Core workout (gym) that was pretty cool

[brenden]

(This is not for people that have never focused on fitness etc)
Went to gym with one of my brothers the other day, and I put him through a core workout that normally had most people hurting, and he just waltzed through it, so I was like "what the fuck have you been doing for your core?"
Asking was my first mistake.
We were at the end of the sesh, so he showed me the "10 minute burnout". You either did four sets of the exercises, or did them for ten minutes.
So,

Low Plank for 30 seconds, with a weight plate on your back. We used 10kg for the purpose of him showing me, it was probably a good weight to start it, I'll move up after a few more times.
Immediately after the 30 seconds, get on your back and do like.. reverse crunches. So if you were on your back, keep your legs straight and elevate your legs, so your body is at a right-angle, with your feet to the ceiling. Using your abs, move your feet closer to the ceiling (and subsequently closer to your head), so you're up on your shoulders, almost with a 90 degree angle between your shoulder blades and the floor. Not sure how well that was explain but that's what you do. Reps: as many as you feel like. I just did it until I felt like I couldn't do another (happened quickly), and then did the same movement with my knees bent (slightly easier).
Immediately, go over to a chin-up bar, pull yourself up so your chin is above the bar and hold yourself there. Bring your knees up to your chin using your abs for the movement. Reps: as many as you want. Aim for no less than 8 just so you don't cheat yourself.
Go straight back to the plank. Do each exercise 4 times. No breaks! As bad as you want, go to each exercise as quickly as you can.
Obvs you can up the weight and reps to suit you, but this was an awesome exercise to get in really quickly at the end of a sesh.. We did a little bit of oblique stuff afterward.