Flexion leg sit up (bent knee)

Lie flat on your back with your knees bent and feet flat on the ground. Place your hands behind your head with your elbows pointing outwards. Engaging your abs, slowly lift your upper body off the ground, curling forward until your torso is at a 45-degree angle. At the same time, lift your legs off the ground, bending your knees and bringing them towards your chest. Pause for a moment at the top, then slowly lower your upper body and legs back down to the starting position. Repeat for the desired number of repetitions.