Running Economy Quantified: Using Data to Assess Your Running Efficiency

Introduction

You may have encountered this situation: a group of runners with similar VO₂max, yet their race times differ by more than 10 minutes. This gap often comes down to Running Economy (RE)—how much oxygen the body needs to consume at the same pace. The better your RE, the lower the physiological cost of maintaining the same pace, much like a more fuel-efficient engine.

Research shows that among elite runners, RE can predict performance even better than VO₂max. This means that even if your VO₂max isn’t high, you can still significantly improve your performance by enhancing your running economy.

What Are the Measurement Standards for Running Economy?

The strictest definition of running economy is: the amount of oxygen consumed per kilogram of body weight per kilometer at a specific pace (mL/kg/km). Laboratory measurement requires a treadmill and a respiratory gas analyzer, which isn’t something the average runner can do on a daily basis.

However, we have several proxy metrics we can track:

Efficiency Factor (EF) is a simple metric provided by Training Peaks, calculated as “normalized pace ÷ average heart rate.” At the same pace and under the same external conditions, a rising EF means you’re maintaining the same speed at a lower heart rate—in other words, your efficiency is improving.

Factors Affecting Running Economy

Biomechanical Aspects:

• Vertical Oscillation: The higher you bounce with each step, the more energy you’re wasting fighting gravity instead of propelling forward. The ideal vertical oscillation should be below 8 cm.
• Overstriding: When your foot lands too far in front of your center of gravity, it creates braking force, directly consuming extra energy.
• Arm Swing: Excessive lateral arm swing causes torso rotation, wasting energy. Elbows bent at 90 degrees with forward-backward arm swing is the most energy-efficient approach.

Physiological Aspects:

• Running Training Age: Research shows that after 3–5 years of running, the neuromuscular system’s coordination efficiency for running movements improves significantly.
• Tendon Elasticity: The ability of the Achilles tendon and plantar fascia to store and release elastic potential energy—up to 40–50% of propulsion comes from this mechanism.
• Body Weight: Every 1 kg reduction corresponds to approximately a 1% improvement in RE. This is also why elite marathoners tend to have lean builds.

How to Track Efficiency Improvements with Existing Tools

Method 1: Efficiency Factor Trend Tracking
In Training Peaks, check your EF value after each steady aerobic run (heart rate maintained in Zone 2). Every 4–6 weeks, compare whether EF has risen on the same route under the same temperature conditions. If your EF on the same route improves from 1.80 to 1.95, it means you’re running faster at the same heart rate.

Method 2: Garmin Vertical Ratio Tracking
Using the HRM-Pro with Garmin Connect’s running dynamics, review your Vertical Ratio trend monthly. By strengthening the glutes (squats, glute bridges) and incorporating hill training, most runners can reduce their Vertical Ratio by 0.5–1% within 3 months.

Method 3: Stryd Critical Power Tracking
The Stryd power sensor provides the most direct running efficiency data. Its Critical Power (CP) metric improves with training, and if your heart rate drops while CP remains unchanged, it indicates improved efficiency.

Training Methods to Improve Running Economy

• Running Technique Drills (A skips, B skips, high knees, butt kicks): 2 sessions per week, 10–15 minutes each. After 8 weeks, most runners naturally see their cadence increase.
• Hill Sprints: 8–10 second all-out uphill efforts, once per week. This is the most effective method for training running power output and leg elasticity.
• Strength Training: Particularly single-leg squats and Nordic hamstring curls, which can significantly improve ground contact time and push-off efficiency.

Practical Recommendations

• Establish an Efficiency Baseline: On the same flat route, run 30 minutes in Zone 2, record your EF value, then test once a month thereafter.
• Fix Cadence First, Then Stride Length: Increasing cadence (target 175–180 spm) is usually the fastest-acting efficiency improvement strategy.
• Avoid Technique Training When Fatigued: Movement patterns under fatigue reinforce bad habits. Technique sessions should be performed in a fresh state.

Conclusion

Running economy is the decisive factor in the latter half of a marathon. When the ceiling of your aerobic engine (VO₂max) has hit a plateau, improving RE is often the final mile to breaking your personal record. Starting today, add EF and Vertical Ratio to your regular tracking checklist.

Related Reading

• Running Economy: Ten Key Factors Affecting Running Efficiency
• Measuring and Improving Running Economy
• Running Economy: Why People with the Same VO2max Perform So Differently
• Running Economy Improvement Guide: Run Faster with Less Energy