Races typically take place in the autumn and winter (the international or "World Cup" season is October–February), and consist of many laps of a short (2.5–3.5 km or 1.5–2 mile) course featuring pavement, wooded trails, grass, steep hills and obstacles requiring the rider to quickly dismount, carry the bike while navigating the obstruction and remount.

[1][2] Races for senior categories are generally between 40 minutes and an hour long,[3] with the distance varying depending on the ground conditions.

The sight of competitors struggling up a muddy slope with bicycles on their shoulders is the classic image of the sport, although unridable sections are generally a very small fraction of the race distance.

Compared with many disciplines of road and track cycle racing, tactics are fairly straightforward, and the emphasis is on the rider's aerobic endurance and bike-handling skills.

Forced running sections, or portage, were incorporated to help deliver warm blood to the feet and toes, as well as exercise other groups of muscles.

[4] Géo Lefèvre, the originator of the idea for the Tour de France, also played a key role in the early days of the sport.

The Cyclo-cross National Championships restarted in 1975 in Berkeley, CA and have continued to be held every year at various locations throughout the United States.

The Surf City race series held in Santa Cruz, CA has contributed to the history of cyclo-cross in the United States.

[8] Cyclo-cross races are now regularly held in the fall and winter seasons throughout the United States and continue to grow in popularity.

Over time as the sport became more formalized, frame angles changed for quicker handling and bottom brackets heights were raised to clear broken ground.

In addition, single speed cyclo-cross bikes are becoming increasingly popular for a variety of reasons, including lower initial cost of setup, ease of use and maintenance, and decreased likelihood of mechanical failure on the course.

While many racers will use standard two-piece road kits, there is a very strong preference to wear one piece skinsuits to maximize freedom of movement.

The other advantage of skinsuits is that they are tighter, preventing the jersey from getting caught on stray tree branches during some singletrack sections of the race course.

Experienced riders racing in dry conditions may eschew gloves, presumably for better tractional feedback though the handlebar, and more natural bike portage.

Instead, tactics are chiefly focused on line choice, pacing strategy, passing technique, and racers' ability to identify and exploit sections of the course that are conducive to attacking or recovery.

This not only allows a standard length course to fit in a relatively small area, but also forces competitors to constantly change speed and effort.

Obstacles that force a rider to dismount and run with their bike or to "bunny hop" include banks too steep to ride up, steps, sand pits and plank barriers.

Most of these conditions are usually considered too extreme to be ridden with the standard 32c tire, and so much of the challenge of cyclo-cross lies in maintaining traction through loose or slippery terrain at speed.

Also common are steps, barriers, ditches, stairs, steep slopes and very deep mud or sand which all require running while carrying the bicycle.

[12][13][14] Therefore the ability to fluidly dismount at speed, pick up and carry the bike, then put it back down and remount without losing momentum is key, and a faulty or slow dismount/remount may cost valuable seconds, waste energy or cause the competitor to crash.

Often, when sections are extremely technical or become impossible to ride due to erosion from repeated wear or inclement weather, the racer will carry the bike and jog for an extended time to save energy.

A more recent development to overcome obstacles such as barriers and sometimes ditches is the bunnyhop, a technique which came to prominence in 1989 when Danny De Bie used it in his successful World Championship run.