Moves (aka tricks) in Footbag Freestyle are made up of components. Components of a move done while the footbag is travelling upwards (immediately after a basic set) are called “uptime” components. (See the page on parabolic motion for a diagram that illustrates this more clearly.)
Examples of uptime components:
See the Freestyle Set List for an expansive list of possible uptime components.
Note: the term front-side generally means uptime and is just older terminology for the same concept. Similarly, back-side usually means downtime. However, the rationale for these older terms is based on a slightly different model, so they don’t map exactly one-to-one. (You will hear people say front-side and back-side generally with other concepts like symposium or paradox to say whether the symposium or paradox components happen in a certain order.)
In more recent usage, alpha and beta take on a similar, but distinct notion — alpha is a prefix used to describe tricks where the first dexterity is symposium or paradox (depending on the trick), and beta refers to the second dexterity.