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This randomized crossover study compared surface electromyographic (sEMG) amplitude across cadence-defined lifting and lowering analytical intervals under four front lat pulldown attachment conditions in resistance-trained men. Sixteen participants performed the exercise with a straight bar, wide V-shaped handle, cambered bar, and rope. Each condition was performed at 70% of its attachment-specific 1-repetition maximum using a metronome-prescribed nominal 2-second lifting and 2-second lowering cadence and standardized grip-width criteria. sEMG was recorded from the latissimus dorsi, middle trapezius, posterior deltoid, biceps brachii, and triceps brachii. Normalized root mean square amplitudes were analyzed with repetition-level linear mixed-effects models, and sensitivity analyses were used to examine robustness. The most consistent attachment-related findings were greater biceps brachii sEMG amplitude in the wide V-shaped handle condition, particularly in the lifting analytical interval, and greater posterior deltoid sEMG amplitude in the rope than cambered-bar condition. Middle trapezius sEMG amplitude was greater in the cadence-defined lowering analytical interval than in the lifting interval. Specifically, the rope exceeded the cambered bar for posterior deltoid sEMG amplitude (mean difference = 8.0 %MVIC, 95% CI = 4.1 to 11.9; p = 0.002), and the wide V-shaped handle showed greater biceps brachii sEMG amplitude in the lifting analytical interval than the straight bar, cambered bar, and rope (mean differences = 11.0 to 15.7 %MVIC; all p < 0.001). Middle trapezius sEMG amplitude was greater in the lowering analytical interval than in the lifting analytical interval (mean difference = 6.2 %MVIC, 95% CI = 3.3 to 9.1; p < 0.001). No consistent between-condition difference was found for latissimus dorsi sEMG amplitude; a small attachment-by-phase interaction in the primary model was attenuated in complete-case sensitivity analysis. Because relative intensity was standardized to attachment-specific 1RM, absolute loads differed among conditions. The results therefore describe differences among attachment-specific relative-load conditions and should not be attributed solely to attachment geometry. The lifting and lowering labels refer to cadence-defined analytical intervals rather than mechanically synchronized phase boundaries, and acute sEMG findings should not be interpreted as evidence of longer-term hypertrophy or strength adaptations. |
