Yes they do. When you are working with weights for your biceps, it also has effect on your stomach muscles. This is getting two workouts for one.
Cross trainers work out many muscles but mainly they work out the abdominal and arm muscles.
You use your pectoral , biceps , triceps , forearm hamstring / thigh (same thing) and calf to keep you standing , shoulder muscles and abdominal
The main muscle used in curls is the biceps.
Rows are primarily used to work your back but they also work your biceps and I suppose your legs a little bit.
A lot of Personal Trainers use medicine balls as abdominal exercise equipment. They come in different sizes so it will work for any body size. They are also easy to store without taking up a lot of space.
I am also looking to purchase an abdominal machine, and have therefore done some research on what types of machines are available. I have found that there are many different types of machines to work your abs, and you can purchase these machines from this site: http://www.csnstores.com/Core-and-Ab-Trainers-C429046.html
eat/drink a lot of protein and work your biceps
The Bowflex Power Pro is ideal for working out all muscle groups. You can work out your abdominal muscles, your biceps, your triceps, your quads, and your glutes on that machine.
Chicks like it.
The gazelle exercise machine works the entire body, such as the glutes, thighs, calves, biceps, triceps, abdominal muscles, deltoids, and pretty much anything else in your body.
You will find that there are many different types of abdominal-specializiing exercise equipment. You will consider an abdominal crunch strap or an abdominal wheel for work on abdominal muscles.
You need to work your biceps and pump the guns until you eventually become stronger.