## 1 Introduction  
Strength can be described as an acceleration of a mass and defined as the ability to produce force [1]. Thus, a capacity to generate force in a short amount of time (force-time relationship) is a good indicator of performance in activities where great acceleration is required [2; 3]. Isoinertial strength assessment resembles training and competition tasks that involve acceleration and deceleration [4; 5] and appears to be an appropriate option to analyze changes in strength produced by regular training [6]. Recently, isoinertial strength tests have been used to examine the kinetic and kinematic behavior by examining velocity- and power-load relationships during the concentric phase of a lift [7; 8; 9]. These studies have included a pause between the eccentric and concentric phases in order to minimize the contribution of the rebound effect and allow for more reproducible, consistent measurements during isoinertial strength tests [7; 8; 9]. However, it is well known that the stretch-shortening cycle (SSC) improves neuromuscular performance [10], influencing both the kinetics and kinematics of the movement in the subsequent concentric muscle action [11]. Greater force and power are generated by muscle in a concentric phase when the concentric muscle action is preceded by an eccentric phase [12]. This performance improvement in the concentric muscle action likely depends on the movement velocity and force generated during the eccentric muscle action and the brief \"coupling\" time between eccentric and concentric muscle actions [13]. The mechanisms underlying this improved performance in the concentric muscle action after SSC have been a matter of debate for many years [14]. In resistance exercises, the effect of the SSC on kinetic and kinematic performance remains controversial during isoinertial strength assessment. [PERSON] et al. (2001) observed that the SSC increased instantaneous power output up to 260 ms in the concentric muscle action for light loads (40% of one repetition maximum (1 RM)) during bench press (BP) throws. At high loads (80% 1 RM), instantaneous power output was enhanced up to 460 ms in the concentric muscle action when the concentric phase was preceded by an eccentric muscle action. The authors found significant differences between light and high loads in the effect induced by the SSC [14]. However, [PERSON] et al. (2014) determined that mechanical parameters linked to the load-power and load-velocity profiles (30-100% of 1 RM) remained essentially unaffected by the SSC in BP and full squat exercises [7]. The authors concluded that the biological within-subject variation for the isoinertial strength assessment was decreased when a pause was established between the eccentric and concentric phases [7]. The contradictory findings of these studies do not clarify [7; 8; 9; 14] whether it is best to undertake the isoinertial strength test with or without countermovement to examine the specific kinetic and kinematic performance. Increased muscle strength appears to be highly specific to the nature of the training task [15]. Therefore, it is plausible to propose a more specific isoinertial strength assessment to determine the neuromuscular adaptations as a consequence of training. For this purpose, it is essential to demonstrate that the eccentric phase affects the kinetic and kinematic performance of the concentric muscle action during the isoinertial strength test. On the other hand, when a load is lifted in a traditional resistance exercise such as the BP, the movement involved starting from zero velocity until peak velocity (PV) is reached at a given time during the concentric phase of exercise, and, thereafter, this velocity gradually decreases again to zero. Thus, during an important portion of the concentric phase, the load is subject to deceleration, and, depending on the loading intensity, this deceleration phase will be of greater magnitude and length (for light or medium loads) or lower magnitude and length (for heavy loads).