it's a strength training regime that concentrates on large compound lifts- squats, bench, overhead press, rows and deadlifts (with some body weight exercises thrown in- core, pull/chin ups and dips) with 5 sets of 5 reps
you start out at low weights and very incrementally you add weight after successfully completing 5 sets of 5 reps
compound lifts hit multiple muscle groups and with the lower weights you learn good form and balance, the incremental buildup will definitely build strength
I would recommend to anyone- experienced or not, to give it a whirl
also look at the 3x5 regime as well- same focus on compound lifts with incremental increases
