Let’s face it: Getting in a long ride sometimes just isn’t an option. There are times when it’s all you can do to sneak in a brief trainer session or neighborhood spin. Fortunately, a half hour is all you need for a quick – but effective – workout to build and maintain fitness.

For days when you’re time-crunched, try one of these five 30-minute workouts. Each workout details what to do, how long to do it for, and at what level. The level indicated is your RPE (rate of perceived exertion), so on a scale of 0 to 10, 0 is easier than a soft pedal while 10 is an all-out, eye-crossing effort.

1. Rock the Block

These sustained, tough efforts increase your calorie burn while helping build your tolerance to riding above of your comfort level.

2. Ramp Jump

Don’t worry, this isn’t about catching air. It’s about ramping up your effort to full throttle, keeping it in the red for just a little longer, bringing it back down to recover, and then doing it all over again. These ramping intervals help you hang on in a pack when the pace gets peppery.

3. Flick the Switch

Lace up the gloves and get in the ring for this punchy workout. These repeated full-gas efforts suck up tons of energy and help raise your fitness ceiling so you can ride faster and longer, with less fatigue.

4. Old School HIIT

Tabatas are named after their originator Japanese scientist Dr. Izumi Tabata, who cooked up the interval scheme with his team of researchers at the National Institute of Fitness and Sports in Tokyo in the 1990s. They’re designed to train both your aerobic and anaerobic systems in a very short amount of time.

5. Riding the Line

To improve your sustainable power, you need to ride that razor’s edge right below your threshold and then a hair over it to coax your body to be better and clearing lactate. These intervals will help. They’re easiest to do on a moderate climb, but you can also do in a big gear on flat roads or on the trainer.

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