Resizing panes in tmux with a shortcut

I've been using tmux for years now, but I keep forgetting the shortcuts for resizing panes.

So, in all it's glory, the shortcut for resizing a pane in tmux is:

(CTRL-B) + ALT/⌥ + (ARROW IN SOME DIRECTION)

I have my tmux prefix set to a like this:

set -g prefix C-a
unbind C-b

So the actual shortcut I use is:

(CTRL-A) + ALT/⌥ + ↑