The effects of different conditioning contraction protocols of post-activation potentiation on variables of eccentric phases and concentric phase of vertical jumps (source from doctoral dissertation)

Abstract

Abstract Purpose Investigation of the influence of different conditioning contraction protocols on the eccentric variables: depth of descent of body centre of mass (CMJ) and capacity of muscle force, power, and velocity (CMJ and DJ), i.e., velocity at time of rebound. Methods In a sample of 29-students (age: 19.6 ± 0.8), 1 RM was determined by estimating 10 RM, to be stratified in a six-week workout: static conditioning contractions-hold back squat at 120°, dynamic-back squat at 120° (x8), combined-2 back squat at 120° and 2 seconds endurance (x2) [for 12 seconds], and control group-6 to 8 hours of activity per week. After the pre-contractions, they continuously performed shock-plyometrics (50 cm box), triple jump and 5-meter sprint. Training load was 80 % 1 RM.Results A statistically significant increase (13.3, and 9.3 %) was found in (CMJ) spontaneous Hdd ES and ED unlike in EC and C (4.4, 5.5 %). In variables (CMJ) F, P, and V ecc significant performance ranges of experimental groups from 5.9 to 13.3 % were found, unlike in (DJ) variables for which there was no significance. Concentric variable (CMJ) V tr exhibits significance for ED and EC groups (3.4, 4.3 %), and variable (DJ) V tr for ES, ED and EC (2.0, 2.9, 4.1 %, respectively, p ≤ 0.05). Conclusion The most indicated increases (CMJ and DJ) V tr, by practicing contrast sessions i.e., conditioning contraction (CC) or post-activation potentiation, were observed after the application of dynamic (CC), referring to sublimated eccentric manifestations and concentric muscular-mechanical effects.