In untrained men performing bench press training over 10 weeks with matched time under tension, the triceps brachii muscle exhibits greater hypertrophy in its distal region (80% of muscle length) compared to its proximal and middle regions, while the pectoralis major shows uniform hypertrophy along its length, indicating that regional muscle adaptation is influenced by exercise mechanics and muscle architecture.

During the bench press, the triceps muscle experiences more force near the elbow than near the shoulder because of how the joint moves and how the muscle is shaped. This causes the part of the muscle closest to the elbow to stretch and contract under higher tension, which triggers more protein building and muscle growth in that specific region. The chest muscle, by contrast, pulls evenly along its length during the movement, so it grows the same amount everywhere.