Drop – set (DS) is an advanced training method widely used by recreational trainees and professional athletes with the goal of achieving additional hypertrophy or strength gains. The purpose of this study was to investigate DS influence on regional hypertrophic development of muscle m. quadriceps femoris and to compare these hypertrophic adaptations with those caused by traditional training method (TS). Design used in this study was a randomized controlled trial within-subject. There were 24 subjects (19,21 ± 1,10 age; 183,13 ± 5,55 cm; 78,50 ± 7,11 kg) who had one leg assigned to a DS condition or experimental condition (participants did 3 – 8 repetitions using 89% of 1 RM as a load) and another leg to TS condition or controlled group in which participants did 13 – 18 repetitions using 69% of 1 RM as training intensity. Participants have been training 3 times a week doing only unilateral seated leg extensions. Following principle of progressive overload, total training volume has been increasing every week till the last one when it was cut in half. Regional muscle thickness was measured before and after training period. Both conditions increased muscle thickness in muscles m. rectus femoris (RF) (DS: +33%; TS: +15,7%) and in m. vastus lateralis (VL) (DS: +20,8%; TS: +19,7%) from pre- to post-training intervention. Statistically greater increases have been found at 30% and 50% of RF length favouring DS condition, but no differences were detected at 70% length or at any measured point along VL length. DS method, if properly integrated in training programme, can have practical benefits in terms of producing non-uniform hypertrophy response in RF muscle after practicing leg extensions. But unfortunately, these advantages were not spotted regarding to VL muscle compared to TS.