Beach OCR’s are mass participation events that take advantage of the sand, sunshine and water of beach environments. Formats include individual, mixed team and relay races.

Beach OCR events are held on all continents and many countries with beach access, from England to Indonesia and the middle east.

Combine OCR’s are typically run on 1,000 to 5,000-meter courses and include obstacles that test upper body, lower body, grip and total strength, including functional exercises. Mass starts typically have up to 100  people at a time.

Popular races include Tough Mudder X (TMx), Hyrox, Spartan Crossfit Challenge and the Civilian Military Combine. These events are designed to be spectator friendly, with exciting, head to head racing.

Similar to Adventure Racing, Ultra and set time OCR’s are typically 4, 8, 12 or 24 hours mass participation events with men, women and team competitions. Competitors compete for as many laps as they can in the time allowed. Laps vary up to about 10 km long.

World’s Toughest Mudder is the 24-hour OCR World Championships, with individuals and teams covering as much distance as possible in 24 hours. The Spartan Ultra World Championships is an annual event held over 50 kilometres.

Track OCR’s are sprint to middle distance competitions from 25 meters and up. Individual and mixed relay events can be time trials (one person at a time) or have 2 to 24 people or more on the start line. The 100 m (10 OCR obstacles) and 400 m (12 OCR obstacles) events have established world records and have been held in Games recognised by the International Olympic Committee.

Track OCR is held on athletic tracks, stadiums, streets or other flat areas. Events in popular culture include the Million Dollar Mile competition show on CBS television network in the United States.