The purposes of this study were to examine the effect of ballistic concentric-only half-squats (COHS) on subsequent squat-jump (SJ) performances at various rest intervals and to examine the relationships between changes in SJ performance and bilateral symmetry at peak performance. Thirteen resistance-trained men performed an SJ immediately and every minute up to 10 min on dual force plates after 2 ballistic COHS repetitions at 90% of their 1-repetition-maximum COHS. SJ peak force, peak power, net impulse, and rate of force development (RFD) were compared using a series of 1-way repeated-measures ANOVAs. The percent change in performance at which peak performance occurred for each variable was correlated with the symmetry index scores at the corresponding time point using Pearson correlation coefficients. Statistical differences in peak power (P = .031) existed between rest intervals; however, no statistically significant pairwise comparisons were present (P > .05). No statistical differences in peak force (P = .201), net impulse (P = .064), and RFD (P = .477) were present between rest intervals. The relationships between changes in SJ performance and bilateral symmetry after the rest interval that produced the greatest performance for peak force (r = .300, P = .319), peak power (r = –.041, P = .894), net impulse (r = –.028, P = .927), and RFD (r = –.434, P = .138) were not statistically significant. Ballistic COHS may enhance SJ performance; however, the changes in performance were not related to bilateral symmetry.

Abstract Post-activation potentiation (PAP) is a phenomenon where force output is acutely enhanced following muscular contraction. Previous research has documented enhanced performance in power-type light exercise following a heavy pre-load, such as vertical jumps following heavy squats. To date, the effect of PAP on moderately heavy exercise following a heavy pre-load has not been investigated. Purpose: The purpose was to examine whether PAP could be elicited in moderately heavy squats following a heavy squat pre-load, and if so, what intensity (as percentage of one repetition-maximum [1RM]) of pre-load elicited the highest PAP effect (measured as mean power, mean force and number of repetitions performed). Subjects: Seventeen resistance-trained males (age 24±2 years, length 182±8 cm, body mass 84.7±13.1 kg, squat 1RM 147.6±29.6 kg) with at least 2 years of experience of the squat exercise. Methods: After testing parallel squat 1RM at a separate session, subjects performed three testing sessions in a randomized order in a cross-over design; performance test at 80% of parallel squat 1RM (control), one repetition at 85% of 1RM followed 8 minutes later by the same performance test (PAP85), and one repetition at 93% of 1RM followed 8 minutes later by the same performance test (PAP93). Sessions were separated by six days. Force and power output was recorded using a linear encoder. Friedman’s test was used to reveal differences between conditions, and a Wilcoxon signed rank test was used to identify these differences. Results: There was an increase in number of repetitions performed for PAP85 (p=0.009) and PAP93 (p=0.001) compared to control, but not for mean power or mean force. There was no significant difference between PAP85 and PAP93 for number of repetitions (p=0.091). Conclusion: PAP can be elicited to improve performance in moderately heavy squats following a heavy squat pre-load in trained subjects, but only measured as number of repetitions performed, not force or power. PAP could therefore be useful not only for designing power training, but also for strength and hypertrophy training. KEYWORDS: squat, post-activation potentiation, PAP, strength, power, hypertrophy.

Background: Post activation potentiation (PAP) is an increased muscular performance thatoccurs after maximal voluntary contraction. Previous studies have shown a significantincrease in explosive movements, such as sprint and jump performance, as an effect ofthese maximal contractions. Aim: The aim of this study was to analyze if PAP, in terms of heavy squats, has aperformance enhancing effect on 30 meter sprint, with a hypothesis that the maximal effortin the squat has a performance enhancing effect on 30 meter sprint. Method: Twelve healthy male Crossfit athletes from Crossfit Halmstad, age between x-x,volunteered to participate in the study, eleven of these completed all of the test sessions in thiscross-sectional study. During the first test session, the subjects attempted to set a onerepetition max (1RM) in the back squat. During the second and third test session, the subjectswere randomly divided into two groups and the subjects got to perform both the non-PAP andthe PAP protocol during different sessions, depending on which group they were in. Thesprint time was measured with a handheld stopwatch. Wilcoxon Signed Rank Test was usedto determine significant differences between sprint time after the two different protocols, andthe level of significance was set at p < 0.05. Result: The result showed that there was no significant difference between PAP and non-PAPprotocols (p = 0,679). With a median value of 4,78 seconds, a minimum value of 4,59seconds and a maximum value of 5,54 seconds for the sprint trials after PAP and a medianvalue of 4,82 seconds, a minimum value of 4,59 seconds and a maximum value of 5,31seconds for the sprint trials without PAP, the results did not confirm the hypothesis. Conclusion: As an effect from the low number of participants, the result could be deceptive.The study could have show a different result if the number of participants would exceed atleast 25 subjects. There are no performance enhancing effects in the sprint after PAP, in thisstudy. Further research is required, to determine possible performance enhancing effectsfrom PAP.

Post activation potentiation (PAP) är ett fenomen genom vilket idrottslig prestation ökas som en följd av tidigare muskelkontraktioner. Tung styrketräning har visat sig ge en akut förbättring vid dynamiska aktiviteter som involverar samma muskelgrupper som styrketräningen. Syftet med denna studie var att undersöka kraftutvecklingsegenskaperna i underkroppen efter ett maximalt marklyftsprotokoll och två olika vilointervaller. Frågeställningar Kommer ett marklyftsprotokoll kunna ge en förbättrad prestation i längdhopp utan ansats? Vilket av experimentets vilointervaller är optimalt för användning av PAP vid hopp efter marklyft? Finns det någon korrelation mellan PAP och atleternas styrka? Metod Tio aktiva styrketräningsutövare (30.8 ± 5.9 år, längd 176.4 ± 7.8 cm, vikt 74.2 ± 12.11 kg) deltog i en experimentell studie bestående av tre delar. Vid första tillfället mättes deltagarnas 1 repetition maximum i marklyft. Vid det andra, respektive det tredje tillfället fick deltagarna utföra längdhopp både före ett marklyftsprotokoll och 2.5 (tillfälle 2), respektive 4 (tillfälle 3) minuter efter marklyftprotokollet. Resultat Ett marklyftsprotokoll där vikten ökas från 40 % till 100 % 1RM leder till en medelsnittökning i prestation i längdhopp utan ansats på 7,95 ± 8,86 cm, p=0,0195. Båda vilointervallerna visade sig vara lika gynnsamma för prestation i längdhopp efter marklyft. Det fanns ett måttligt positiv samband mellan PAP och deltagarnas styrka (r=0.43). Slutsats Den praktiska betydelsen av dessa resultat är att idrottare bör försöka genomföra tunga marklyft för att förbättra sin prestation i längdhopp utan ansats. Fler omfattande studier behövs för att mer detaljerat undersöka en optimal vilotid mellan marklyft och längdhopp, samt typen av atleter som kan ha mest nytta av ett protokoll som i föreliggande studie. / <p>Fristående kurs: Idrott III</p>

O efeito da potencialização pós-ativação (PPA) tem sido estudado, mas a sua aplicação no desempenho de atletas é muito controversa. Estudos descrevem a possibilidade de que a PPA possa compensar o mecanismo de fadiga, aumentando a taxa de desenvolvimento de força e melhorando a potência muscular. O objetivo deste estudo foi avaliar os efeitos agudos e crônicos de um treinamento pliométrico com e sem indução da PPA na potência muscular de membros inferiores em atletas de voleibol. A amostra foi composta por 16 atletas de voleibol masculino participantes da Superliga Nacional, divididos em grupo pliométrico (GPLIO) e grupo PPA (GPPA). O grupo pliométrico foi submetido a um treinamento de pliometria e o grupo PPA acrescentou ao treinamento pliométrico uma rotina de treinos que estimularam o mecanismo de PPA. O período de treinamento foi de 4 semanas com 2 sessões semanais. Durante a avaliação do pré e pós-treinamento para a determinação dos efeitos crônicos, foi mensurada a potência muscular dos membros inferiores através do salto vertical counter movement jump (CMJ), conforme protocolo sugerido por Bosco (1994), em uma plataforma de força, e contração voluntária máxima para a musculatura da articulação do joelho em um equipamento isocinético. Na avaliação pré e pós-teste para a determinação do efeito agudo, foi utilizado um tapete de contato para obtenção da altura de salto vertical CMJ. Para análise estatística foi utilizado o teste de equações de estimação generalizadas (GEE) no fator tempo e no fator grupo para determinar os efeitos do treinamento em cada grupo (GPLIO e GPPA). Os resultados referente aos efeitos agudos indicam a interação grupo*tempo para o grupo PPA significativa de p<0,001 (38,26 cms / 44,51 cms) do período pré-treinamento para o período de treinamento e de p=0,002 (38,26 cms /44,07 cms) do período pré para o pós treinamento. Ainda observamos que o grupo PPA obteve altura de salto significativamente melhor ao grupo PLIO, tanto no período de treinamento (44,51 cms/35,38cms) como no pós-treinamento pliométrico (44,07cms / 39,32 cms). Quanto aos efeitos crônicos, os resultados demonstraram não haver diferença significativa para as variáveis de torque isocinético. No que diz respeito à altura e potência de salto após o treinamento crônico foi observada diferença significativa nos dois grupos do período pré para o pós-treinamento, não havendo diferença entre os grupos. Concluímos que o treinamento pliométrico com indução de PPA melhora os efeitos agudos do salto vertical, tanto durante o treinamento como até 80 minutos após o treinamento pliométrico. Já no que diz respeito aos efeitos crônicos da indução ou não de PPA no treinamento pliométrico, os resultados indicam não haver diferença significativa no torque isocinético dos músculos extensores do joelho, porém na altura de salto CMJ e potência os resultados indicam que os dois modelos de treinamento têm uma resposta semelhante. / The effect of post-activation potentiation (PPA) has been studied, but its application in the performance of athletes is very controversial. Studies have described the possibility that PPP can compensate for the fatigue mechanism, increasing the rate of strength development and improving muscle power. The objective of this study was to evaluate the acute and chronic effects of a plyometric training with and without PPA induction on lower limb muscle power in volleyball athletes. The sample consisted of 16 male volleyball players participating in the National Superliga, divided into plyometric group (GPLIO) and PPA group (GPPA). The plyometric group underwent a plyometrics training and the PPA group added to the plyometric training a routine of training that stimulated the PPA mechanism. The training period was 4 weeks with 2 weekly sessions. During the pre and post-training evaluation for the determination of the chronic effects, the muscular power of the lower limbs was measured through the vertical jump movement movement (CMJ), according to a protocol suggested by Bosco (1994), on a force platform, And maximal voluntary contraction for the musculature of the knee joint in an isokinetic equipment. In the pre and post-test evaluation for the determination of the acute effect, a contact mat was used to obtain the vertical jump height CMJ. For statistical analysis, the test of generalized estimation equations (GEE) in the time factor and in the group factor was used to determine the effects of the training in each group (GPLIO and GPPA). The results for the acute effects indicate the group*time interaction for the PPA group significant of p<0.001 (38.26 cms / 44.51 cms) of the pre-training period for the training period and p=0.002 (38, 26 cm / 44.07 cm) from the pre and post training period. We also observed that the PPA group had a significantly better jump height in the PLIO group, both in the training period (44.51 cm / 35.38 cm) and in the plyometric training (44.07 cm / 39.32 cm). Regarding the chronic effects, the results showed no significant difference for the isokinetic torque variables. Regarding the height and jumping power after the chronic training, a significant difference was observed in the two groups from the pre-post-training period, with no difference between the groups. We conclude that plyometric training with PPA induction improves the acute effects of vertical jump, both during training and up to 80 minutes after plyometric training. Regarding the chronic effects of PPA or non-PPA induction in plyometric training, the results indicate that there is no significant difference in the isokinetic torque of the knee extensor muscles, but at the height of the CMJ and power jump the results indicate that the two models of Have a similar response.

The purposes of this dissertation were to examine bilateral asymmetry as a factor of postactivation potentiation, examine and compare the acute effects of ballistic and non-ballistic concentric-only half-squats on squat jump performance, and compare the potentiation and temporal profiles of strong and weak subjects following potentiation protocols that included ballistic and non-ballistic concentric-only half-squats. The following are major findings of the dissertation. Squat jump performance may be acutely enhanced following ballistic concentriconly half-squats; however the changes in performance do not appear to be related to bilateral symmetry. Ballistic concentric-only half-squats acutely improve various squat jump performance variables at various time intervals; however the changes in performance are not related to the bilateral symmetry of the subject. Ballistic concentric-only half-squats produced superior acute potentiation effects with regard to jump height, peak power, and allometricallyscaled peak power as compared to non-ballistic concentric-only half-squats and a control protocol. Stronger subjects potentiated earlier and to a greater extent as compared to their weaker counterparts. This dissertation indicates that bilateral symmetry may not be considered as an underlying factor affecting postactivation potentiation. However, it is suggested that future research should continue to investigate the factors that are associated with postactivation potentiation. The findings of this dissertation also demonstrate the importance of how an individual performs a concentric-only squatting motion. By training with ballistic movements, a greater training stimulus may be achieved as compared to training with non-ballistic movements. While this dissertation discussed the acute potentiation differences between ballistic and nonballistic concentric-only half-squats, longitudinal research is needed to determine if different training effects result from each training method. This dissertation also supports that notion that stronger individuals may benefit more with regard to potentiation effects. In order to optimize performance and realize the greatest potentiation effects, it is recommended that greater levels of relative strength should be sought. It is suggested that further research is needed on the longitudinal differences in the potentiation effects an individual can realize based on their strength levels.

The computational ability of principal neurons and interneurons in the brain and their ability to work together in concert are thought to underlie higher order cognitive processes such as learning, memory, and attention. Dendrites play a very important role in neuronal information processing because they receive and integrate incoming input and can undergo experience-dependent changes that will alter the future output of the neuron. Here, I have used whole-cell patch clamp recordings and fluorescent Ca2+-imaging to examine the modulation of dendritic excitability in principal neurons of the rat and human hippocampus and neocortex. First, I determined that dendrites of dentate granule cells of the hippocampus are tuned to high frequencies of both afferent input and backpropagating action potentials. Under these conditions they are also capable of generating regenerative dendritic activity that can propagate to the soma, which is prone to modulation. In particular, Neuropeptide Y (NPY) Y1 receptors can decrease frequency-dependent dendritic Ca2+ influx. Dopamine D1 receptors (D1Rs) have an opposite effect; they potentiate frequency-dependent dendritic excitability. These two neuromodulators also have an opposing effect on plasticity, with dopamine acting to induce, and NPY acting to inhibit long-term potentiation (LTP). Parallel observations of D1-induced LTP and an NPY-mediated decrease in dendritic excitability in rodents were complemented by findings in human dentate granule cells. Second, I examined the role of NPY receptors on dendrites of layer 5 pyramidal neurons. In these neurons I found that NPY acts post-synaptically on distal dendrites via the Y1 receptor to inhibit frequency-dependent Ca2+-currents, similar to the findings in dentate granule cells. NPY also decreased regenerative Ca2+ currents caused by the appropriate pairing of pre- and post-synaptic input. Together, these observations demonstrate that the role of NPY in the hippocampus and neocortex is not solely as an anti-epileptic agent. NPY release, likely to occur during high frequency oscillatory activity, can act locally to limit dendritic excitability, which can have a profound effect on plasticity. In the dentate gyrus, NPY can inhibit a D1R induced increased dendritic excitability and resultant changes in synaptic strength. These findings will further the understanding of dendritic information processing in the hippocampus and neocortex.

No description available.

Following contractile activity, fast twitch skeletal muscle exhibits increases in submaximal force known as potentiation. Although there is no consensus on the purpose of potentiation, it is known to enhance power during rapid dynamic contractions and counteract the early stages of peripheral fatigue. Potentiation is primarily attributed to phosphorylation of the myosin regulatory light chain (RLC) through a calcium-mediated process which results in increased calcium-sensitivity of crossbridge formation. However, there is a growing body of evidence showing that potentiation can be achieved in the absence of RLC phosphorylation, albeit to a lesser degree. A secondary characteristic of the potentiated contraction is an acceleration of relaxation properties, which could be teleologically beneficial to enhance the cycling rate of rapid motions (e.g. running). However, accelerated relaxation is inconsistent with elevations in calcium-sensitivity as this would tend to slow the time course and slow relaxation. Therefore there are multiple mechanisms involved in potentiation, some of which enhance crossbridge formation, and some of which enhance crossbridge detachment. A possible explanation for these events involves contraction-induced changes in the intracellular cytosolic calcium signal that triggers muscle contraction. For example, elevations in submaximal force could be achieved by increasing the amplitude of the calcium signal while enhanced relaxation speed could be achieved by a shorter duration of the calcium signal. Thus the main objective of this thesis was to investigate the contribution of changes in cytosolic Ca²⁺ to force potentiation. To achieve this objective, intact lumbrical muscles were extracted from the hind feet of C57BL/6 mice for use as the experimental model. The first study in this thesis examined cytosolic calcium signals during posttetanic potentiation using high (AM-fura-2 and AM-indo-1) and low (AM-furaptra) affinity calcium-sensitive fluorescent indicators to monitor resting and peak calcium respectively, both before and after a potentiating stimulation protocol of 2.5 s of 20 Hz stimulation at 37^oC. This protocol resulted in an immediate 17±3% increase in twitch force (n=10; P<0.05), though this potentiation dissipated quickly, lasting only 30 s. Resting cytosolic Ca²⁺ was also increased following the potentiating stimulus as indicated by increases of 11.1 ± 1.3% and 8.1 ± 1.3% in the fura-2 and indo-1 fluorescence ratios respectively. Like the force potentiation, these increases were short lived, lasting 20-30 s. No changes were detected in either the amplitude or kinetics of the Ca²⁺ transients following the potentiating stimulus. Western blotting analysis of the myosin heavy chain isoforms which determine the contractile phenotype of lumbrical muscle revealed predominance of fast type IIX fibres, while immunohistochemical analysis of proteins important for relaxation, namely parvalbumin, sarco-endoplasmic reticulum Ca²⁺ ATPase (SERCA) 1a and SERCA2a, revealed that the expression of these proteins in lumbrical moderated those found in the soleus (slow) and EDL (fast) archetypes. Surprisingly, despite the fast phenotype of the lumbrical, it exhibited low expression of the skeletal muscle isoform of myosin light chain kinase, the enzyme responsible for phosphorylating the myosin RLC, and high expression of myosin targeting phosphatase subunit 2, the enzyme responsible for dephosphorylating the myosin RLC. These data were corroborated by a complete lack of myosin RLC phosphorylation in either the rested or potentiated states. It was thus concluded that elevations in resting cytosolic calcium concentration, in the absence of changes in the intracellular calcium transient and RLC phosphorylation, can potentiate twitch force. The next objective of this thesis was to determine if there are changes in the cytosolic calcium transient during staircase potentiation, defined as a stepwise increase in twitch force during low frequency stimulation (<10 Hz). Staircase potentiation has been repeatedly demonstrated to exhibit more robust potentiation than posttetanic potentiation in the absence of RLC phosphorylation. It was hypothesized that while the calcium transient is not altered during posttetanic potentiation, it may be an important potentiating factor in staircase due to the lower rest intervals between successive contractions. The effects of temperature on the intracellular calcium transient during staircase potentiation were also examined as part of this investigation. Here, lumbricals were loaded with AM- furaptra and then subjected to stimulation at 8 Hz for 8.0 s to induce staircase potentiation at either 30 or 37^oC. This stimulation protocol resulted in a 26.8 ± 3.2 % increase in twitch force at 37^oC (P<0.05) and a 6.8 ± 1.9 % decrease in twitch force at 30^oC (P<0.05) at the 8 s mark. Both the peak amplitude and the calcium-time integral of the calcium transient decreased during the first 2.0 s of the protocol (P<0.05), however these decreases were greater at 30^oC than 37^oC (P<0.05 amplitude; P=0.09 area). While peak amplitude remained low throughout the duration of the protocol, the calcium-time integral began to increase after the 2 s time point (P<0.05), a change reflective of the progressive increases in the 50% decay time and full width at half maximum of the calcium transient (P<0.05). Regression analysis of raw furaptra fluorescence ratios revealed a progressive decline in the peak amplitude of the calcium transients throughout the protocol which was not present at 37^oC. The increases in the duration of the calcium transient were mirrored by increases in the half relaxation time of the twitch contractions at both 30 and 37^oC, which had initially been reduced by ~20 and 9 % at 30 and 37^oC during the first 2 s of the protocol. Therefore the degree of staircase potentiation depends, in part, on the magnitude of the decline in the amplitude and the degree of slowing of the cytosolic calcium transient. The declines in calcium transient amplitude noted above occurred simultaneously with increased rates of relaxation and abbreviated contraction times. To determine if there was a causal relationship between the reduced amplitude and the faster contractions, AM-furaptra-loaded lumbrical muscles were stimulated at 8 Hz for 2 s in the presence and absence of caffeine, an agonist of the calcium release channel. Caffeine treatment attenuated the decline of the calcium transient amplitude (P<0.05), and was associated with greater potentiation at 37^oC (P<0.05), and attenuated force loss at 30^oC (P<0.05). Despite the increases in calcium and force, the relaxation times and rates of relaxation exhibited a greater acceleration following caffeine treatment (P<0.05). Therefore the relaxation-enhancing factor during potentiated twitches cannot be attributed to the calcium transient, and must be localized to changes on the myofilament. The case for inorganic phosphate as the effector is made. Similar to the findings of the posttetanic potentiation study, the resting cytosolic calcium concentration was elevated during staircase potentiation, as revealed by fura-2 ratio signals. The largest increase occurring immediately following the first twitch of the protocol. This coincided with the largest increases in force potentiation at both 30 and 37^oC. This finding is in accordance with the initial conclusion that elevations in resting calcium can enhance twitch force and contribute to potentiation, though the mechanism of action is unclear. One possibility is that increases in resting calcium, sub-threshold for force production, can enhance the number of attached but non-force producing crossbridges, thereby accelerating the transition of crossbridges to force-producing states upon calcium-release following stimulation. To test this hypothesis, the resting stiffness, a measure of crossbridge attachment, of lumbrical muscles was examined before and after a potentiating stimulus of 20 Hz 2.5 s. Resting stiffness was assessed using sinusoidal length oscillations, ~0.5 nm per half sarcomere in amplitude and ranging in frequency from 10-200 Hz. Subsequent analysis revealed decreases in the elastic stiffness (P<0.05) that lasted for ~20 s which were greater in magnitude (P<0.05) than increases in viscous stiffness which only lasted for ~5 s. This finding is consistent with the disappearance of short range elastic component (SREC) upon stretch or muscle activation which is commonly attributed to a population of stable, bound crossbridges in resting muscle. Subsequent analysis using imposed length changes to eliminate the SREC prior to contraction had no effect on the amplitude or duration of a subsequent twitch or tetanic contraction, and the changes in elastic and viscous stiffness of resting muscle were identical whether SREC was ablated by a contraction or imposed length change. Therefore it appears that potentiation occurs without an associated increase in bound crossbridges at rest, and may actually occur with fewer bound crossbridges at rest than the unpotentiated state. The lack of effect may be related to the relaxation-enhancing factor discussed above, and be an important feature of skeletal muscle serving to protect against damage via an involuntary eccentric contraction. This thesis describes potentiation as a complex and important biological function which is the sum of factors that serve to enhance and oppose force production.

Orientador: Alessandro Moura Zagatto / Banca: Daniel Alexandre Boullosa / Banca: Claudio Alexandre Gobatto / Resumo: O objetivo do presente estudo foi investigar os efeitos da potenciação pós ativação (PAP) induzida por drop jumps no tempo até a exaustão a 115% da intensidade associada ao consumo máximo de oxigênio (("iV" ) ̇"O" _"2max" ) em ciclo ergômetro, em aspectos neuromusculares da fadiga (central e periférica) e sobre as vias metabólicas não oxidativas (capacidade anaeróbia, via glicolítica e dos fosfagênios). Para isso, o projeto foi dividido em dois estudos independentes. No Estudo A, 14 ciclistas recreacionais do sexo masculino (34 ± 4 anos) foram submetidos a 5 sessões de avaliações. Na primeira sessão realizaram teste incremental até exaustão (TInc), na segunda e terceira avaliações realizaram familiarização ao esforço supramáximo a 115% da ("iV" ) ̇"O" _"2max", enquanto que na quarta e quinta sessões os participantes realizaram de maneira randomizada o esforço supramáximo a 115% da ("iV" ) ̇"O" _"2max" com e sem PAP (controle). Como esforço indutor da PAP, foram realizados 5 drop jumps (15s de intervalo entre eles) antes do esforço supramáximo. Nas sessões 4 e 5, a fadiga neuromuscular foi avaliada por meio de contrações voluntárias máximas (CVM) de extensão do joelho e estimulação elétrica periférica (PNS) realizadas antes e após o esforço supramáximo. Além disso, a eletromiografia de superfície foi realizada durante o esforço supramáximo para mensuração da roots mean square (EMGRMS) e a frequência mediana (EMGFM) e analisadas de forma estratificada a cada 25% de tempo total... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of the present study was investigating the effects of post activation potentiation (PAP) induced by drop jumps in performance during a supramaximal effort at 115% of the intensity associated with maximal oxygen uptake (iV̇ O2max) on a cycle ergometer, also investigating the influence of PAP on neuromuscular fatigue (central and peripheral) and, on the non-oxidative metabolic pathways (anaerobic capacity, glycolytic pathway and phosphagen). Therefore, the project was divided in two independent studies. In Study A, 14 recreational male cyclists (34 ± 4 years) underwent 5 sessions of evaluations, in the first session they performed a graded exercise test (GXT), in the second and third evaluations they performed familiarization to the supramaximal effort to 115% of the iV̇ O2max. In the fourth and fifth sessions, the participants randomly performed the supramaximal effort at 115% of the iV̇ O2max with PAP and without PAP (control). To induce PAP, the volunteers performed 5 drop jumps (15s interval between them) 2 minutes before the supramaximal effort. In sessions 4 and 5, neuromuscular fatigue was assessed by maximal voluntary contractions (CVM) of knee extension with peripheral electrical stimulation (SNP) performed before and after the supramaximal effort. In addition, surface electromyography was performed during the supramaximal effort to measure roots mean square (EMGRMS) and the median frequency (EMGFM) for every 25% of total effort time (0-25%, 25-50%, 50-75% and ... (Complete abstract click electronic access below) / Mestre