The Reactive Strength Index (RSI) is one component of the Strength Qualities Assessment Test (SQAT). This test is used at the Australian Institute of Sport (Young, 1995) to differentiate between the various strength qualities of sprinters and jumpers. Using a contact mat with drop jump protocol the RSI value is derived by dividing the height jumped by the time in contact prior to take-off (height jumped/time). Tests are conducted from a range of drop heights to impose increasing stretch loads on the leg extensors and RSI is interpreted as an indicator of the ability of the athletes to withstand those stretch loads during the plyometric component of their conditioning and general preparation. This report is based on use of the RSI in monitoring the drop heights of players in a professional Rugby Union Franchise (Study 1), and as a secondary consideration (Study 2), the effects of pre-season training on the Reactive Strength Index.