Bike (Assault Bike) — CrossFit Technique Guide
Assault Bike (fan bike) cycling is CrossFit's most notoriously demanding cardio modality. Unlike a standard stationary bike, the Assault Bike uses both arms and legs simultaneously, with air resistance that scales with effort — the harder you push, the harder it gets. In WODs, bike is typically prescribed in calories. The Assault Bike is used for short, high-intensity intervals and as a warm-up tool, but also appears in longer conditioning pieces for athletes with lower-body injuries who cannot run. Its reputation is well-earned: a max 10-second sprint on the Assault Bike produces one of the highest heart-rate responses of any exercise.
Muscles Worked
Equipment
Watch the movement demo
Video tutorial on YouTube — opens in new tab
How to Do the Bike
Adjust seat height: leg should be nearly fully extended at the bottom of the pedal stroke.
Grip the handles firmly — you will push AND pull throughout.
Begin with even push-pull on handles coordinated with the pedal stroke.
For high-intensity efforts: drive the legs hard, pull handles toward you, push them away simultaneously.
Maintain an upright torso — do not collapse forward when fatigued.
Monitor RPM and calorie output to maintain consistent effort across the workout.
Common Mistakes
Using only the legs — the Assault Bike is not a regular stationary bike. The upper body contributes significantly.
Setting saddle too high or low — incorrect height reduces power and increases joint stress.
Sprinting at maximum effort in long WODs — the Assault Bike punishes uneven pacing severely.
Coaching Tips
Find a sustainable RPM you can hold for the entire prescribed calorie count before red-lining.
For max-effort sprint intervals, an all-out 10-second effort on the Assault Bike produces extreme HR spikes — use for testing or Tabata.
"Pace yourself" advice is especially critical on the Assault Bike — most athletes go out too hard and crater in the second half.
Scaling Options
Easier / Beginner
Reduce calories, substitute with 400m run or 500m row.
Harder / Advanced
Higher target RPM, or add a time cap to force intensity across the set.
Frequently Asked Questions
Why is the Assault Bike so much harder than other cardio equipment?
The Assault Bike uses air resistance that scales with effort — there is no ceiling. It also requires simultaneous upper and lower body work, engaging more total muscle mass than running or rowing alone. This creates a cardiovascular demand that can be overwhelming, especially for athletes who are strong but lack upper-body cardio conditioning.
Related Exercises
Ready to put the Bike to work?
Generate a WOD that includes this movement, calibrated to your level and equipment.