Oblique Curl — Feet Flat: A Complete Guide
Quick Intro
Oblique Curl — Feet Flat is a mat Pilates exercise that performs the same rotating curl as Oblique Curl, but keeps both feet planted flat on the mat with the knees bent instead of any tabletop leg position. Giving the legs a stable base takes the hip flexors mostly out of the equation, so the effort can stay focused on rotating the ribcage.
Equipment Needed
No equipment is required. A Yoga Mat is an optional way to pad the spine on a hard floor, nothing more.
Why It Matters
A stable foot position still asks for the same sustained curling effort and rotation range, with less for the legs to do. The waist muscles along the side of the torso (obliques) drive the rotation. The abdominal muscles running down the front of the stomach (rectus abdominis) support the curl underneath the twist, a deep core muscle that wraps around the torso like a corset (transverse abdominis) keeps the hips from rocking and the deep hip flexor (hip flexors, iliopsoas) plays a much smaller supporting role now that the feet are grounded.
When to Do It
This version works well as an entry point into Oblique Curl for anyone whose hip flexors tend to take over before the waist gets much of a workout. Two or three sessions a week is enough to let the rotation settle into the ribcage.
Anyone with a current neck or lower back issue should get individual guidance before adding this exercise, since the rotation still adds demand on top of the underlying curl.
Getting Ready
Running through a few reps of Chest Lift first confirms the underlying curl and the imprinted lower back are both dependable before adding rotation. Pressing both flat feet gently into the mat for a breath, without curling yet, gives an early feel for the stable base this version relies on.
Step-by-Step Instructions
1. The setup. Lie on the back with both feet flat on the mat, knees bent, hands resting lightly behind the head.
2. The curl. Exhale and lift the head and shoulder blades into the same curl height used for Chest Lift.
3. The rotation. Staying in that same exhale, turn one shoulder toward the opposite knee, elbow wide and both feet pressing steadily down.
4. The switch. Inhale to return through center, then rotate to the other side on the following exhale.
How Many, How Often
Oblique Curl — Feet Flat is dosed by reps, with each rotation to one side counting as one.
| Level | Where you’re at | What to do |
|---|---|---|
| Beginner | New to rotating with a grounded foot base | 2 sets of 6 to 8 reps per side, keeping the turn small |
| Intermediate | The rotation feels controlled with the hips staying square | 2 to 3 sets of 10 to 12 reps per side |
| Advanced | Comfortable with a full rotation on both sides | 3 sets of 12 to 15 reps per side, or move to Oblique Curl for a tabletop leg position |
The feet staying grounded and still through every rotation matters more here than how far the shoulder travels, since letting the feet shift or lift is a sign momentum is creeping into a movement meant to stay isolated at the waist.
Modifications and Variations
As a harder version, Oblique Curl lifts the legs into a tabletop position, adding a hip-flexor and stability demand on top of the same rotation.
Common Mistakes to Avoid
Letting the feet shift or lift during the turn. Allowing the planted feet to slide or come up off the mat as the shoulder rotates removes the stable base this version is built around. Pressing both feet down evenly throughout every rep keeps the base steady.
Letting the elbow lead the turn, with the ribcage barely moving. An elbow that swings toward the knee while the ribcage stays nearly still bypasses the rotation this exercise trains through the waist. The turn starts in the ribcage, with the elbow along for the ride.
Letting the hips rock side to side. Allowing the pelvis to tip or rotate along with the shoulder trades a controlled waist rotation for a whole-body rocking motion. Anchoring both hip points level for the whole rep is what keeps the rotation isolated to the obliques.
After Your Set
Hugging both knees in and rolling gently from side to side gives the lower back a chance to settle after a set of repeated rotations. A slow twist toward each side while seated finishes releasing the waist muscles that just did the work.
Going Deeper
This version usually works well as a way to isolate the waist rotation from any hip-flexor assistance, since a grounded foot base takes away the leverage the legs could otherwise use to help. The feet are already on the mat, so it’s tempting to let them press or shift slightly to assist the turn. Keeping the feet still through every rep, even if that means a smaller rotation, trains the obliques better than a bigger twist helped by the legs.
Someone new to this exercise generally manages a controlled rotation to both sides within the first few sessions, then works toward a full set with a still foot position over two to three weeks.
How to Know You’re Improving
- Feet that stay still and grounded through every rotation
- A rotation that comes visibly from the ribcage
- Hips that stay anchored and level through every turn
- Equal rotation reached comfortably on both the left and right sides
Feet that stay planted and hips that stay square matter more than how far the shoulder reaches.
Muscles Worked
- Obliques (the waist muscles along the side of the torso, turning the ribs with both feet resting flat on the mat)
- Rectus Abdominis (the abdominal muscles running down the front of the stomach, supporting the curl underneath the twist)
- Transverse Abdominis (a deep core muscle that wraps around the torso like a corset, keeping the hips from rocking)
- Iliopsoas (the deep hip flexor, playing a smaller supporting role now that the feet are grounded)
FAQ
Why does keeping the feet flat make this easier than the standard Oblique Curl? Lifting the legs into a tabletop position adds a hip-flexor and stability demand on top of the rotation. Keeping the feet flat on the mat removes that added demand, letting the effort stay focused on the waist alone.
Should the feet press hard into the mat? A steady, even press is enough. The goal is stillness, not force, so the feet aren’t adding any extra effort to the rotation.
Is some oblique fatigue after this exercise normal? Yes, fatigue through the waist muscles after several rotations on each side is expected. A sharp, localized pain along the neck or spine is a separate issue, one to raise with a doctor or physical therapist if easing off doesn’t settle it.
How does the standard Oblique Curl differ? Oblique Curl lifts the legs into a tabletop position, which adds a hip-flexor and stability demand this feet-flat version removes by keeping both feet grounded on the mat.
How often should the feet-flat curl be practiced? Two or three times a week, as an entry point before the standard version, builds rotational control at a comfortable pace.
Related to Oblique Curl as the harder version performed with the legs lifted into a tabletop position.