The V-up, also known as the jackknife sit-up, is a core exercise that targets your abdominal muscles as well as your glutes and hip flexors . By activating your rectus abdominis, V-ups allow you to build core strength.
What are V ups good for?
The V-up, also known as the jackknife sit-up, is a core exercise that targets your abdominal muscles as well as your glutes and hip flexors . By activating your rectus abdominis, V-ups allow you to build core strength.