by Thomas Kurz
In this article I show a test of your potential to do a side split that is simpler and in some ways better than the test shown in my article Misconceptions on Stretching and Flexibility and the Method of Testing Your Potential to Do a Side Split.
The test I show here is less comprehensive than the other one–it shows the hip joints’ range of motion as determined by the shape of their bones, and length of their ligaments and of the muscles which rotate the thighs inward (internal rotators of the hip)–but does not test the length of thigh adductors. It is better than the other test in that it requires less keen observation and the instructions are easier to follow for correct form. Of course, it can be botched up too–typically, by “screwing out the knees” to show greater turnout than one’s hip joints allow. (If you don’t know what “screwing out the knees” is, you can ask a dancer–just don’t do the action – it will inevitably end in injury. This is also sometimes called “wrenching the knee.”.)
Here is the test:
Turnout as a test of potential to do a side split
The amount of turnout or external rotation in the hip joint determines the quality of the side split. This rotation is limited by the length of the ligaments of your hip joint, by the muscles that rotate the thigh inward, and in a few cases by the configuration of the thigh bone. It is measured as an angle between the center line and the direction in which your kneecap is pointing–and the foot should be pointing in the same direction as the kneecap (if your knee caps and toes are not in line, you are “screwing out the knees,” causing injury).
So, the above photo shows my maximal external rotation and this is enough for side splits. If you have greater external rotation, good for you. If you have a little bit less of this rotation, it is likely you can still do splits. If you have a much smaller angle, then it is not likely you can do splits.
Info on the relation of the external (outward) rotation in the hip joint to the side or straddle split is in articles at stadion.com/flexibility-training-for-sports-and-martial-arts/