Exercise guide · intermediate
V-Up
The v-up, also known as a jackknife, is an advanced bodyweight core exercise that simultaneously engages the upper and lower abs. By lifting both the torso and legs together, it creates a full abdominal contraction and challenges hip flexor strength.
- Equipment
- bodyweight
- Typical range
- 8–15 reps
- Also works
- hip flexors, back
01 · Set up
Take the exercise-specific start position with your hands, feet, and resistance secured.
Brace your abdomen before moving and keep your pelvis and rib cage aligned.
02 · Perform
Move the trunk through the exercise-specific path while the hips and limbs remain controlled.
Use a range you can own without pulling on the neck or using momentum.
Return slowly to the starting position and re-establish your brace.
Coaching tips
- Keep the non-working joints still.
- Use the full controlled range.
- Own the return phase.
Common mistakes
- Moving the torso to create momentum.
- Using resistance that shortens the range.
- Letting the resistance drop on the return.
What it should feel like
Expect the core to do most of the work, without sharp or joint-focused pain.
Stop or modify when
Stop or shorten the range for sharp, sudden, worsening, or joint-focused pain.
Reviewed alternatives