Proving Heavy Lifts Work Core to Friend

[timtimtimmah19]

So friend, who I started on lifting, wanted me to come with him and do an ab workout today (to supposedly work core). I invited him to instead come do a leg workout with me that consists of all compound movement and a couple major lifts (Squat, Power Clean) that I've heard from experts on here work core just as much/more than traditional ab exercises. Long story short, I could not explain to friend why or how these exercises work and activate the core more than ab-targeting exercises, especially when you don't especially notice the core working during them. He then went on to relate to me how he no longer even bothers working legs most weeks and when he does he doesn't bother with the big 3 (squat, deadlift, power clean), since all he wants is a cut upper body. AHHH! So a couple questions:

How can I prove to friend that the major lifts in fact work core as much/more than these ab exercises? and How can I save him from "the dark side" of beach muscle lifters and convince him that legs are as/more important than any other muscle group to work????

I tried explaining how you don't notice the core as much when you have hundreds of pounds on your back, stabilization as the purpose of the core, and that the reason I have a six pack now is mainly due to these exercises (in compilation with other stabilization exercises such as various Bridges and whatnot...thank you Swanso...). Any other ideas are desperately needed...

[swanso5]

- he's a dick
- have him do chin ups with wt strapped to him going as heavy as he can for sets of 5 or push ups with wt strapped to him with feet on a bench and the bar set up at about wast on a power rack
- you can convince him by training that way and looking 8 times as good as well as being 10 times as strong...even better have an arm wrestle in front of a chick he likes...he won't be happy than

[timtimtimmah19]

Good ideas, I especially like the pushup one. I had him doing them before with me when I was lifting with him and some other guys I was starting out, but since lacrosse started I haven't been around and it's all gone to hell. I figure I'll give it another go tomorrow and if I can't convince him stop wasting breath until he comes around on his own...