# Post-Activation Potentiation Enhancement Response of Two Complex Training Sequences
## 2 Materials and Methods
### Procedure  
To control the PAPE effect and standardize the neuromuscular fatigue we ensured that the participants were familiar with the CMJ test and parallel squat by previously analyzing that they performed it correctly. In addition, the participants performed both training sessions at the same time to avoid circadian variation-derived influence and similar eating and resting habits [18].  
The warm-up was standardized for both sequences and consisted of 5 min of cycling followed by one set of 5 submaximal CMJ with a recovery time of 30 s. Then, participants performed a maximal CMJ on a force platform (Kistler Quattro Jump, Kistler, Switzerland) at 1000 Hz considered the gold standard [19] just before starting the training. The first part of the LL-HL session consisted of three sets of maximal CMJ. The set volume was established by height loss as it has been seen as an accurate fatigue indicator [20]. Therefore, participants stopped jumping when the height loss was more than 10% from the highest jump. CMJ was instructed to be performed with both hands placed on the hips and full leg extensions during the flight phase. Additionally, participants were informed to conduct the jump \"as fast and as high as you can with contact times as short as possible\". Five minutes  
Figure 1: Experimental design including HH-LL and LL-HL protocols. “CMJ”: Countermovement Jump. “r”: recovery.  
after performing the light loads, participants performed a set of squats to approximate the load to 80% 1 RM (\(\approx\)0.68 m\(\cdot\)s\({}^{-1}\)). The approximation process was conducted in both training sequences, as 1 RM can vary in a short period of time [21; 22]. The squat velocity was recorded through a linear velocity transducer (Vitruve encoder, Madrid, Spain). Afterward, three sets of squats with a 15% velocity loss were performed, as a low degree of fatigue has been shown effective to induce improvements in neuromuscular performance previously. Two continuous repetitions above the 15% velocity threshold were needed to stop the set [23]. To the best of our knowledge, this is the first study in which volume and intensity are internally controlled through measures of velocity or jump height rather than by fixed repetition sets, which do not provide the same relative volume for all participants. We chose this combination of exercises as a similar movement pattern and objective in the heavy and the pylemetric exercise provides greater potentiation. The inter-set recovery time was 3 min. HL-LL session followed the same structure but in the opposite order (heavy loads first followed by light loads).  
The back squat was parallel and to ensure this position, participants should touch the supports with the bar, positioned at the height at which the top of the thigh was parallel to the ground [24], and rise as fast as possible.  
Participants performed maximal CMJ again at 1, 4, and 8 min after the end of the training session. These time intervals were chosen because a recent meta-analysis [19] found that sufficient recovery occurs after 3-7 min in trained athletes. However, recreational, or less experienced athletes may need more time to recover from high-intensity protocols [11]. All CMJ variables were automatically calculated through take-off velocity using Kistler Mars Quattro Jump software (v5.3.0.245) (Kistler, Winterthur, Switzerland).  
Following the instructions proposed by [PERSON] et al. [25] to check the PAPE effect, the subsequent variables were analyzed: Jump height (cm), average power (W), average force (N), and average velocity (m\(\cdot\)s\({}^{-1}\)) and to examine neuromuscular fatigue we considered reactive strength index (RSI) (cm\(\cdot\)s\({}^{-1}\)), time to take off (s) and propulsive phase duration (s).