I can't see any TM issues (I'm not a lawyer) as the .com and the .net are just parked pages. I'm surprised nobody has bothered to develop them - maybe they get lots of visitors withot development?
Estibot reckons the .com is worth $11K the .net $180 and the .info $50
Why not send an e-mail to the .com owner to see how much he wants for it just to get an idea ? Then offer the .info to some body building site ?
P.S. I've just seen that the .com belongs to Rick Schwarz, who just sold iReport.com for $750,000 so he probably doesn't agree with the estibot estimate of $11K for MrUniverse.