Range of Motion and Sticking Region Effects on the Bench Press Load-Velocity Relationship

Abstract

This study aimed to analyze the influence of range of motion (ROM) on main biomechanical parameters of the bench press (BP) exercise: i) load-velocity relationship by mean (MV) and mean propulsive velocity (MPV), ii) one-repetition maximum strength (1RM); iii) contribution of the propulsive and braking phases, and iv) presence of the sticking region key parameters (first peak barbell velocity: V_max1, minimum velocity: V_min and second peak barbell velocity: V_max2). Forty-two strength-trained males performed a progressive loading test, starting at 20 kg and gradually increasing the load in 10 kg until MPV ≤ 0.50 m·s^-1 and 5 down to 2.5 kg until 1RM, in three different ROMs: full ROM (BP_FULL), two-thirds (BP_2/3) and one-third (BP_1/3). While significant differences were detected in the velocity attained against loads between 30-95% 1RM (BP_FULL, BP_2/3 and BP_1/3, p < 0.05), both MV and MPV showed a very close relationship to %1RM for the three BP variations (R² = 0.935-0.966). The contribution of the braking phase decreased progressively until it completely disappeared at the 80%, 95% and 100% 1RM loads in BP_1/3, BP_2/3 and BP_FULL, respectively. The 1RM increased as the ROM decreased (BP_FULL < BP_2/3 < BP_1/3, p < 0.05). Despite the three biomechanical parameters that define the sticking region on the velocity-time curves were only observed in BP_FULL variation, in 54.5% of the cases the subjects started their BP_2/3 displacement before reaching the position at which the V_min occurs in their BP_FULL exercise. The complete or partial presence of the sticking region during the concentric action of the lift seems to underlie the differences in the 1RM strength, load-velocity profiles and the contribution of the propulsive phase in the BP exercise at different ROMs.

Keywords: Resistance training; biomechanics; maximum strength; sticking point; testing.