Amumu Runes explained
There's one set of runes for Amumu on patch 15.14 that is the clear favorite for LoL players and pros alike. The best Amumu rune paths on the position 
Support are 
Resolve as the primary path and Inspiration as the secondary path with a pick rate of 56%. Besides picking runes on Amumu you should learn how to play Amumu and if you are interested in pro matches take a look on how a pro builds Amumu. If you want to discuss 
Amumu then you should visit the champion subreddit.
Amumu runes from primary path
Resolve empowers the survivability of Amumu and increases the tankiness. Most of high elo players – and our LoL pros in the the major regions – have agreed that Aftershock is the best keystone rune to run on Amumu. This keystone rune bulks you up, increasing both armour and magic resistance, once you immobilized a champion. Aftershock synergises both with the sheer amount of crowd control Amumu possesses and the need to be tanky as soon as you engage. Other primary runes on Amumu are Font of Life, Bone Plating and Unflinching.
Font of Life provides your teammates with more sustain by healing them whenever they attack a champion whose movement you've recently impaired. Bone Plating make Amumu overall tankier, by decreasing the amount of poke damage in the early game. Unflinching inceases Amumu tenacity based on your missing health.
Amumu runes from secondary path
When it comes to your secondary path, most Amumu players prefer to go with Inspiration. Inspiration opens creative opportunities on Amumu troughout the match. On the Inspiration path, the best runes for Amumu are Cosmic Insight and Magical Footwear.
Cosmic Insight grants summoner spell and item haste. Magical Footwear allows Amumu to focus on those essential core items without the need to spend the additional 300 gold on boots.
FAQ for Amumu Runes
Which is the best keystone rune on Amumu?
The best keystone rune on Amumu is Aftershock. This Amumu runes setup is then referred as Amumu Aftershock.
What runes does Amumu use?
Runes from the paths Resolve and Inspiration are the most used runes on Amumu. For the exact pick rates of Amumu runes used, you have to study the rune distribution presented.