Strength training: the 3rd pillar of performance
Beyond VO₂ Max and energy, musculoskeletal resistance is what limits runners. Strength training improves running economy by 2 to 8% and helps prevent injuries.
The three obstacles of the marathon (and every endurance race)
To understand the importance of strength training, you first need to identify the three major obstacles that limit your running performance:
- The cardiovascular obstacle: Your ability to transport oxygen to your muscles. This is what you develop with long runs and threshold sessions.
- The energy obstacle: Your ability to use glycogen and fat stores efficiently. This is the famous "pace management" and easy endurance training.
- The musculoskeletal obstacle: The resistance of your muscles, tendons, and joints to thousands of repeated impacts. This is where strength training becomes crucial. Stronger ground contacts come from improved tendon stiffness (leg spring), which acts like a spring to store and return elastic energy at every stride.
💡 Did you know?
Over a marathon, your legs absorb about 30,000 to 40,000 impacts. If your muscles are not strong enough, your stride deteriorates, your running economy drops, and your injury risk increases significantly.
What is running economy?
Running economy measures your ability to run at a given speed while using as little energy as possible. In other words, it is your mechanical efficiency.
A runner with good running economy has stronger ground contacts, a stride that deteriorates less at the end of a race, and better transmission of ground forces into forward movement.
🔬 What the science says
Scientific studies (Paavolainen et al. 1999, Saunders et al. 2006) show that strength training, especially through plyometric exercises or force work, improves running economy by 2 to 8% and reduces race times by 2 to 5% over 5K. And the most remarkable part? These gains do not come from an improvement in your VO₂ Max (cardiovascular capacity), but from neuromuscular and biomechanical adaptations.
In concrete terms, this means you can improve performance without increasing your cardiovascular capacity, simply by making your stride more efficient and your muscles more powerful.
Strength training improves running economy by:
- Increasing tendon stiffness: your tendons become more effective "springs", able to store and return elastic energy with every stride (up to a 16% increase in Achilles tendon stiffness, reducing oxygen cost by ~4%)
- Stabilizing your pelvis and trunk: fewer parasitic oscillations, so all your energy is directed forward
- Improving neuromuscular recruitment: your nervous system learns to activate the right muscle fibers at the right time, with less wasted effort
The principles of GPP (general physical preparation)
GPP is the set of strengthening exercises that prepare your body to handle the specific demands of running. Unlike pure bodybuilding (hypertrophy), GPP aims for:
- Strength endurance: ability to maintain repeated contractions (long sets, +12 repetitions)
- Muscular power: developing the ability to produce force quickly, essential for propulsion at every stride
- Prevention of imbalances: correcting left/right asymmetries
- Joint stability: strengthening the small stabilizing muscles
- Resistance to fatigue: maintaining correct technique even when tired
Key muscle zones for runners
1. The lower limbs
These are your main "engines". They generate push-off power at every stride.
- Quadriceps and hamstrings: squats, lunges, step-ups
- Glutes (maximus, medius, minimus): hip thrust, bridge, single-leg squats
- Calves (gastrocnemius and soleus): calf raises, drop down
- Foot muscles: barefoot exercises, arch strengthening
2. The abdominal-lumbar belt (core)
Your "stability center". A strong core allows forces to transfer efficiently from the legs to the upper body and helps maintain optimal posture.
- Abdominals (rectus abdominis, obliques): plank, crunch, rotations
- Lumbar muscles and spinal erectors: lumbar extensions, Superman
- Transverse abdominis: static plank, vacuum
3. The upper body
Often neglected, the upper body plays a role in balance and arm swing.
- Shoulders and arms: push-ups, light dips
- Back muscles: pulldowns, rows
The 8 fundamental exercises for runners
Here are the exercises with the best effort/benefit ratio for a runner. All can be done with bodyweight, without equipment. For each exercise: the starting position, execution, and why it matters for your running.
1. Single-leg squat
Target muscles: gluteus maximus, quadriceps, ankle stabilizers
Position: Stand on one foot, arms extended in front of you for balance. Keep your back straight and your gaze fixed forward.
Execution: Lower slowly by bending the knee (3 seconds on the descent), making sure the knee stays aligned with the toes; do not let it collapse inward. Rise back up by pushing into the ground.
Why it is key: Every stride is a single-leg squat. This exercise strengthens the exact running movement and helps prevent knee pain (patellofemoral syndrome).
2. Walking forward lunge
Target muscles: quadriceps, glutes, hamstrings
Position: Stand with feet hip-width apart. Engage your core before starting.
Execution: Take a big step forward. Lower until the back knee is close to the ground (without touching it). The front knee does not move past the toes. Push through the front heel to stand up and continue with the other leg as you walk.
Why it is key: Mimics running propulsion. Strengthens push-off and shock absorption at the same time, the two critical phases of the stride.
3. Glute bridge (hip thrust)
Target muscles: gluteus maximus, hamstrings, lumbar stabilizers
Position: Lie on your back, knees bent to 90°, feet flat on the ground hip-width apart.
Execution: Contract your glutes and push your hips upward until you form a straight shoulder-hip-knee line. Hold 2 seconds at the top, squeezing the glutes hard. Lower slowly without fully resting the hips between reps.
Why it is key: The gluteus maximus is the main propulsion engine in running. Weak glutes = less power in your stride and overload on the knees and back.
4. Single-leg calf raise
Target muscles: gastrocnemius, soleus, Achilles tendon
Position: Stand on a step or ledge, forefoot on the edge, heel hanging free. Keep one hand lightly on a wall for balance if needed.
Execution: Lower the heel slowly below the level of the step (3 seconds), then rise onto the ball of the foot as high as possible. Do the exercise on one foot for maximal load on the Achilles tendon.
Why it is key: Achilles tendon stiffness is the number one factor in running economy. Eihara et al. (2022) show that eccentric calf strengthening increases tendon stiffness by 16%, reducing the energy cost of the stride by ~4%.
5. Explosive step-up
Target muscles: quadriceps, gluteus maximus, proprioception
Position: Face a stable step or box 30 to 40 cm high. One foot on the step, the other on the ground.
Execution: Push through the heel of the foot on the step and rise explosively while driving the opposite knee upward (like a sprint). Lower slowly. Alternate legs with each repetition.
Why it is key: Specifically develops uphill power. Strengthens the knee in its functional running path.
6. Front + side plank
Target muscles: transverse abdominis, obliques, pelvic stabilizers
Position (front): On forearms and toes, body aligned from head to heels. No lumbar arching and no hips in the air.
Execution: Brace your abdomen as if you were about to take a hit, and breathe normally. For the side plank: support yourself on one forearm, body side-on, hips aligned with shoulders and ankles.
Why it is key: An unstable pelvis while running = energy dissipated sideways at every stride. Core work reduces these parasitic oscillations and improves overall mechanical efficiency.
7. Superman
Target muscles: spinal erectors, gluteus maximus, hamstrings
Position: Lie face down, arms extended in front of you, legs straight.
Execution: Raise arms and legs from the ground at the same time by contracting the glutes and lower back. Hold 2 to 3 seconds at the top, then lower slowly without fully resting.
Why it is key: The posterior chain (back, glutes, hamstrings) is the force line of propulsion. A weak back shows up late in races as a collapsed posture that kills running economy.
8. Drop jump
Target muscles: entire lower body — Method: plyometrics
Position: Stand on a low step or stable box (20 to 30 cm). Reserved for intermediate and advanced runners, after 3 to 4 weeks of base strengthening.
Execution: Step down from the box (do not jump), absorb the impact by bending the knees (braking phase), then rebound upward immediately and explosively. Ground contact should be as short as possible.
Why it is key: This is the most effective plyometric exercise for increasing tendon stiffness. Paavolainen et al. (1999) show that explosive strength training improves 5K time by 3.1% without any change in VO₂ Max.
Your 4-week strength program
Here is a concrete program: two sessions per week, progressive from week to week. Sessions A and B alternate to stress the muscles differently each time. To know exactly where to place these sessions in your running week, read our guide on integrating strength training into your schedule.
Weeks 1 and 2 — Foundation
Goal: discover the movements and build the neuromuscular base. Take time to learn technique before increasing the load.
| Session A (Monday or Tuesday) | Sets × Reps | Rest |
|---|---|---|
| Glute bridge | 3 × 15 | 45 sec |
| Walking forward lunge | 3 × 8/leg | 60 sec |
| Front plank | 3 × 20 sec | 45 sec |
| Superman | 3 × 10 | 45 sec |
| Calf raise (two-leg) | 3 × 15 | 45 sec |
| Session B (Thursday or Friday) | Sets × Reps | Rest |
|---|---|---|
| Single-leg squat (assistance if needed) | 3 × 6/leg | 60 sec |
| Step-up (slow) | 3 × 8/leg | 60 sec |
| Side plank | 3 × 15 sec/side | 45 sec |
| Calf raise (two-leg) | 3 × 15 | 45 sec |
Weeks 3 and 4 — Progression
Goal: increase load and introduce plyometrics. Technique is now learned, so intensity rises.
| Session A | Sets × Reps | Rest |
|---|---|---|
| Single-leg glute bridge | 3 × 12/leg | 45 sec |
| Walking forward lunge | 4 × 12/leg | 60 sec |
| Front plank | 3 × 35 sec | 45 sec |
| Superman | 3 × 15 | 45 sec |
| Calf raise (single-leg) | 3 × 12/foot | 60 sec |
| Session B | Sets × Reps | Rest |
|---|---|---|
| Single-leg squat | 4 × 10/leg | 60 sec |
| Explosive step-up | 3 × 10/leg | 60 sec |
| Drop jump | 3 × 6 | 90 sec |
| Side plank | 3 × 25 sec/side | 45 sec |
| Calf raise (single-leg) | 3 × 12/foot | 60 sec |
📅 What happens after 4 weeks?
Keep progressing the difficulty: increase repetitions, reduce rest times, or move to advanced variants. Progression must remain regular over 8 to 12 weeks for tendon and neuromuscular adaptations to become fully established.
Why 2 sessions of 20 minutes per week are enough
Science and field experience converge: the most optimal plan is the one you really do. There is no point planning 5 sessions per week if you only do one in reality.
2 sessions of 20 minutes allow you to:
- Stimulate your muscles without creating excessive fatigue
- Maintain sufficient frequency to progress (repeated stimulus)
- Fit easily into a busy schedule
- Avoid soreness that would harm your running workouts
Practical tip: session timing
Place your strength session the day before your long run. This creates muscular pre-fatigue that forces your body to recruit more muscle fibers during the long run, improving your strength endurance. Read our complete guide on when and how to integrate strength training into your running week.
Concrete benefits of strength training
- ⚡ Better race times: 2 to 5% faster in your races thanks to better running economy (confirmed by scientific studies)
- 🛡️ Injury prevention: Stronger muscles and tendons = a more resilient runner, less prone to tendinopathy, patellofemoral syndrome, and shin splints
- 💪 Uphill power: Stronger glutes and quadriceps = climbing more easily in trail running without draining your reserves
- 🏃 Less stride deterioration: Your technique stays clean even when tired late in the race, thanks to stronger ground contacts and better neuromuscular coordination
- 🔋 Better fatigue management: Your muscles become more resistant to repeated effort, allowing you to hold your pace longer
- 😊 More enjoyment: Less post-run pain, faster recovery, and a feeling of power at every stride
How to start strength training?
- Assess your level: Beginner, intermediate, or experienced? Read our guide specifically designed for beginner runners if you are starting from zero.
- Choose the basic exercises: glute bridge, lunge, single-leg squat, plank, calves — the 5 fundamentals in this guide
- Progress gradually: start with beginner variants, increase difficulty week after week
- Integrate it into your plan: 2 sessions of 20 minutes, intelligently placed in your week
- Be consistent: consistency matters more than occasional intensity — 6 to 12 weeks for measurable results
Frequently asked questions about strength training for running
How many times per week should you do strength training when you run?
2 sessions per week is the effective minimum, confirmed by studies on recreational runners. If you run 5 times or more per week, you can go up to 3 sessions; but 2 well-executed sessions already produce significant running economy results after 6 weeks. The essential factor is long-term regularity, not frequency.
When should I place strength sessions in my running week?
The golden rule: never the day before a key session (VO₂max intervals, threshold, intensive long run). Ideally, place them the day before an easy run or easy endurance run. Another option: the same day as your run, with at least 4 hours between them — strength in the morning, running in the evening. For a complete week-by-week schedule, read our guide to integrating strength training.
Does strength training make your legs bigger or heavier?
No — not with this type of program. Muscle mass gain (hypertrophy) requires progressive heavy loads AND a calorie surplus. High-repetition bodyweight exercises develop strength endurance and functional power, not muscle size. Runners who practice GPP do not bulk up; they become more efficient at the same body weight.
How long before I see results in my race times?
The first neuromuscular adaptations(improved muscle recruitment, increased stability) are felt after 3 to 4 weeks. Measurable improvement in running economy — 2 to 8% — appears after 6 to 12 weeks of regular practice at 2 sessions per week (Saunders et al., 2006). On a 50-minute 10K, a 4% gain represents 2 minutes faster.
Which muscles should runners prioritize in strength training?
In order of priority for runners: (1) the glutes — main propulsion engine, (2) the calves and Achilles tendon — tendon stiffness and running economy, (3) the core — pelvic stability and force transmission, then (4) quadriceps and hamstrings — shock absorption downhill. The upper body (back, shoulders) completes the picture but is not the priority.
Is plyometrics really useful for runners?
Yes — it is even the strengthening method that most directly impacts running economy. Paavolainen et al. (1999) showed that an explosive and plyometric strength program improves 5K time by 3.1% without any change in VO₂ Max. Plyometrics improves tendon stiffness, which acts like a spring at every stride; the more effective the spring, the less energy you waste. To go further: our complete guide to plyometrics for runners.
Can bodyweight exercises replace the weight room?
For the vast majority of runners, yes. Bodyweight exercises (GPP) are better adapted to running specificity than heavy bodybuilding: they train stability, coordination, and strength endurance through functional ranges of motion. The comparison of strength training methods shows that GPP and plyometrics obtain better running economy gains than traditional strength training alone.
Simple RenfoRun-style version
To make the plan easier to read, structure it like a RenfoRun session: one main block plus one short accessory block.
- Session A — AMRAP (as many rounds as possible) for 8 min: front lunge, good morning, sit-ups. Then accessory block: 3 rounds of calf raises.
- Session B — Tabata (20 sec effort / 10 sec rest): hip dips, back extension, shoulder touches. Keep 2 min rest between blocks.
Progression: add a round, slightly increase reps, or move to a harder variation.
You understand the method. RenfoRun gives you the workout.
No planning, no hesitation — just open the app and follow the session.
- ✓ Guided workouts with timer — just follow along
- ✓ Automatic progressions: your sessions evolve every week
- ✓ 12 to 25-minute sessions, designed to fit your running schedule
- ✓ Built exclusively for runners — road or trail
Conclusion
Strength training is not optional for runners who want to progress sustainably. It is an essential pillar, just like your long runs and interval sessions.
By working on strength endurance, stability, and running economy, you will become a stronger, more resilient runner and, above all, you will enjoy running more.
Start today with RenfoRun. 🚀