in Leadville. I thought it was a crazy thing that people run 100 miles on mountain trails, with high altitudes and lots of vertical climbing, but at the same time, I was excited about the prospect of attempting it! In the back of my mind, I thought I would love to challenge myself to run that “SOME DAY.” 

My first 100-mile run in Leadville in 2011 was an amazing experience and exceeded my expectations! The briefing for that race was exceptional and included a memorable motivational speech by Ken Chlouber, the race director at that time. I made many great friends there and connected with an amazing trail-running community. I also developed a special emotional attachment to Leadville.  

You’ve since run over twenty 100-mile races, many of which are considered some of the world’s toughest. What is your approach to training for a 100-mile event, and what is your usual nutrition strategy?
I have completed twenty-one 100-mile events, and as of today, I hope to add another couple of 100s this year. My approach to training for a 100-mile event is to plan my training sufficiently ahead of the race (I usually start training at least 8 months ahead); build up fitness and endurance, so I am training injury free; pay attention to my body; and make sure to have rest days. I also make sure to include strength training to support running strong. 

My nutrition strategy includes eating and hydrating well throughout training, so I have the energy to train. For race day, I try to find real foods – usually Japanese rice balls (along with bars and gels) that I have an appetite for during the race. My usual goal is to make sure I nibble small portions throughout the race. If I sweat a lot in hot weather, I make sure to hydrate well and take salt tablets (if needed) to avoid problems.  

In 2015 you were the first person ever to complete the Leadwoman and the ultrarunning Grand Slam in the space of 4 months (wow!). Can you tell us what this period in your life was like? 
I have been establishing different challenges for myself each year since my first 100-mile run challenge after cancer in 2011. In 2014, I finished the Leadwoman (all Leadville MTB + running events in one season) for the first time, and I ran a couple of hundred-mile races and road marathons in the same year. In 2015, I got into the Western States 100 through their lottery (it is hard to get in), which provided the opportunity to do the Grand Slam of ultrarunning. At that point in time, I felt that I had a good chance of finishing these challenges, which in turn generated lots of excitement.  

I decided to sign up to do the Grand Slam and Leadwoman in one season. Some of my friends cautioned that I might crush my body by doing too much, but I had no pressure. I just enjoyed the challenge and training. I was probably in the best condition of my life, as well as mentally tough at that time! I believe that ultra-races require more mental strength once one has the base endurance and fitness.

I trained hard to build up base fitness and endurance and peaked toward the first race of the series, which was the Western States 100 in June. For the Leadwoman series, I did lots of mountain bike training since I’m not a strong biker – I have no technical skills on the bike! Training on the bike made me strong for the run and kept me from beating up my body. After the Western States race, I maintained conditioning and made sure to rest, eat well and stay well-hydrated, keeping my motivation and excitement high throughout the season. I had a great time and loved every minute of training and the races. I had a great season and completed all the races!

You’re often referred to as a very positive person. Do you bring this positivity into your racing mindset? What keeps you going during the challenging moments in an ultra?
I enjoy the challenge of these tough races. As the race gets tough, the more I get excited. I talk to myself sometimes in my head during a tough race, reminding myself that, “I survived through cancer twice, I can do this!” The struggle to finish tough ultra-distance races makes me feel alive and gives me such joy, confidence, and encouragement. 

Importantly, I try to find some great reasons for running each race, which keeps my motivation high and helps me get through tough times.

When you’re in race season, what does a typical week of training look like for you? 
I cross-train a lot. Since I am an older athlete, I need to cross-train to keep my body from breaking down. I mix strength training, hiking, and biking with running. If the race includes lots of elevation gains, I train to climb more verticals. Making sure to get plenty of rest days, I’ll complete two days of back-to-back long runs on the weekend. My weekly base mileage is around 40-50 miles (including my commute run miles) and up to 60-70 miles some weeks. I take a recovery week with easy workouts every three weeks. I also do some training races prior to my “A” race with enough recovery time in between. 

You’re a running coach. Can you tell us about your coaching? 
I love coaching runners to run any distance. Currently, most of my athletes are ultra-runners, and I get especially excited to coach athletes who are running their first ultra-distance. I coach my athletes with an individualized, periodized training plan, with frequent communications to monitor their progress and conditions. I also create a running-specific strength training program to keep their body healthy and strong for running. I have been a strength trainer for a long time, and I am a huge believer in adding strength training to the training calendar. 

What are your hopes and plans for your running in 2023 and beyond? 
My plan for 2023 includes completing the Bighorn 100 and the Leadville 100 Run (my 9th time!), along with some training races, including marathon races, 50 milers, and 100K.

My big challenge for 2024 is the Leadville 100, as my tenth time [racing it] for a total of 1,000 miles. I’m considering doing my third Leadwoman to celebrate those 1,000 miles if I am fit enough… We’ll see… 

What are your favourite items of kit, and are you sponsored by anyone right now?
I wear Altra trail shoes, as they fit my feet so well. I am an ambassador for Nuun hydration and the local running store “BP-RUN-CO” in Denver, CO. I love Patagonia for my own favourite outdoor gear, and I was once featured in one of their storyteller videos!

You can follow Junko via her social media: www.instagram.com/runjunkorun and facebook.com/junko.kazukawa. To learn more about Junko and find out about her running coaching, visit www.Junkomtntraining.com.