What core exercise involves lying flat on the back and raising the head and feet off the ground to form a 'V' shape?

The exercise that involves lying flat on the back and raising both the head and feet off the ground to create a 'V' shape is known as V-ups. This movement is specifically designed to engage the core muscles effectively, targeting primarily the abdominal region while also utilizing hip flexors and lower back muscles.

During a V-up, the lifter initiates the movement by simultaneously lifting their torso and legs off the ground, creating that characteristic 'V' form. This action not only strengthens the abdominal muscles but also promotes coordination and balance.

In contrast, crunches primarily focus on flexing the spine and engaging the upper abdominal muscles, while leg raises involve lifting the legs without considerable engagement of the upper body. Russian twists introduce a lateral rotation that targets the obliques but does not involve raising both the head and feet off the ground. Thus, V-ups distinctly characterize a complete lifting of the body into the 'V' position.