Barefoot running is increasing in popularity within the running community, yet the biomechanical differences compared to traditional shod running are not well understood. This study investigates the changes in spinal dynamics during the gait cycle of runners wearing traditional running shoes (shod) compared to those wearing no shoes (barefoot). Pedal force distribution, kyphotic angle, lordotic angle, and trunk inclination were measured during shod and barefoot gait at three different speeds on a treadmill. Subjects were examined using the DIERS Formetric 4D system and DIERS Pedoscan system. While running barefoot, pedal force distribution analysis showed that 21.0% more force load goes through the forefoot vs. a 10.2% increase in forefoot force with shod (p = 0.0006). At 8.0 km·h −1 the average kyphotic angle was 1.6 degrees greater under barefoot conditions vs. shod conditions (p = 0.008). At 8.0 km·h −1 the average lordotic angle was 0.8 degrees greater under barefoot conditions vs. shod conditions (p = 0.05). Trunk inclination was 0.6 degrees and 0.8 degrees greater under barefoot conditions compared to shod conditions at natural speeds (p = 0.005) and 8.0 km·h −1 (p = 0.015), respectively. Barefoot runners show an increased force load in the forefoot, eliciting a forefoot strike pattern while running barefoot compared to shod running, and it was also found that barefoot runners have reduced trunk inclination. These dynamic changes allow for a more spring-like effect for barefoot runners creating a less transient and slower rise in force. In contrast, a heel strike pattern yields a rapid and high impact collision between heel and ground. As a result, barefoot running translates into less stress on the joints of the lower extremity and back and therefore less risk of injury.