Apparently when volume is equated dropsets sill produce double the hypertrophy.
Normal sets increased muscle growth by 5% and strength by 25% over 6 weeks
Dropsets increase muscle growth by 10% and strength by 16% over 6 weeks
Effects of drop set resistance training on acute stress indicators and long-term muscle hypertrophy and strength
Background: We investigated the effects of 2 different resistance training (RT) protocols on muscle hypertrophy and strength. The first group (n = 8) performed a single drop set (DS) and the second group (n = 8) performed 3 sets of conventional RT (normal set, NS). Methods: Eight young men in each group completed 6 weeks of RT. Muscle hypertrophy was assessed via magnetic resonance imaging (MRI) and strength via 12 RM tests before and after the 6 weeks. Acute stress markers such as muscle thickness (MT), blood lactate (BL), maximal voluntary contraction (MVC), heart rate (HR) and rating of perceived exertion (RPE) before and after one bout of RT. Results: Both groups showed significant increases in triceps muscle cross-sectional area (CSA) (10.0 ± 3.7%, effect size (ES) = 0.47 for DS and 5.1 ± 2.1%, ES = 0.25 for NS). Strength increased in both groups (16.1 ± 12.1%, ES = 0.88 for DS and 25.2 ± 17.5%, ES = 1.34 for NS). Acute pre/post measurements for one bout of RT showed significant changes in MT (18.3 ± 5.8%, p < 0.001) and MVC (-13.3 ± 7.1, p < 0.05) in the DS group only and a significant difference (p < 0.01) in RPE was observed between groups (7.7 ± 1.5 for DS and 5.3 ± 1.4 for NS). Conclusions: Superior muscle gains might be achieved with a single set of DS compared to 3 sets of conventional RT, probably due to higher stress experienced in the DS protocol
Another study shows that dropsets can increase strength, hypertrophy and endurance while cutting training time in half.
Effects of drop sets with resistance training on increases in muscle CSA, strength, and endurance: a pilot study.
To investigate the effects of a single high-load (80% of one repetition maximum [1RM]) set with additional drop sets descending to a low-load (30% 1RM) without recovery intervals on muscle strength, endurance, and size in untrained young men. Nine untrained young men performed dumbbell curls to concentric failure 2-3 days per week for 8 weeks. Each arm was randomly assigned to one of the following three conditions: 3 sets of high-load (HL, 80% 1RM) resistance exercise, 3 sets of low-load [LL, 30% 1RM] resistance exercise, and a single high-load (SDS) set with additional drop sets descending to a low-load. The mean training time per session, including recovery intervals, was lowest in the SDS condition. Elbow flexor muscle cross-sectional area (CSA) increased similarly in all three conditions. Maximum isometric and 1RM strength of the elbow flexors increased from pre to post only in the HL and SDS conditions. Muscular endurance measured by maximum repetitions at 30% 1RM increased only in the LL and SDS conditions. A SDS resistance training program can simultaneously increase muscle CSA, strength, and endurance in untrained young men, even with lower training time compared to typical resistance exercise protocols using only high- or low-loads.