Made available in DSpace on 2014-12-17T15:16:10Z (GMT). No. of bitstreams: 1 NiciaFBM_DISSERT.pdf: 1728497 bytes, checksum: a256b529408b17ed552e700e78441abd (MD5) Previous issue date: 2010-05-14 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Muscle fatigue is a phenomenon that promotes physiological and biomechanical disorders and their changes in healthy subjects have been widely studied and have significant importance for care in preventing injuries, but we do not have many information about its effects in patients after ACL reconstruction. Thus, this study is to analyze the effects of fatigue on neuromuscular behavior of quadriceps after ACL reconstruction. To reach this objective, participants were forty men, twenty healthy (26,90 ? 6,29 years) and twenty after ACL reconstruction (29,75 ? 7,01 years) with a graft of semitendinosus and gracilis tendons, between four to six months after surgery. At first, there was an assessment of joint position sense (JPS) at the isokinetic dynamometer at a speed of 5?/s and target angle of 45? to analyze the absolute error of JPS. Next, we applied the a muscle fatigue protocol, running 100 repetitions of isokinetic knee flexion-extension at 90?/s. Concurrently with this protocol, there was the assessment of muscle performance, as the peak torque (PT) and fatigue index, and electromyographic activity (RMS and median frequency). Finally, we repeated the assessment of JPS. The statistical analysis showed that patients after ACL reconstruction have, even under normal conditions, the amended JPS compared with healthy subjects and that after fatigue, both have disturbances in the JPS, but this alteration is significantly exacerbated in patients after ACL reconstruction. About muscle performance, we could notice that these patients have a lower PT, although there are no differences between the dynamometric and EMG fatigue index. These findings show the necessity about the cares of pacients with ACL reconstruction in respect of the risks of articulate instability and overload in ligamentar graft / A fadiga muscular ? um fen?meno que envolve dist?rbios fisiol?gicos e biomec?nicos. A an?lise de suas altera??es, em indiv?duos sadios, possui grande import?ncia na preven??o de les?es, mas pouco se sabe sobre suas repercuss?es em pacientes ap?s reconstru??o do LCA. Dessa forma, o objetivo deste estudo foi avaliar os efeitos da fadiga no comportamento neuromuscular do quadr?ceps femoral de indiv?duos ap?s reconstru??o do LCA. Para tanto, participaram deste estudo quarenta homens, sendo vinte saud?veis (26,90 ? 6,29 anos) e vinte ap?s reconstru??o de LCA (29,75 ? 7,01 anos) com enxerto dos tend?es semitendinoso e gr?cil, entre 4 a 6 meses de p?s-operat?rio. Em princ?pio, realizou-se uma avalia??o do senso de posi??o articular (SPA) ativo, no dinam?metro isocin?tico, a uma velocidade de 5?/s e ?ngulo-alvo de 45?, sendo a vari?vel analisada o seu erro absoluto. Em seguida, aplicou-se uma avalia??o isom?trica m?xima em extens?o do joelho, a 60? de flex?o, por 10 segundos e um protocolo de fadiga muscular, sendo executadas 100 repeti??es isocin?ticas conc?ntricas de flexo-extens?o do joelho a 90?/s. Concomitantemente a esse protocolo, realizou-se a avalia??o do desempenho muscular, observando o pico de torque (PT), o ?ndice de fadiga (IFD) e a atividade eletromiogr?fica (Root Mean Square - RMS e freq??ncia mediana - Fm). Por fim, repetiu-se a avalia??o da SPA. As avalia??es detectaram que pacientes ap?s reconstru??o do LCA apresentaram, ainda em condi??es pr?-fadiga, o SPA alterado quando comparado com indiv?duos sadios e que quando fatigados, ambos possu?ram dist?rbios no SPA, sendo que essa altera??o foi significativamente mais exacerbada em pacientes ap?s reconstru??o de LCA. Quanto ao desempenho muscular, constatou-se que esses pacientes apresentam um menor PT, RMS e Fm quando comparado ao grupo controle, mas n?o possuem diferen?as quanto ao ?ndice de fadiga, dado pela Fm e pela dinamometria. Ademais, constatou-se que as vari?veis isocin?ticas e eletromiogr?ficas, em sua grande maioria, apresentam correla??es positivas. Os achados refor?am a necessidade dos cuidados aos pacientes ap?s reconstru??o do LCA, quando submetidos ? fadiga, no que diz respeito aos riscos de instabilidade articular e sobrecarga do enxerto ligamentar