This study investigated the effects of a 10-week powerlifting-style bench press resistance training program, with (EBD) and without an elastic bench press device (RAW), on one-repetition maximum (1-RM), body mass (BM), muscle mass (MM), fat-free mass (FFM), and muscle thickness of the triceps brachii and pectoralis major. Twenty-two trained males (EBD: n = 10, age 25.1 ± 4.5 years, relative 1-RM 1.05 ± 0.31; RAW: n = 12, age 24.9 ± 3.9 years, relative 1-RM 1.07 ± 0.31) performed training three times weekly, with the EBD group training at 10% higher intensity than the RAW group. Analysis revealed significant time effects for 1-RM (EBD: +8.5 ± 2 5.3%, d = 0.34, p ≤ 0.001; RAW: +7.8 ± 28%, d = 0.28, p ≤ 0.001) and pectoralis major muscle thickness (EBD: +15.5 ± 23.9%, d = 0.65, p = 0.007; RAW: +17.2 ± 13.2%, d = 1.31, p = 0.001). Despite significant time effects, BM revealed no relevant post hoc changes (EBD: +1.0 ± 23.8%, d = 0.04, p = 0.406; RAW: 0.0 ± 19.5%, d = 0.00, p = 1.000). No significant interaction effects emerged for any outcome, and triceps thickness, MM, FFM, and fat mass did not show statistically significant changes. EBD and RAW training produced comparable strength and hypertrophic adaptations. Although the RAW group showed slightly greater gains in pectoralis major thickness, the difference was not statistically significant. This study highlights that while EBD provides a viable alternative to conventional resistance training, it does not confer superior gains.