Flight time
The milliseconds both feet are off the ground between one foot's push-off and the next foot's landing.
Why it matters
Flight time relative to ground contact time reveals whether you are moving efficiently forward or bouncing upward and wasting energy.
What it means
Flight time plus contact time defines the gait cycle. Excessive flight time relative to contact time often signals high vertical oscillation — bouncing instead of moving forward. Sprinters have long flight times relative to short contact times; efficient distance runners aim for a lower ratio, favoring quick, springy contacts over big vertical pops.
Related reading
The complete guide to running form analysis