Often called simply trial/s (with or without the plural "s"), this is a non-speed event on specialized motorcycles. The sport is most popular in the United Kingdom and Spain, though there are participants around the globe.

Modern trials motorcycles are distinctive in that they have evolved to become extremely lightweight, lack seating (they are designed to be ridden standing up) and have suspension travel that is short, relative to a motocross or enduro motorcycle.

Motorcycle trials are often utilized by competitors in other motorcycle sports (such as enduro, motocross or road racers) as a way to cross-train, as trials require fine throttle, balance, and machine control.

The event is split into sections where a competitor rides through an obstacle course while attempting to avoid touching the ground with their feet. The obstacles in the course may be of natural or constructed elements. 

In all sections, regardless of content, the designated route is carefully contrived to test the skill of the rider. 

In many locally observed trials events, the sections are divided into separate courses to accommodate the different skill level of riders, who compete in skill-rated classes.

In every section, the competitor is scored by an observer (hence the sport's name) who counts how many times the competitor touches the ground with the foot (or any other part of the body). 

Each time a competitor touches the ground with a foot (commonly called "dabs" or "prods"), the penalty is one point.

The possible scores in each section consist of 0, 1, 2, 3, or 5. If a competitor makes their way through the section without touching the ground with a foot, they earn a score of 0 (which is called "cleaning the section"). 

If they touch the ground once, they receive a score of 1. If they touch down twice, they receive a score of 2. 

If they touch the ground three or more times, they earn a score of 3—as long as they complete the section without stalling the motor, dismounting, going out of bounds, or going backward. 

If the competitor fails to complete the section a score of 5 (sometimes colourfully called "a fiasco") is earned. 

The winner is the competitor with the fewest points at the end of the event. Some events are also timed with penalty points assessed to late riders.

https://en.wikipedia.org/wiki/Motorcycle_trials

For complete CMA Trials Rules go to this Sites Rules and Regulations Tab, then the Trials Competition Rules