Nailed one off camera then set camera up to record. After the failed second attempt on camera I nailed the 3rd one with a bit of strain unlike the first one off camera.
My MU training consisted of many, many pull ups ( dead hang and kipping) on rings bars and anything I could hang from. My muscles eventually adapted to the transition phase of the muscle up where I previously got hung up…… repeatedly.
In addition to the obvious pulling strength needed i trained my core through the use of L-pull ups. My dropping a few pounds also helped my efforts. In the end it was practice and adaptation that made my recent attempts easier.

Watch my first video Muscle Up: