Running economy is the oxygen cost of running at a given pace. It represents how efficiently the body converts energy into forward motion. Two runners with identical aerobic capacity can perform very differently in a marathon based solely on differences in running economy.
This article defines running economy, explains its physiological and biomechanical determinants, outlines how training influences economy, and provides practical strategies for improvement.
Definition
Running economy is the steady-state oxygen consumption (VO₂) required to run at a specific submaximal pace. It is typically expressed as milliliters of oxygen per kilogram of body weight per kilometer (ml/kg/km).
Lower oxygen consumption at a given pace indicates better economy:
- Better economy: Less oxygen needed to maintain pace (more efficient)
- Worse economy: More oxygen needed to maintain pace (less efficient)
Example: Runner A requires 200 ml/kg/km at 8:00/mile pace. Runner B requires 220 ml/kg/km at the same pace. Runner A has better running economy and can sustain that pace with less physiological strain.
Why running economy matters
Performance impact
Running economy can vary by 20-30% among runners with similar VO₂max values. This means:
- Two runners with identical maximal aerobic capacity may differ significantly in race performance
- The runner with better economy runs faster at the same relative effort
- Small improvements in economy translate to meaningful time gains over 26.2 miles
Differentiator among elite runners
At the elite level, VO₂max values plateau. Further performance gains come primarily from:
- Improved running economy
- Raised lactate threshold
- Superior pacing and fueling strategies
Many elite marathoners do not have the highest VO₂max in the field, but they possess exceptional running economy.
Physiological determinants of running economy
Muscle fiber composition
Fast-twitch fibers (Type II):
- Generate force quickly but consume more energy
- Less economical for sustained efforts
Slow-twitch fibers (Type I):
- More fatigue-resistant
- Better suited for aerobic endurance
- Generally more economical
Training impact: Endurance training enhances the oxidative capacity of all fiber types, improving overall economy.
Mitochondrial density and efficiency
Role:
- Mitochondria are the cellular engines that produce ATP aerobically
- Greater mitochondrial density improves aerobic energy production
Training impact:
- Consistent aerobic training increases mitochondrial number and function
- Improved mitochondrial efficiency reduces oxygen cost at submaximal paces
Cardiovascular efficiency
Factors:
- Stroke volume (amount of blood pumped per heartbeat)
- Cardiac output (total blood flow per minute)
- Capillary density in muscles
Training impact:
- Endurance training increases stroke volume and capillary networks
- More efficient oxygen delivery reduces energy cost
Substrate utilization (fuel selection)
Fat vs. carbohydrate:
- Fat oxidation is slower but spares limited glycogen
- Better fat utilization at race pace improves endurance
Training impact:
- Aerobic base training enhances fat oxidation capacity
- This allows the body to rely less on carbohydrates at moderate paces
Biomechanical factors influencing running economy
Stride mechanics
Ground contact time:
- Shorter ground contact generally correlates with better economy
- Excessive braking forces waste energy
Vertical oscillation:
- Excessive up-and-down movement wastes energy
- Efficient runners minimize vertical displacement
Cadence:
- Most economical cadence is individually determined
- Very low cadence often increases braking forces; very high cadence may increase muscle work
Running form and posture
Trunk stability:
- Core strength reduces unnecessary torso rotation
- Stable posture improves force transmission
Arm swing:
- Arms counterbalance leg movement
- Excessive or inefficient arm motion wastes energy
Foot strike:
- No single foot strike pattern is universally optimal
- Consistency and reduced braking forces matter more than strike type
Body composition
Impact of excess weight:
- Carrying extra body weight increases energy cost per step
- Leaner runners generally exhibit better economy
Muscle mass:
- Excessive muscle mass (especially upper body) adds weight without performance benefit
- Balanced strength supports form without unnecessary bulk
Flexibility and stiffness
Tendon stiffness:
- Stiffer tendons store and return elastic energy more effectively
- Contributes to propulsion efficiency
Joint flexibility:
- Excessive flexibility may reduce elastic energy return
- Moderate, functional flexibility supports healthy mechanics
How training influences running economy
High-volume aerobic training
Mechanism:
- Builds aerobic base and mitochondrial density
- Enhances fat oxidation and cardiovascular efficiency
Effect on economy: Consistent mileage over time is one of the most reliable ways to improve running economy.
Tempo and threshold work
Mechanism:
- Trains the body to sustain faster paces efficiently
- Improves lactate clearance and muscular endurance
Effect on economy: Running at controlled hard efforts reinforces efficient mechanics under fatigue.
Strength training
Mechanism:
- Increases muscular power and tendon stiffness
- Improves force production and propulsion
Effect on economy: Heavy strength training and plyometrics improve economy by enhancing neuromuscular efficiency and elastic energy storage.
Running drills and strides
Mechanism:
- Reinforce proper mechanics and coordination
- Improve neuromuscular patterns
Effect on economy: Drills (A-skips, B-skips, high knees) and short bursts of fast running (strides) refine form and efficiency.
Consistency and training age
Mechanism:
- Years of consistent training yield adaptations that accumulate over time
- Experienced runners often display superior economy compared to newer runners with similar VO₂max
Effect on economy: Long-term training history is one of the strongest predictors of running economy.
Common misconceptions
"Changing your form drastically will improve economy"
Reality: Running form is highly individual. Drastic changes can disrupt established neuromuscular patterns and increase injury risk. Gradual refinement through drills and strength work is more effective.
"Lighter shoes always improve economy"
Reality: While shoe weight matters, cushioning and support also influence economy and injury risk. The optimal shoe balances weight, comfort, and protection for the individual runner.
"Stretching improves running economy"
Reality: Excessive static stretching may reduce tendon stiffness and elastic energy return, potentially harming economy. Dynamic mobility and functional flexibility are more beneficial.
"Only elite runners need to worry about economy"
Reality: All runners benefit from improved economy. Even small efficiency gains reduce fatigue and improve performance over marathon distance.
Practical strategies to improve running economy
Build a strong aerobic base
- Prioritize consistent, easy mileage
- Allow time for adaptations to accumulate (months to years)
- Avoid excessive intensity early in training
Incorporate strength training
- Focus on lower-body exercises: squats, lunges, calf raises
- Include plyometric work: box jumps, bounding
- Maintain twice-per-week strength sessions during base and build phases
Use running drills and strides
- Perform 2-3 sessions per week of dynamic drills
- Add 4-6 × 100m strides after easy runs
- Emphasize quality of movement over volume
Maintain healthy body composition
- Avoid excessive calorie restriction that compromises recovery
- Focus on nutrient-dense foods that support training
- Balance leanness with strength and health
Train consistently over time
- Prioritize long-term, progressive training over short-term intensity
- Build gradually through training cycles
- Trust the process—economy improves with sustained effort
Summary
Running economy is the oxygen cost of running at a given pace, representing how efficiently the body converts energy into forward motion. It is a critical determinant of marathon performance, often distinguishing runners with similar aerobic capacity. Physiological factors influencing economy include muscle fiber composition, mitochondrial density, cardiovascular efficiency, and substrate utilization. Biomechanical factors include stride mechanics, running form, body composition, and tendon stiffness. Training improves economy through high-volume aerobic work, tempo runs, strength training, running drills, and long-term consistency. Runners can enhance economy by building a strong aerobic base, incorporating targeted strength work, refining mechanics through drills, and maintaining healthy body composition. Small improvements in running economy yield meaningful performance gains over the marathon distance.