Groin Crunch

beginner strength exercise · body weight · targets abs

Body part: waist
Primary target: abs
Equipment: body weight
Difficulty: beginner

The groin crunch is a focused ab exercise targeting the lower abdominals and inner thighs simultaneously. From a face-up position with the soles of the feet pressed together (knees splayed out to the sides in a butterfly position), you contract the lower abs and inner thighs to lift the hips slightly off the floor while the upper body remains stationary. The combination loads the lower abs and adductors (inner thigh muscles) in one efficient movement. It's particularly useful for trainees who want lower-ab work that simultaneously activates the inner thighs. Most ab exercises ignore the adductors completely, while most adductor exercises ignore the abs. The groin crunch combines both, making it efficient when training time is limited or when you want a single exercise that addresses both areas. The trade-off is the moderate intensity per rep. The combined movement loads neither the abs nor the adductors as heavily as their dedicated exercises do. For maximum strength gain in either area, separate exercises are more effective. But for general fitness training and time-efficient programming, the groin crunch earns its place.

Why train the Groin Crunch?

Trains lower abs and inner thighs (adductors) simultaneously — efficient combination.
Activates muscles that most ab and lower-body exercises ignore.
Easier on the lower back than full sit-ups or weighted lower-ab work.
Requires no equipment and minimal space.
Useful for postural concerns related to weak adductors and lower abs.
Can be done at moderate volume daily without recovery concerns.

How to do the Groin Crunch: step by step

1Lie flat on your back with your knees bent and feet flat on the ground.
2Place your hands behind your head with your elbows pointing outwards.
3Engaging your abs, lift your legs off the ground, bringing your knees towards your chest.
4Pause for a moment at the top, then slowly lower your legs back down to the starting position.
5Repeat for the desired number of repetitions.

Muscles worked

Primary

abs

Secondary

hip flexors, inner thighs

Common mistakes to avoid

Letting the upper body lift instead of the hips
The groin crunch should lift the hips, not the shoulders. If you find yourself doing a partial sit-up, you've shifted the focus away from the lower abs and inner thighs. Keep the upper body relaxed and the shoulders on the floor — only the hips lift.
Not pressing the soles together actively
The butterfly foot position should be active — press the soles into each other firmly throughout the rep. Without this active pressing, the inner thighs don't engage and the exercise becomes a regular reverse crunch.
Using momentum to bounce the hips up
Bouncing the hips off the floor uses momentum and skips the contraction work. Move slowly: 1-2 seconds up, brief pause at the top, 2-3 seconds down. The slow tempo forces the abs and adductors to do the work.
Letting the lower back arch off the floor
If a hand could slide between your back and the floor at the bottom of the rep, you've lost core engagement. Press the lower back into the floor throughout — even at the lowest position.
Choosing it as the primary ab exercise
Groin crunches work as supplementary ab work, not as a primary exercise. Pair them with crunches and planks for complete core development.

Easier and harder variations

Easier

Reduce the range — only lift the hips an inch off the floor. Or perform with the feet flat on the floor instead of in butterfly position, removing the inner thigh component.

Harder

Add a brief hold at the top (1-3 seconds with maximum contraction). Add a leg extension at the top (extend the legs out to the sides at the top of the rep). Or progress to weighted reverse crunches with a different focus.

Alternative exercises

Reverse crunch
Standard lower-ab exercise without the inner thigh component. More direct lower-ab work but less adductor recruitment.
Bridge with adductor squeeze
Glute bridge with a ball or pillow squeezed between the knees. Different position with similar combined glute and adductor focus.
Sumo squat
Standing wide-stance squat that activates the adductors. Different exercise modality but addresses the same muscles.

How to program the Groin Crunch into your training

Groin crunches work as accessory or supplementary core work, not as a primary ab exercise. Pair with crunches, planks, and other core exercises for complete development. Sets and reps: 3 sets of 12-20 reps with 30-60 seconds rest. Total weekly volume of 75-150 reps drives most adaptations. In a complete core circuit: 3 sets of 15 groin crunches, 3 sets of 30-second front planks, 3 sets of 12 reverse crunches, 3 sets of 30-second side planks per side. Done 2-3 times per week. As supplementary work in a hip-focused session: 2-3 sets at the end of a lower body workout. Combines core and inner thigh work without significantly extending the session. Daily groin crunches in moderate volume (30-50 reps) are fine and useful as part of a morning core routine.

Recovery and frequency

Groin crunches at moderate volume have low recovery cost — daily training is fine for most people. The combined lower-ab and adductor demand can leave both areas slightly sore in the first 1-2 weeks of training, but the soreness fades quickly. Inner thigh tightness is the most common feedback. Daily inner thigh stretches between sessions help. The lower abs and hip flexors recover quickly between sessions.

Frequently asked questions

How many sets and reps of groin crunches should I do?

3 sets of 12-20 reps with 30-60 seconds rest. Total weekly volume of 75-150 reps drives most adaptations.

How often should I train the groin crunch?

2-3 times per week as part of a structured core program; daily at moderate volume is fine.

Are groin crunches effective for the inner thighs?

They activate the inner thighs but don't load them heavily. For dedicated inner thigh strength, exercises like Cossack squats, sumo squats, or adductor machine work are more effective. Use groin crunches for combined work, not primary inner thigh training.

Will groin crunches give me visible abs?

They build the lower abs, but visible abs come from low body fat. Diet drives the visibility; training drives the size.

Are groin crunches safe with hip issues?

Depends on the issue. The butterfly hip position requires hip mobility some people don't have comfortably. If the position causes hip pain, regress to standard reverse crunches. Confirm with a healthcare provider if you have known hip conditions.

Why don't I feel my inner thighs working?

Probably because you're not pressing the soles together actively enough. Increase the pressure between the feet — they should push against each other firmly throughout the entire rep.