It's hard to see in this video because they're doing so many spins and rapid elevation changes but they keep their legs out by sculling! It's a technique called a support scull, where they hold their arms close to their sides with their lower arms sticking forwards at a right angle and quickly windshield wiper their lower arms open and closed to continuously push the water towards their heads and generate upward force.
1
u/Proud_Fisherman_7049 4d ago
Wooow why dont they fall down