Gyrate allows Sen to rotate any part of his body at high speeds.
The effects of Gyrate turn Sen's limbs into something akin to a drill. This enhances his hand-to-hand combat capabilities significantly.
Gyrate doesn't prevent Sen from being grappled and carried around, although he is still capable of fighting back to an extent.
Gyrate is suited to close range combat, which appears to be Sen's specialty.
Sen wears a pair of small gauntlets that cover only his fingers. These gauntlets increase Sen's offensive capabilities as they can be used to damage his foes greatly and make physically defending against his Quirk impractical.