Endurance Performance Coaching, Sports Nutrition and Bike Fitting Designed to Help You Perform at Your Best
Helping athletes Become Stronger, Healthier,
and More Resilient.
Coaching and Sports Nutrition Consulting Backed by Experience and Science
Most coaches focus only on training.
Most dietitians focus only on nutrition.
Most bike fitters focus only on the bike.
At Trimarni, we do it all.
With more than 20 years of endurance racing experience and professional expertise, we take a fully integrated approach to performance, combining coaching, fueling, and bike optimization to help athletes train smarter, perform stronger, and race with confidence.
Our
Services
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Sports Nutrition
Fuel for performance, health and recovery.
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Bike Fit and Optimization
Precision fitting for comfort, power, and efficiency.
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Training Plans
Strategic programming for your next starting line.
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Coaching
Coaching tailored to your goals and lifestyle.
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Training Camp
Train smarter alongside expert coaching.
Train Smarter. Fuel Better. Perform Stronger.
Let us help you improve your Athletic performance
At Trimarni we combine structured coaching, bike fitting and personalized nutrition to help endurance athletes:
● Improve performance without burnout and minimizing risk for injury
● Nourish the body and fuel properly for training and racing
● Build strength, endurance, and resilience
● Stay healthy while stretching the comfort zone
● Optimize cycling aerodynamics, comfort, speed and power
Our
Team
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Marni Sumbal MS, RD, CSSD, LD/N
Owner and founder of Trimarni
Greenville, SCBoard Certified Sport Dietitian
Master of Science in Exercise Physiology
USAT Certified Coach (20-years)
Owner of Trimarni Coaching and Nutrition.
3x Author
22x Ironman finisher
4x Extreme triathlon finisher
6x Ironman World Championship finisher. -

Karel Sumbal
Co-owner of Trimarni
Greenville, SC
Born and raised in Czech Republic.
Category 1 cyclist turned endurance triathlete.
5 year GM of Trek Bicycle Store (Jax, FL)
25+ years experience as a skilled bike mechanic.
RETUL bike fit specialist.
20x Ironman finisher
6x Ironman World Championship finisher
3x XTRI finisher -

Joe Nagy
Assistant Coach
Fort Mill, SCIronman Certified
Engineer
3x 70.3 World Championship Qualified (2021, 2025, 2026)
2024 Richmond Marathon - 2:53:09
2x Boston Marathon Qualified (2025 and 2026) -

Katie Colville
Assistant Coach
Decatur, GeorgiaBachelor degree in exercise and sports science
NASM certified personal trainer
31x Ironman finisher
8x Ironman World Championship qualifier
2026 Ironman Maryland 3rd place female pro -

Sunny
Certified Therapy Dog
What Our Athletes Say