if you have a busy schedule and need to get things done fast, follow my full core workout for people in a hurry series. make sure you watch the videos about the instruction of these exercises below as well.
some of these exercises are shown with different variations. make sure you watch the videos first and then do the exercises and not while you are doing them so you have a better focus on what you are doing.
there are 3 warm-up exercises that come after the warm-up routine mentioned below via link, after that, you do 9 exercises three times(or at least twice but if you can push it, go for 4 but not more than that since intensity is going to fall). perform 3 exercises back to back then rest for one set and go to the next 3 as shown in the video. each set is 30 seconds.
warm-up and dynamic stretching:
https://youtu.be/BUSInuoaxbE
https://youtu.be/yfpb_6SLHFs
https://youtu.be/TW3AY1IHWQA
cool-down and static stretching:
https://youtu.be/w6lEw7ZqfiI
main core videos:
https://youtu.be/XR90MoSMcho
https://youtu.be/SND6dQDliA0
https://youtu.be/Fr3g_PebHs8
side bridge: https://youtu.be/sHlVbym7xTM
push-plank: https://youtu.be/T1__mr3TngY
superman and birddog: https://youtu.be/AidnCNdxGV4
mountain climbers: https://youtu.be/_LVZ7Sgom4w
make sure you do the warm-up and cool-down as well.