Kinetic and kinematic changes induced by performance of accentuated eccentric overload in competitive weightlifters: an exploratory study.

In this 8-week exploratory study, investigators compared the effects of accentuated eccentric loading (AEL) and traditional loading on the dip and propulsive phases of the split jerk, as well as on countermovement jump (CMJ) kinetics and kinematics. Eighteen participants were randomly assigned to one of two parallel groups: an AEL group that performed the split jerk using weight releasers that disengaged at the end of the dip phase, or a traditional loading (TLT) group that executed the split jerk with the same load for both eccentric and concentric phases and also performed jerk dips. Both groups trained the split jerk twice weekly using five working sets per session. Primary outcome measures included kinetic and kinematic variables obtained during the split jerk one-repetition maximum and the CMJ. Results showed that both interventions elicited small improvements across most jerk-related variables, including slight reductions in braking duration and potentially moderate-to-large decreases in unweighting duration. The estimated group differences in most of the kinetic and kinematic variables for the jerk showed little difference between the TLT and AEL groups, as reflected in the pooled average treatment at mid-intervention (-0.12; 95% CrI: -0.36 to 0.12; Pr[SMD > 0] = 0.155) and post-intervention (0.02; 95% CrI: -0.24 to 0.28; Pr[SMD > 0] = 0.569). In conclusion, applying AEL to the split jerk produced adaptations in jerk and CMJ kinetics and kinematics that were comparable to those observed with traditional training that incorporated the jerk dip, with most changes attributable to adaptations occurring during the dip phase.