Author(s): CHEN, C.M.1, CHENG, K.2, LI, T.1, Institution: NATIONAL TAIWAN SPORT UNIVERSITY, Country: TAIWAN, Abstract-ID: 465

INTRODUCTION:
Previous studies indicated that the primary contributor of contrast training improving explosive performance might be the post-activation performance enhancement (PAPE) and further emphasizing to conduct plyometric training at the optimal PAPE time. However, its applicability in practical training is not yet clarified since the PAPE appeared to be influenced susceptibly by relative strength level, training protocol, fatigue, and etc. Thus, the purposes of this study were to: 1) examine the effects of three contrast training sessions in a week on individual and group’s PAPE and the optimal PAPE timepoint. 2) assess the intrasession reliability of the optimal PAPE timepoints.
METHODS:
Eighteen trained male (age, 23.2 ± 3.3 years; body mass, 73.5 ± 8.9 kg; parallel back squat 1-repetition maximum [1-RM], 154.7 ± 22.9 kg and relative parallel squat 1-RM, 2.11 ± 0.21 kg·kg-1) performed three contrast training sessions, which consists of three sets of three repetitions of parallel squats at 90% 1-RM in a week. Alongside this, countermovement jump (CMJ) tests were conducted before the first set of squats and at 1, 3, 5, 7, 9, and 11 minutes after each squat set, with the kinematic parameters of the parallel squats also being collected. Data analyzed using Cochrans Q test, repeated measures one-way ANOVA with post hoc Bonferroni, and coefficient of variation (CV). Statistical significance was set at α = .05.
RESULTS:
Sixteen participants experienced individual PAPE whose data was adopted in statistics. The occurrence percentage of individual PAPE at nine sets of contrast training was significant difference (12/16, 5/16, 1/16, 10/16, 9/16, 8/16, 7/16, 2/16 and 4/16; Cochrans Q test, p < .001). The intrasession CVs of the optimal PAPE timepoints in three contrast training sessions were 60.9%, 59.4% and 39.6%, respectively. No group’ PAPE was found at any sets of the three contrast training sessions. Concentric mean velocity of squat decreased at the second and third set compared with the first set in every contrast training session (P <.05), whereas the velocity loss of squat decreased at the second and third set compared to the first set only in the first and second training session (P <.05).
CONCLUSION:
The findings of this study indicated that the reliability of the optimal PAPE timepoints was inconsistent and varied with the numbers of set and training session, even absent. It was also suggested that the arrangement of plyometric training based on the PAPE during contrast training might not be practicality.