Force Production and Barbell Velocity Characteristics Across Multiple Sets of Different Accentuated Eccentric Loading Conditions.

ABSTRACT Cantwell, CJ, Schroeder, ZS, Marshall-Ciochon, LK, Campbell, BA, Taber, CB, and Suchomel, TJ. Force production and barbell velocity characteristics across multiple sets of different accentuated eccentric loading conditions. J Strength Cond Res XX(X): 000-000, 2025-The purpose of this study was to examine the impact that multiple accentuated eccentric loaded (AEL) back squat sets have on force production and barbell velocity characteristics within 2 different loading conditions. Sixteen resistance-trained men performed 3 sets of 3 back squat repetitions while using 100% of their 1 repetition maximum (1RM) during the eccentric phase of the first repetition and either 60% (100-60) or 80% (100-80) 1RM on the concentric phase of the first repetition and the eccentric-concentric phases of the subsequent 2 repetitions. Braking and propulsion net mean force, duration, and net impulse as well as mean and peak barbell velocity were compared between loading schemes and sets using a series of 2-way repeated measures ANOVA. Significantly greater propulsion net mean force and mean barbell velocity were produced during the 100-60 condition than during the 100-80 condition across all sets (p < 0.001). In addition, significantly greater (p < 0.001) set-averaged braking net mean force and net impulse and peak barbell velocity were produced during the 100-60 condition while greater braking and propulsion duration (p < 0.001) and net impulse (p = 0.031) were produced during the 100-80 condition. Within each loading condition, trivial-small differences existed across sets for all variables (g ≤ 0.39). Multiple sets of AEL back squats can be prescribed using 100-60 and 100-80 loading schemes without negatively affecting force or velocity characteristics. Strength and conditioning practitioners may prescribe 100-60 to enhance rapid force production characteristics and 100-80 to provide a strength stimulus to enhance force development.