Hello I am a 23y old female and when I lay flat on my back am completely unable to lift my legs up straight but have no bother if I bend my knees first, I have no history of any injuries and am a health weight and fitness level and am flexible and have been doing palates and other activities to try and straighten my legs over the years but zero improvement? It's disheartening and frustrating as it does start to hurt when I try to lift. I am just baffled as to why this is? Seen doctors and spoke with Phsio and all say to stranghen my muscels which haven't help even with weekly exercises for the past 3 years? Any ideas?