What phase occurs when the body is propelled with no base support?

The phase where the body is propelled with no base support is running. In running, there are periods when both feet are off the ground, resulting in a moment where the body has no base of support. This distinguishes running from other locomotion patterns, such as walking, where at least one foot remains on the ground at all times, providing continuous support.

During running, the mechanics involve a cycle of aerial phases and ground contact, allowing for greater speed and propulsion compared to walking. The absence of base support when both feet are airborne is crucial to understanding what characterizes running as a dynamic and powerful movement form. In contrast, activities like walking, crawling, and jumping involve either consistent ground contact or a different form of movement that does not match the specific description of the question.