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"Ground effect is an aerodynamic phenomenon, which reduces lift-induced drag when an airfoil is close enough to the ground (usually within 1 wingspan) that circulation is significantly affected. Some vehicles and many birds and bats make use of this effect to increase their efficiency of operation."

"This comic uses a different interpretation of the term 'ground effect'. Runners depend on their feet making contact with the ground in order to push against it and generate forward motion. In order to do this, all of them must be within one (their own) body length of the ground in order to push against it. This could be considered to be reducing their 'efficiency' to zero. This process has little to do with aerodynamic effects."

"The title text is a pun. In airplane aerodynamics, wingtip vortices are longitudinal vortices (horizontal whirlpools parallel to the airplane fuselage) that a wing creates near the tip when it generates lift. These create unhelpful drag without adding lift, so modern airplanes generally have winglets at the end of the wings to make these vortices smaller. In fashion, there is a style of dress shoe called wingtips with small holes in the upper leather in a pattern that somewhat resembles a bird's wings. In reality, runners would not wear dress shoes because they would be heavy, uncomfortable, and restrictive, and they typically have soles that do not provide sufficient grip on the running surface."

"An airfoil (i.e aircraft wing) generating drag and lift in level left-to-right flight can be modeled as a wedge with horizontal lower surface, vertical leading edge, and sloping upper surface. Undisturbed air has molecules (mostly nitrogen) moving in all directions, at different speeds, some as fast as the speed of sound. (Air molecule motion conveys sound and sets its speed.) A hand placed in a stream creates a depression in the water behind the hand, as the flowing water takes time to go under the hand. Likewise, the leading edge pushes forward air molecules moving forward slower than the wing. The lower surface pushes down the air molecules moving up. The air molecules left to hit the sloping upper surface are mostly those moving down and faster forward than the wing."

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