I’ve raced enough to know a truth that nobody puts on a recruiting brochure: the difference between a good race and a great one is almost never about your legs. It’s about what’s happening between your ears in the last 200 meters, when everything in your body is begging you to slow down. That’s the gap I wanted to help close. So I built an app called Relentless: Mental Toughness, alongside developer Rahul Kumar, to put real mental-performance tools in the hands of athletes who need them.

- Real lessons grounded in sports psychology
- Connects athletes with mental-performance coaches
- Puts coaches in front of qualified leads
- Built with developer Rahul Kumar
The Problem I Kept Running Into
Here’s the thing about sports psychology. Almost every athlete I talk to agrees it’s important. Coaches preach it. The best performers in every sport swear by it. And yet, when it comes time to actually get coached on the mental side, most athletes have no idea where to start.
The resources are scattered, the qualified professionals are hard to find, and a lot of what’s out there is generic motivation that doesn’t hold up when you’re actually standing on the line. Mental coaching can feel like this thing reserved for pros with budgets and connections, not for the high schooler or college athlete grinding through a season on their own.
There’s a second half to this problem, and it’s one I didn’t fully appreciate until I started building. The mental-performance coaches — the real, qualified ones — have the opposite issue. They’re great at what they do, but they struggle to find athletes who actually need them and are ready to commit. You’ve got athletes who can’t find help and coaches who can’t find athletes, and nobody’s connecting the two.
That’s a bridge waiting to be built. So we built it.
What Relentless Actually Does
Relentless does two things, and I tried to keep both of them honest.
First, it gives athletes real lessons grounded in sports psychology. Not fluff, not empty hype — actual frameworks and tools for the mental side of competing. The kind of thing that helps you reframe a bad warm-up, manage pre-race nerves, or stay locked in when the race gets ugly. I wanted it to be the resource I wish I’d had when I was fifteen and just starting to figure out how much of running is mental.
Second, it’s a bridge between athletes and mental-performance coaches. For athletes, that means a path to qualified help instead of a dead end. For coaches, it means a stream of athletes who are genuinely looking for what they offer. Everybody wins, and the connection actually makes sense for both sides.
That dual purpose is the whole point. I didn’t want to build one more app that throws content at you and disappears. I wanted to solve the matching problem — to make it easier for the right athlete and the right coach to find each other.
How Mindset Has Shaped My Own Racing
I don’t build things I haven’t lived. The reason this app matters to me is that the mental side has been the deciding factor in my own career more times than I can count.
When I ran my mile down to 4:01.91, that wasn’t just fitness. That was learning to stay calm when the pace got honest, to trust the work, to keep my head when the voice in my chest wanted me to back off. Some of my most important races came down to a single decision in a single moment — and that decision is a skill you can train, the same way you train a workout.
I’ve written before about a race that reminded me who I am, because that’s exactly the kind of mental turning point I’m talking about. The races that change you are rarely the ones where your body felt great. They’re the ones where your mind refused to quit. That’s the muscle Relentless is built to train.
Download Relentless
If you’re an athlete who’s tired of being told mental toughness matters without anyone showing you how to build it — this is for you. And if you’re a coach in the mental-performance space, I’d love for you to be part of it too.
You can learn more at relentlessmentaltoughness.com or download it straight from the App Store.
Building this is part of a bigger thing I’m doing — combining what I’ve learned as an athlete with the products and businesses I want to create. If you want to know more about that side of me, my about page tells the story, and you can always reach out if you want to connect. Stay relentless.
- Subscribe on YouTube for race vlogs, training, and the build.
- Follow me on Instagram and TikTok for daily behind-the-scenes.
- Download Relentless: Mental Toughness on the App Store.
- Brands: reach out at trentonsandler@gmail.com or via my Connect page.
Want More?
Follow along with my journey as a D1 distance runner, content creator, and entrepreneur. New content every week across YouTube, Instagram, TikTok, and this blog.
