Reading step velocity, contact & flight time

TrackStat captures the spatiotemporal parameters of a sprint: the timing and distance of every step. On their own they’re just numbers. The skill is reading them together to understand how an athlete is moving — and what to change.

The core metrics

Metric	What it is	Units
Step length	Distance covered in one step	m
Contact time	Time the foot spends on the ground	s
Flight time	Time airborne between steps	s
Step frequency	Steps per second	Hz
Step velocity	Step length × step frequency	m/s

Step velocity is the headline

Step velocity is what wins races, and it’s the product of exactly two things:

Step velocity = step length × step frequency

That simple relationship is the whole game. A faster athlete takes longer steps, quicker steps, or both. So when you want to make someone faster, you’re really asking one question: which of those two has the most room to improve?

Contact and flight time tell you how

Two athletes can post the same step velocity in very different ways:

• Short contact, longer flight — a bouncy, elastic sprinter applying force fast.
• Longer contact, shorter flight — a more push-dominant, grinding pattern.

Neither is “wrong”, but the pattern points at the work. Long ground contacts at max velocity, for example, often point to a strength or stiffness limitation better addressed in the gym than on the track.

Putting it to work

1. Establish a baseline from clean footage — filmed the way our filming guide describes, so the numbers are worth trusting.
2. Read the pattern, not a single number. One step’s contact time is noise; the average across a rep is signal.
3. Pick the one lever with the most room — length or frequency — and train it deliberately.
4. Re-measure after the training block, marking your frames by the same rule every time, and compare.

That last step is where TrackStat earns its place: because every analysis lands on the athlete’s profile, you watch the trend across a whole season instead of arguing about one Tuesday’s numbers.