When performing your bicep exercises there are a few important things you must remember for the ultimte biceps workouts :
First you must always ensure that your elbows stay as close to the sides of your body as possible. Far too often individuals performing bicep exercises will start letting their arms swing around midway through the lift. Usually this is seen with the elbows moving in an outwards direction rather than staying locked forwards. This is not beneficial because it will place more strain in the shoulder joint and could potentially lead to shoulder injuries.
The second thing to remember during your bicep exercises is to never allow momentum to do the work for you. This is probably the number one mistake people make. If you've ever watched a guy in the gym who is clearly trying to impress people with the weight he's lifting, this will undoubtedly be occurring. Since he's using too high of a weight for his muscular strength, he needs a small amount of additional help to get it raised upwards.
Where does this additional force come from? The momentum of his body. He'll swing his hips outwards slightly then transfer this movement to the stomach and then to the arms. The really bad part about this is in doing so, the spine becomes disastrously out of alignment and a huge load of stress is placed upon it as well as the shoulders. You really must make sure you do not perform this error because not only are you not strengthening your biceps when you do, you are also risking severe injury.
Finally, remember to always try and lower the weight as low as you can. If you are only able to perform half reps you are probably using too much weight and it would be very beneficial for you to decrease it. This is a relatively small muscle and for most people it can't handle huge loads. You will see much greater benefits using correct form than trying to load on the resistance but moving out of correct form. Train smarter - not harder!