What muscles do jack knives work?
- Transverse abdominis.
- Rectus abdominis.
- Lower back.
Are jack knives good for abs?
The jack knife provides some additional challenge and variation to the sit-up, and trains both the abs and hip flexors. It can also be used as a way to scale the V-up to work toward them.
What is Jack knife use for?
The jackknife is also known as a pocket knife as many men would carry the knife in a pocket and use it to whittle, or carve, sticks and pieces of wood. The jackknife is a handy camping tool, especially in backpacking as it doesn’t take up much room or weigh a lot.