Oblique Crunches
Oblique crunches are a bodyweight ab exercise where you curl and twist your upper body toward the opposite knee, targeting the obliques along the sides of your core rather than the straight line of muscle down the front. It's a beginner-friendly move that needs no equipment, making it an easy addition to any core routine or a quick session on the floor at home.
Why it works
The obliques run diagonally along the sides of your torso, so a straight-ahead crunch that only flexes the spine forward barely touches them. Adding rotation, twisting your ribcage toward the opposite hip while your pelvis stays still, puts those diagonal fibers under tension the way a plain crunch can't. Because it's an isolation move rather than a full-body compound lift, you can do a meaningful set without needing any added load or equipment.
Set up
- Lie on your back with your knees bent and feet flat on the floor.
- Place your fingertips lightly behind your ears or temples, elbows out wide, without clasping your hands and pulling on your neck.
- Engage your core so your lower back stays gently pressed toward the floor.
How to do it
- Curl your shoulder blades off the floor using your abs, not your arms.
- Rotate your ribcage toward one knee as you curl up, leading with your shoulder rather than your elbow.
- Pause briefly when you feel the squeeze on that side of your waist.
- Lower back down with control until your shoulder blades touch the floor again.
- Repeat the curl and twist toward the other side.
- Continue alternating sides for the set, keeping your hips still throughout.
Form cues
- Lead the twist with your shoulder, not your elbow.
- Keep your hips and lower back quiet on the floor.
- Squeeze at the top of each twist before lowering.
- Move slow enough to feel the obliques, not momentum.
Breathing: Exhale as you curl and twist up, inhale as you lower back down.
Common mistakes
Pulling the head forward with the hands to force the crunch up.
Fix: Rest your fingertips lightly and let your abs do the lifting; your hands are just support, not a lever.
Rocking the hips or letting the lower back arch off the floor.
Fix: Keep your feet planted and your lower back gently pressed down so the movement stays isolated to your upper torso.
Yanking the elbow toward the knee instead of rotating the ribcage.
Fix: Think of turning your chest toward the ceiling and then the opposite hip, not just swinging an elbow across.
How to program it
- Two to three sets of 12 to 15 reps per side is a solid starting point for a beginner bodyweight move like this.
- Since it's a small isolation exercise with a low fatigue cost, it works well tacked onto the end of a workout rather than as a standalone session.
- Slow the tempo down, roughly a two-count up and a two-count down, once the standard pace stops feeling challenging, instead of just adding more reps.
Safety notes
- Stop if you feel the movement in your neck instead of your abs, and lighten the hand position.
- Skip loading this exercise with extra weight until the bodyweight twist is fully controlled on both sides.
Exercise profile
- Force
- Pull
- Mechanics
- Isolation
- Category
- Strength
Frequently asked questions
How many reps of oblique crunches should I do?
12 to 15 reps per side for 2 to 3 sets is a good starting range. Once that feels easy, slow the tempo down before adding weight.
Can I do oblique crunches without any equipment?
Yes, this version only needs a floor. If you want more resistance later, holding a light weight against your chest works well.
Why don't I feel oblique crunches in my sides?
You're probably crunching straight up instead of rotating. Focus on turning your ribcage toward the opposite hip rather than just lifting your shoulders.
Oblique crunches vs regular crunches: what's the difference?
A regular crunch flexes the spine straight forward and mainly hits the front abs. Oblique crunches add rotation, which shifts more of the work to the muscles along the sides of your waist.