Inaccurate depiction of lighting conditions in the filmed scene.

The distortion of a measured distance, due to an offset camera angle.

The misinterpretation of an object's length change as it moves towards or away from the camera.

The blurring effect caused by rapid movement in the frame.

Displacement or difference in the apparent position of an object viewed along two different lines of sight.

Presence of a flight phase.

Take-off and Landing phases with propulsive and braking forces, respectively.

Equal distribution of stance and swing phases.

Presence of a single-support phase.

Same stride length regardless of speed.

To make sure the video camera is recording in high definition.

To identify individual anatomical landmarks for tracking.

To improve the lighting conditions for clearer images.

To convert pixel coordinates into real-world units, like metres.

To check the subject’s starting position on the video frame.

Toe-off of one foot to the next heel strike of the opposite foot.

Heel strike of one foot to the next heel strike of the same foot.

Toe-off of one foot to the next toe-off of the same foot.

Heel strike of one foot to the next heel strike of the opposite foot.

Heel strike of one foot to the next toe-off of the same foot.