We all dream of a flat stomach and great abs. So, it’s no surprise that we still see secured feet sit-ups proliferating in gyms and homes around the country. However, those sit-ups may be wrecking the muscles that keep your spine healthy and pain-free, whether you’re 18 or 68.
What happens?
Your powerful hip flexors (the big muscles that run from your thighs to your lower spine) take over the movement. They pull your pelvis forward like a lever, jamming your lower back into the floor and putting enormous stress on the small, deep stabilisers that are supposed to protect your spine—the multifidus and transversus abdominis.
These tiny “core heroes” switch off under the strain. Over weeks and months, they weaken, tire, or stop firing properly.
The result? A back that feels fine today but starts aching tomorrow, or worse, sets you up for disc problems down the track.
People carrying extra belly fat are often hit hardest. They crank out even more reps, hoping to “burn the fat away.” Yet spot-reducing doesn’t work. You can’t out-crunch your waistline, and the harder you push with bad form, the more you punish your spine.
Why?
- Repetitive overload: Your spine has a limited number of safe bending cycles in a lifetime. Think of the farmer or long-time gardener whose back eventually protests after decades of the same forward-bending motion.
- Crushing compression: A standard crunch can generate around 2,000 Newtons of force through your lower back — far more than discs can sustain.
- Hip-flexor tug-of-war: The psoas muscle attaches directly to your lumbar vertebrae. When it dominates, it pulls your lower spine out of its natural curve, creating shear forces that add up silently over time.
- Silent damage: The pain often shows up years later, long after the bad habit has done its work.
What to do!
- Alternating Superman. On all fours, brace, extend one arm forward and the opposite leg back. Hold, then switch sides. It teaches your deep stabilisers to fire while keeping your spine neutral—exactly what the anchored sit-up fails to do.
- Dead Bug Lie on your back, knees bent at 90 degrees, arms pointing at the ceiling. Press your lower back into the floor, then slowly lower one arm overhead and the opposite leg toward the ground. Return and swap sides.
- Leg Raises with a Twist Lie on your back, legs straight up at 90 degrees (or slightly bent if that’s more comfortable). Lift your hips just off the mat, then lower them with control, your lower back never arches.
Train abs properly – you’ll look better and your future spine will thank you!
