How do you measure stance phase and stance time?

Stance is the part of the gait cycle when a foot is in contact with the ground, roughly 60 percent of the cycle at usual walking pace. Measuring it means detecting two events per limb — initial contact and toe-off — and timing the interval between them. It is reported in seconds or as a percentage of the gait cycle, separately for each limb.

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What stance phase is

Stance begins at initial contact, when the foot first touches the ground, and ends at toe-off, when it leaves. Everything in between is stance; the remainder of the cycle is swing.

Stance subdivides further — loading response, mid-stance, terminal stance, and pre-swing — and overlaps with the opposite limb during the two double-support periods of each cycle. Single support is the interval when only the limb in question is loaded.

Detecting the two events

Every stance measurement reduces to how accurately initial contact and toe-off are identified. Methods differ in what signal they use.

MethodSignal used to find the events
Force plate or instrumented walkwayVertical ground reaction force or plantar pressure rising above and falling below a threshold. Generally treated as the reference.
Foot-mounted inertial sensorsCharacteristic acceleration and angular velocity patterns at heel strike and toe-off.
Marker-based motion captureKinematics of foot and heel markers, using vertical position and velocity minima.
Markerless, video-based pose estimationEstimated ankle, heel, and toe key point trajectories across frames, using the same kinematic logic without physical markers.

How stance is reported

  • Stance time in seconds, per limb.
  • Stance as a percentage of the gait cycle, which normalizes for walking speed and is usually the more comparable form.
  • Single and double support time, which separate loaded-on-one-leg from loaded-on-two.
  • Stance symmetry — the ratio or difference between limbs, often the most informative single number when one side is affected.

Stance time in seconds shortens as walking speed increases. Comparing raw stance time between visits without accounting for speed can suggest a change that is only a change in pace.

Why stance is often the informative part

When a limb is painful, weak, or unstable, a common response is to spend less time loaded on it and more time in double support. That shows up in stance timing and in symmetry, sometimes while overall walking speed is still within a normal range.

Validation work on markerless systems has generally found spatiotemporal measures including stance time to agree well with reference systems, while noting that measures depending on narrow lateral distances, such as stride width and some single-limb support values, agree less well.

Where CurveAssure fits

CurveAssure estimates body key point positions across the recorded walk, which is the input from which contact events and phase timing are derived. For the Timed Up and Go, the report separates the stand, walk, turn, and sit portions of the task rather than returning only a total time.

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