Question on what is the correct hand position for side plank?
A) in same direction as body like Abi does in the yoga videos? This is how I position my hand and it’s relatively “comfortable” (but not in a couchlandrian sense of comfort).
B) At 45 degree angle as in some of strength and mobility videos? Attempts at this are very uncomfortable and slightly painful.
C) At 90 degrees (is on right side so back of wrist points to right side of mat, finger tips point to left side of mat) as in some of the strength and mobility videos? I find this excruciatingly more painful than Hammer 9 after Hammers 1-8 with fresh numbers from Half Monty.
In my experience there is no one way that is going to suit everybody because of the structure of the shoulder joint. I am able to create a straight line from my heels to my wrists but this is not going to be accessible to others. As @Mecons says, the goal of Side Plank is core strength (and also arm and shoulder strength) so however you get there is great.