Running Economy: The Hidden Performance Factor

Running economy (RE) measures the oxygen cost of running at a given submaximal speed, typically expressed as ml of O2 per kilogram of body weight per kilometer (ml/kg/km). A more economical runner uses less oxygen -- and therefore less energy -- to cover the same distance at the same pace. Among runners with equal VO2max values, the one with better economy will always be faster. While VO2max tells you the size of your aerobic engine and lactate threshold tells you how much of it you can use, running economy tells you how far each unit of fuel takes you. The good news: unlike VO2max, running economy can be improved significantly throughout an athletic career, even after decades of training.

Why Running Economy Matters So Much

To understand economy's impact, consider a simple thought experiment. Two runners both have a VO2max of 60 ml/kg/min and a lactate threshold at 85% of VO2max. They can both sustain an oxygen consumption of 51 ml/kg/min at threshold.

Runner B covers every kilometer burning 12% less oxygen. Same engine, same threshold, but 29 seconds per kilometer faster. Over a marathon, that is a difference of over 20 minutes.

This example is not extreme. Barnes & Kilding (2015) documented that running economy varies by up to 30% among runners with similar VO2max values. That variation is enormous.

What Determines Running Economy

Running economy is a composite of biomechanical, neuromuscular, metabolic, and environmental factors. Here are the most important ones, ranked roughly by how much they contribute.

1. Biomechanical Factors

Cadence. Most elite distance runners naturally settle into a cadence of 180-190 steps per minute at race pace. Recreational runners often run at 155-170 spm. Higher cadence generally means shorter ground contact time, less vertical oscillation, and lower braking forces. However, forcing cadence higher than what naturally emerges at a given pace often increases energy cost. The goal is to let cadence rise organically as pace increases, not to impose a fixed number.

Vertical oscillation. The energy spent bouncing up and down is energy not spent moving forward. Elite runners typically oscillate 6-8 cm per stride. Recreational runners often exceed 10 cm. Reducing unnecessary vertical movement improves economy.

Ground contact time. Faster, more economical runners spend less time on the ground per step. Elite marathon runners typically have ground contact times of 200-220 ms. Recreational runners may have 280-320 ms. Shorter ground contact time reflects better elastic energy return and faster force application.

Ankle and leg stiffness. The lower leg and Achilles tendon act as a spring. Stiffer tendons store and return elastic energy more efficiently. This is partly genetic (tendon length and collagen structure), partly trainable (plyometrics increase tendon stiffness), and partly influenced by footwear (racing flats and carbon-plated shoes enhance this spring mechanism).

2. Anthropometric Factors: The East African Advantage

Mooses & Hackney (2017) investigated why East African runners consistently demonstrate 5-10% better running economy than European runners. Several anthropometric factors contribute:

• Lower body mass index with long, slender limbs
• Lower calf circumference and lighter distal limbs (less rotational inertia means less energy to swing each leg)
• Longer Achilles tendons relative to calf muscle length (better elastic energy storage)
• Narrower hips reducing lateral pelvic movement

These factors are largely genetic, but they illustrate why the formula for economy is more complex than just "run more." A 5 kg reduction in body weight, if it comes from non-functional mass, improves economy by roughly 3-5%. However, losing muscle mass needed for force production is counterproductive.

3. Metabolic Factors

Mitochondrial efficiency. Years of aerobic training increase both the number and the efficiency of mitochondria, reducing the oxygen cost per unit of ATP produced.

Substrate utilization. A well-trained athlete burns a higher proportion of fat at any given submaximal pace, sparing glycogen. Fat oxidation is more oxygen-costly per calorie but more sustainable, and the metabolic adaptations that support it also improve overall economy at moderate paces.

Muscle fiber type. Type I (slow-twitch) fibers are more efficient than Type II for sustained efforts. High-mileage training recruits and develops Type I fibers preferentially.

How to Improve Running Economy

The research points to several evidence-based interventions:

High Running Volume

Simply running more -- particularly easy miles -- is the most reliable way to improve economy over time. The mechanical repetition refines neuromuscular coordination, improves elastic energy storage, and enhances metabolic efficiency. Studies show that economy continues to improve even after 5+ years of training, long after VO2max has plateaued.

Strength Training

Heavy resistance training (3-5 sets of 3-6 reps at 80-90% of 1RM) targeting the legs and hips improves economy by 2-5% over 8-12 weeks. Key exercises: squats, Romanian deadlifts, single-leg work, and calf raises. The mechanism is improved neuromuscular coordination and tendon stiffness, not muscle hypertrophy.

Plyometrics

Jumping drills -- box jumps, bounding, single-leg hops, drop jumps -- train the stretch-shortening cycle that governs elastic energy return. Saunders et al. (2004) reported 2-8% improvements in economy from 6-9 weeks of plyometric training. Start conservatively: 2 sessions per week, 60-80 foot contacts per session, progressing over 6 weeks.

Altitude Training or Simulation

Living and training at moderate altitude (1800-2500m) improves economy through increased hemoglobin mass and potentially enhanced mitochondrial efficiency. The "live high, train low" model is the gold standard, but even altitude camps of 3-4 weeks produce measurable improvements.

Running Drills and Strides

Regular drills (high knees, butt kicks, A-skips) and strides (80-100m accelerations at mile race pace) reinforce efficient movement patterns and develop the neuromuscular speed needed for elastic recoil.

Worked Example: Two Runners, Same VO2max, Different Economy

Profile: - Alex: VO2max 55 ml/kg/min, running economy 215 ml/kg/km - Jordan: VO2max 55 ml/kg/min, running economy 195 ml/kg/km

Calculating threshold pace (assuming LT at 82% VO2max for both):

Available O2 at threshold: 55 x 0.82 = 45.1 ml/kg/min

Alex's threshold pace: - O2 per km: 215 ml/kg/km - Pace = 215 / 45.1 = 4.77 min/km = 4:46/km

Jordan's threshold pace: - O2 per km: 195 ml/kg/km - Pace = 195 / 45.1 = 4.32 min/km = 4:19/km

Predicted race times (approximate):

The gap widens as race distance increases because economy's influence compounds over time. This is exactly why marathon performance is so strongly correlated with running economy.

Jordan's advantage is equivalent to having a VO2max roughly 6 ml/kg/min higher than Alex -- a difference that would take Alex years to achieve through VO2max training alone, if it were even genetically possible. Meanwhile, Alex could realistically improve running economy by 5-8% through 12 weeks of strength training and plyometrics, closing much of that gap.

Practical Rules for Improving Running Economy

1. Run consistently at easy paces. The single most powerful economy stimulus is accumulated mileage at low intensity. Economy improvements from volume continue for years after VO2max gains have plateaued.

2. Add heavy strength training. Perform 2 sessions per week of lower-body strength work during the base and early build phases. Squats, deadlifts, and single-leg exercises at 3-5 sets of 4-6 reps. Reduce to 1 session during peak training and racing.

3. Incorporate plyometrics gradually. Start with 2 sessions per week of low-level plyometrics (skipping, bounding, ankle hops). Progress to box jumps and drop jumps after 4-6 weeks of adaptation. Keep volume at 60-100 foot contacts per session.

4. Do not chase a specific cadence number. Instead, focus on reducing over-striding (landing with the foot well ahead of your center of mass). Cadence will naturally increase as a result.

5. Run strides 2-3 times per week. Six to eight repetitions of 80-100 meters at approximately mile race effort, with full walk-back recovery. This maintains neuromuscular speed and reinforces efficient mechanics without meaningful fatigue.

6. Lose non-functional body mass if applicable. Every kilogram of excess weight costs approximately 1% in economy. But never sacrifice muscle mass or health for a lighter number on the scale.

7. Be patient. Economy improves slowly. Expect 2-4% improvement over 12 weeks from a combined strength and plyometric program, and ongoing incremental gains over years from consistent mileage.

Evidence Base

Saunders et al. (2004) published a comprehensive review in Sports Medicine identifying the key determinants of running economy. They established that RE is influenced by training history (more experienced runners are more economical), biomechanics (lower vertical oscillation, appropriate cadence), physiology (muscle fiber composition, mitochondrial density), and anthropometry (limb length, body mass distribution). Their most practically significant finding was that plyometric training improved economy by 2-8% across multiple studies, with the effect appearing within 6-9 weeks and persisting after the intervention.

Barnes & Kilding (2015) provided updated norms and an expanded analysis of factors affecting running economy. Their work quantified the extraordinary variation in RE among trained runners -- up to 30% at the same speed -- and demonstrated that this variation explains performance differences that VO2max alone cannot account for. They also conducted a meta-analysis showing that both heavy resistance training and plyometric training produce statistically significant improvements in RE, with typical effect sizes of 2-8%.

Mooses & Hackney (2017) compared the anthropometric profiles and running economy of East African and European distance runners. They found that Kenyan and Ethiopian runners had significantly lower body mass, lighter calves (by 8-12%), longer Achilles tendons, and narrower pelvises. These structural differences accounted for a substantial portion of the 5-10% economy advantage observed in East African populations. While these findings highlight the role of genetics in economy, they also underscore the importance of modifiable factors like body composition and tendon stiffness, which can be influenced through training and weight management.

The collective evidence makes a strong case: for any runner who has already spent several years developing VO2max and lactate threshold, running economy represents the frontier with the most remaining potential for improvement.