Clubs are normally thrown so that they rotate at least once while in the air, with the top of the club rotating toward the juggler. The rotations of a club are also called spins or flips.
Higher throws are usually done with more rotations, but throw height and rotation speed can be controlled separately to change the number of rotations per throw. Arm movement controls the height, and wrist movement controls the rotation speed. Club juggling patterns can be done at the same height that would be used for the basic pattern, while using a higher or lower number of rotations per throw.
The basic pattern for any number of clubs is normally done with each throw rotating half as many times as the number of clubs being juggled, rounding down for odd numbers: 3 clubs are done with single rotations, 4 and 5 are done with doubles, 6 and 7 are done with triples, 8 and 9 are done with quads. Any higher or lower number of rotations is usually considered a more difficult trick.
Due to variation in the speeds of basic patterns, the easiest number of spins for a number in a siteswap doesn't necessarily correspond to the easiest number of spins to use for the basic pattern with that number of clubs. 744 may be easier with the 4s as singles rather than doubles if you're juggling 5 clubs faster (more throws per second) than you would juggle 4 clubs.
Throws with no (visible) spin where the clubs remain horizontal in the air are called flats. Taken further, reverse spins can be thrown, so the clubs rotate in the opposite direction, with the top of the club moving away from the juggler. Helicopters are throws where the club stays horizontal in the air and rotates around the vertical axis.
- Prop rotation category on Juggle Wiki