How to Strength Train During Your Next Marathon Build and Why
October 2, 2025
By Coach Collen McLain
3 min to read
Kinesis Integrated is a personalized strength training app for endurance athletes. Trusted by Olympians and elite athletes, our app helps you build strength, prevent injuries, and hit new PRs.
When most runners think about marathon prep, the focus is on mileage, workouts, and long runs. But an often-overlooked piece of the puzzle is strength training for marathon runners. Many fear lifting will make them “big and bulky,” slowing them down. The truth? Done correctly, strength training delivers a massive return on a small investment.
Just two sessions per week, 1 hour each, for 16 weeks (32 total sessions, less than 1% of your total living time) can significantly reduce injury risk and boost performance.
Weak Things Break: Why Runners Need Strength Training for Injury Prevention
Every marathoner knows the pounding your body takes: thousands of steps, each with ground impact forces up to 3–5x bodyweight. If your structure is weak, injuries become inevitable. Even with “perfect” form, underlying weaknesses can cause breakdowns.
Example:
Weak inner thigh muscles = knees collapsing inward with every stride → hip/knee strain → injury.
Common Running Injuries Linked to Weakness:
Tendon pain (Achilles, patellar, hamstring tendinopathy)
Shin splints
IT band syndrome
Stress reactions & stress fractures
How Strength Training Helps:
Tendons: Respond best to heavy, slow resistance training.
Bones: Adapt to impact (plyometrics/jumping) but require variation in intensity and direction to keep progressing.
Muscles: Grow stronger, more resilient, and better balanced.
Bottom line: strength training builds durability. Durability = consistency = performance.
Stronger Is Faster: The Performance Benefits of Strength Training
Strength training isn’t just about injury prevention, it’s a performance enhancer.
How It Helps Marathon Performance:
Supports Higher Training Volume: A stronger body can handle more miles without breaking down.
Boosts Running Economy: Research shows strength training improves efficiency more than super shoes, without the risk of injury.
Adds Power: Stronger glutes, quads, hamstrings = greater force production, better hill running, and late-race finishing speed.
Improves Posture: Even light upper body work can improve form and help you hold strong through mile 26.
Think of strength training as the secret weapon to train harder, race faster, and recover better.
How to Add Strength Training to Your Marathon Plan
The golden rule: 2 sessions per week for at least 16 weeks to see lasting structural adaptations.
Here’s a sample training week:
Monday: Easy run
Tuesday: AM hard run / PM strength training
Wednesday: Easy run
Thursday: Easy run
Friday: AM hard run / PM strength training
Saturday: Easy run
Sunday: Long run
Why This Works:
Hard Days Hard, Easy Days Easy: Strength work is stacked with hard running days to protect recovery days.
Timing Matters: Ideally, run in the AM, lift at least 4 hours later after refueling.
Life Happens: If you can’t lift the same day, shift strength to the next morning, still within a 24-hour “intensity block.”
Remember: Strength training supports running, it doesn’t replace it. Prioritize your run workouts, but never skip strength.
FAQ: Strength Training for Marathon Runners
How often should marathoners strength train?
2x per week is ideal. That will be enough to ensure adaptations but not too much to take away from your running. Even 1x per week helps maintain benefits during peak training.
Will lifting make me bulky?
No. Proper programming for endurance athletes builds strength, not size.
What exercises should runners focus on?
First master the basics. Squats, lunges, deadlifts, step-ups, hip thrusts, calf raises, and core stability work. Don’t forget the inner thigh by adding in Copenhagen side planks.
When is the best time to start strength training?
Today. The earlier you begin and stick to it, the greater the long-term benefits. The offseason is the BEST window to begin building lasting strength.
Final Thoughts
If you’ve been skipping strength training, you’re leaving speed, efficiency, and resilience on the table. Even if your marathon build is already underway, it’s not too late, and your post-race offseason is the perfect time to commit to a year-round program.
Just ask on of our athletes, Olympian Elise Cranny, who credits strength training with finally overcoming chronic injuries. Watch her story here.
At Kinesis, we help endurance athletes stay healthy and perform year-round. Whether you’re training for Boston, UTMB, or your local 10K, our strength plans plug into your routine and make you stronger where it counts.
Our app auto-builds a race-specific plan in minutes so you climb harder, descend cleaner, and finish fresher. Start for free here.
