The inverted paradiddle is the same four hands as the regular paradiddle — two singles and a double — but in a different order: R L L R · L R R L. The double moves into the middle of the four-note group, with a single bookending each end. Some books call this an "inward paradiddle"; the term refers to the double being inside the shape rather than at the end.
Why bother? Because accent placement determines what a sticking feels like. A regular paradiddle with the accent on note 1 is a strong-then-weak shape. The inverted paradiddle, with the accent on note 1, has its double in the middle — meaning the rebound from the accent immediately sets up a controlled double, then a final single. The hands move differently, even though the same four strokes are present.
Once it's under your hands you'll start hearing the inverted version everywhere — it's the natural sticking when a fill needs a strong-soft-soft-strong shape, or when you're moving from snare to a tom on the closing single.
Exercises
Sticking: R L L R · L R R L, twice per bar. Accent on the lead-hand single of each group (counts 1, 2, 3, 4). The double sits in positions 2-3 of each four — the inverse of the standard paradiddle, which has its double in 3-4.
Beats 1-2: standard paradiddle (RLRR LRLL). Beats 3-4: inverted (RLLR LRRL). Same accent placement on counts 1, 2, 3, 4. Listen to how the second half feels different — the doubles arrive earlier in each group, making the back half of each four-note shape lighter.
Accent moves from position 1 to position 2 — the first note of the inner double. This shifts the felt downbeat by one 16th, making the rudiment sound like it starts on the e. Useful displacement — same sticking, completely new feel.
Both notes of each inner double accented; the leading and closing singles are quiet. This is the opposite-side test of Exercise 1: do the doubles speak as a clean accented pair, or does the second note collapse? If you can play this evenly, the rudiment is yours.