Syfte och frågeställningar: Syftet var att genom en tvärsnittsstudie ta reda på om det fanns asymmetrier mellan dominant och icke-dominant ben hos skadefria kvinnliga fotbollsspelare gällande sagittal knälaxitet. Frågeställningar i studien var: Hur stor är den anteriora och posteriora knälaxiteten i dominant respektive icke-dominant ben uppmätt med KT-1000 vid belastningar på 20 lb, 30 lb samt vid ett manuellt maxtest i anterior riktning? Föreligger det någon sidoskillnad mellan dominant och icke-dominant ben gällande knälaxitet uppmätt med KT-1000 vid anteriora och posteriora belastningar på 20 lb, 30 lb samt vid ett manuellt maxtest i anterior riktning? Hur stor andel av deltagarna uppvisar en sidoskillnad av sagittal knälaxitet på ≥ 2 mm respektive ≥ 3 mm uppmätt med KT-1000 och hur är frekvensen fördelad mellan dominant och icke-dominant ben hos dessa? Metod: För att besvara syfte och frågeställningar genomfördes en tvärsnittsstudie där 56 kvinnliga fotbollsspelare inom division 1-2 deltog. Samtliga deltagare var ≥ 18 år, skadefria och hade spelat fotboll i minst 5 år. Mätinstrumentet KT-1000 användes för att registrera knälaxitet mellan dominant och icke-dominant ben. Alla mätningar utfördes av samma testledare och med samma mätinstrument och genomfördes i en standardiserad position inför träning. Statistiska beräkningar utfördes på belastningarna P-20/30 lb, A-20/30 lb, Total AP-20/30 lb samt ett manuellt maxtest. Data för knälaxitet registrerades och analyserades utifrån bendominans genom ett Mann Whitney U-test. Resultat: Resultatet visade på en liksidig knälaxitet av dominant och icke-dominant ben vid anteriora och posteriora mätningar. Medelvärden varierade mellan 1,91–2,91 mm i posterior riktning med en spridning på 1-4 mm. Motsvarande mätvärden i anterior riktning var 4,03–9,53 mm med en spridning på 4-19 mm. Inga signifikanta sidoskillnader framkom mellan dominant och icke-dominant ben men en ökad knälaxitet uppmättes i dominant ben vid samtliga belastningar i anterior riktning. En sidoskillnad på ≥ 2 mm visade sig hos 16,6-51,8 % av deltagarna beroende på vilken belastning som testades. Av dessa registrerades en ökad anterior knälaxitet i det dominanta benet hos 62,1-81,2 %. Slutsats: Genomförda mätningar av sagittal knälaxitet visade inga signifikanta skillnader gällande asymmetrier mellan dominant och icke-dominant ben hos kvinnliga fotbollsspelare. Vid belastningen A-MMT uppvisade drygt hälften av deltagarna en individuell sidoskillnad på ≥ 2 mm. Studien belyser vikten av ytterligare forskning för att kartlägga individuella sidoskillnader gällande sagittal knälaxitet. / Aim: The aim of the cross-sectional study was to find out if there were asymmetries between the dominant and non-dominant leg in non-injured female soccer players regarding sagittal knee laxity. The aims were: What´s the anterior and posterior knee laxity in the dominant and non-dominant leg measured with KT-1000 at loads of 20 lb, 30 lb, and a manual maximum test in anterior direction? Is there side-to-side differences in knee laxity between the dominant and non- dominant leg measured with KT-1000 at the anterior and posterior loads of 20 lb, 30 lb and with a manual maximum test in anterior direction? How many of the participants show a side-to-side difference of sagittal knee laxity of ≥ 2 mm and ≥ 3 mm measured with the KT-1000 and how is the frequency between the dominant and non-dominant leg of these distributed? Method: In order to answer the aim of the cross-sectional study 56 female soccer players from division 1-2 participated. All participants were ≥ 18 years old, no previous knee injury and had played football for at least 5 years. The KT -1000 instrument was used to measure knee laxity between the dominant and non-dominant leg. All measurements were performed by the same test leader, with the same test-instrument and in a standardized position. Statistical calculations were performed on loads P-20/30 lb, A-20/30 lb, Total AP-20/30 lb and a manual maximum test. Data for knee laxity were measured and analyzed by leg dominance through the Mann Whitney U-test. Results: The results of all participants showed an equivalent of knee laxity of dominant and non-dominant leg at the anterior and posterior measurements. Mean values ranged from 1.91 to 2.91 mm in the posterior direction (range of 1-4 mm). The corresponding measured values in the anterior direction were 4.03 to 9.53 mm (range 4-19 mm). No significant side-to-side differences were revealed between the dominant and non-dominant leg but an increased knee laxity was documented in the dominant leg at all loads in the anterior direction. Depending on the load 16.6 to 51.8 % of the participated had a side-to-side difference ≥ 2 mm. 62.1 to 81.2 % of these registered increased anterior knee laxity in the dominant leg. Conclusions: The measurements of sagittal knee laxity revealed no significant differences in the asymmetries between the dominant and non-dominant leg in non-injured female soccer players. At the A-MMT load over half of the participants revealed a side-to-side difference ≥ 2 mm. The study highlights the need for further research to identify individual side-to-side differences regarding sagittal knee laxity.

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Made available in DSpace on 2016-12-06T17:07:26Z (GMT). No. of bitstreams: 1 DISSERTACAO PRONTA.pdf: 1254266 bytes, checksum: f6cd46c7547dc4db63544d5dade63617 (MD5) Previous issue date: 2011-03-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The anterior knee laxity has been described as a risk factor for anterior cruciate ligament injuries of the knee. During exercise it has been verified an increase in knee laxity due to cyclic loading. This increase can alter the neuromuscular control and also decrease the joint dynamic stability. Thus, this study aimed to evaluate the neuromuscular response during jump landing after incresing anterior knee laxity. Nineteen male subjects were evaluated (mean age 27,47 ±4,56 years; mean body mass 73 ±9,41 kg; mean height 1,75 ±0,05 m). Neuromuscular response was verified through semitendinosus, biceps femoris, vastus medialis and vastus lateralis muscular activation. In order to evaluate joint dynamic stability, the co-activation index between medialis and lateralis muscles was also verified. Subjects performed five trials of unipodal jumps from a 30 cm height. The subject s knee was submitted to cyclic passive anterior traction for 15 min, with 0,1 Hz frequency. Traction load was normalized for 40% of body mass to induce increase laxity. The knee was positioned at 30 degrees of flexion, and a cable was fixed right below the tuberosity of the tibia. After cyclic loads, subjects were revaluated. The jump was divided in three windows: 100ms before landing, 100ms after landing and 200ms after landing. Paired t test was used to compare muscle activities before and after inducing anterior knee laxity. The results showed a decrease in semitendinosus activity during 100ms after landing, as well as decrease in vastus lateralis in 100ms before and after landing. However, vastus medialis, biceps femoris and co-activation index were not affected by anterior knee laxity. The results show that increased anterior knee laxity can change the neuromuscular control. However, this alteration may not be sufficient to reduce the dynamic joint stability / A lassidão anterior do joelho tem sido descrita como um dos fatores de risco para as lesões do ligamento cruzado anterior do joelho. Tem-se verificado que cargas cíclicas durante o exercício provocam o aumento dessa lassidão. Esse aumento pode alterar o controle neuromuscular e diminuir a estabilidade articular dinâmica. Dessa forma este estudo teve por objetivo avaliar a resposta neuromuscular durante o salto após o aumento da lassidão anterior do joelho. Para isso foram avaliados 19 sujeitos do sexo masculino, com idade média de 27,47 anos (±4,56), massa corporal de 73 kg (±9,41), e estatura de 1,75 m (±0,05). Para a avaliação da resposta neuromuscular foi mensurada a atividade muscular dos músculos semitendíneo, bíceps femoral, vasto medial, e vasto lateral. Para a avaliação da estabilidade articular dinâmica foi obtido ainda o índice de co-ativação entre os músculos mediais e laterais da coxa. Estas variáveis foram obtidas em 5 saltos unipodais, realizados de uma altura de 30 cm. Em seguida, o aumento da lassidão foi provocado por meio de uma força de tração anterior cíclica passiva aplicada à tíbia por 15 min., a uma freqüência de 0,1 Hz, com a magnitude da força correspondente a 40% da massa corporal do sujeito. Para a aplicação da carga o joelho foi posicionado a 30 ° de flexão e um cabo fixado abaixo da tuberosidade da tíbia. Para a avaliação da atividade muscular o salto foi dividido em três instantes: 100ms pré-aterrissagem, 100ms pós-aterrissagem e 200ms pós-aterrissagem.Em cada instante do salto analisado a atividade muscular foi comparada estatisticamente nas situações pré e pós-aumento da lassidão por meio de teste t de student para medidas repetidas. O resultado do teste t demonstrou que houve diminuição significativa na ativação do músculo semitendíneo no instante 100ms pós-aterrissagem, e do músculo vasto lateral no instante 100ms pré-aterrissagem e 100ms pós-aterrissagem. Nos demais músculos e no índice de co-ativação não foram observados alterações. A partir dos resultados concluiu-se que o aumento da lassidão anterior do joelho pode alterar o controle neuromuscular. Todavia, estas alterações podem não ser suficientes para alterar a estabilidade articular dinâmica

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