What is TCI? How does it relate to shoe support?
The Torsion Control Index (TCI) is a measurement of shoe stability through the mid-foot portion of the shoe and is indicated in inch-pound units (in.-lbs.). TCI is measured through actively twisting a shoe along the long axis of the shoe, simulating rotational forces of the foot, and then recording the shoe’s resistance to this motion. After applying standard hindfoot and forefoot pressure, each shoe is twisted through the portion of the shoe where foot rotation naturally occurs, and through a set number of degrees. The amount of torque required to complete this motion is registered as the TCI. A higher TCI, as generally seen in shoes of higher stability, indicates a greater ability of the shoe to control the rotational forces of the foot, as seen in pronation and supination.
