Blue straggler stars (BSSs) in globular clusters are located as an extrapolation of the main sequence, they are located in a region that is brighter and bluer (hotter) than the turnoff (TO) point. Recent studies shows BSSs can act as a dynamical clock to probe the internal dynamics of the cluster. In this talk, I will discuss the principle mechanism behind the segregation of BSSs towards the cluster center and some of the recent techniques towards understanding the dynamical status of the cluster.