Building strength in an L-Sit will help build a functionally strong core and stable shoulders, whether you’re practising the hanging or holding variation. Using these strengths and transferring them into other areas of your training proves to be hugely beneficial. You’ll develop a more stable trunk in addition to improving hip and spine stability. Adding L-Sits into your workout sessions will help towards achieving your goals, whether that's in your yoga practice, handstands, lever variations in your gymnastics and calisthenics or being able to lift more in your weight training.
I remember trying an L-Sit hang for the first time after my coach demonstrated it so easily and thinking, “that looks alright!”. I jumped on the rig, used some momentum to raise my legs up, which then dropped straight back down as as fast as I’d lifted them up. I felt instant cramp in my quads and my hips ached. Getting my whole body to connect in this movement felt impossible. I’m still no master of the L-Sit hang or hold but I frequently add them in to my training. I’m currently working towards some of the progressions mentioned myself to build strength and help achieve my own personal goals.
Sit on the ground. Can you sit up tall at 90 degrees with your legs straight out in front of you? Can you hold yourself there comfortably without the hamstrings screaming at you? If so, then your passive hamstring flexibility most likely isn’t an issue. You don't need to be able to get your chest all the way to your thighs in a full fold to be able to do an L-Sit, but if you can sit at 90 degrees comfortably then you're pretty good to go.
To work on your hamstring flexibility you could sit on the edge of an ab mat to help tilt the pelvis more anteriorly so you can work deeper into the fold. You can also bend your knees when folding to avoid overly rounding your back.
Hip Flexor Strength
Sit up tall with your legs out in front. Can you sit tall without the use of your hands and without feeling like you're going to fall backward? If so, you have the basic hip flexor strength required to get in to an L-sit. However, if you slump backward or really struggle to sit up in this position it’s likely you need to work a little more on your hip flexor strength.