A classic variation on the bicep curl. By twisting part way up, you further activate the biceps brachii, the pop-eye biceps muscle.
The chap doing the exercise does several things that make this exercise more effective.
- He is doing the exercise one arm at a time. This gives better results, but it isn’t wrong to do the exercise both arms at once.
- Putting a pause in just before twisting the dumbbell really activates the muscle and helps to maintain good form. The better the form, the bigger the biceps. The wilder the form, the heavier the weight and the more of a dork you look, not to mention the increased risk of injury.
- He is holding the dumbbell with his thumb by the plate end. This little factor really makes those biceps work to turn the dumbbell, since now more of the weight is loaded on the little finger side of the hand.
- Try putting the pause in at 40° of elbow flexion and pause here for 2 seconds. Complete the lift in 1 second then lower smoothly for 4 seconds, ensuring control all the way down. You untwist the dumbbell at the same point.
- He is standing – this requires more activation of the abdominal muscles. I suppose it depends upon what the goal of the exercise is. For variation, it is good to sometimes sit and sometimes stand. For pure bicep development, it is better to sit since more of the mental energy goes into moving those dumbbells well and less into keeping the body still.