This study quantified the biomechanical (movements and forces) and physiological (energy expenditure) demands of postal delivery performed with electrically assisted bicycles (EABs). Ten postal workers and 10 recreational athletes performed three simulated postal tasks (simulated mail delivery circuit, delivery distance [close vs. far], and 3-min stationary cycling) while carrying 0, 16 and 32 kg. Physiological (energy expenditure) and biomechanical (internal and external forces and joint angles) responses were calculated. Energy expenditure (10-20%; p < 0.05) and power output (30-44%; p < 0.05) increased with increasing mail loads. Ground reaction force increased (∼10%) for the far delivery distance, but joint reaction forces were unchanged. Lower hip flexion (p < 0.01), less hip abduction (p < 0.01) and larger spine anterior flexion (p < 0.01) were observed for the far delivery distance. Joint forces were not affected by the mail load transported (0-32 kg) or distance from the mailbox (close vs far). EABs can provide a suitable transportation method to assist mail delivery in terms of energy expenditure reduction.