TREELINE
ENDURANCE
run • roads • trails • ultra

Run Faster. Train Smarter.
Race like you mean it.

UESCA-certified coaching for athletes who want a plan built around their life, not a template pulled off the internet.

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No pressure, no sales pitch. Just a real conversation about your goals and whether we're the right fit.

200+ Athletes Coached • 100 Mile Finishers • Boston Marathon Qualifiers • TrainingPeaks Coach

Why Athletes Trust Treeline

Treeline's coaching philosophy has been featured by Outside and experienced firsthand by Believe in the Run, highlighting both the expertise behind our coaching and the results it delivers.

Outside Magazine

Read the Outside article →

David J. (World Majors Finisher)

"Greg is an excellent, informed listener who has the skills and patience to get to know me, and to then provide targeted assistance to help me improve my running."

Will B. (100k Finisher)

"Working with Treeline Endurance has hands-down been the best decision I've made for my training."

Mac L. (Sub 4 hr marathon finisher)

"I crushed my first-ever marathon thanks to Greg. His passion and knowledge as a coach is unmatched and makes you realize how far you can push yourself."

Train with Us

Running

Ultrarunning

Nutrition

Book Your Free Consult

No pressure, no sales pitch. Just a real conversation about your goals and whether we're the right fit.

$50/month

Custom Training Plan

Get a custom-built training plan to prepare for your next event, reach a new goal, or develop your base fitness. 3 months minimum.

Build My Plan

$229/month

Silver Coaching

1:1 Coaching Subscription.

Receive a custom built training plan, with bi-weekly plan adjustments, personalized feedback on key workouts, unlimited emails, access to the Treeline Endurance Core Community, and monthly phone calls with your coach.

Book Coach Call

$359/month

Gold Coaching Unlimited

1:1 Coaching Subscription.

Our highest level of coaching. Receive a custom built training plan, supported with unlimited plan adjustments, personalized feedback on every workout, unlimited emails with your coach, access the the Treeline Endurance Core Community, and unlimited phone calls with your coach.

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Latest on the Blog

I Kept Losing Toenails. Here’s What I Learned About Shoe Sizing for Ultras.

If you’ve run long enough, you already know this: your feet at mile 5 are not the same feet at mile 45. After a series of races that absolutely trashed my feet, I decided to dig into what's actually happening during long efforts. How do blisters really form? Why does a shoe that feels fine in training fall apart on race day? What actually matters when picking the right fit?

Shaelyn Marshall

May 137 min read

2025 Treeline Endurance Book List Cover Image

The 2025 Treeline Endurance Book List

One of the things that drove me to coaching years ago was how the learning process has no end. New ideas, perspectives, and data are always emerging. Along that grain, I know it's been a good year when I feel like I see the world in a slightly different light than when the year started. I found that these titles added perspective. Perhaps next year one or two of them can widen yours as well. Here's our 2025 book list.