At the start of the 1930s the Soviet Union was the worlds largest aircraft producer by far. And as war clouds gathered during the late 1930s, the countrys production grew rapidly: Soviet production quadrupled from 2,529 in 1935 to 10,382 in 1939.
Gym Machines & Equipment. Most gyms have machines or equipment that will target the abdominals specifically. The seated abdominal crunch and captain's chair are two such machines that tone the rectus abdominis and lower abs respectively. Ask a fitness trainer to show you how to properly use machines to avoid improper technique and injury risk.
You will perform this exercise as a variation on ab crunches. The difference is that you always have both feet off the ground during these bicycle crunches. This makes bicycle crunches a bit harder, than standard ab crunches. Also, it tends to work the lower abs more. Typically, keeping your legs off the ground works the lower abs. Keeping your legs flat, on the other hand, works the middle abs. Interestingly, bicycle crunches also work the rectus abdominus muscle (upper abs). This is the highest set of ab muscles you have.