I, too, cannot positively identify the bike. But it does look similar to ones offered by Nashbar back around 1985-6. And some did, in fact, come outfitted with the Shimano Biopace chainrings. I had one I bought in 1984 that was so outfitted. I doubt they would put more strain on your knees that a "normal" chainring. Might even be less. I'd suggest simply trying them yourself, though.
I, for one, was quite surprised when the Biopace cranksets were withdrawn from the market. I liked them - they helped make you go a bit further & faster, for the same amount of energy expended, than you would otherwise. My bike was my local beater, and I loaned it out to many friends who needed a bike - like for losing their license due to a fascist police department that ruled our town back then. They all very much liked them, too.