Video Coming Soon
We're working on adding video demonstrations for this exercise.
Stability Ball Jackknife
A bodyweight core exercise from plank position with shins on a stability ball, pulling knees to chest to target abs and hip flexors for anti-extension stability and strength; builds core control and balance.
About Exercise
Equipment
Stability Ball
Difficulty
4/5 • Intermediate
Primary Muscle Groups
Abs, Hip Flexors, Obliques
Secondary Muscles
Glutes, Hamstrings, Quads
Accessory Muscles
Shoulders
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
Hip Flexors
9/10Iliopsoas
Obliques
8/10External Obliques, Internal Obliques
Glutes
4/10Glute Max
Hamstrings
3/10Biceps Femoris
Quads
3/10Rectus Femoris
Shoulders
2/10Anterior Delts
Programming
Typical Rep Range
8-20 reps
Rest Between Sets
30-60 seconds
How to Perform
Position hands shoulder-width on floor under shoulders in high plank, with shins or tops of feet on stability ball, body straight from head to heels.
- Brace core to stabilize spine.
- Exhale and flex hips and knees to roll ball forward toward chest.
- Squeeze abs as knees approach chest.
- Pause briefly with knees near chest.
- Inhale and slowly extend legs to roll ball back.
- Return to full plank position without sagging hips.
- Repeat for reps.
Coaching Tips
Form Cues
- Keep spine neutral.
- Drive with abs.
- Avoid hip drop.
- Roll smoothly.
- Eyes forward.
- Hips level.
Breathing
Exhale during hip flexion pull-in; inhale during leg extension return. Brace core throughout.
Tempo
2-1-2
Range of Motion
Full hip and knee flexion until knees near chest; extend to straight legs with neutral spine, no arching or sagging.
Safety
Safety Notes
- Avoid if acute lower back pain.
- Ensure ball is properly inflated and sized.
- Stop if shoulder or wrist discomfort.
- Maintain control to prevent rolling off.
- Supervise beginners.
- Use anti-burst ball.
Spotting
Not typically needed; perform in open space with spotter nearby for balance assistance if beginner.
Common Mistakes
- Arching lower back
- Sagging hips
- Rushing the roll
- Uneven leg extension
- Poor hand placement
- Ball too small
When to Avoid
- Acute lower back injury
- Shoulder impingement
- Wrist instability
- Recent abdominal surgery
Flexibility Needed
- Adequate shoulder flexion for plank
- Core stability to hold neutral spine
- Hip mobility for flexion
Build Up First
- Proficient high plank hold
- Basic hip flexion control
- Familiarity with stability ball balance
Also known as
Swiss Ball Jackknife, Physio Ball Jackknife, Stability Ball Knee Tuck
Found this helpful?
Share your thoughts or help us improve this guide.
Similar Exercises
Stability Ball V-Up
Stability Ball
Abs
Stability Ball Pike
Stability Ball
Abs
Stability Ball Plank
Stability Ball
Abs
Stability Ball Pull In
Stability Ball
Abs
Stability Ball Rollout
Stability Ball
Abs
Stability Ball Dead Bug
Stability Ball
Abs
Stability Ball Half Moon
Stability Ball
Obliques
Stability Ball Sprinters
Stability Ball
Abs
Stability Ball Ab Rollout
Stability Ball
Abs
Stability Ball Stir the Pot
Stability Ball
Abs
Master your movement.
Experience automatic exercise detection and rep counting - powered by the motion of your Apple Watch.
subscribe to our newsletter
ProductContact Us
hello@trainfitness.aiFind Us
130 Spadina Avenue, Toronto,
Ontario, M5V 0H4, Canada
©2025 All Rights Reserved
