Rookie of the Year Mal O’Brien Opens Up About Lyme Disease

September 14, 2021

Nicole Peyton

At just 17, O'Brien exemplifies resilience and determination — and she's just getting started.

Top-ranked CrossFit athletes have dialed in everything from sleep, to nutrition, to recovery. As the sport has continued to evolve, numerous CrossFit Games athletes report that even the most minute details make a big difference in their training and success as the field of competitors improves each year. Five-time fittest Man on Earth Mat Fraser wakes up with a sunlight alarm clock. Reigning Fittest Woman on Earth Tia-Clair Toomey has a gratitude practice. Details matter. 

When an athlete endures an injury, illness, or ailment, it’s essential to their longevity in the sport of CrossFit that they give special care to the details when approaching recovery. This is especially true if they are hit with a potentially chronic illness of which the effects can linger for months or even years after treatment.

Headaches, joint pain, and extreme fatigue can be fatal when it comes to the career of an aspiring CrossFit Games athlete and are just a few of the debilitating effects of Lyme disease. Living with the tick-borne illness has been described by survivors as inhumane, painful, surreal, exhausting, and isolating. 

“Back when my symptoms were at their worst, I wasn’t functioning well overall, at all,” seventh-fittest woman on Earth Mallory O’Brien said. 

The 17-year-old was diagnosed with Lyme disease in 2020 after a long road of blood tests, MRIs, CT scans, and stress tests, all of which yielded no answers. 

“I had a lot of different issues going on, none of which seemed related, and I think that’s why the doctors had so much trouble coming up with a diagnosis,” O’Brien said. “The symptoms that were affecting me the most were headaches and exhaustion. The headaches were severe, daily, and lasting all day.”

Lyme disease can be difficult to diagnose as the typical symptoms mimic other conditions such as fibromyalgia, chronic fatigue syndrome, and Parkinson’s and Alzheimer’s diseases. Eventually, with much perseverance and the help and support of her family, O’Brien was correctly diagnosed and received treatment to begin the recovery process. 

“After over a year of going to different doctors and specialists trying to diagnose my symptoms, I learned in early 2020 that I had Lyme disease,” O’Brien said. “I received treatment for Lyme in the spring of 2020, and it has changed my life for the better.”

Just more than a year after her diagnosis, O’Brien was named Rookie of the Year after a most impressive performance at the 2021 NOBULL CrossFit Games, proving her resilience alongside exceptional motivation, determination, and dedication. 

Early Years

An athlete since the age of 3, O’Brien said her competitive drive developed while she was in childhood gymnastics. Being an active kid laid the foundation for her success in athletics. 

“When you start competitive gymnastics at such a young age, the coaches are immediately hard on you, and that’s something I grew up with in the sport of gymnastics,” she said. 

As many children do, O’Brien eventually got bored and decided she wanted to try something new. She dabbled in a few other sports before finally finding CrossFit. 

“I’ve always been super active,” she said. “I did volleyball, track, and dance.”

When O’Brien was 10, her mom brought her to CrossFit Max Oxygen in Des Moines, Iowa, to participate in what O’Brien called “the moms class.” O’Brien took to the training right away and knew she had found something special. 

“I loved (CrossFit). The coaches saw a lot of potential in me just from the drive I had from childhood gymnastics,” she said. “I had that competitive mindset already … so I just took it from there.”

O'Brien at the 2021 NOBULL CrossFit Games

It wasn’t long before she realized she wanted to compete in the sport of CrossFit, and she got right to work, seeking out the help of former Games athlete Elijah Muahmmad to coach her. 

O’Brien had lofty goals. 

“When I realized I could qualify for the CrossFit Games at 14 years old, that became my goal,” she said.

At just 12, O’Brien began to compete in online qualifiers such as Wodapalooza, and by 14 she had realized her goal, making her CrossFit Games debut in 2018 in the Girls 14-15 division. O’Brien took fourth that year, earning four top-five finishes over the course of the competition.

O’Brien’s health issues worsened in 2019 as symptoms of Lyme disease became more apparent, and the teenage athlete took the following year off from training and competing to focus on her mental and physical wellness.


For more than a year, O’Brien suffered from severe headaches and exhaustion before she was diagnosed with Lyme disease. She recalled having two tick bites around ages 10 or 11, but it wasn’t until right before the 2019 CrossFit Open, when she was 15, that she started feeling the effects of the disease. O’Brien said she felt overtrained and underfueled, both of which exacerbated her worsening symptoms. Still, she came fifth at the Games that year in the Girls 14-15 division. 

“I was definitely underfueling my training (in 2019). I train longer days now than I did then, but I’ve developed a greater understanding of fueling to perform and to sustain my training blocks,” O’Brien said. 

Unable to train as she was accustomed to, let alone compete in 2020, she made the wise decision to pull back the throttle, and allow her body and mind time to recover.

As a young athlete with so much potential and an entire career ahead of her, Lyme disease could have severely derailed O’Brien’s trajectory. She also suffered from body-image issues at the same time, she said, which lent to her inclination to overtrain. 

But a combination of focused treatment, sound nutrition, and functional fitness have helped O’Brien keep Lyme disease under control and allowed her to thrive against the odds in a physically demanding sport.  

“I became very aware of how nutrition and vitamins can heal our bodies and learned to look at food labels so that I know what I’m putting into my body. I’m really into healing my body naturally now, and understanding the science behind nutrition and natural medicine,” O’Brien said. “CrossFit was my outlet. … Even if I wasn’t physically up to training at the capacity I wanted to, just being in the gym trying to do what I could motivated me to not give up on finding an answer to what was happening to my body.”

Today, O’Brien works with M2 Performance Nutrition and said her mindset around food as fuel has greatly shifted. 

“I eat a ton year round. I know that I’m fueled, and I feel healthy and happy,” she said. “I sleep well … I’m not worried about overtraining now because I know what that feels like already. If I ever feel like I’m overtraining I know to take a step back, but I haven’t felt like that since I’ve been with James and M2.”

O'Brien at the 2021 NOBULL CrossFit Games

Her mentality around body image has greatly improved as well. 

“I just came to accept that it was OK to be muscular and not be ashamed of my strength because this very body allows me to do what I love: CrossFit,” O’Brien said. “I don’t compare my body to other athletes or peers because we all are different, and all have our own journeys. If I don’t fuel my body to perform, then I can’t reasonably expect the results I want, so I listen to my nutrition coach, and it works!”

Rookie of the Year

O’Brien wanted to start from scratch in 2021. After all the struggles she endured the year prior, she was ready to take on the season with a new coach and a fresh outlook on her health and wellness. 

She now had a solid grip on how to properly fuel her body so she could thrive in the sport she loved. 

She began working with James Townsend at Lion Brave CrossFit in Clive, Iowa, and the partnership-turned-friendship is a great match, O’Brien said. Coupled with her year off, the fresh coaching has catapulted her into the top ranks of CrossFit competition. 

O’Brien earned her 2021 Games ticket to the Teenage Girls 16-17 division after placing first in her division in the Age Group Online Qualifier. And while she could have likely dominated her division at the Games, she wanted to compete with the top individual women of the sport — so she took on the 2021 Granite Games Semifinal event, where she placed second and qualified for the individual competition at the CrossFit Games.

“The (Granite Games) were one of the big highlights of this year for me,” O’Brien said. “I went into the competition not knowing what to expect.” 

O’Brien remembered comments from social media and CrossFit Games commentators complimenting her ability to perform in her gym but questioning how she’d fare on the field. 

“That was in my head, but I knew I was fit enough to do it … I went into the Granite Games without any expectations,” she said.

After such an impressive lead-up to the Games, O’Brien’s individual Games debut was highly anticipated, and she said she could feel the pressure. 

“I think that’s going to be a huge lesson learned heading into 2022 — no matter the pressure, I’m still going to perform how I want to and how I know I can,” she said.

O’Brien shone more than once in Madison, Wisconsin, but perhaps her most impressive performance came on Day 1. Four-time reigning and defending champion Tia-Clair Toomey had swept the first three events, and heading into Event 4, a couplet of wall walks and heavy thrusters, Toomey was looking to make history by becoming the first athlete to ever close out a perfect Day 1.

O’Brien had other plans.

Known for her wall-walking prowess after taking fourth in the world in Open Workout 21.1, O’Brien attacked Event 4 from the start. She and Toomey traded the lead for the first half, but O’Brien’s unbroken thrusters and flawless wall walks helped her pull ahead inch by inch. Soon she found herself out front, all by herself on the Coliseum floor at the Alliant Energy Center. 

Beating the champ by more than 34 seconds, O’Brien won the event and became the youngest CrossFit Games individual event winner in history. 

The rest of the weekend saw O’Brien earn five more top-10 finishes, and at the closing ceremony, she was named Rookie of the Year for her performance. O’Brien was recognized as having exceeded the accomplishments of former rookies by qualifying for the individual competition while still eligible for the teenage division. 

“(Becoming Rookie of the Year) was one of the most special moments of the Games for me,” she said. “How we act off the competition floor really matters when it comes to that award, and I think they could tell how I was treating others outside of the competition.”

O’Brien’s motivation, determination, and dedication have helped her achieve big goals at a young age, and it appears there’s no stopping her. She has demonstrated an enormous amount of resilience in her recovery from Lyme disease, and she has a few words of encouragement for anyone suffering from the disease and losing hope.

“Never give up! I was told so many times that there was nothing wrong with me, or that they couldn’t explain my symptoms,” O’Brien said. “It felt like no one was listening. My mom and I became obsessed with finding an answer. We knew there was no way this was not explainable. Trust your instincts. You know your body better than anyone! Find a doctor that listens to you and is committed to helping you.”