Hand grip measures age of a person

This was a recent study that said they could measure a person's true age by hand grip. With one of the benefits of poling being a better grip, does this mean us polers age slower? http://sb.cc.stonybrook.edu/news/general/2014-05-07-new-tool-to-measure-aging%20speed.php http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0096289