Breaking the Mold: How Femmi is Revolutionizing Fitness for Women Through Cycle-Aligned Training
In a fitness industry built by and for men, elite runner and coach Lydia O'Donnell (@lydiaodo) is leading a quiet revolution. As co-founder of Femmi, she's addressing a stark reality: 50% of women decrease or stop exercising entirely, often because generic training plans completely ignore female physiology.
O'Donnell's journey to founding Femmi wasn't just professional—it was deeply personal. After years of over-training and underfueling as a young athlete, she developed RED-s (relative energy deficiency syndrome in sport), lost her period, and ended up hospitalized. It wasn't until age 27 that she learned about her own menstrual cycle and female hormones—knowledge that transformed not only her athletic performance but her entire relationship with her body and training.
Today, Femmi's cycle-aligned training approach has generated remarkable results, with 85% of users reporting increased performance. But O'Donnell's mission extends far beyond individual metrics. She's building a movement where women learn to "move in their own way," challenging decades of fitness culture that told women they needed to train like men to succeed.
In this conversation, Lydia shares how understanding female physiology became the foundation for sustainable fitness, why community and empowerment are just as crucial as the science, and her vision for how women can continue reshaping the wellness landscape—one cycle-informed workout at a time.
1. You co-founded Femmi to address a huge gap in the fitness industry — the fact that 50% of women decrease or stop exercise completely, often because generic training plans ignore female physiology. As a woman entrepreneur in wellness, what was the moment you realized this needed to change, and how has building Femmi shaped your understanding of what women really need from wellness and fitness?
Femmi was founded by my best friend, Esther, and myself based on our own lived experiences as female athletes. We both very much struggled in a system built for men by men, and unknowingly fell into over-training and underfueling behaviors at a young age, due to two major factors. One being the lack of education we had on our own female physiology, including the impact of our menstrual cycles, and the second being the narrative that the sports and fitness industry was feeding women - this narrative being that our performance (and worth) was tied to our appearance.
After many years of disordered eating and body image issues, I fell into a state of RED-s (relative energy deficiency syndrome in sport), lost my period completely and ended up in hospital. Having to step away from my sport I realized that the way I was training was unsustainable and change needed to be made.
I learnt about my menstrual cycle and my female hormones when I was 27 years old and this learning changed my life. I learnt that having a regular cycle and period was actually incredibly beneficial for both my health and my performance as an athlete, and that in order to run I needed to fuel accordingly to my training.
At Femmi we have proven that confidence comes from showing up and doing hard things over and over again.
At that time, as a coach of 8 years, I teamed up with Esther and we built Femmi as a way to educate and coach women to the unique needs of their female physiology, including their psychology, and began our mission to empower women all over the world through sustainable movement.
What we have witnessed over the last 5 years with Femmi has been incredibly eye-opening, not just to us, but to the running world, and the fitness industry as a whole. No longer do women think they need to train like a man to be successful, no longer do women think that ignoring their cycle is going to benefit their performance, and no longer do women think that counting calories is going to improve their self worth. At Femmi we have proven that confidence comes from showing up and doing hard things over and over again. But the consistency can only come from training that is personalized to the individual women with adaptations to her physiology.
2. Femmi's cycle-aligned training approach is revolutionary, with 85% of users reporting increased performance. As an elite runner yourself, how do you balance the scientific, evidence-based side of female physiology with the community and empowerment aspects that seem equally central to your mission? What role do you think women play in redefining fitness culture?
Our entire mission is about empowering more women to have a sustainable relationship with exercise, and with running in particular. We understand that every woman is different, and their motivation to exercise is all driven by various internal and external factors.
We have women in the community who are incredibly self driven and are focused on race results and times, whereas we have a huge audience of women who are purely driven to run to connect to others and feel like they are part of a much bigger movement.
Sustainability comes through finding that motivation and honing into it.
I believe there is no better feeling than being connected to an army of women who are simply there to support you.
Our community who is driven by constantly chasing performance progress is able to access the most personalized and female centered running programming in the world, giving them the best guidance to run consistently and reach their goals. We have run plans for those wanting to chase 5k-marathon startlines, as well as more fluid goals, such as wanting to get stronger or build a stronger base.
At Femmi, and even as an elite athlete, I believe there is no better feeling than being connected to an army of women who are simply there to support you. Traditionally women have been pinned up against one another due to the limited opportunities we have had in the past, but times have changed and now there is space for everyone. This shift in pushing each other forward as women is evident at the Femmi communities, as we all support one another's ambitious goals and celebrate one another's successes.
As we have become such a collective, not only do we feel more empowered, we have a much bigger voice to drive change in the fitness industry. We call out when things aren’t fair, we push back on gender inequalities and we crush down ‘once-thought-of-as-taboo’ conversations.
3. You've created more than just a running app — you've built a movement where women are "learning to move in their own way." As a female founder in the wellness space, how do you see technology's role in empowering women's relationship with their bodies and fitness? What advice would you give to other women looking to challenge the status quo in wellness and sport?
The impact of technology on our relationship with both ourselves, our sport and our bodies is deeply under-estimated. We are living in a world where we are constantly connected to a digital realm, yet most of that digital landscape, including social media tools and fitness platforms, have been designed for and by men.
Technology that gives women the space to explore, express, and understand themselves, and their needs - has the power to transform how we see ourselves and our place in the world.
When we understand what truly makes a woman feel confident in her own skin, from how she trains to the words she needs to hear to stay motivated, we can help her to build a stronger, more positive relationship with herself. And that confidence doesn't stay isolated; it radiates into every part of her life, reshaping how she shows up in the world.
This is even more so why a technology like Femmi is needed and why I hope to see more women-led innovation shaping the future.
Innovating in an industry long shaped by a male mindset, one rooted in competition, comparison, aesthetics, and toughness, is no easy task. Challenging the traditional, male-centric approach to training felt risky at first. But the thousands of women who have backed Femmi from the beginning have given us the confidence to keep pushing forward - to keep creating tools that truly support how women want to feel in their training, and in themselves.
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