Strength training is the most neglected element of marathon preparation, and the omission is costly. Weak glutes, hips, and core force the body to compensate with movement patterns that waste energy and overload the structures — IT bands, knee tendons, plantar fascia — that are most prone to breaking down over 26.2 miles. Runners who include two strength sessions per week consistently run more economically, suffer fewer overuse injuries, and finish marathons with better form than those who only run.
Why Strength Training Matters for Marathon Performance
Running economy — the oxygen cost of running at a given pace — improves significantly with strength training. Research shows that 8–10 weeks of heavy resistance training (squats, deadlifts, single-leg work) improves running economy by 4–8% in trained distance runners without increasing body mass. For a 4:00 marathoner, a 5% economy improvement is worth approximately 12 minutes of race time.
The mechanism is twofold. Stronger muscles generate more force per stride, reducing the number of strides needed to cover a given distance. And stronger tendons store and return elastic energy more efficiently — the Achilles and calf complex function like springs, and stiffer springs (stronger tendons) return more energy per stride.
Essential Strength Exercises for Marathon Runners
| Exercise | Primary Muscles | Running Benefit |
|---|---|---|
| Single-leg squat | Glutes, quads, stabilisers | Hip stability, reduces knee collapse |
| Romanian deadlift | Hamstrings, glutes | Posterior chain strength, stride power |
| Calf raises (single-leg) | Gastrocnemius, soleus | Push-off power, Achilles tendon stiffness |
| Glute bridge / hip thrust | Glutes, core | Hip extension power, pelvic stability |
| Side-lying clamshell | Gluteus medius | Hip abduction, IT band protection |
| Plank variations | Core stabilisers | Trunk rigidity, arm drive efficiency |
How to Structure Strength Sessions
Two strength sessions per week is the sweet spot for most marathon runners — enough to stimulate adaptation without creating fatigue that degrades running quality. Schedule sessions on the same day as a running workout (ideally after the run, not before), or on easy running days. Never strength train the day before a long run or key workout.
Each session should take 30–45 minutes. Focus on single-leg exercises (single-leg squat, single-leg calf raise, single-leg Romanian deadlift) since running is entirely a single-leg sport. Bilateral exercises like squats and deadlifts are valuable but should not dominate the session. For marathon runners, 3 sets of 8–12 repetitions with moderate-to-heavy resistance develops the strength-to-weight ratio most relevant to running economy.
Common mistake — too light, too many reps: Many runners do strength work with very light weights and high repetitions (20–30 reps), treating it as cardio. This builds muscular endurance but not the strength and tendon stiffness that actually improve running economy. Use weights heavy enough that the final 2–3 reps of each set are genuinely challenging.
Injury Prevention: The Key Exercises
Most marathon running injuries share a common root cause: weakness or instability at the hip that forces downstream compensation at the knee and foot. Three exercises address this most directly:
Clamshells: Lie on your side with knees bent at 90 degrees and feet together. Rotate the top knee upward like a clamshell opening, keeping hips stacked. This isolates the gluteus medius — the primary hip abductor and the most commonly weak muscle in runners with IT band syndrome and patellofemoral pain.
Single-leg glute bridge: Lie on your back with one foot flat on the floor and the other extended. Drive through the grounded heel to lift the hips, squeezing the glute at the top. Hold for 2 seconds. This builds the single-leg hip extension strength that drives running power.
Eccentric calf lowering (heel drops): Stand on a step on one foot, rise up on both feet, then lower slowly on one foot only over 3–4 seconds. This builds Achilles tendon resilience and is the most evidence-backed treatment and prevention for Achilles tendinopathy in runners.
Strength training works in concert with smart mileage progression, which we cover in our complete marathon training guide.
Overlay Your Running Stats
Add your pace, distance, and heart rate to your running photos and videos — share your stats the way the pros do.
Try PaceOverlay Free →Frequently Asked Questions
Will strength training make me too bulky to run marathons?
No. The training volumes required to gain significant muscle mass — very high lifting volume with caloric surplus — are incompatible with marathon training. Two strength sessions per week while running 40–60 miles will not produce meaningful muscle hypertrophy. It will produce strength and tendon adaptations that improve your running, not weight that slows you down.
Should I stop strength training during marathon taper?
Reduce volume but do not stop entirely. Maintain one abbreviated strength session per week during the taper (final 3 weeks), using lighter weights and familiar exercises. Stopping completely risks losing neuromuscular adaptations accumulated over months of training. The goal of taper is to reduce fatigue, not to erase fitness.
What is more important for injury prevention — stretching or strength training?
Strength training is significantly more important than static stretching for marathon injury prevention. The research is clear: static stretching has minimal effect on injury rates, while targeted strengthening of weak muscles (particularly hip abductors and posterior chain) substantially reduces common running injuries. Include both, but prioritize strength work.
Can I do strength training if I am already running 50+ miles per week?
Yes, but be strategic with scheduling. At high mileage, place strength sessions immediately after the easiest running days and ensure they are finished at least 36 hours before any key running workout. If total fatigue rises significantly, reduce strength volume first (drop one set per exercise) before reducing running mileage.
Final Thoughts
strength training marathon runners is one of the most evidence-backed ways to improve your running performance. The techniques and principles here — spanning Why Strength Training Matters for Marathon Performance, Essential Strength Exercises for Marathon Runners — give you everything you need to train smarter rather than just harder.
The biggest gains come from consistent, progressive application over weeks and months — not from any single workout. Use this guide as your starting framework, track your results honestly, and adjust based on what your body tells you.