Strength Training for Runners: The Science-Based Guide

Should marathon runners lift weights? Look at how the world’s best are training, and the answer becomes obvious.

Elite distance runners — from 5000m specialists to full marathoners — almost universally include strength training in their programs. Japanese marathon stars Suguru Osako and Kengo Suzuki (who set the national record at the Biwako Mainichi Marathon) are no exception.

The objective evidence suggests that strength training can support performance in the marathon and other long-distance events.

Yet some coaches still worry it might undermine the endurance base built through running — or that added muscle mass will slow athletes down.

This article examines the effects of strength training on the body and the methodology for using it to improve long-distance performance, drawing on the latest research findings.

Does Strength Training Directly Improve Marathon Performance?

Strength training doesn’t directly raise aerobic capacity like VO2 max. However, multiple meta-analyses※1 ※2 show that adding heavy resistance training to a running program improves running economy — how efficiently you use oxygen at a given pace.

Think of strength training as an indirect but powerful support system for running performance.

Several studies have examined the relationship between strength training and endurance performance in limited settings and over short time frames. However, long-term data is scarce, and findings across studies are often inconsistent.

Across the body of existing research, no negative effects of strength training on endurance performance have been demonstrated — except in cases of excessive muscle hypertrophy causing significant weight gain.

You don’t need to worry that adding strength training will hurt your endurance performance.

Elite runners consistently demonstrate that strength training supports high-level performance. This article focuses specifically on the methodology of strength training for improving endurance performance.

This article draws in part from “Concurrent Training: The Science of Optimizing Training Order for Peak Performance.”

Two Types of Strength Training for Runners

Strength training for marathon runners falls into two broad categories:

Heavy Resistance Training (High Load, Low Reps)

Weight training targets maximal strength and muscular power.

This includes standard lower-body exercises — squats, Bulgarian split squats, deadlifts, and lunges — as well as plyometric movements like jump squats and countermovement jumps.

Weight training uses movement patterns that differ from running, so it doesn’t directly translate into endurance performance gains. Plyometric training, on the other hand, closely mimics running mechanics and bridges the gap more effectively.

Treat weight training as the foundation for building endurance capacity. Once you’ve developed maximal strength and muscular power, bounding drills and hill sprints help apply those gains to actual running performance.

Supplementary and Corrective Training

Supplementary training focuses on injury prevention and improving running posture. Core training and other low-load exercises fall into this category.

Core training also belongs here. However, supplementary training alone won’t directly improve your marathon time.

Think of it this way: supplementary training builds a body that’s resistant to injury and capable of handling harder training — and that’s ultimately what leads to better race times.

Benefits of Strength Training and How to Apply Each

Here’s a summary of what strength training can do for runners:

Across all levels of distance runners — from recreational to elite — aerobic capacity (as measured by VO2 max) correlates significantly with race times.

However, among elite runners, this correlation weakens considerably.

This suggests that running economy and sprint capacity play a significant role in determining performance at the elite level.

In events like the 5000m, races often come down to a final sprint — and a higher top speed is essential for competitive performance.

The mechanisms by which heavy resistance training improves running economy include※3:

• Fast-twitch muscle fibers (Type IIX) convert to more fatigue-resistant fibers (Type IIa), allowing you to sustain the same pace with less muscular fatigue
• Neuromuscular efficiency improves, reducing the energy cost of generating the same output
• Optimal musculotendinous stiffness increases, allowing you to convert ground reaction force into propulsion more efficiently

The diagram below illustrates how these effects interact:

The pyramid represents the metabolic functions that influence endurance performance. As strength training increases your power output, your maximum speed ceiling rises.

Gains in movement efficiency and injury prevention also raise the foundational capacity that underlies running performance.

Strength training also helps maintain efficiency in the second half of a marathon. A study※4 of well-trained runners found that adding maximal strength training and plyometrics twice a week for 10 weeks helped preserve running economy even after 90 minutes of running.

That group also sustained high-intensity running 35% longer than the control group — demonstrating that strength training improves the ability to run efficiently even when fatigued.

Below, we outline the training approach for achieving each of these benefits.

Year-Round Training Schedule Overview

Strength training should progress through the following schedule as you build toward race season:

Maximal Strength Phase

To build maximal strength, use heavy loads (4–12 RM) with slow, controlled movements.

Key exercises include squats, deadlifts, and Bulgarian split squats — the core movements of weight training.

Keep in mind that maximal strength improvements don’t directly translate into better endurance performance. The goal is to stimulate specific neuromuscular adaptations and raise your peak force output.

Maximal strength is the foundation for all subsequent training phases. For this reason, maximal strength work is primarily done in the off-season rather than during race season.

During race season, the focus shifts to maintenance — just enough training to preserve the strength you’ve built.

Ideally, aim for about two maximal strength sessions per week during the off-season.

Muscular Power Phase

Muscular power training uses moderate-to-heavy loads with fast, explosive movements to develop rate of force development. Key exercises include power cleans and jump squats — training that converts maximal strength into rapid force expression.

Muscular power training has stronger ties to endurance performance than maximal strength work. As race season approaches, maximal strength training decreases while muscular power training takes center stage.

This allows you to maintain minimal levels of maximal strength while sustaining or improving rate of force development.

Sport-Specific Movement Transfer

As muscular power training progresses, gradually introduce low-load, high-velocity movements that mimic running mechanics. Bounding drills and sprint training fall into this category.

This is commonly known as plyometrics. Because it closely replicates running movement patterns, it serves as the bridge that applies your accumulated maximal strength and muscular power to actual running.

Incorporating these movements into your warm-up or as running drills helps your body adapt to them naturally.

Improving Movement Efficiency and Reducing Injury Risk

Separate from performance-oriented strength training, there is also training aimed at improving movement efficiency and reducing injury risk.

For most recreational runners, this is likely the type of strength training they’re already doing — core training and low-load, high-rep exercises.

The goals are threefold: ① strengthening specific muscle groups, ② improving local muscular endurance, and ③ enhancing movement efficiency and injury prevention through bone and tendon adaptations and better posture control.

Think of this type of training as “training to train” — building the foundation that allows you to stay healthy and consistently perform the key workouts that actually drive improvement.

Strength Training Prevents Muscle Loss in Runners

For marathon runners in particular, strength training is recommended as a way to prevent muscle loss.

When the body runs low on energy or sustains exercise for more than two hours, protein breakdown exceeds protein synthesis — leading to skeletal muscle degradation.

Lower-body muscles are regularly recruited during running and tend to maintain their strength. Upper-body muscles, however, see little use in running — left unchecked, they will steadily weaken.

If this muscle loss progresses too far, even the core strength needed for running form can deteriorate — compromising long-distance running mechanics.

To prevent this, runners need at least a minimum level of strength training. Boosting protein intake is another key strategy for minimizing muscle breakdown.

How Concurrent Training Affects Strength and Endurance

Any runner training for distance events will be doing both strength training and running simultaneously. A common concern is whether muscle hypertrophy might negatively impact endurance performance.

Conversely, those who primarily lift and use running for fat loss worry whether endurance training might interfere with muscle hypertrophy.

Performing both resistance training and endurance training simultaneously is known as concurrent training. In this section, we’ll explore how each influences the other.

Does Muscle Hypertrophy Hurt Marathon Performance?

When muscle hypertrophy occurs and muscle fiber cross-sectional area increases, the diffusion distance within and around muscle cells also increases — potentially making it harder to transport glucose and free fatty acids across the cell membrane.

However, the existing body of research has not demonstrated any negative effect of strength training on endurance performance.

Significant weight gain from muscle hypertrophy could potentially hurt endurance performance, but hypertrophy that doesn’t substantially change body weight has been shown to have no adverse effects.

Endurance Training Does Not Block Muscle Hypertrophy

The conclusion from the research is clear: endurance training does not prevent muscle hypertrophy.

The conditions required for muscle hypertrophy are:

A detailed breakdown of each condition is beyond the scope of this article.

Muscular Power Is Clearly Compromised by Endurance Training

Performing endurance training and strength training concurrently has been shown to reduce the muscular power gains that strength training would otherwise produce.

The primary cause is thought to be endurance-induced fatigue reducing the quality of muscular power training sessions.

According to a meta-analysis※5, this interference effect varies by type of aerobic exercise. Combining strength training with running causes greater impairment of muscular power than combining it with cycling.

For runners targeting muscular power development, managing the frequency and duration of aerobic training is especially important.

To minimize this interference effect, the following strategies are recommended:

Following these guidelines will minimize the negative impact of endurance training on muscular power development.

High Load vs. Low Load: Which Is Better for Runners?

Since the marathon is essentially a prolonged, relatively low-intensity effort, it might seem logical to match your strength training to that profile — light loads, high reps. But is that really the right approach?

As we’ve covered, the answer depends on your training goals — different objectives call for different approaches.

Heavy Loads (85%+ of 1RM) Improve Running Economy

When combining strength training with endurance training, heavy loads (approximately 85% of one-rep max for 5–8 reps) are the most effective approach.

To gain top-speed improvements from strength training, you need to specifically train maximal strength and muscular power.

Achieving these adaptations requires high-load, low-rep training.

A meta-analysis※1 of multiple studies on runners found significant improvements in running economy in groups that added heavy resistance training. The improvements were particularly pronounced when training at 90%+ of 1RM.

Studies using lighter loads (below 80% of 1RM) failed to produce significant improvements — underscoring the importance of lifting heavy enough to drive meaningful adaptation.

The Role of Low-Load, High-Rep Training

Low-load, high-rep training primarily targets movement efficiency and injury prevention. It also allows for targeted muscle hypertrophy in specific areas and helps build muscular endurance.

One well-known example of low-load, high-rep training practiced by elite runners is “Ao-Tore” — the training system developed by Aoyama Gakuin University, a perennial powerhouse at the Hakone Ekiden relay race.

The program, led by head coach Hara, is essentially core training using bodyweight — not heavy resistance training by any standard.

Another goal of low-load training is neural adaptation.

Neural adaptation is essentially about increasing the proportion of muscle fibers you can consciously activate. Low-load, high-rep training may help you recruit more of your available muscle on demand.

How to Integrate Strength Training into Your Running Schedule

Timing is one of the trickiest aspects of adding strength training to a running program.

Train too hard in the gym and you’ll compromise the quality of your next run — or the following day’s workout. Train too lightly and you won’t get the adaptations you’re after.

Finding the right schedule requires trial and error — listen to your body and experiment with timing within your existing running training cycle.

References

※1 Eihara Y et al. (2022) “Heavy Resistance Training Versus Plyometric Training for Improving Running Economy and Running Time Trial Performance: A Systematic Review and Meta-analysis” Sports Medicine Open

※2 Denadai BS et al. (2017) “Explosive Training and Heavy Weight Training are Effective for Improving Running Economy in Endurance Athletes: A Systematic Review and Meta-Analysis” Sports Medicine

※3 Rønnestad BR & Mujika I (2014) “Optimizing strength training for running and cycling endurance performance: A review” Scandinavian Journal of Medicine & Science in Sports

※4 Zanini M et al. (2025) “Strength Training Improves Running Economy Durability and Fatigued High-Intensity Performance in Well-Trained Male Runners: A Randomized Control Trial” Medicine & Science in Sports & Exercise

※5 Wilson JM et al. (2012) “Concurrent training: a meta-analysis examining interference of aerobic and resistance exercises” Journal of Strength and Conditioning Research