Hips rotate to one side
Anti-rotation core fails under the unstable surface challenge.
Overactive muscles
ObliquesTFL
Corrective work
Foam RollTFL↗StretchQL side-bend stretch↗Core · Core
Swiss Ball Jackknife
Coaching cues
- Push-up position; feet on top of the stability ball
- Brace; pull knees toward the chest by rolling the ball in
- Hips stay level — no rotation
- Extend legs back to starting position under control
Common faults 2
Lower back rounds excessively
Spinal flexion dominates; hip flexors drive instead of abs.
Overactive muscles
Hip flexorsErector spinae
Corrective work
Foam RollHip flexors↗StretchHalf-kneeling hip flexor stretch↗