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Medicine Ball Leg Crunch
This core exercise involves lying supine, holding a medicine ball between the feet or knees, and simultaneously crunching the legs and upper body toward the center. It builds abdominal strength and stability.
About Exercise
Equipment
Medicine Ball
Difficulty
2/5 • Intermediate
Primary Muscle Groups
Abs
Secondary Muscles
Adductors
Popularity Score
7
Goals
Training Style
Setup Requirements
Requires Rack
No
Requires Bench
No
Requires Spotter
No
Space Needed
Small
Noise Level
Low
Muscle Breakdown
View Muscle MapAbs
10/10Rectus Abdominis, Transverse Abdominis
Hip Flexors
7/10Iliopsoas
Adductors
4/10Programming
Typical Rep Range
10-20 reps
Rest Between Sets
45-90 seconds • Rest shorter for high-volume or endurance focus.
How to Perform
Lie supine on the floor with your knees bent at 90 degrees and secure a medicine ball between your knees or ankles. Place your hands lightly behind your head or crossed over your chest.
- Engage your core to simultaneously lift your shoulder blades and knees toward your chest.
- Crunch up until your core is fully contracted, squeezing the medicine ball tightly.
- Hold the peak contraction briefly, focusing on maximum core tension.
- Slowly lower your upper body and legs back towards the floor.
- Stop just short of touching the floor to maintain continuous core tension.
- Repeat for the prescribed repetitions.
Coaching Tips
Form Cues
- Squeeze the ball tight.
- Ribs to hips.
- Slow controlled return.
- Do not pull neck.
Breathing
Exhale forcefully as you crunch up into spinal flexion and inhale slowly as you return to the starting position.
Tempo
2-1-1
Range of Motion
Crunch from a supine position until the shoulder blades are off the ground and knees move closer to the chest, maintaining the lower back pressed into the floor.
Safety
Safety Notes
- Avoid if experiencing acute lower back or hip flexor pain.
- Ensure neck position is neutral throughout; avoid straining.
- If you cannot maintain core stability, use a lighter or no ball.
Spotting
Not recommended; focus on controlling the movement and use a lighter ball if form breaks down.
Common Mistakes
- Letting the lower back arch on the descent.
- Pulling excessively on the neck.
- Using momentum instead of controlled core action.
- Dropping the medicine ball.
When to Avoid
- Acute lower back pain.
- Recent abdominal surgery.
Flexibility Needed
- Adequate hip flexion mobility.
Build Up First
- Basic bodyweight crunch competency.
- Ability to stabilize the lower back.
Also known as
MB Leg Crunch, Medicine Ball V-Up Crunch
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