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.

Background: everal studies mean that individuals accustomed to running barefoot and habitually barefoot individuals choose a fore foot or mid foot strike rather than a rear foot strike when running. This is partly to do with the proprioceptive feedback given from the soles of the feet. The common denominator of the barefoot runner and the Muay Thai fighter would be this proprioceptive feedback due to general bare foot training. A contributing factor to a non heal strike pattern could perhaps also be found in the sport specific movement pattern of Muay Thai where the athlete is trained to execute several actions from the fore foot. Aim: The first aim was to analyse differences in angles of the knee, ankle and foot at initial contact while running shod compared to barefoot in Muay Thai fighters accustomed to training barefoot. A second aim was to investigate if there was a difference in running technique regarding foot strike pattern when running shod compared to bare foot. The foot strike pattern is defined as heal strike, mid foot strike or forefoot strike. Method: Seventeen Muay Thai fighters (13 male 4 female) volunteered to participate in the test of the cross- sectional experimental study. The study took place at PT-Studion Halmstad. The participants performed 2x3minutes of running shod and barefoot respectively at a subjective speed equal to a 12 on the Borg scale. Both conditions were video recorded from a sagittal plane using an iPhone 6. The dominant leg defined as the non-weight bearing leg at the preferred boxing stance was analysed. Data was collected two-dimensionally of the angels of the knee, ankle and foot position to horizontal. Foot strike pattern was also determined. Landmarks were marked to ease the analysis. T-tests of paired samples were used to examine whether there were any differences between the angle of the knee, ankle and foot at barefoot and shod conditions. The significance level for this study was set to be statistically significant if p ≤ 0.05. Foot strike frequency distributions were compared between shod and barefoot runners using chi-square (X2) analysis. Result: A significant difference at the angle of the foot (p=0,034) at initial contact with the ground while running between shod (12 ± 9) and barefoot (17 ± 9) was found. No significant difference in the angle of the knee (p=0,076) or ankle (p=0,081) was found. Changes in foot strike pattern were observed. At shod condition 88% used a rear foot strike, 6% used a mid foot strike and 6% used a forefoot strike. At barefoot condition 41% used a rear foot strike, 0% used a mid foot strike and 59% a fore foot strike. Conclusion: This study shows that the there is a significant difference in foot strike pattern when running shod and barefoot which confirms previous studies. The test group have in common that they train Muay Thai although; their sport specific training doesn’t appear to in this case have any impact on the foot strike pattern. / Bakgrund: Flera studier menar att individer vana att springa barfota samt individer som lever barfota väljer en framfota insättning vid löpning snarare än en hälisättning. Detta har delvis att göra med den proprioceptiva återkopplingen från fotsulan. Den gemensamma nämnaren mellan barfotalöparen och Muay Thai atleten skulle kunna vara denna feedback beroende av barfotaträning. En bidragande faktor till en icke hälisättning skulle kunna förklaras av det idrottsspecifika rörelsemönstret i Muay Thai där flera moment utförs stående på den främre delen av foten. Syfte: Ett syfte var att analysera skillnader i knä, ankel och fotvinklar vid initial kontakt i löpsteget vid skodd och barfota löpning av i Muay Thai-fighters vana vid träning barfota. Ett andra syfte var att undersöka eventuella skillnader i fotisättning vid barfotalöpning samt löpning med skor. Fotisättning definieras som framfot, mellan fot eller bakre/häl-isättning. Metod: Sjutton (17) Muay Thai atleter (13manliga 4kvinnliga) ställde frivilligt upp att delta i tvärsnittsstudien. Studien ägde rum på PT-Studion Halmstad. Testpersoner utförde 2x3minuter av löpning med och utan skor vid en subjektiv hastighet lika med en 12 på Borg skalan. Båda förhållandena filmades i sagitalplan med iPhone 6. Det dominanta benet definierat som det icke viktbärande benet vid den föredragna boxningspositionen analyserades. Tvådimensionell analys av förändringar i fotisättning, vinklar i knäled, ankelled och fotens position till det horisontella samt fotisättning dokumenterades. Landmärken markerades för att underlätta analysen. T-test användes för att undersöka om det fanns några skillnader i vinkeln av knäled, fotled och ankel vid löpning med skor och barfota. Signifikansnivån för denna studie bestämdes vara statistiskt signifikant om p <0,05. Frekvensen av fotisättningen fördelning jämfördes via chi-square (X2) analys. Resultat: En signifikant skillnad (p=0,034) i fotvinkeln vid initial kontakt med marken under löpning med skor (12 ± 9) och barfota (17 ± 9) hittades, men inga signifikanta skillnader i knäets vinkel ((p=0,076) eller ankel (p=0,081) hittades. Med skor vald 88 % en hälisättning, 6 % en mittfotsisättning och 6 % en främre fotisättning. Vid löpning barfota valde 41 % en hälisättning, 0 % en mittfotsisättning och 59 % en främre fotisättning. Slutsats: Studien visar att det finns en signifikant skillnad i fotisättningen mellan löpning barfota och med skor vilket bekräftar tidigare studier. Testgruppen har gemensamt att de tränar thaiboxning, dock kan inte den sportspecifika träningen förklara det valda fotisättningsmönstret.