The aim of this study was to establish reliability of post-activation performance enhancement in three manners: (1) interday morning and afternoon reliability; (2) intraday morning and afternoon reliability; (3) intraday set-to-set reliability. Twelve elite male volleyball players experienced in resistance training performed four identical experimental sessions-two in the morning and two in the afternoon. During each session participants performed a mini complex training session-three sets of a conditioning activity (CA) (3 repetitions of a trap bar deadlift at 80% 1RM with 15% of accommodating resistance) and 90 s after a CA performed squat jump (SJ) with 4 min intra-set rest interval. The ANOVA with repeated measures was used to assess significance of the effect of a CA and ICC to assess reliability of measurements. The PAPE protocol was found to be ineffective to subsequently enhance JH on various occasions. Also, the results of this study suggest that the practitioners may effectively implement appropriately organized complex training as both intraday set-to-set (0.87 and 0.82 for morning sessions; 0.83 and 0.58 for afternoon sessions) and interday morning (0.67) and afternoon (0.8) reliabilities seem to be acceptable. However, introducing two CT sessions within one day is highly questionable as at the moment intraday morning and afternoon reliability is vague (0.88 and 0.48).

UNASSIGNED: Prior work regarding post-activation performance enhancement (PAPE) has shown that various resistance training methods and conditioning activities may induce a PAPE effect such as free weight resistance, accommodating resistance or isoinertial resistance. However, the accommodating resistance and other types of resistance have rarely been directly compared. Thus, the aim of this study was to compare the effects of two different conditioning activities (CA) - a trap bar deadlift with (FW + AR condition) or without (FW condition) accommodating resistance - on subsequent squat jump (SJ) performance after a short rest interval of 90s.
UNASSIGNED: The study had a cross-over design and fifteen strength trained males (mean age: 22.9 ± 2.1 years; mean relative strength level 2.01 ± 0.27 kg/body mass) participated in one familiarization, two experimental and one control session (CNTR condition). Two CAs were implemented throughout the study - a single set of 3 repetitions of a trap bar deadlift at 80 % of 1RM using solely free weight resistance or with the addition of approximately 15 % of 1RM elastic band tension. The SJ measurements were performed at the baseline and 90s after CAs.
UNASSIGNED: The FW + AR condition significantly improved subsequent SJ performance (p < 0.05, effect size 0.34) whereas the FW and CNTR conditions were found to be ineffective to acutely enhance performance.
UNASSIGNED: Our results suggest that the addition of accommodating resistance is superior to free weight resistance in order to acutely improve jump performance after a 90s rest interval. To observe the performance enhancement effect with solely free weight resistance it should be considered to introduce alteration in loading strategies or possibly lengthening the rest interval.

BACKGROUND: Post-activation potentiation performance (PAPE) is a physiological phenomenon that has been studied numerously but the researchers are still seeking for the optimal application methods. The accommodating resistance was found to be an effective training method to acutely enhance subsequent explosive performance. The purpose of this study was to evaluate the effects of performing a trap bar deadlift with accommodating resistance on squat jump (SJ) performance with different rest intervals (90, 120, 150s).
METHODS: The study had a cross-over design and fifteen strength-trained males (age 22.9 ± 2.1 years; body height 182 ± 6.5 cm; body mass: 80.4 ± 9.8 kg; body fat 15.8 ± 7.0%; BMI 24.1 ± 2.8; lean body mass 67.5 ± 8.8 kg) participated in one familiarization, three experimental and three control sessions within three weeks. The conditioning activity (CA) used in the study was a single set of 3 repetitions of a trap bar deadlift at 80% 1RM with approximately 15% 1RM of an elastic band. The SJ measurements were performed at the baseline and post-CA after 90 or 120 or 150s.
RESULTS: The 90s experimental protocol significantly improved (p < 0.05, effect size 0.34) acute SJ performance whereas 120 and 150 s experimental protocols did not significantly improve performance. The following tendency was observed - the longer the rest interval, the smaller the potentiation effect; p value for 90s (0.046), 120s (0.166), 150s (0.745).
CONCLUSIONS: A trap bar deadlift with accommodating resistance and 90s rest interval can be used to acutely enhance jump performance. A 90s rest interval was found to be optimal to enhance subsequent SJ performance, but the potential rest interval extension to 120s could also be taken by strength and conditioning coaches as the PAPE effect is highly individual. However, exceeding the rest interval to more than 120s may not be effective in optimising the PAPE effect.