Muscle Group: Forearms & Biceps
Place your wrists in a pronated position (palms down). When you do this, the biceps effectiveness in flexing the forearm is minimized and more pressure is placed on the brachioradialis, which is one of the most prominent muscles in the forearm.
Standing or seated grab a pair of dumbbells and have your arms hanging at your sides, with your palms down.
Having your elbows fixed in position at your sides, curl the dumbbells upward, beginning by really flexing the wrists hard upward. Bring the dumbbells up until you feel a peak in your biceps at the top, then lower the weight methodically down to the starting point.