This was posted on AR by retreever;

"It is isometric exercises and it works..
My forend hand pushes the rifle into my shoulder...my pistol grip hand pushes it away from the shoulder...The rifle is against the shoulder just like a firm handshake...The hands are holding the rifle with a crushing handshake...Your arms are flexed and tensed, just like showing off your muscles...When fired your arms take the recoil like shockabsorbers...
This takes practice to perfect, but I can tell you from experience the rifle only goes up about 6 inches and is right back ready to fire is a sec...I fired 14 shots in an hour and no bruising or soreness face or shoulder...I did have a video clip of me firing three rapid fire shots at 25yds and they were all inside of a 6inch circle in 6 seconds...Wife shot it with camera...
I have a 990 decelerator pad and I use those hand wrist strengtheners to get grip strong.."

He said it is very effective. Haven't tried it yet.

I do think that big guys get beat up more by recoil because it takes a lot more to get them moving.

Allen has the right idea aswell as Dan and 500 Nitro.