The Potentiating Response to Accentuated Eccentric Loading in Professional Football Players

Abstract

The purpose of this study was to assess the acute effect of Accentuated Eccentric Loading (AEL) on countermovement jump (CMJ) height, peak power output (PPO) and peak velocity in male professional footballers using loads of 20% or 40% of body mass (AEL20 or AEL40, respectively). Twenty-three male professional football players (age 24 ± 4.5 years, range 18–34 years; body mass 80.21 ± 8.4 kg; height 178.26 ± 7.62 cm) took part in a randomised, cross-over design to test the potentiating responses of two AEL conditions (AEL20 and AEL40) versus a body weight control group (CON). Mean loads for the two conditions were 15.84 ± 1.70 kg (AEL20) and 31.67 ± 3.40 kg (AEL40). There was no significant difference between the three conditions for jump height (p = 0.507, η2G = 0.022). There were significant differences in peak power between the groups (p = 0.001, η2G = 0.154). Post hoc analysis with Bonferroni adjustment showed significantly higher peak power for both AEL conditions compared to the control group, but no significant differences between AEL conditions (CON vs. AEL20, p = 0.029, 95% CI −1016.735, −41.815, Cohen’s d = −0.56; CON vs. AEL40, p = 0.001, 95% CI −1244.995, −270.075, Cohen’s d = −0.81; AEL20 vs. AEL40, p = 0.75, 95% CI −715.720, 259.201, Cohen’s d = −0.24). There was no significant difference between the three conditions for peak velocity (p = 0.269, η2G = 0.046). AEL using either 20% or 40% of body mass may be used to increase peak power in the countermovement jump in well-trained professional football players.

The Effects of Accentuated Eccentric Loading on Barbell and Trap Bar Countermovement Jumps

“…9,11,19 Previous studies have employed AEL by having subjects hold then release dumbbells or resistance bands after completing the eccentric phase to improve jumping ability. [7][8][9]16,21 For example, AEL with 20kg dumbbells improved jump height (4.3%), power (9.4%), velocity (3.1%), and force (3.9%) of countermovement and block jumps of trained volleyball players compared to jumps without AEL. 16 In professional football players, AEL with 20% and 40% of body mass did not influence countermovement jump height or velocity, but did improve peak power likely as a result of the additional forces from the AEL.…”

“…One emerging method for developing muscular power, strength, hypertrophy, and eccentric control is the use of accentuated eccentric loading (AEL). [6][7][8][9][10][11][12][13][14][15][16][17][18][19] The AEL method involves applying more weight during the eccentric (or braking subphase) portion of the movement compared to the concentric (or propulsive) portion while attempting to elicit little to no disruptions in natural movement mechanics. 11,18 Due to most training methods using a concentric focused exercise prescription, the use of AEL may enable greater recruitment of motor units during the eccentric phase and subsequently potentiate concentric performances.…”

“…16 In professional football players, AEL with 20% and 40% of body mass did not influence countermovement jump height or velocity, but did improve peak power likely as a result of the additional forces from the AEL. 7 Others have employed AEL with 20 or 30% of the subject's body mass via elastic bands and found improved propulsion ground reaction forces, power output, net impulse and jump height in the countermovement jump but not the depth jump. 21,22 Evidence has been presented that AEL incorporating dumbbells and elastic bands can improve jumping performance as long as the jump type and load employed is appropriate.…”