Does Performing Drop Jumps With Additional Eccentric Loading Improve Jump Performance?

Abstract

Previous investigators have speculated that applying additional external load throughout the eccentric phase of the jumping movement could amplify the stretch-shortening cycle mechanism and modulate jumping performance and jump exercise intensity. The aims of this study, therefore, were to determine the effect of increased eccentric phase loading, as delivered using an elastic device, on drop jumps (DJs) performed from different drop heights. Of specific interest were changes in (a) the kinetics; eccentric and concentric impulse, rate of force development (RFD), concentric velocity and (b) the electromyographic (EMG) activity of leg muscles. In a randomized repeated-measure study, 15 highly resistance trained male subjects performed DJs from 3 heights (20, 35, and 50 cm) under 3 different conditions: body weight only (free DJ) and with elastic bands providing downward force equivalent to 20% (+20% DJ) and 30% (+30% DJ) of body mass. All DJs were recorded using video and force plate data that were synchronized with EMG data. Results demonstrated that using additional tensile load during the airborne and eccentric phases of the DJ could enhance eccentric impulse (p = 0.042) and RFD (p < 0.001) and resulted in small to moderate effect size (ES) increases in quadriceps intergrated EMG across the eccentric phase (0.23 > ES > 0.51). The observed greater eccentric loading, however, did not immediately alter concentric kinetics and jump height nor did it alter muscle activation levels during this phase. The findings indicated that, in addition to the conventional technique of increasing drop height, using a tensile load during the airborne and eccentric phases of the DJ could further improve eccentric loading of DJs. As it has been suggested that eccentric impulse and RFD are indicators of DJ exercise intensity, these findings suggest that the loaded DJs, using additional elastic load, may be an effective technique for improving DJ exercise intensity without acute effects on the jumping performance and neuromuscular activation level in highly trained athletes.

Effects of resistance training using known vs unknown loads on eccentric‐phase adaptations and concentric velocity

“…Several eccentric‐phase variables (eg, peak velocity, peak force, RFD) have been shown to be sensitive to change in response to various strength training methodologies. In the present study, increases in eccentric‐phase kinetic energy were observed in both unknown (UL) and known load (KL) training groups (ES=0.98‐1.38 and 0.75‐1.09, for UL and KL, respectively) along with significant increases in eccentric velocity (ES=1.10‐1.33 and 0.39‐0.98).…”

“…Moreover, changes in the pattern of neural activation in the early muscle activation period during the SSC could potentially influence the force at the start of the concentric phase. Indeed, Aboodarda et al . observed earlier quadriceps, biceps femoris and soleus EMG activity onsets when participants performed a drop jump with an additional load of 30% body mass.…”

The Effects of Augmented Eccentric Loading upon Kinematics and Muscle Activation in Bench Press Performance

“…In addition, by increasing the loading during the eccentric phase it can further increase vertical jump height, such as in the depth jump [6]. Numerous studies have also compared the efficacy of a loaded eccentric phase using an additional 20-30% of body mass on a drop jump, which also led to an increase in subsequent jump height in (highly) trained athletes [7,8].…”

Implementing Eccentric Resistance Training—Part 1: A Brief Review of Existing Methods

“…However, the higher absolute loading required of AEL makes it an attractive strategy for applying additional stress to the muscle and connective tissue while maintaining the CON stimulus. The ability to preserve mechanical similarity and coupled actions may also explain previous reports of favorable changes in jumping and throwing actions, demonstrating that the training effects from AEL may transfer well to sport tasks and performance when applied to both strength and PT exercises [117][118][119][120][121][122][123][124]. Maintaining technical quality has important practical implications as well as including a reduced risk of injury in its application.…”