have the athlete hang on the bar in eagle grip. then slowly, slide their hands in until they come together and touch. then hang there with their hands/outside of the hands touching and comfortably hanging. if they can do so, you have a candidate for L-grip invert giants.
sorry, was interupted by a phone call.
if you have noticed recent trends, male gymnasts are more likely to "higgins" roll, or a roll of some sort, into inverts or L-grip. only a few every year will "jamb". there is a historical reason for this.
only a handful of girls have "jambed" to inverts or L-grip. their consistent choice of entry is also a "higgins" roll. memmel "jambing" to invert and pama " "stooping" for german giants are unique to their anatomy. you cannot expect to have a general population of children doing these skills and even after everything a coach knows how to do and will impart to their athletes.
if my generation of coaches knew the invert test...we would not have trashed shoulders ie; torn rotators & torn ac joints today. my generation is a living testament that not all of us should have been "jambing" into inverts or even doing "eagle" giants. and in my day, only a select few did german & czech giants.
todays female athletes have experienced an uptick in torn labrums of the shoulder. female gymnasts did not tear labrums prior to invert work. it was almost unheard of at one time.
going into these extreme positions cause the shoulder to "sublux". being anatomically predisposed is not enough but also must be very strong in this position to prevent injury, both boys and girls. you see, it's not just the flexibility. it is the strength in that flexibility to sustain the forces that are placed on the body and its proximal joints. most will never be anatomically predisposed, and most will never achieve the strength required at the shoulder to sustain a consistent level of performance. this is where human biology comes in. no matter what a coach knows or does will change what certain body types will learn. once a coach accepts this simple scientific fact, then a coach who is a student of the sport can carry on with an athlete in making good decisions about skill selection. example: why would you waste precious time teaching a slow muscle twitched ectomorph a double back on floor? better to teach a triple twist which is better suited to that athlete's biology. i hope this point is understood.