V-ups / Jackknife

3 × 12-15  ·  Equipment: No equipment, Mat

Muscle groups: Core & abs

How to do v-ups / jackknife

1. Lie on your back with your arms extended behind your head.
2. Brace your core and lift both your straight legs and your torso at the same time.
3. Reach your hands toward your feet, forming a V with your body.
4. Keep your legs straight and lower under control.
5. Don't let your feet or arms touch the floor between reps.
6. Keep your lower back pressed into the floor to protect it.

Mistakes to avoid

• Don't arch your lower back while lifting or lowering; keep it pressed to the floor.
• Don't bend your knees to make it easier; keep your legs straight.
• Lower in a controlled 3 seconds to protect your core.
• If your lower back hurts, reduce the range and build it up with planks.

Progression

• Start with 12-15 reps at a comfortable range.
• Once you master the form, lower slower and control every phase.
• Add reps or a 1-second pause at the top point.
• Over time, combine with hanging raises or the ab wheel to advance.