I've been working out for a very long time. I enjoy running and aerobics and I think I have good stamina. I go to a class and will jump, dance, jog etc for an hour without breaks. I also do my own strength program (which would probably be classed as mild). I use hand weights (2 kg in each hand) and do a 20 minute session 3x/week.
Why do I struggle so much with planks/push-ups? I can hold a plank for about 5 seconds and then collapse. I've been told often that over time it will improve, bit it hasn't. I've been told to start on my knees, which I can do fine and hold for about 20 seconds but I've been doing that forever with no change.
Same with push-ups. I can't do them properly at all. My arms just can't seem to do them right. I just can't go down. PT I had years ago was constantly telling me my arms should be alligned with my shoulders but mine are always sort of slanting forwards.
I want to improve my core, it's just so frustrating!