In summary, here is a brief description of the six events male gymnasts compete in:
Composed predominantly of acrobatic elements that are combined with gymnastic elements such as strength, balance, elements of flexibility, handstands, etc. All of these elements form a fluid, rhythmic exercise which is performed using the entire floor exercise area (12m x 12m).
Pommel Horse (a.k.a. “Horse”) / Mushroom
Characterized by pendulum swings and by different types of circular swings with legs apart and together. These swings are done in a variety of support positions using all parts of the “horse”. Swings through handstand, with or without turns, are permitted. All elements on “horse” must be executed with swing and without the slightest interruption. Strength and hold elements are not permitted. At the younger levels, a mushroom is used both as a training tool and for competition.
Composed of swing, strength, and hold parts in approximately equal portions. These parts and combinations are executed in a hang position, to or through a support position, or to or through the handstand position, and execution with straight arms should be predominant. Routines are characterized by transitions between elements of swing and strength or the reverse. Swinging of the cables and the crossing of the cables is not permitted.
Consists of one or two vaults, depending on the competition. Each vault begins with a run and a take off from both feet (with or without a round off) to the vault board with legs together and is executed with a brief support phase on the horse with both hands. The vault may contain single or multiple flips and twist of the body.
Parallel Bars (a.k.a. “P-bars”)
Consists predominantly of swings and flight elements selected from all element groups (e.g. swing elements through support on both bars). Skills are performed with continuous transitions through various hang and support positions in such a way as to reflect the full potential of the apparatus.
Horizontal Bar (a.k.a. “High Bar”)
Must be a dynamic presentation that consists entirely of the fluid connection of swinging, turning, and flight (release and re-grasp) elements alternating between elements performed near to and far from the bar in a variety of hand grips so as to demonstrate the full potential of the apparatus.
Link to Olympia Booster Club