The main goal in the sport of roller derby is to score points by having designated players, known as "jammers," lap members of the opposing team while simultaneously playing strong defense to prevent the opposing team's jammer from doing the same. Roller derby is a fast-paced, full-contact, and highly strategic sport played on roller skates. Here are the key objectives and elements of roller derby:

1. Scoring Points: The fundamental objective in roller derby is for a team's jammer to pass members of the opposing team, known as blockers and pivots, while skating around the track. Each opponent a jammer passes legally earns their team one point. Jammers aim to complete as many laps as possible during a "jam" (a two-minute period) to accumulate points for their team.

2. Offense and Defense: Roller derby is unique in that it combines offensive and defensive plays simultaneously. Teams must balance their efforts between assisting their jammer in scoring points while preventing the opposing jammer from passing their blockers. Blockers and pivots use their bodies to create walls and obstacles to impede the progress of the opposing jammer.

3. Lead Jammer: The first jammer to legally pass all opposing blockers in a jam earns the status of "lead jammer." The lead jammer has the strategic advantage of being able to call off the jam prematurely by tapping their hands on their hips. This can be used strategically to prevent the opposing jammer from scoring additional points.

4. Pack and Penalties: Both teams form a "pack," which includes blockers and pivots, while the jammers attempt to pass through them. Roller derby has strict rules regarding legal blocking zones and the use of elbows, forearms, and other body parts. Players who commit penalties may be sent to the penalty box, temporarily reducing their team's strength on the track.

5. Strategy: Roller derby is a highly strategic sport where teams employ tactics to control the pace of the game, protect their own jammers, and hinder the opposing team's progress. Strategies may include offense to create scoring opportunities or defense to block and impede the opposing jammer.

6. Teamwork and Communication: Effective teamwork and communication are vital in roller derby. Skaters must work together to execute plays, provide offense for their jammer, and build strong defensive walls.

7. Safety: Roller derby values safety and sportsmanship. Players wear protective gear, including helmets, mouthguards, knee and elbow pads, and wrist guards to minimize the risk of injury.

Roller derby is a physically demanding and exciting sport that requires a combination of agility, strength, strategy, and endurance. It is known for its vibrant and inclusive community of athletes and fans. Roller derby competitions, often held in "bouts" or matches, provide thrilling and action-packed entertainment for spectators while showcasing the athleticism and skill of the participants.