To swing in the straps with an eagle grip  the hands are placed through the straps like for undergrip swings.  The gymnast then makes a backwards roll to dislocate.  The athlete must shift the wrists to maintain proper weight support at peak height or his body may collapse against the bar.  Notice also the wrists shift on each inverted giants ascending phase to support.  To come out of the straps once the athlete stops  he uses the elevated spotting surface to initiate a forward roll coming in this way out of the eagle grip toward an undergrip.  Clip #2  Check again in this closer view how the gymnast sets his hands on the straps for undergrip swings and by means of a backward roll with a dislocate he gets into the disired position to practice his eagle grip swings and inverted giants.  Notcie also how in each inverted giant the body shortens with a pike to facilitate the return to support and then straightens up again for maximum presentation amplitude and to increase the swing down.