This spell increases your base land speed by 30 feet. This adjustment is treated as an enhancement bonus. There is no effect on other modes of movement, such as burrow, climb, fly, or swim. As with any effect that increases your speed, this spell affects your jumping distance (see the Acrobatics skill).

Mythic Expeditious Retreat

The speed bonus from the spell increases to 40 feet. Add your tier to Acrobatics checks to avoid attacks of opportunity from movement, and when your movement provokes an attack of opportunity, add your tier to your AC against that attack.