The purpose of this review was to provide a physiological rationale for the use of eccentric resistance training and to provide an overview of the most commonly prescribed eccentric training methods. Based on the existing literature, there is a strong physiological rationale for the incorporation of eccentric training into a training program for an individual seeking to maximize muscle size, strength, and power. Specific adaptations may include an increase in muscle cross-sectional area, force output, and fiber shortening velocities, all of which have the potential to benefit power production characteristics. Tempo eccentric training, flywheel inertial training, accentuated eccentric loading, and plyometric training are commonly implemented in applied contexts. These methods tend to involve different force absorption characteristics and thus, overload the muscle or musculotendinous unit in different ways during lengthening actions. For this reason, they may produce different magnitudes of improvement in hypertrophy, strength, and power. The constraints to which they are implemented can have a marked effect on the characteristics of force absorption and therefore, could affect the nature of the adaptive response. However, the versatility of the constraints when prescribing these methods mean that they can be effectively implemented to induce these adaptations within a variety of populations.

Thesis (MEd)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The purpose of the study was to compare the effectiveness of an aquatic- and landbased plyometric programme upon selected, sport-specific performance variables in adolescent male, rugby union players. A group of 52 rugby players (age: 16.3 ± 0.8 years, height: 176 ± 6.9 cm and body mass: 76.1 ± 11.9 kg) were randomly assigned to one of three groups: aquatic group (n=18), land group (n=17), and a control group (n=17). Prior to and after the sevenweeks of training, the power, agility and speed of participants were assessed by means of Fitrodyne repeated countermovement jumps, the Sergeant vertical jump, the Illinois agility test, a standing broad jump, and a 10- and 40- metre sprint. All three groups maintained their summer extra-curricular sport commitments during the intervention period. When the three groups were analysed, no significant differences were found between the groups with regard to all tested performance variables. With regard to withingroup changes, the aquatic group improved significantly (p<0.05) in the Illinois agility test, performed to the right. The land group showed significant (p<0.05) improvements in peak concentric power during Fitrodyne repeated countermovement jumps. All groups reflected highly significant (p<0.01) improvements in the Sergeant vertical jump. None of the groups displayed any improvements in sprint speed. The control was the only group to improve significantly in the standing broad jump (p<0.05). Land-based plyometric training might be a functionally superior training modality for athletes, although aquatic plyometrics could also offer an effective training modality for performance enhancement in power-based sports such as rugby union football. Aquatic-based plyometrics should not completely replace land-based plyometrics, as it might not adequately develop the specific neuromuscular patterns or functional needs of explosive sports. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die effektiwiteit van ‘n water- en landgebaseerde pliometriese program met mekaar te vergelyk in terme van geselekteerde, sportspesifieke uitvoeringsveranderlikes in manlike adolessente rugbyspelers. ‘n Groep van 52 rugbyspelers (ouderdom: 16.3 ± 0.8 jaar, lengte: 176 ± 6.9 cm en liggaamsmassa: 76.1 ± 11.9 kg) is lukraak in een van drie groepe ingedeel: watergroep (n=18), landgroep (n=17), en ‘n kontrolegroep (n=17). Voor en na die sewe-weke oefenprogram, is spelers se plofkrag, ratsheid en spoed getoets deur middel van Fitrodyne herhaalde spronge, Sergeant vertikale sprong, Illinois ratsheidstoets, staande verspring, en ‘n 10- en 40-m spoedtoets. Al drie groepe het vir die duur van die intervensieperiode met hulle somersport aangegaan. Na analise van die drie groepe se data, is daar geen statisties betekenisvolle verskille tussen die groepe ten opsigte van die prestasieveranderlikes gevind nie. Die waterpliometriese groep se prestasie in die Illinois ratsheidstoets na regs het statisties beduidend (p<0.05) verbeter. Die landgroep het betekenisvolle (p<0.05) verbetering in die piek konsentriese plofkrag met die Fitrodyne herhaalde spronge getoon. Aldrie groepe het betekenisvolle (p<0.01) verbetering getoon in die Sergeant vertikale sprong. Geen groep se spoed het verbeter nie. Slegs die kontrolegroep se staande verspring het statisties betekenisvol verbeter. Land-gebaseerde pliometriese oefening kan moontlik, vanuit ‘n funksionele oogpunt, ‘n beter oefenmodaliteit vir atlete wees. Watergebaseerde pliometriese oefening kan egter ook ‘n oefenmodaliteit vir sport wat plofkrag vereis, soos rugby, wees. Watergebaseerde pliometriese oefening behoort nie land-gebaseerde pliometriese oefening te vervang nie, omdat dit moontlik nie aan die spesifieke neuromuskulêre patrone en funksionele behoeftes van eksplosiewe sport voldoen nie.

O objetivo deste estudo foi investigar o efeito dos exercícios meio-agachamento, salto e complexo (agachamento + saltos), seguido por intervalos de 5 min, 10 min ou auto-selecionado sobre o desempenho no salto vertical com contramovimento (CMJ - countermovement jump) e frequency speed of kick test (FSKT). Para isso, 11 atletas de taekwondo, faixas-preta foram submetidos a nove protocolos experimentais e um controle realizados aleatoriamente. Cada sessão experimental foi composta pelo aquecimento, uma atividade condicionante (meio-agachamento: três séries de uma repetição a 95% de 1RM; pliometria: três séries de 10 saltos sobre barreira de 40 cm; ou exercicio complexo: meio-agachamento com três séries de duas repetições a 95% de 1RM seguido por quatro saltos sobre barreira de 40 cm), e um intervalo (5 min, 10 min ou intervalo auto-selecionado) antes da realização do CMJ e FSKT. Houve diferença estatisticamente significativa sobre o número de golpes aplicados (F9,90 = 2,90; P = 0,005, h2 = 0,225 [pequeno]). O exercício complexo com intervalo de 10 min (23 ± 5 repetições) foi superior a condição controle (19 ± 3 repetições), meio-agachamento com intervalo auto-selecionado (18 ± 2 repetições, P = 0,015) e saltos com intervalo de 5 min (18 ± 3 repetições, P < 0,001). Nossos resultados indicam que atletas de taekwondo podem aumentar o número de golpes aplicados em teste específico após a realização do exercício complexo. Outro objetivo deste estudo foi investigar o efeito do volume e intensidade sobre o desempenho no CMJ e FSKT. Para isso, nove atletas de taekwondo, faixaspreta foram submetidos a quatro sessões experimentais e uma sessão controle realizadas aleatoriamente. Cada sessão experimental foi composta pelo aquecimento, uma atividade condicionante no exercício meio-agachamento (sessões experimentais: uma série de três repetições a 50% ou 90% de 1RM ou três séries de três repetições a 50% ou 90% de 1RM), seguido por intervalo de 10 min antes da realização do CMJ e cinco séries do FSKT. O desempenho do FSKT caiu ao longo das séries (F3,21;128,36 = 25,344; P < 0,001, h2 = 0,388 [muito grande]). Não houve efeito do volume e intensidade sobre as variáveis investigadas. Nossos resultados indicam que os atletas de taekwondo não foram afetados pelo uso de diferentes volumes e intensidades em atividade de potência específica e não específica visando a manifestação da potencialização pós-ativação / The purpose of this study was to investigate the effect of half-squat, jump and complex exercise (half-squat + jump), followed by intervals of 5-min, 10-min or selfselected rest interval on performance of countermovement jump (CMJ) and the frequency speed of kick test (FSKT). Eleven black-belt taekwondo athletes were randomly submitted to nine experimental section and one control were randomly. Each experimental section was composed by warm-up, conditioning activity (halfsquat: three sets of one repetition at 95% of 1-RM; plyometric: three sets of 10 jumps above 40-cm barrier; or complex exercise: half-squat with three sets of two repetitions at 95% of 1-RM followed for four jumps above 40-cm barrier), and a rest interval (5-min, 10-min or self-selected rest interval) before performing CMJ and FSKT. There was statistically significant difference regarding the number of kicks applied (F9,90 = 2.90; P = 0.005, h2 = 0.225 [small]). The complex exercise with 10- min of rest interval (23 ± 5 repetitions) was higher that the control (19 ± 3 repetitions), as well as the half-squat with self-selected rest interval (18 ± 2 repetitions, P = 0.015) and the plyometric with 5-min rest interval (18 ± 3 repetitions, P < 0.001). Our results indicate that taekwondo athletes can increase the number of kicks applied in a specific test after perfoming the complex exercise. An other purpose of this study was to investigate the effect of volume and intensity of CMJ and FSKT. Nine blackbelt taekwondo athletes were randomly submitted to four experimental section and one control. Each experimental section was composed by warm-up, one conditioning activity on half-squat exercise (experimental section: one set of three repetitions at 50% or 90% 1-RM or three sets of three repetitions at 50% or 90% of 1-RM), followed by 10-min of interval before performance of CMJ and five sets of FSKT. The FSKT performance declined along of sets (F3,21;128,36 = 25.344; P < 0.001, h2 = 0.388 [very large]). It was not found difference regarding exercise volume and intensity on the investigated variables. Our results indicate that taekwondo athletes were not affected by different volume and intensities of specific and non-specific power activities on post-activation potentiation

O objetivo deste estudo foi investigar o efeito dos exercícios meio-agachamento, salto e complexo (agachamento + saltos), seguido por intervalos de 5 min, 10 min ou auto-selecionado sobre o desempenho no salto vertical com contramovimento (CMJ - countermovement jump) e frequency speed of kick test (FSKT). Para isso, 11 atletas de taekwondo, faixas-preta foram submetidos a nove protocolos experimentais e um controle realizados aleatoriamente. Cada sessão experimental foi composta pelo aquecimento, uma atividade condicionante (meio-agachamento: três séries de uma repetição a 95% de 1RM; pliometria: três séries de 10 saltos sobre barreira de 40 cm; ou exercicio complexo: meio-agachamento com três séries de duas repetições a 95% de 1RM seguido por quatro saltos sobre barreira de 40 cm), e um intervalo (5 min, 10 min ou intervalo auto-selecionado) antes da realização do CMJ e FSKT. Houve diferença estatisticamente significativa sobre o número de golpes aplicados (F9,90 = 2,90; P = 0,005, h2 = 0,225 [pequeno]). O exercício complexo com intervalo de 10 min (23 ± 5 repetições) foi superior a condição controle (19 ± 3 repetições), meio-agachamento com intervalo auto-selecionado (18 ± 2 repetições, P = 0,015) e saltos com intervalo de 5 min (18 ± 3 repetições, P < 0,001). Nossos resultados indicam que atletas de taekwondo podem aumentar o número de golpes aplicados em teste específico após a realização do exercício complexo. Outro objetivo deste estudo foi investigar o efeito do volume e intensidade sobre o desempenho no CMJ e FSKT. Para isso, nove atletas de taekwondo, faixaspreta foram submetidos a quatro sessões experimentais e uma sessão controle realizadas aleatoriamente. Cada sessão experimental foi composta pelo aquecimento, uma atividade condicionante no exercício meio-agachamento (sessões experimentais: uma série de três repetições a 50% ou 90% de 1RM ou três séries de três repetições a 50% ou 90% de 1RM), seguido por intervalo de 10 min antes da realização do CMJ e cinco séries do FSKT. O desempenho do FSKT caiu ao longo das séries (F3,21;128,36 = 25,344; P < 0,001, h2 = 0,388 [muito grande]). Não houve efeito do volume e intensidade sobre as variáveis investigadas. Nossos resultados indicam que os atletas de taekwondo não foram afetados pelo uso de diferentes volumes e intensidades em atividade de potência específica e não específica visando a manifestação da potencialização pós-ativação / The purpose of this study was to investigate the effect of half-squat, jump and complex exercise (half-squat + jump), followed by intervals of 5-min, 10-min or selfselected rest interval on performance of countermovement jump (CMJ) and the frequency speed of kick test (FSKT). Eleven black-belt taekwondo athletes were randomly submitted to nine experimental section and one control were randomly. Each experimental section was composed by warm-up, conditioning activity (halfsquat: three sets of one repetition at 95% of 1-RM; plyometric: three sets of 10 jumps above 40-cm barrier; or complex exercise: half-squat with three sets of two repetitions at 95% of 1-RM followed for four jumps above 40-cm barrier), and a rest interval (5-min, 10-min or self-selected rest interval) before performing CMJ and FSKT. There was statistically significant difference regarding the number of kicks applied (F9,90 = 2.90; P = 0.005, h2 = 0.225 [small]). The complex exercise with 10- min of rest interval (23 ± 5 repetitions) was higher that the control (19 ± 3 repetitions), as well as the half-squat with self-selected rest interval (18 ± 2 repetitions, P = 0.015) and the plyometric with 5-min rest interval (18 ± 3 repetitions, P < 0.001). Our results indicate that taekwondo athletes can increase the number of kicks applied in a specific test after perfoming the complex exercise. An other purpose of this study was to investigate the effect of volume and intensity of CMJ and FSKT. Nine blackbelt taekwondo athletes were randomly submitted to four experimental section and one control. Each experimental section was composed by warm-up, one conditioning activity on half-squat exercise (experimental section: one set of three repetitions at 50% or 90% 1-RM or three sets of three repetitions at 50% or 90% of 1-RM), followed by 10-min of interval before performance of CMJ and five sets of FSKT. The FSKT performance declined along of sets (F3,21;128,36 = 25.344; P < 0.001, h2 = 0.388 [very large]). It was not found difference regarding exercise volume and intensity on the investigated variables. Our results indicate that taekwondo athletes were not affected by different volume and intensities of specific and non-specific power activities on post-activation potentiation

Background: Plyometric training is a form of conditioning with increasing popularity that involves the performance of body weight jumping type exercises with the use of the stretch-shortening cycle muscle action. It is widely accepted that plyometric training has beneficial effects on many sports, including soccer. Objectives: To assess the effect of plyometric training on explosive actions of soccer performance (sprinting, jumping, agility, ball kicking) and indicated the kind, the frequency and targeted age groups on which the plyometrics should be executed. Methods: A search for all types of trials was performed on Pubmed, Web of Science and Sport Discus databases and the results were recorded according to PRISMA recommendations. 24 studies were included and judged for risk of bias and quality of evidence according to Cochrane guidelines and GRADE. Results: The studies were judges to have “low”, “high” and “unclear” risk of bias and were judged as “moderate”, “low” and very low quality of evidence. The finding of most of the studies show that plyometric training has beneficial effects and statistically significant improvements on the explosive actions (sprinting, jumping, agility and ball kicking) of young soccer players between 10 and 19 years old. Conclusions: The level of evidence of the review is moderate which means that further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. The current study suggests that plyometric training can be beneficial for young soccer players when is applied with gradual intensity, frequency of 2-3 times per week and along with regular soccer and strength training. Future research of higher quality of evidence studies and lower risk of bias should be performed in this field.

The purpose of this review is to provide strength and conditioning practitioners with recommendations on how best to implement tempo eccentric training (TEMPO), flywheel inertial training (FIT), accentuated eccentric loading (AEL), and plyometric training (PT) into resistance training programs that seek to improve an athlete’s hypertrophy, strength, and power output. Based on the existing literature, TEMPO may be best implemented with weaker athletes to benefit positional strength and hypertrophy due to the time under tension. FIT may provide an effective hypertrophy, strength, and power stimulus for untrained and weaker individuals; however, stronger individuals may not receive the same eccentric (ECC) overload stimulus. Although AEL may be implemented throughout the training year to benefit hypertrophy, strength, and power output, this strategy is better suited for stronger individuals. When weaker and stronger individuals are exposed to PT, they are exposed to an ECC overload stimulus as a result of increases in the ECC force and ECC rate of force development. In conclusion, when choosing to utilize ECC training methods, the practitioner must integrate these methods into a holistic training program that is designed to improve the athlete’s performance capacity.

Bakgrund: Idrott kan utföras i många olika former och av en bred population. I flera idrotter är det fördelaktigt att ha god spänst och/eller snabbhet. Flera olika fysiska faktorer har påverkan på snabbhet och spänst, däribland explosivitet och muskelstyrka. Plyometrisk träning (PT) är en träningsform där Stretch-shortening-cycle (SSC) utnyttjas. SSC beskrivs som en muskulärt förlängande (excentrisk) rörelse följt av en muskulärt förkortande (koncentrisk) rörelse som syftar till att träna explosivitet.  Syfte: Analysera vilken effekt plyometrisk träning har på spänst och snabbhet hos idrottare, jämfört med ordinarie idrottsträning samt förekomst av skador Metod: En systematisk litteraturstudie som utgår från databaserna PubMed, PEDro, Cochrane Library och Cinahl. Studiernas kvalitet granskades med TESTEX och tillförlitligheten enligt GRADEstud.  Resultat: Nio randomiserade kontrollerade studier inkluderades i litteraturöversikten. Studiekvalitén var mellan 8-12 poäng enligt TESTEX. Studiernas tillförlitlighet enligt GRADEstud var mycket låg (+). Studiernas resultat var varierande gällande signifikans för PT och dess effekt för spänst och snabbhet hos idrottare jämfört med kontrollgrupp. Ingen studie rapporterade skada i samband med PT. Konklusion: De studier som analyserades bedömdes ha, på grund av olikheter i intervention och resultat, en låg evidensgrad. PT har viss effekt på spänst och snabbhet hos idrottare jämfört med kontrollgrupp som utför ordinarie idrottsträning. Inga skador rapporterades i de inkluderade studierna. Fler homogena studier krävs för att klargöra PT´s effekt på spänst och snabbhet hos idrottare. / Background: Sports can be performed in many forms and is being performed by a wide population. In different sports it’s beneficial to have good jumping ability and to be fast. Many physical factors affect the ability to jump and sprint, where muscle strength and explosiveness are two of them. Plyometric training (PT) is a training form that utilizes the stretch-shortening-cycle (SSC). SSC is an eccentric muscle contraction followed by concentric contraction of the same muscle that aims to train muscle explosiveness.    Objective: Evaluate the effect of plyometric training on jumping ability and sprinting within athletes compared with athletes only performing ordinary sport training.  Method: A systematic review. The search was performed on the databases PubMed, PEDro, Cochrane Library and Cinahl. The included studies quality was examined with TESTEX and the reliability with GRADEstud.  Results: Nine randomized controlled trials were included. The quality of the studies varied between 8 to 12 points. The reliability, examined with GRADEstud, was deemed very low (+). The effect of PT on jumping and sprinting for athletes compared with the control groups varied. None of the studies reported injuries associated with PT. Conclusion: The studies included had, due to differences in intervention and results, a low level of evidence. PT has a certain effect on jumping ability and sprinting for athletes compared with athletes only performing ordinary sport training. No injuries were reported by the studies included. More homogeneous studies are required to clarify the effect of PT on jump ability and sprint in athletes.

Aim The purpose of this study is to investigate whether plyometric training improves ice hockey goalies' change of direction (COD) at junior level on-ice. The study is based on the following question: Does the COD of ice hockey goalies improve after an eight-week training intervention consisting of plyometric training?Null hypothesis: Plyometric training does not improve COD for junior ice hockey goaltenders. Method The questions in the study were by conducting a training study with male ice hockey goalies (n=13) at the junior level (born 2004-2008). Based on randomization, the participants in the study were be divided into two groups, a training group (n-7) and a control group (n-6). Before and after the training intervention, an on-ice test will be carried out by all participants. After that, the intervention group will perform plyometric training, twice per week during an eight-week period. The effect of the training intervention will be evaluated by comparing the groups' results (before and after the intervention) to investigate whether there are differences between the intervention and control groups.  Result The results showed that the training group's mean value (3.82 seconds) improved more than the control group's mean value (4.03 seconds), however, the difference between the groups was not statistically significant (p=0.05), thus the null hypothesis is retained in the study. The results show that there is a tendency for improvement (p=0.082), thus a low assumption of the null hypothesis. The significance level was set at p &lt;0.05 and the tendency level values were set at 0.05&lt;p&lt;0.1. Conclusion There was a tendency towards improvement in COD for the training group, however, the differences between the training group and the control group were not significant at post-test. The results show that plyometric training tends to have a positive effect on COD, which can be used as a framework for players and coaches as well as useful as a basis for future training planning for ice hockey goalies at junior level. / Syfte Syftet med denna studie är att undersöka om plyometrisk träning förbättra rishockeymålvakters change of direction (COD) på juniornivå on-ice. Studien utgår ifrånföljande frågeställning: Förbättras ishockeymålvakters COD efter en åtta veckorsträningsintervention bestående av plyometrisk träning? Nollhypotes; Plyometrisk träning förbättrar inte COD för ishockeymålvakter på juniornivå. Metod Frågeställningarna i studien besvarades genom att en träningsstudie genomfördes med manliga ishockeymålvakter (n=13) på juniornivå (födda 2004–2008). Utifrån randomiseringkommer deltagarna i studien delas in i två grupper, en träningsgrupp (n-7) och en kontrollgrupp (n-6). Innan och efter träningsinterventionen kommer ett on-ice test genomförasav samtliga deltagare. Därefter kommer träningsgruppen genomföra plyometrisk träning, två gånger per vecka under en åttaveckorsperiod. Effekten av träningsinterventionen kommer attutvärderas genom att jämföra gruppernas resultat (före och efter interventionen) för att undersöka eventuella skillnader mellan tränings-, och kontrollgruppen. Resultat Resultaten visade att träningsgruppens medelvärde (3,82 sekunder) förbättrades mer än kontrollgruppens medelvärde (4,03 sekunder), dock var skillnaden mellan grupperna inte statistisk signifikant (p=0,05). Resultaten visar att det finns tendens till förbättring (p=0,082),d ärmed ett lågt antagande om nollhypotesen. Signifikants nivån sattes till p &lt;0,05 och värdenaför tendensnivån sattes till 0,05&lt;p &lt;0,1. Slutsats Det fanns tendens till förbättring av COD för träningsgruppen, dock var skillnaderna mellanträningsgruppen och kontrollgruppen inte statistiskt signifikanta vid eftertestet. Resultatenvisar att plyometrisk träning har tendens till positiv påverkan på COD, vilket kan användassom ett ramverk för spelare och tränare samt vara användbara som grund i framtida träningsplanering för ishockeymålvakter på juniornivå.

Introdução: o processo fisiológico de envelhecimento traduz-se em diversas alterações estruturais do sistema musculoesquelético. Estas, por sua vez, acarretam em modificações funcionais que se repercutem na dependência do senescente, determinando a diminuição da sua qualidade de vida. Das estratégias existentes para atenuar os efeitos da senescência o treinamento de potência tem sido apontado como preferido. Existem, contudo, indícios de que um treinamento baseado na potencialização da ação do ciclo alongamento-encurtamento seja uma melhor escolha. Hipóteses do estudo: pelos resultados obtidos em intervenções similares, hipotetiza-se que as participantes do protocolo de intervenção proposto apresentarão um aumento da densidade mineral óssea, do volume muscular, da capacidade funcional e melhora de alguns parâmetros biomecânicos da marcha, bem como da sua qualidade de vida. Objetivos: o objetivo geral do presente trabalho é, portanto, propor um modelo de treinamento fundamentado na potencialização da ação do ciclo alongamento-encurtamento e averiguar os seus efeitos em parâmetros selecionados da morfologia osteomuscular, capacidade funcional e qualidade de vida de idosas. Materiais e Métodos: 21 idosas sedentárias (66,9±4,2 anos) executaram o protocolo proposto durante 20 semanas, tendo os efeitos na densidade mineral óssea de fêmur, coluna, tíbia e rádio; efeitos na composição corporal, na força, no equilíbrio, na marcha, na flexibilidade e na qualidade de vida comparados aos efeitos obtidos pelo grupo controle (N=17, 65,0±3,4 anos), que não alterou o seu nível de atividade física. O protocolo de intervenção, composto por onze exercícios de força realizados com o intuito de potencializar a ação do ciclo alongamento-encurtamento, que apresentava duas modalidades de salto (salto vertical com contramovimento e drop jump), exigia a realização da fase concêntrica na maior velocidade possível. Resultados: quando comparado com o grupo controle, o grupo experimental apresentou alterações significantes (p<0,05) na densidade mineral óssea de coluna (g=1,06) e sua microarquitetura (g=0,80), na microarquitetura da tíbia (g=0,82), na força máxima (g=2,39) e potência (g=1,38) de extensores de joelho, na velocidade máxima de marcha (g=0,96), na flexibilidade de membros inferiores (g=1,05) e superiores (g=0,86) e no domínio Atividades passadas, presentes e futuras da qualidade de vida (g=1,08). Conclusão: os resultados apontam para a eficácia da proposta de intervenção, apresentando-se como uma nova estratégia para atenuar e até mesmo reverter algumas perdas estruturais e funcionais impostas pelo processo de envelhecimento / Introduction: the physiological aging process induces several structural changes in the musculoskeletal system. These, in turn, result in functional changes that are reflected in the senescent dependency, determining the reduction in their quality of life. Power training has been identified as ideal to mitigate the effects of aging. However, there are indications that an intervention based on the potentiation of the stretch-shortening cycle action is a better choice. Study hypotheses: the participants of the proposed intervention will increase their bone mineral density, muscle volume, functional capacity and will show some improvement in their gait, as well as in their quality of life. Purposes: the main objective of this study was to propose a training model based in the potentiation of the stretch-shortening cycle action and assess its effects on selected parameters of musculoskeletal morphology, functional capacity and quality of life of elderly women. Methods: 21 sendentary elderly women (66.9 ± 4.2 years) performed the proposed intervention protocol for 20 weeks and the effects on bone mineral density of the femur, spine, tibia and radio; effects on body composition, strength, balance, gait, flexibility and quality of life were compared to the effects obtained by the control group (N = 17, 65.0 ± 3.4 years) that did not change their level of physical activity. The program was composed by eleven strength exercises performed in order to enhance stretch-shortening cycle action, had two jump exercises (vertical jump with countermovement and drop jump) and had the concentric phase of the movements performed as fast as possible. Results: when compared to the control group the experimental group showed significant changes (p <0.05) in bone mineral density of the spine (g = 1.06) and its microarchitecture (g = 0.80), the microarchitecture of the tibia (g = 0.82), the knee extensors maximum force (g = 2.39) and power (g = 1.38), the maximum walking speed (g = 0.96), the lower (g = 1.05) and upper (g = 0.86) limbs flexibility and in the domain past, present and future activities of the quality of life (g = 1.08). Conclusion: the results point to the effectiveness of the proposed intervention, suggesting it as a new strategy to slow down and even reverse some structural and functional losses imposed by the aging process

Com o objetivo de comparar os efeitos do treinamento de força rápida em parâmetros fisiológicos, mecânicos e neuromusculares de corredores de fundo, o presente trabalho contou com uma amostra de 18 atletas amadores do sexo masculino, praticantes de corrida de rua e com experiência em provas de longa distância (21km ou acima). A amostra foi selecionada para o grupo \"treinamento de força rápida\", (RPG - grupo experimental) ou \"exercícios educativos técnicos de corrida\" (RTG - grupo controle), que realizaram seis semanas de exercícios distintos. No intuito de avaliar o desempenho em variáveis-chave para o rendimento de fundistas, os sujeitos foram submetidos a uma série de testes em dois momentos distintos: após a semana de aprendizagem e adaptação aos exercícios (pré) e ao final das seis semanas dos protocolos propostos (pós). A bateria de testes foi composta por: testes de saltos verticais (Altura [H], Potência Pico [PP] e Potência Relativa [PR] do salto para as técnicas Squat Jump [SJ], Counter Movement Jump [CMJ] e Drop Jump 40cm [DJ40]); salto horizontal [SH] e salto sêxtuplo alternado [S6A] (distância saltada); uma repetição máxima no agachamento guiado (carga absoluta [1RM Abs.] e relativa à massa corporal [1RM Rel.]); teste de contração isométrica voluntária máxima (CIVM - força pico [Fpico], força pico relativa à massa corporal [Fpico R.], tempo da força pico [TFPICO] e taxa de desenvolvimento de força [TDF]); teste incremental de esteira (Velocidade Pico em Esteira [VPE] e Velocidade do Limiar de Lactato [vLL]); e tempo limite em esteira na VPE (Tlim). O tratamento estatístico foi realizado por meio do Software IBM® SPSS® Statistics v. 20.0, para Windows (IBM Corporation, Chicago, USA). A ANOVA Modelo Misto foi utilizada para as comparações das variáveis de desempenho entre momentos e entre grupos, com teste post-hoc de Bonferroni quando necessário, e o teste t de Student para amostras independentes foi realizado para comparar as variáveis relativas ao treinamento entre os grupos. Todas as variáveis foram submetidas aos testes estatísticos Cohen\'s \"d\" de Magnitude de Efeito (ES) e Probabilidade Quantitativa de Chances (QC). Foram encontradas diferenças estatisticamente significantes para as variáveis Altura de Salto e Potência Relativa para a técnica de salto vertical Squat Jump entre os momentos pré e pós treinamento para o grupo RPG (HSJ: F = 6,973; p = 0,018; PRSJ: F = 8,421; p = 0,01) e Altura de Salto e Potência Relativa para a técnica de salto vertical Counter Movement Jump entre os grupos RPG e RTG, após as seis semanas de exercícios (HCMJ: F = 6,163; p = 0,025; PRCMJ: F = 4,667; p = 0,046). Foi identificada diferença significativa para a variável \'tempo da Fpico\' (F = 7,731; p = 0,013) durante o teste de CIVM para o grupo RPG entre os momentos. O grupo Controle, ainda, apresentou queda na variável VPE após as seis semanas do protocolo (F = 5,493; p = 0,032), o que não foi observado no grupo Pliometria. Ademais, o grupo experimental apresentou redução nos valores de lactato sanguíneo nos minutos 1, 3 e 5 após o teste de Tlim (F = 16,858; p = 0,001; F = 8,406; p = 0,01; F = 12,092; p = 0,003, respectivamente). É possível concluir que o treinamento pliométrico foi superior ao protocolo de exercícios educativos no intuito de melhorar o desempenho da força rápida de membros inferiores, contribuindo, ainda, para a manutenção dos níveis iniciais de desempenho em corrida e a melhora da remoção do lactato sanguíneo, o que não pode ser observado no grupo RTG. / With the purpose to compare the effects of explosive-strength training in physiologic and neuromuscular variables of endurance runners, the present study accounted with 18 male amateur athletes experienced in long distance races (21km and above). The sample was divided between explosive-strength training - RPG (running plyometrics group) and technique exercises protocol - RTG (running techniques group), which performed six weeks of distinct exercise protocols. With the aim to evaluate key-variables for endurance running performance the subjects were submitted to batteries of assessments in two different moments: after the exercises adaptation week and right before the beginning of the protocols, and at the end of the exercise protocols. The assessments battery contained vertical jump tests (Jump Height [H], Peak Power [PP] and Relative Power [RP] for the techniques Squat Jump [SJ], Counter Movement Jump [CMJ] and Drop Jump 40cm [DJ40])/ horizontal long jump (SH) and sextuple jump alternating legs (S6A), one maximum repetition for squat at Smith Machine (absolute [1RM Abs.] and relative to body mass loads [1RM Rel.]), maximum voluntary isometric contraction test (MVIC - peak force [Fpico], peak force relative to body mass [Fpico R.], time to peak force [TFPICO] and rate of force development [TDF]); maximum incremental treadmill test (treadmill peak velocity [VPE] and lactate threshold velocity [vLL]), and time limit test at treadmill peak velocity (Tlim). The statistical procedures were performed at IBM® SPSS® Statistics Software v. 20.0, para Windows (IBM Corporation, Chicago, USA) The Mixed Model ANOVA was performed with dependent variables to identify time and group interactions, using the Bonferroni post-hoc test when necessary, while the training variables were analyzed by the Student\'s t test for independent samples. All data were also analyzed with Cohen\'s \"d\" Effect Size test (ES) and Probability of Quantitative Chances (QC). There were found in RPG significant differences for H and PR for Squat Jump technique between moments pre- and post-protocol (HSJ: F = 6,973; p = 0,018; PRSJ: F = 8,421; p = 0,01), and for the same variables for Counter Movement Jump technique between RPG and RTG (HCMJ: F = 6,163; p = 0,025; PRCMJ: F = 4,667; p = 0,046) after the exercise protocols. Also, significant difference was found for \'time to peak force\' variable (F = 7,731; p = 0,013) during the MVIC test for the group RPG between moments. Yet, the control group presented significant decrease of peak treadmill velocity in the moment post- compared to the pre-training (F = 5,493; p = 0,032), which was not observed in the experimental group. Still, the experimental group presented lower values for lactate concentrations 1, 3 and 5 minutes after Tlim test (F = 16,858; p = 0,001; F = 8,406; p = 0,01; F = 12,092; p = 0,003, respectively). It is possible to conclude that the plyometric training performed by the RPG was superior to the technique exercises protocol in the objective of increasing lower-limbs explosive-strength parameters, contributing to the maintenance of running performance and a better lactate clearance capacity, which did not happen in the RTG.