Getting on to a ladder or vines at the bottom or off of it at the top increments the Jumps stat.
Scoreboard Jump Objective triggers when going up ladders
Climbing to the top of a ladder increases the 'jumps' statistic
Reaching the top of a ladder counts as jumping in statistics
The Scoreboard Objective "minecraft.custom:minecraft.jump" is broken
Climbing scaffolding increases the jump stat every block climbed