I’ve run 7 marathons in 5 years. When I first started training for distance, I had a favorite mantra: all I have to do is finish. I didn’t entertain the possibility that I would quit, but I also didn’t set any strict expectations on myself for finishing times. Instead, I would repeat this phrase: All I have to do is finish. I would say it to myself; I’d say it to my running partners, and I would say it to anyone who willingly listened to me talking about running.

All I have to do is finish.

In some ways, the phrase served as an inoculation against disappointment in any given race. If I went out and finished, I could feel successful.

The phrase served to let me off the hook. It was a shrug of the shoulders, a surrender to slowing down if I wanted to. It was a concession to the inevitable internal doubters, those voices in your head that show up around mile 20 of a marathon telling you to quit. My reply: I won’t quit. All I have to do is finish.

All I have to do is finish as a phrase, for me, became self-limiting. It defined what I could do and provided a justification for not doing more.

I’ve noticed a similar pattern of self-limiting thoughts and behaviors in my business, too. A few years ago, I set a big financial goal for my company.

I didn’t reach it. I didn’t reach it the next year either. Or the year after that. Or this year.

Instead, after growing from nothing to this level-set by the 4th year of my business, I came to accept this plateau. For business, my version of “just finishing” became maintaining a business of a certain size. I figured out, intuitively, what effort, focus, and concentration I needed to invest to maintain “this size.” I told myself that because my business has been “this size,” it must be all I’m capable of.

I wonder if these self-limitations are also a subtle form of self-sabotage. I tell myself I can only run this fast or grow my business to this level and in my saying so, it becomes so.

In my running, at least, I am working to toss aside those self-imposed limits. I’ve started competing — if not with others, at least with myself. I want to improve, and I’m racing against my younger self; I’m racing to beat my own personal best. It’s not enough to finish — I want to train well, race well, and perform at my best in every race.

I entered a marathon earlier this fall with that expectation of myself to run my best. An on-again, off-again runner of 25+ years, I’ve only trained consistently for about 18 months. Because of my consistency, I’ve noticed significant improvements in my endurance and pace.

This time, I threw out the mantra “all I have to do is finish” because it didn’t fit any more. Instead, I focused on pushing as hard as I could, for as long as I could, because I wanted to see what I’m capable of and run my absolute best race.

But when those internal doubters showed up, late in the race, I struggled. I ran most of the last six miles completely alone. When I realized I would likely finish with a new PR even if I slowed down, my mental determination waned. I gave in to my fatigue and pulled back on my pace. I told myself I’d reach my big goal (finishing a marathon under 4 hours) some other day.

I discovered a new mantra — The only way to finish is to keep going. But I failed to hold onto this — the only way to finish strong is to keep running strong.

As I consider who I want to be in the coming year, as a runner, and as a business owner, I’m curious about how I can overcome my self-imposed limitations. How can I push through when things get hard, and overcome my tendency to let myself slow down, settling for lesser achievements? How can I break past the revenue goal I’ve let slip past year after year? What will it take for me to shatter my goal of a marathon under four hours? How do I hold myself accountable and not give in to excuses or crutches?

I know now that  whatever I say to myself in my head influences my performance. When I am able to stay positive and strong, my legs live out the truth my mind is telling them.

At work, when I keep my goals in mind, I dive into my work with a greater intensity. But in running or business, when my thoughts admit defeat, or I give myself a way out, that message finds its way through my body to my limbs, too.

Since those mental messages fuel my outcomes, I need to find a new story, a new mantra,  some gritty self-talk phrase that will keep me pushing strong and determined to reach both my running and my business goals, even when the going gets tough. I’ll need to hold tightly to both my goals, no matter how lofty, and my belief in my capability to reach them. And I’ll need to ruthlessly banish any excuses and tendency to let myself off the hook. I’m realizing now that staying strong does not have to be done alone. I can look to others to help me hold myself accountable (in the business — from my coach and team, and in running from my running teammates) and keep me pushing hard when the road gets tough.

I’m curious. What approaches have you tried to muscle through when perseverance is required? Share in the comments below.