Troy Aikman -- Hey Eddie Lacy ... P90X Worked For Me!

If Eddie Lacy is on the fence about training with the P90X guy ... this could be the video that pushes him into the "yes" camp.

We ran into Troy Aikman in NYC -- and since he's a huge fitness enthusiast (not to mention an NFL Hall of Famer) ... we asked if P90X could actually do the trick for Lacy, who's been under fire for being overweight.

Long story short -- Aikman approves in a big way.

And in case you forgot ... Troy is pretty shredded.