Seated side crunch (wall)

Sit on the floor with your back against a wall and your legs extended in front of you. Bend your knees and place your feet flat on the floor, hip-width apart. Place your hands behind your head with your elbows pointing outwards. Engage your abs and lean to one side, bringing your elbow towards your hip. Pause for a moment, then return to the starting position. Repeat on the other side. Continue alternating sides for the desired number of repetitions.