1. Full Range of Motion - the feet are home to a quarter of the body's bones, and 20 of the 33 joints found in each foot are articulating joints, meaning movement is their function and can help to preserve their function. Training barefoot allows these articulating joints to go through full ranges of motion. So program accordingly! Walk, hop, skip, run, lift...there really isn't any limitation of movement for healthy feet.
2. Improve Proprioception - the body has three primary systems to send balance and coordination information to the brain and Central Nervous System. These systems are the visual system, vestibular system, and proprioceptive system. Training barefoot allows for optimal proprioceptive function from the feet, which would otherwise be dampened if covered with shoes. The most direct path of stimulus, as it pertains to balance, being received by the CNS does not come from the eyes or inner ear, it comes from the the bottom of the feet. Training barefoot on the TrueForm, balance beams, slack lines, logs, airex pads, and moving barefoot across constantly changing surfaces at varying speeds are great ways to stimulate the proprioceptive function of the feet.
3. Reaction Time - without the added weight of shoes, one can optimize reaction time, which is effective in training quicker ground reaction times by reinforcing the elastic nature of the connective tissue found in the feet and lower legs.
4. Strength - leg day includes the feet! While there are plenty of isolated exercises for improving foot strength, they can also be strengthened by being kept bare during lifts and dynamic full body movements; for instance, overhead squatting, farmer's carries, sled pushes, push presses, burpees, planks, bridges, etc. The list goes on. Want to improve your running program? Train strength head to toes.