Progression for the side plank involves moving from bent knees to straight legs, potentially placing the top foot in front, and holding for 8-10 seconds for 3-5 repetitions per set.

“if you find that you can do that and it's fairly straightforward for you well then feel free to then extend your feet out further put the top foot on top of the other foot and out to the front Okay so you're not stacking the feet right on top of one another we just shoe on top of shoe but you've got or foot on top of foot if you're doing this Barefoot or in socks but you've got one foot in front of you for some stability and then you're generating that long side plank pose and holding that for 8 to 10 seconds then pause for 10 maybe 30 seconds if you have to and then repeat again again all that part of one set just as we talked about for the curl up previously so you're working through the progression from bent legs to straightening your legs if the top foot is placed in front of the other foot with legs straight and that's something that you can do for say anywhere three to five repetitions of those 8 to 10 second holds which make up one set”