L Sit Tuck on Parallel Bar. How-to, proper form and tips

Focused on abs and upper body, holding this position for a couple of minutes is a demanding exercise.
Video demonstration
(excerpt from 'Tuck Hold on Parallel Bars'
by TotalTaiso)
How to and step by step instructions:
- Stand on parallel bars raising your feet of the ground.
- Keep your arms straight and shoulders pressed down, your ears away from the shoulders.
- Bring your knees close to chest, toes pointing straight to the floor in a ballerina position.
- Count the seconds you can hold the position.
Hints & tips:
- Prepare your shoulders and triceps holding the bar up to one minute, regardless the legs position.
- Press your shoulders down, moving your ears away from the shoulders.
Benefits:
- Strengthen shoulders and core.
- Good preparation for the L Sit on the bars.
Counting & gamification:
- Count the seconds you can hold, accumulating in a period (session, day, week).
- Set an accumulated goal for a workout session, say 60 seconds, and do the necessary repetitions to reach that goal.
Muscles worked and body parts involved:

Muscles: Core & Upper body
Primary muscles: Shoulder, Triceps, Abs, Lats
Secondary muscles: Obliques, Lowerback, Hip Flexor, Quads
Other names
The exercise can be found with other names. Examples are:
- L Sit Tuck on Parallel Bar
- Knee Tuck on Parallel Bar
Muscle: Core and Upper body
Collection: L Sit Friendly
Category: Bodyweight
Same exercise, different set:

L Sit Tuck on Parallel Bar