Quick answer: a prep holds the flyer with their feet at about the bases' shoulder height, arms bent, while an extension pushes the flyer all the way up so their whole body is above the bases' heads, with the bases' arms locked straight. An extension is essentially a prep taken to full height - and it's a big step up in difficulty.
| Prep | Extension | |
|---|---|---|
| Flyer height | Feet at about the bases' shoulder or chin height | Whole body above the bases' heads |
| Base arm position | Bent, with the flyer's feet held at shoulder height | Arms locked straight overhead |
| Official height category (USASF) | Prep level | Extended |
| Typical use | Foundational stunt and transition point | Higher stunt, and a base for single-leg positions |
| First allowed (USASF) | Level 1 | Level 2 (two legs), Level 3 (single leg) |
| Spotter required (USASF) | At Level 1 only | At every level |
The Core Difference
Both are two-leg stunts in which the flyer stands with one foot in each base's hands, supported from behind by a back spot. The difference is height:
- In a prep, the bases hold the flyer's feet at about shoulder height with their arms bent. The flyer stands roughly a body-height above the floor.
- In an extension, the bases press their arms fully straight overhead, lifting the flyer so their whole body is above the bases' heads.
How the Rules Define Them
The USASF rulebook defines stunts by height category rather than by name:
- Prep level - the lowest connection between bases and flyer is above waist level but below extended level. Preps, shoulder sits and shoulder-level hitches are all prep-level stunts.
- Extended - the flyer's entire body is above the bases' heads. If the bases squat or kneel while straightening their arms, the stunt still counts as extended.
The definition depends on the flyer's height, not just the bases' arms: some stunts held with straight arms overhead (such as a flyer lying flat) still count as prep level, because the flyer's body isn't fully above the bases' heads.
Why the Progression Matters
Extensions demand much more from everyone. Bases have to press the flyer's full weight overhead and hold it steady with straight arms; the flyer has to stay tight and balanced much higher up; and the back spot has further to reach. That's why preps are allowed from Level 1, while extended two-leg stunts aren't allowed until Level 2, and extended single-leg stunts such as an extended liberty until Level 3. USASF rules also require a spotter for every stunt above prep level, at every level.
How They're Used Differently
Preps are often a transition point: many stunts pass through a prep before going higher, and preps are common in pyramids and as bracers for higher stunts. Extensions are more often held as the "hit" position, or used as the starting point for single-leg positions and more advanced transitions.
What Judges Notice
In both, judges look for a stable, still stunt with the flyer tight and upright, bases' arms at matching heights, and every stunt group hitting at exactly the same time. In an extension, any bend in the bases' arms or wobble in the flyer is much more visible.
Related Skills
See Liberty for the common next step built from either position, and Waist Level for a position lower than a prep.