Acrobatics is an McMMO ability that is leveled by taking fall damage. It allows one to 'roll', reducing/cancelling damage on occasion, holding the sneak key you can execute a 'graceful roll' if you want a more-guaranteed cushion, and adds a dodge chance for halving damage.
Effects
Higher percentage to roll or graceful roll upon falling. Higher dodge percentage.
Roll
Decreases fall damage, sometimes to the point of nullifying it entirely up to 23 blocks. Likelihood of occurring is directly related to level, with a 0.05% increase for every additional level of acrobatics. This caps at level 2000 with a 100.00% chance to Roll.
Graceful Landing
If you hold down sneak as you fall, there is a chance double that of your roll, for you to perform a Graceful Landing. As well as having double the chance of a roll, it is twice as effective at reducing fall damage as an ordinary roll and work up to 36 blocks. This caps at level 2000 with a 100.00% chance to perform a Graceful Landing
Dodge
Half attack damage received. Chance increases by .001% each level of acrobatics,
Dodge caps at level 2000 with a 20% chance to dodge.
Experience In Acrobatics
The experience gained in Acrobatics is tied directly to fall damage. Each half heart of damage earns 120 XP from a fall with no roll, or 80 XP from a fall where a (graceful) roll was executed. Damage before the (graceful) roll damage reduction is used to calculate the XP, gain. If the fall is fatal, you gain no XP.
In the default config for Mcmmo, wearing boots with feather falling enchanted on them give twice the XP per fall.
Because a player has a maximum of 10 hearts of health, the maximum XP you can earn in Acrobatics is 2280 from a height of 23 with no (graceful) roll, or 2640 from a height of 36 with a graceful landing. As of version 1.4.07 XP can further be gained by wearing enchanted boots with the feather falling protection.
Ender Pearls can no longer be used to quickly gain experience in Acrobatics; not only are they \quick return to the 'fall point'.
Beacons of regeneration are a good idea, but resistance will slow down xp gain because xp is tied directly to fall damage.
How to level up quickly
Acrobatics Automation
One way to automatically farm acrobatics experience is to create a redstone elevator. Using this, you can be quickly transported to the top and dropped down. If you have the materials, consider adding a dispenser at the bottom for instant healing. Or a beacon of regeneration, though very demanding in terms of the resources needed.
Acrobatics grinder: https://www.youtube.com/watch?v=D5ZJJApdAzo
Low Material Farming
One way to farm acrobatics for resource is to make a 23 high tower with ladders on one side with a bed on top, and a cactus near the bottom. You can walk (Not Jump) down to the bottom, and will have half a heart. Kill yourself on the cactus, and you should respawn back on top of the pillar (If you have slept in the bed). Repeat for fast xp. This is not recommended for servers with the factions plugin, as you will lose all of your power from dying.
Non-Falling
If you are in a server that does not allow fall damage to train on try this one; get 4 dispensers get a god apple (if not regen or regular golden apple and wait 5 seconds to regen) diamond/iron armour, get lever and redstone connect the redstone to the dispensers and then to the lever after push the lever to fire 4 arrows there is a chance that you might dodge these 4 arrows and that will give you *dodged* word on chat that means that you have gained experience from dodging arrows.