Bouldering is a test of strength, power endurance and rigorous technique as athletes climb very short, difficult climbs without rope. As it is without rope, the climbs rarely exceed 4-5 meters in height. There are four main formats used in competition, each with their own set of rules: Scrambles, modified scrambles, 5 on 5 off, and world cup format.
Perhaps the most common in the younger groups, scrambles (or, redpoint, in the United States) are typically 35-75 boulder problems set in relative difficulty to each other. As a general rule, the problems are numbered 1-Highest with 1 being the easiest and increasing in difficulty as you increase in number. Thus, the harder problems are worth more points. An athlete's final score is based off of their number of attempts (1st, 2nd or 3rd+) taken on their top 5 or 6 climbs topped.
A modification on scrambles, these competitions only have 7 or 8 boulder problems that tend to be more difficult than regular scramble problems. The key differences between mod. scramble and regular scramble is the attempts allowed and the presence of the "zone," which acts as a sort of half-way marker for each boulder problem. As ties are frequent, the order of importance goes: Number of tops, attempts to tops, number of zones, attempts to zones.
Note: To be awarded a zone an athlete must show control and use of the zone hold by shifting their center of gravity while holding the zone hold.
5 on 5 off
The more formal and internationally recognized format, this is the format used in most upper level youth competitions, adult competitions as well as semi-finals and finals formats. The idea is simple. Athletes are not to look at the problems before climbing them. They are kept in a designated isolation area until it is their turn to climb the 4-5 boulder problems set for their category and gender. At this time the athlete will have 5 minutes to climb each boulder problem with 5 minutes of rest in between each problem. The same scoring rules that apply for mod. scrambles apply in 5 on 5 off.
A format used almost exclusively in high-level youth and adult finals, world cup format is essentially the same as 5 on 5 off, however only one climber climbs at a time and they only have 4 minutes to climb each of 4 problems. Everything else is kept the same.