An adjustable roller skate includes a skate device and a boot body. The boot body includes a base frame having a bottom side coupled to the skate device, an insole platform having a rear heel portion and a front toe portion frontwardly extended therefrom, and a vamp cover attached to the front toe portion of the insole platform. The insole platform is slidably coupled at the base frame to define an adjustable accommodating cavity between a rear end of the base frame and a front end of the insole platform, wherein the insole platform is frontwardly slid to extend the adjustable accommodating cavity at its maximum size and is rearwardly slid to reduce the adjustable accommodating cavity at its minimum size.

A wearable article such as an article of athletic gear (e.g., a skate, an article of protective athletic equipment such as a helmet, etc.) wearable by a user and comprising an expandable user-engaging structure that is configured to be expanded (e.g., by heat or another stimulus) after manufacturing of the wearable article to conform it to the user or otherwise improve a fit of the wearable article on the user.

A size-adjustable sport shoe includes a shoe head, a shoe insole, and an adjusting telescopic device including a gear, a shaft gear, first and second gear racks, and handle. The first and second gear racks are located at two lateral sides of an elongated adjustment groove at the shoe head, wherein the upper surface of the second gear rack is lower than the upper surface of the first gear rack. The gear shaft is coupled between the gear and the handle. When the handle is folded perpendicularly to an axis direction of the gear shaft, the gear meshes with the first gear rack to lock up the shoe head at the shoe insole. When the handle is folded to coincide with the axis direction of the gear shaft, the gear meshes with the second gear rack to allow the shoe head to be slid from the shoe insole.

A size-adjustable sport shoe includes a shoe head, a shoe insole, and an adjusting telescopic device including a gear, a shaft gear, first and second gear racks, and handle. The first and second gear racks are located at two lateral sides of an elongated adjustment groove at the shoe head, wherein the upper surface of the second gear rack is lower than the upper surface of the first gear rack. The gear shaft is coupled between the gear and the handle. When the handle is folded perpendicularly to an axis direction of the gear shaft, the gear meshes with the first gear rack to lock up the shoe head at the shoe insole. When the handle is folded to coincide with the axis direction of the gear shaft, the gear meshes with the second gear rack to allow the shoe head to be slid from the shoe insole.

A size-adjustable sport shoe includes a shoe head, a shoe insole, and an adjusting telescopic device including a gear, a shaft gear, first and second gear racks, and handle. The first and second gear racks are located at two lateral sides of an elongated adjustment groove at the shoe head, wherein the upper surface of the second gear rack is lower than the upper surface of the first gear rack. The gear shaft is coupled between the gear and the handle. When the handle is folded perpendicularly to an axis direction of the gear shaft, the gear meshes with the first gear rack to lock up the shoe head at the shoe insole. When the handle is folded to coincide with the axis direction of the gear shaft, the gear meshes with the second gear rack to allow the shoe head to be slid from the shoe insole.

A protective cover for an article of footwear can include a first portion covering the top and sides of the footwear and a second portion covering the back of the footwear. The first portion can include locations to receive at least part of a connecting mechanism, and the second portion of the cover can be connected to the first portion of the cover by the connecting mechanism.

A size-adjustable sport shoe includes a shoe head, a shoe insole, and an adjusting telescopic device including a gear, a shaft gear, first and second gear racks, and handle. The first and second gear racks are located at two lateral sides of an elongated adjustment groove at the shoe head, wherein the upper surface of the second gear rack is lower than the upper surface of the first gear rack. The gear shaft is coupled between the gear and the handle. When the handle is folded perpendicularly to an axis direction of the gear shaft, the gear meshes with the first gear rack to lock up the shoe head at the shoe insole. When the handle is folded to coincide with the axis direction of the gear shaft, the gear meshes with the second gear rack to allow the shoe head to be slid from the shoe insole.