I picked up a spare racquet that was strung at some unknown date in the past with some unknown brand of black poly. The strings don't straighten themselves out after a hit and seem loose, so I suspect they are really old. My primary racquet is getting restrung, so I was using the spare this morning. I usually play with a cheap "syn gut" and didn't notice any big difference between my normal racquet and this one but I don't really know what I'm looking for. What is the problem with old poly strings? (fyi - I plan on getting the spare re-strung with syn gut once my primary racquet gets back).