Clinical Research Directory

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.