Mastered the Front Split: Once in a while people ask me this question: “Paul, you say that all the muscles stretched in a front split are also stretched in a side split (people usually mean true front split when they say front split) so, how come there are many people who can do a true front split, and yet, are not able to do a side split without training for it separately?”
The reason is, when most people are able to do a true front split, the true front split that they perform is usually a deep flexibility of the front hamstrings and combined with hyper extension of the lower back and very little flexibility of the rear leg
You can see that in the video below:
You see it’s the rear leg where the adductors or the inner thighs are most stretched. Because, all four adductors are also flexors of the hip. And because these muscles are poorly stretched when majority of people perform their true front split, there is little carry over of that flexibility to the side split which of course requires lengthening of the adductors.
In theory if someone is doing a true front split or hip squared front split, where a lot of flexibility is taken from the rear leg and not just the front leg, that person will be able to carry that flexibility into a side split.
Providing that there’s no issues with the hip joint or other tissues besides the muscles, a person who mastered a structural true front split should have a very easy time converting that flexibility to the side split.
Even if the true front split is not completely structural but something close to it, it will be easier to master the side split already having the flexibility from the other split.