Twisting squats (SLS iM2) are the hardest, due to old injuries on left ankle and right knee. When I first tried to get up from a cross legged position, I could not even lift my but off the ground. After 8 weeks I now can get up from a cross legged position (and then sit down again) 5 times in a row (no twisting; I call it 0.25 of SLS iM2). Be that as it may, I am ecstatic that I even got this far and have high hopes that mastery of SLS iM2 will be mine in say 12 months.
Arch body hold (SL PE1) is hard too but a different story. It will take longer to progress (now at 5x30 sec.), but that is because I don’t see much of a benefit to put myself through “hell†to be able to say that I have reached mastery level. If I can’t do any of the exercises while enjoying it, then to me it is not “masteryâ€. So, I will just take my time to get there even if it takes half a year.
I could hardly do 3 x HB PE2 when I started, but HB PE1 in combination with the straight arm, scapula and abs work in sPL PE1, 2 and 3, and FL PE1 and 2 appear to have resulted in sufficient strength gains to now feel pretty comfortable doing 5 x12 with pretty good form. Please note that I am milking the iM exercises for every second possible to rest a bit. So, probably another 8 weeks to reach mastery.