The horizontal bar, also known as the high bar, is an apparatus used by male gymnasts in artistic gymnastics. It traditionally consists of a cylindrical metal (typically steel) bar that is rigidly held above and parallel to the floor by a system of cables and stiff vertical supports. Gymnasts typically wear suede leather grips while performing on the bar. Current elite-level competition uses a more elastic fiberglass core rail similar in material to the rails used in the women’s uneven bars and men’s parallel bars apparatus.
引用元：Horizontal bar – Wikipedia https://en.wikipedia.org/wiki/Horizontal_bar
Parallel bars are floor apparatus consisting of two wooden bars slightly over 11 feet (340 cm) long and positioned at roughly hand height. Parallel bars are used in artistic gymnastics and also for physical therapy and home exercise. Gymnasts may optionally wear grips when performing a routine on the parallel bars, although this is uncommon.
引用元：Parallel bars – Wikipedia https://en.wikipedia.org/wiki/Parallel_bars
The uneven bars or asymmetric bars is an artistic gymnastics apparatus. It is made of a steel frame. The bars are made of fiberglass with wood coating, or less commonly wood. The English abbreviation for the event in gymnastics scoring is UB or AB, and the apparatus and event are often referred to simply as “bars”. The bars are placed at different heights and widths, allowing the gymnast to transition from bar to bar. A gymnast usually adds white chalk to the hands so that they can grip the bar better.
引用元：Uneven bars – Wikipedia https://en.wikipedia.org/wiki/Uneven_bars