Vertical Oscillation and Ground Contact Time: Two Key Metrics of Running Efficiency

Two Underrated Efficiency Metrics

Advanced running watches provide “vertical oscillation” and “ground contact time (GCT).” Many people see these numbers without understanding them, but they directly reflect whether your running is moving “forward” or wasting energy going “up and down.”

Vertical Oscillation: Are You Jumping or Running?

Vertical oscillation is the vertical displacement of your body’s center of mass with each step (in centimeters). Running inherently requires some airtime, but excessive oscillation means energy is being used to push the body upward rather than forward, which is a classic sign of inefficiency.

More useful is the vertical ratio (vertical ratio = vertical oscillation / stride length), which allows comparison across different heights—the lower it is, the more economical.

Ground Contact Time: How Long Your Foot Sticks to the Ground

GCT is the number of milliseconds from when your foot lands to when it leaves the ground. A short GCT indicates good elastic return (tendons acting like springs) and a crisp push-off; a long GCT is often accompanied by braking and insufficient stiffness.

Note: GCT shortens as pace increases, so comparisons should be made at the same pace. Also look at “ground contact balance” (left-right GCT symmetry)—long-term asymmetry may reflect compensatory patterns from old injuries.

Training to Improve Vertical Oscillation

• Increase cadence: As cadence rises, airtime shortens, and oscillation typically decreases. This is the most direct lever.
• Think “forward, not upward”: Imagine your head height staying constant, pushing your force backward toward the ground rather than into it.
• Jump rope and low box jumps: Train elastic landings that are “springy but not high”—quality over height.

Training to Improve Ground Contact Time

To shorten GCT, the essence is improving lower-limb “tendon stiffness and reactive strength”:

• Plyometrics: Jump rope, pogo jumps, continuous low-hurdle hops—emphasizing “bounce on contact, minimal ground time.”
• Calf/Achilles tendon eccentric + fast-twitch work: Slow-lowering heel raises with quick rebounds to improve tendon elastic return.
• Short sprints and running drills: A-skips, strides—forcing short, powerful ground contact.

Don’t Just Chase the Numbers

These two metrics are “byproducts of overall running form.” Forcing a single number down (e.g., deliberately landing on your toes to shorten GCT) will create compensatory injuries. The correct sequence: first work on cadence, foot strike, and push-off, then look back to see whether vertical oscillation and GCT improve accordingly—they are a health report, not training targets in themselves.

Use for Fatigue Monitoring

How much these two metrics deteriorate in the later stages of a long run is an excellent “running form endurance” indicator: if vertical oscillation spikes and GCT lengthens after 30 km, it means your strength endurance cannot hold up for the target distance. What you need is strength work and long-run specificity, not more easy runs.

Coach’s perspective: Vertical oscillation and ground contact time are the first two columns I look at when reviewing an athlete’s watch data, but I never tell anyone to “go make them lower.” What I look at is how quickly they fall apart at the end of a long run—that curve tells me more honestly than the average whether this person will fall apart in the late stages of a marathon.

Related Reading

• Garmin Running Dynamics Data Explained: Training Applications of Vertical Oscillation, Ground Contact Time, and Stride Length
• In-Depth Running Efficiency Analysis: The Scientific Relationship Between Vertical Oscillation, Ground Contact Time, and Running Economy
• Vertical Oscillation Optimization: Reducing Energy Waste Per Step
• Running GPS Watch Features Explained: What Are Heart Rate, Cadence, and Vertical Oscillation