Core
Splinter Sit-ups
A precise rotational core movement designed to isolate the obliques and improve trunk stabilization through a controlled range of motion.
How to perform.
Follow the sequence — setup is half the lift.
Lie flat on your back on a firm surface with your legs extended straight and arms resting at your sides.
Engage your core to lift your upper back off the floor while simultaneously pulling one knee toward your chest.
Rotate your torso to bring the opposite elbow toward the rising knee, meeting in a controlled crunch at the center of the movement.
Squeeze your obliques at the peak of the contraction for one second while maintaining a neutral neck position.
Lower your leg and torso back to the starting position with control, ensuring your lower back remains pressed against the floor.
Repeat the motion on the opposite side to complete one full repetition.
Common mistakes.
Fix these first — they cost reps, kilos, and joints.
- Pulling on the back of the neck during the upward phase
- Using momentum or swinging the legs to lift the torso
- Allowing the lower back to arch off the floor
- Rushing through the rotation without a full contraction
Muscles worked.
The primary movers do the work; the stabilizers keep the path honest.