Post-starburst galaxies are a vital link between late- and early- type galaxies but throughout the literature many different methods of selecting post-starburst galaxies are being used. We present a low redshift study into how the two main different selection techniques have consequences on post-starburst galaxy parameters, such as colour, morphology and environment. We identify a sample of H delta strong post-starburst galaxies from the MPA/JHU value-added catalogue in SDSS DR7. From this sample we select two E+A subsets, both having a very little OII emission but has an additional cut on H alpha emission. We examine the differences in colour, morphology, environment and AGN fractions so see what effect the H alpha cut has on the properties of post-starburst galaxies and what these differing samples can tell us about the duty cycle of post-starburst galaxies. We find that whilst H delta strong galaxies and E+A galaxies share many attributes, E+As with low H alpha emission are redder, smaller and have a higher fraction of elliptical morphologies that those with significant H alpha emission. We conclude that by including a cut in H alpha we are intrinsically selecting post-starburst galaxies located in the `red sequence'. We also witness a significant fraction of AGN in our main post-starburst and E+A samples, from this we are able to discuss the implications for the E+A duty cycle. Assuming the low H alpha E+A population is older, then this infers star formation could take a significant amount of time to quench after the initial starburst