## 1 Introduction  
Post-activation potentiation (PAP) has been defined as an enhancement in the contractile response, measured with supramaximal electrical stimulation, following an intense voluntary contraction [1]. On the contrary, the ergogenic effect of a resistance exercise on subsequent power output has been defined as post-activation performance enhancement (PAPE) [2]. This physiological effect, reported by several studies on both the upper and lower body [3, 4], has been frequently attributed to local factors such as muscle excitability and contractility due to increased phosphorylation of the myosin regulatory light chains [5]. However, some authors hypothesized that a relevant role may be played by the increased neural drive, activation of the central nervous system and by circulating catecholamines [6]. Considering the nature of PAPE, the acute effects could involve muscles that were not previously engaged in the conditioning intervention, producing a non-localized effect. This non-localized effect may induce an increase in the performance of the lower body when the upper body muscles have been exercised, and vice versa. Chronic influences of different lower body resistance exercise protocols on the upper body strength adaptations have been previously reported [7]. Furthermore, some authors investigated the acute non-localized effects of both upper and lower body resistance exercises. [PERSON] et al. [8] and [PERSON] et al. [9] investigated the acute effects of a monolateral exercise session for the upper body on the contralateral arm. No non-localized PAPE, however, were detected in these studies. Consistently, [PERSON] et al. [10] did not report significant non-localized PAPE 15 s, 90 s and 3 min following a conditioning intervention consisting of bench press and vertical jumps. Although these studies did not show any significant non-localized effect, several parameters may be responsible for the lack of ergogenic effects on performance. The type of resistance exercise and muscle contractions performed in the conditioning intervention, as well as the amount of muscle mass involved, affect localized PAPE [11; 12] and may also affect non-localized PAPE. A single set of a high-intensity resistance exercise, including concentric contractions, has been shown to induce greater localized-PAPE compared to solely concentric contractions [2]. In addition, acute improvements in sprint and vertical jump performance were registered following power exercises such as weighted jumps [13] and pylemetric exercises [14]. The recovery time between the last set and the assessment may represent another important variable. A time of 8-12 min has been reported by the literature as optimal to dissipate fatigue and to magnify PAPE [15]. The same recovery time may be optimal to detect non-localized effects.  
Despite the aforementioned studies have investigated the acute localized effects of a resistance intervention, no studies to date have studied the non-localized effects of a resistance training protocol including high-intensity or power exercises focused on different muscle groups. Indeed, some exercises and training protocols may be more appropriate than other to induce non-localized PAPE.  
Thus, the aim of the present study was to compare the non-localized PAPE of an upper body exercise session on the lower body performance to the acute effects of a lower body exercise session on the upper body. Another aim was to compare the non-localized PAPE following a high-intensity resistance exercise session and a power session for either the upper or the lower body. The authors hypothesized that non-localized PAPE may be different based on the muscle groups involved in the intervention.