Exercise guide
Bottoms-Up
- Beginner
- Isolation
- Rep-based
- Waist
The Bottoms-Up is a highly effective lower-abdominal exercise that focuses on posterior pelvic tilt to engage the deep core and obliques while improving hip stability.
Reviewed by the Crucible Fit team · Updated June 2026
Muscles worked
Setup
- Lie flat on your back on a mat with your arms extended by your sides and palms facing down for stability.
- Bring your knees toward your chest so your thighs are perpendicular to the floor and your knees are bent at a 90-degree angle.
- Press your lower back firmly into the floor to eliminate any arch and pre-engage your core.
How to do it
- Exhale as you use your lower abdominals to lift your hips and lower back off the floor, curling your pelvis toward your ribcage.
- Drive your feet toward the ceiling in a controlled, vertical motion rather than swinging your knees toward your head.
- Inhale as you slowly lower your hips back to the starting position, maintaining constant tension in your abs.
- Follow a controlled tempo, pausing for one second at the peak of the contraction.
Form checklist
- Keep your head and shoulders relaxed on the floor throughout the movement.
- Avoid using your arms to aggressively push off the ground; use them only for balance.
- Ensure your lower back makes full contact with the floor at the bottom of every rep.
- Focus on a vertical lift of the sacrum rather than a horizontal rocking motion.
Pro tips
- Imagine trying to 'stamp' the ceiling with your heels to ensure the movement is driven by abdominal contraction rather than hip flexor momentum.
- Squeeze your inner thighs together to increase pelvic floor engagement and stabilize the pelvis.
Make it harder
- Perform the movement with straight legs to increase the lever length and resistance on the lower abs.
- Add a three-second eccentric (lowering) phase to maximize time under tension.
Frequently asked
- What muscles does the bottoms-up work?
- The bottoms-up primarily targets the abs and obliques, and also works the erector spinae as secondary muscles.
- What equipment do you need for the bottoms-up?
- The bottoms-up requires no equipment — just your body weight.
- Is the bottoms-up good for beginners?
- Yes. The bottoms-up is a beginner-friendly movement and a strong foundation to build on.