ACTN3 and Insulin resistance: As the results regarding ACTN3 and insulin resistance are under-explored (Riedl et al., 2015), this leg of the trifecta is the most unknown; whilst there is a mechanism underpinning muscle mass and insulin resistance (Srikanthan and Karlamangla, 2011), and ACTN3 does modify muscle mass and type in athletic cohorts (Vincent et al., 2007), it isn’t clear whether this holds true in the elderly.