Teams often improve immediately after a manager is dismissed, then drift back towards their previous level within weeks. The pattern is consistent enough to have a name, and its causes are mechanical rather than mystical.
The squad was usually underperforming its ability
Managers are dismissed when results fall well below what the squad appears capable of. That gap is the reason for the sacking in the first place.
Performance that far below expectation tends to move back towards the middle regardless of who is in charge. The bounce is partly a return to a normal level.
This is why a change made when a team is already performing about as well as its squad allows rarely produces a lift. There is nothing to regress towards.
Caretakers simplify rather than rebuild
An interim has days, not months. Attempting a new philosophy in that window would leave the team with neither the old structure nor a working new one.
The usual response is to strip instructions back: a familiar shape, clearer defensive roles, fewer conditional triggers. Players stop hesitating over which of two rules applies.
Reduced hesitation shows up as sharper pressing and quicker first touches, which look like renewed energy but are actually decision speed.
Selection changes reset the pecking order
Every squad contains players who had fallen out of favour for reasons the interim did not create and does not inherit emotionally.
Those players return with something to prove and no accumulated frustration, while the previously guaranteed starters can no longer assume selection.
Competition across the whole squad tends to raise training intensity for a period, and training intensity feeds directly into match sharpness.
Opponents lose their scouting file
Opposition analysts prepare against known patterns. A managerial change invalidates part of that preparation because the recent footage no longer describes the team.
The advantage is temporary. Two or three matches produce enough new footage for opponents to rebuild the file.
That timing lines up closely with when bounces typically fade, which suggests the informational edge is a real part of the effect.
The bounce ends when the underlying problems reappear
Simplification hides structural weaknesses rather than fixing them. A squad short of pace in midfield is still short of pace once opponents adapt.
Clubs that treat the bounce as evidence the interim has solved the problem often appoint on the strength of a small and unrepresentative run.
The more informative signal is what happens after the novelty expires, when the team is being judged on structure rather than on freshness.