Acute Effects of Variable-Resistance and Free-Weight Bench Pull Exercise in Resistance-Trained Men

This study used a randomized, counterbalanced crossover design to compare high-load chain-based variable-resistance (VR) and free-weight (FW) bench pulls. Resistance-trained men completed two experimental sessions separated by 72 hours, with the order of the VR and FW conditions randomized. Before each experimental condition, participants completed a standardized general and bench pull-specific warm-up followed by a 10-minute rest period. In each session, participants performed one set of three bench pull repetitions at approximately 85% of their free-weight one-repetition maximum (1RM). In the VR condition, the external resistance was provided by a combination of barbell load and chains, with chains contributing approximately 20% of the effective mean total load. In the FW condition, the external resistance was provided entirely by the barbell. Following the high-load bench pull, participants rested for 3 minutes and then completed three standardized sets of free-weight bench pulls at approximately 75% 1RM, with 3-minute rest intervals between sets. Each subsequent set was terminated when the mean velocity of a repetition fell below 0.65 m·s-¹ or when the participant was unable to complete the prescribed range of motion. Direct exercise responses during the high-load bench pulls were assessed using movement velocity and surface electromyography. Residual effects during the subsequent free-weight sets were assessed using repetition count, movement velocity, and surface electromyography. The crossover design allowed each participant to complete both loading conditions and therefore serve as his own control.

Inclusion Criteria: * Male adults aged 18-30 years. * At least 1 year of resistance-training experience. * Proficiency in the bench-pull technique. * Bench-pull one-repetition maximum (1RM) of at least 1.0 × body mass. * No current use of medications that could affect neuromuscular performance. * No history of cardiovascular, neurological, or metabolic disease. * No upper-body musculoskeletal injury within the previous year. * Willing and able to provide written informed consent. Exclusion Criteria: * Consumption of caffeine within 12 hours before testing. * Consumption of alcohol within 24 hours before testing. * Performance of any upper-body pulling exercise within 48 hours before testing.