Preacher curls are done with your arms pressed against a pad. You can still use a very heavy weight, but the pad will help keep you from using a swinging motion to bring the weight up. Concentration curls are done with or without your arm pressed against your inner thigh. The idea is that you do the reps very slowly while concentrating on your working muscles and get a good squeeze, or contraction at the top. Both are very good exercises which work the muscle in very different ways.
Dan
"Train Smarter, not longer." http://danshealth.dan4fitness.com
Preacher curls vs. concentration curls
Preacher curls are done with your arms pressed against a pad. You can still use a very heavy weight, but the pad will help keep you from using a swinging motion to bring the weight up. Concentration curls are done with or without your arm pressed against your inner thigh. The idea is that you do the reps very slowly while concentrating on your working muscles and get a good squeeze, or contraction at the top. Both are very good exercises which work the muscle in very different ways.
Dan
"Train Smarter, not longer."
http://danshealth.dan4fitness.com