When you think about training for a marathon, what muscles come to mind? Probably the big players—your quads, hamstrings, calves, and glutes. They’re the showstoppers of running, and yes, they’re crucial.
But what if we told you that some of the most important muscles for marathon performance and injury prevention are ones you’ve probably never trained on purpose?
Whether you’re 17 or 70, these forgotten stabilisers are doing silent work behind every stride—and when they fail, pain, compensation, and inefficiency creep in.
Let’s shine a light on the unsung heroes of distance running.
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Peroneals (Outer Lower Leg)
These tiny muscles on the outside of your lower leg control ankle stability, especially on uneven surfaces and during fatigue in the final miles.
Why They’re Important:
- Prevent ankle sprains and overpronation
- Key for midfoot control and energy return
- Older runners with balance concerns benefit greatly from strong peroneals
Activation Drill:
Banded Eversion
- Loop a resistance band around your feet
- Push one foot outward against the band (away from the midline)
- 3 sets of 15 reps per side
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Deep Hip Rotators (Piriformis, Gemelli, Obturators)
Most runners know about glutes, but the deep six hip rotators control pelvic alignment, leg tracking, and lateral stability. They’re critical in preventing knee pain and IT band irritation.
Especially Important For:
- Older runners with hip arthritis or knee issues
- Female runners (due to wider pelvis)
- Anyone with a history of lateral hip or SI joint pain
Activation Drill:
Clamshells with Resistance Band
- Lie on your side, knees bent, band around thighs
- Lift top knee without shifting pelvis
- 2–3 sets of 15 reps
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Serratus Anterior (Upper Ribcage Stabiliser)
Yes, an upper body muscle—because efficient running requires stable, rhythmic breathing and arm swing. The serratus anterior anchors your shoulder blades and supports deep breathing.
Important For:
- Teen runners with growing bodies learning form
- Middle-aged runners working at desks all day
- Anyone with asthma, shallow breathing, or poor posture
Activation Drill:
Wall Push Plus
- Stand facing a wall, hands flat against the wall
- Push shoulder blades around your ribs (like you’re spreading your back)
- Hold 5 seconds, repeat 12–15 reps
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Tibialis Posterior (Inside of Lower Leg)
This one gets almost no attention—until you’re injured. Tib post helps maintain your arch, preventing overpronation, shin splints, and posterior tibial tendinopathy (a brutal injury for distance runners).
Important For:
- Master athletes or walkers returning to running
- Flat-footed runners
- Anyone who uses orthotics or complains of “achy feet”
Activation Drill:
Arch Doming (Short Foot Exercise)
- While seated, press big toe into the ground and lift the arch
- Hold 5 seconds, repeat 10–12 reps per side
- Can be done barefoot while brushing your teeth!
Your “Forgotten Muscles” Activation Plan (By Age)
| Age Group | Focus Areas | Recommended Frequency |
| Teens (12–19) | Serratus anterior, hip rotators | 2x/week post-run |
| 20s–40s | Peroneal, tib post, core balance | 3x/week (pre-run warmup) |
| 50s–70s+ | All of the above + ankle/foot work | Daily light activation + recovery care |
Final Takeaway
The muscles that keep you upright, aligned, and breathing smoothly aren’t the ones everyone talks about—but they’re the ones that often break down first in a marathon.
If you’ve ever dealt with recurring ankle sprains, nagging hip pain, or side stitches at mile 20—it’s probably time to training only the obvious muscles.
Book an appointment with us to help you run better!
Locations: The Sherwood Clinics (Harrow HA2 0NP / Edgware HA8 8NP)
URL: www.sherwoodtherapy.co.uk
You’ve trained hard. Let us help you train smart—and stay strong, steady, and injury-free, one step at a time.
