Here's Theresa (aka Big-T) performing an L-sit. She was already pretty strong when she first started training with us, but with hard work she has made remarkable gains in strength in a short amount of time.
Basic gymnastic strength elements have played a part in that and is a great tool to get you strong quickly and with the right preparation, safely.
Gymnasts are strong for a reason! Strength is just one element, but a very important one when it comes to being a well rounded mover. Use the tools that give most bang for buck and that work for you.