Quick Drop
From A complete guide to Super Metroid speedrunning
It is possible to pass through the location of crumble blocks without losing vertical velocity if Samus is in a turnaround animation when she makes contact with the block.
This also works for blocks that are being destroyed by bombs or Power Bombs, such as those in Red Tower and Aqueduct.
Similarly, if Samus is rising and hits her head on a ceiling during a turnaround animation, she will continue rising if her head is no longer hitting a ceiling when the turnaround finishes. This is useful as a backup for a late jump into Fish Tank for Any%, or when doing a Gravity Jump in Glass Tunnel.
