Bicep Tendinitus
I found this article on bicep tendinitus very helpful:
Many lifters experience pain on the medial portion of their elbow joints. Often bodybuilders aggravate the pain by performing biceps curls with a straight barbell or by doing the eccentric, or lowering, phase of dumbbell curls with their forearm in a supinated position. If you understand the anatomy and biomechanics of the elbow joint, you can see why this stress occurs.
To determine how you should perform an exercise to avoid undue stress and injury to joints and to focus the work on the correct muscle, you must observe how your body functions naturally. For example, when your arm hangs naturally at your side, your palm faces your thigh. When you raise your hand to touch your shoulder-that is, perform elbow flexion, or a biceps curl-your palm rotates to face your shoulder during the upward motion. This is supination. As you lower your arm to the starting position, your forearm rotates back, or pronates, so that your palm once again faces your thigh. This natural rotation places the work on your biceps and relieves the stress on the joints.
When you perform biceps curls with a straight bar, your forearms are in a fully supinated position at the bottom of the exercise, not the natural pronated position. This exposes the medial regions of your elbow joints to excess stress. It stands to reason, then, that if you do your biceps curls with dumbbells, you will place less stress on your elbow joints and reduce the likelihood of injury.
