Source: Player's Handbook

You have undergone extensive physical training to gain the following benefits:

• Increase your Strength or Dexterity score by 1, to a maximum of 20.

• When you are prone, standing up uses only 5 feet of your movement.

• Climbing doesn't cost you extra movement.

• You can make a running long jump or a running high jump after moving only 5 feet on foot, rather than 10 feet.