Saturday anatomy: 💪 elbow flexors.
So often we only associate the biceps brachii (upper right) with elbow flexion (it is the most superficial so we can easily touch and see it), but the brachialis (upper left) is the only true elbow flexor because it inserts on the ulna which does not rotate.
The biceps are an effective supinator (going from a palm down to a palm up position). The brachioradialis (bottom left) returns the radioular joint to a neutral (thumb up) position, and is a highly effective elbow flexor because it inserts near the wrist on the distal radius. Lastly, the pronator teres (bottom right) crosses the elbow joint and provides a weaker flexion contribution, as it serves a dominate role as a pronator (palm down position).
If you are only doing standing biceps curls, you are missing the opportunity to train the flexors in their full range of motion, along their best line of pull, using a perpendicular force application. Try using a pronated or neutral grip to emphasize the brachialis and brachioradialis, this reduces the ability of the biceps to provide a significant force contribution. Use cables or an incline bench to change the angle of force application. Strong and smart, happy Saturday everyone! (Photo credit: Floyd, 2012)