Source: Unearthed Arcana 83 - Giant Options

You have absorbed primeval magic that allows you, despite your relatively small stature, to embody the might of titanic creatures. This grants you the following benefits:

Little but Mighty. You gain proficiency in either the Athletics or Acrobatics skill.
Powerful Build. You count as one size larger when determining your carrying capacity and the amount you can push, drag, or lift.
Stalwart. You have advantage on saving throws against being moved or knocked prone.