Exercise
AIR BIKE
Form cues
About
The air bike — also called the bicycle crunch — is a bodyweight abdominal exercise that simultaneously targets the rectus abdominis and obliques through rotational spinal flexion paired with alternating hip extension. Unlike standard crunches, the cycling leg movement increases hip flexor involvement and raises the metabolic demand, making it one of the highest EMG-rated ab exercises in electromyography research. It requires no equipment and fits naturally into any core circuit.
Instructions
Step-by-step technique
Lie on your back
Lie flat with knees bent and feet hovering just above the floor. Lace your fingers lightly behind your head — the weight of your hands should rest there, not pull on your neck.
Fingers lace, not gripLift your shoulder blades
Curl your shoulder blades off the mat by contracting the upper abs. Keep your lower back in contact with the floor. This is your starting position for every rep.
Shoulder blades stay lifted all setRotate and extend
Exhale, rotate your right shoulder toward your left knee while simultaneously extending your right leg straight out low to the floor. The rotation drives from your ribcage, not just your elbow.
Ribcage rotates, leg extends fullySwitch sides with control
Without flopping back to the mat, rotate to the opposite side — left shoulder to right knee, left leg extends. Keep the transition deliberate rather than letting momentum take over.
Controlled switch, no floppingMaintain tension throughout
Continue alternating for the full set while keeping the core continuously engaged. Resist the urge to let your lower back arch as you fatigue. If it does, stop, reset, and continue with fewer reps.
Lower back stays neutral the whole setCommon mistakes
What goes wrong — and why
Pulling on the neck
Yanking the head forward with the hands creates cervical strain and only moves the elbows — not the thoracic spine — reducing oblique activation.
Soften your grip completely. Imagine your hands are just resting on your head for support. The rotation comes from your abs, not your arms.
Not extending the opposite leg
Keeping both legs bent removes the lengthening component that increases hip flexor engagement and reduces the rotational demand on the obliques.
Fully extend the non-working leg so it hovers 6–12 inches above the floor. This creates the full bicycle pedaling motion.
Moving too fast
Racing through reps turns the exercise into a momentum exercise. The obliques are barely recruited and the hip flexors dominate — which is the opposite of the intended stimulus.
Slow to a 2-second rotation per side. You will likely need to reduce the rep count, but the quality of ab activation increases dramatically.
Variations · Progressions · Regressions
Adaptations for every level
Lying Knee Twist
Keep both knees bent and simply rotate the knees side to side while the upper body stays still. Builds rotational core awareness without the full crunch component.
Dead Bug
Lying on your back, extend opposite arm and leg simultaneously from a tabletop position while pressing your lower back into the floor. Longer lever arms and anti-extension demand make it more core-stability focused.
Weighted Bicycle Crunch
Hold a light weight plate behind the head or a medicine ball at the chest to increase resistance. Alternatively, anchor the feet and perform cable rope bicycle crunches.