sEMG amplitude of core muscles under specialized core and snatch pull exercise conditions

Objective This study used surface electromyography (sEMG) to evaluate rectus abdominis (RA) and erector spinae (ES) sEMG amplitude in resistance-trained women performing the snatch pull, inverted sit-up, and hyperextension, and to examine whether any snatch pull intensity produces sEMG amplitude equivalent to that of the specialized core exercises. Methods Twenty female university students with at least three years of resistance training experience (age: 22.2 ± 5.3 years; height: 161.4 ± 7.2 cm; body mass: 61.5 ± 10.4 kg) performed all three exercises. Equivalence was assessed with paired TOST (±10% MVC bounds). Results RA amplitude was highest during the inverted sit-up (57.66% MVC), significantly greater than the snatch pull at 100% 1RM (25.52%) and hyperextension (9.22%, p < 0.01). ES amplitude was highest during the snatch pull at 100% 1RM (135.96% MVC), significantly greater than the inverted sit-up (9.61%) and hyperextension (69.39%, p < 0.001), and increased with snatch pull intensity (11.14% MVC per 10% 1RM, p < 0.001; marginal R 2 = 0.168). None of the snatch pull intensities produced RA amplitude equivalent to the inverted sit-up, and none produced ES amplitude equivalent to that observed during hyperextension; with the 40% 1RM condition showing the smallest difference (−3.29% MVC, 90% CI −17.58 to 11.00). Conclusion The snatch pull and the specialized core exercises produced distinct and non equivalent trunk muscle sEMG amplitude profiles. The snatch pull imposed high, load dependent ES demand but low RA demand, indicating that these exercises are complementary rather than interchangeable in weightlifting training.