Perform accelerations. Criteriums involve constant accelerations and recoveries, so your body must be conditioned to handle them. High intensity intervals on the bike can help you master attacks and breakaways. For example, after a five- to ten minute warm-up, sprint as hard as you can for one minute and then recover at an easy spin for another minute. Repeat the intervals for 10 to 20 minutes, and then end the workout with a moderately intense, steady-state ride of 20 to 30 minutes.
Participate in short, intense group rides. Since criteriums rarely last longer than an hour, it's not necessary to do four-hour endurance rides as a part of your training. Instead, opt for shorter rides of one to two hours with riders who maintain an intense pace for the duration. As a bonus, practice your attacks and breakaways if you train with other racers and the group permits it.
Practice your technical skills. Criteriums usually involve tight turns and require excellent bike handling skills. Have a friend or group of cyclist’s help you get comfortable with the close quarter contact of criteriums racing. At low speeds, practice your recoveries by making light handlebar or shoulder contact with other riders. If you're new to cycling, do this in a grassy field in case you fall.
Train off the bike. Although the majority of criterium training should be done in the saddle, resistance training and plyometric will help you to further develop the explosive, anaerobic power you'll need to perform well. Use moderate to heavy resistance when weight training, and incorporate plyometric exercises such as box jumps and wind sprints to dial in your criterium training.
Talk with your doctor before beginning an exercise program. Always keep bike safety in mind and never ride without a helmet. Respect the rules of the road and avoid training in high traffic areas. If you must ride with traffic, keep yourself visible to drivers by wearing bright-colored clothes, and don't ride in low-light conditions. Criteriums can be intimidating for someone new to cycling, and it's important that you're completely comfortable with your bike handling skills before taking on a race. Close-quarter riding when you aren't confident on the bike can cause crashes.
If possible, ride the course before the race. It's good to familiarize yourself with the turns and the course length ahead of time so you can plan your accelerations and recoveries. If you can't ride the exact course, at least study it and practice your turns on a comparable course.