Originally posted by: SnapIT
70 reps is WAY to much, up the weight and lower the reps to 15 for warmup and 3-10 for workout sets...
Do full motion reps, from the lowest position (rest) to the highest you can lift...
As barbell curls is the mother of all bicep excersises i will not suggest you do other (concentration) excersises, you can't form what you don't have...
[edited for clarification]
Just for an alternate viewpoint, Muscle & Fitness recommends a minimum set of reps as 6, with their half pyramid being 12->8->6 reps. That works well for me, though I must admit I don't always make the 6 on the last set.
For me, the concentration curl is a good way to avoid hitting the forearm (brachiallis?) muscles which tend to fatigue before the bicep, especially if I've already done some other exercises that have worn them out. Obviously you want to start with a more compound exercise like the barbell curls, but a good way to fatigue the biceps completely is to hit them later with a concentration as well. Personal preference, I suppose.
One other thing on the 70 reps. While there are some people who use that many reps in their workouts (I know some climbers do monster sets like that to build endurance), you risk some good tendon and joint damage with overexertion. I read an article about Marcus Allen awhile back who said that he basically did hundreds and hundreds of push-ups every day (maybe even over a thousand -- it was insane) to build his upper body, and it obviously worked. However, the author stated that most people's joints would not be able to handle that kind of strain and would wear out.