Influência do treinamento excêntrico nas razões de torque de flexores/extensores do joelho

O treinamento excêntrico (Texc) produz adaptações musculares que minimizam a ocorrência de lesões e é usado em reabilitação e treinamento de força, mas pouco se sabe sobre seus efeitos no equilíbrio entre músculos antagonistas do joelho. As razões de torque permitem determinar esses desequilíbrios musculares. O objetivo do estudo foi avaliar os efeitos de 12 semanas de Texc nas razões de torque excêntrico (Iexc:Qexc) entre os músculos isquiotibiais (I) e quadríceps (Q). Vinte e quatro sujeitos saudáveis do sexo masculino foram distribuídos nos grupos controle (GC, n=13, idade 27,7±4,6 anos) e experimental (GE, n=11, idade 28,5±9,5 anos), submetido ao treinamento. Um dinamômetro isocinético foi utilizado para o Texc (velocidade de -60 º/s) e para as avaliações (uma a cada quatro semanas). As razões de torque medidas foram comparadas estatisticamente entre os grupos e intragrupos entre as avaliações, com nível de significância de 5%. No GE, foi observada redução das razões de torque da avaliação (AV) inicial para as demais: AV1x AV2, p=0,005; AV1x AV3, p=0,001; e AV1x AV4, pEccentric training produces skeletal muscle adaptations that help preventing muscle injuries, being often used in rehabilitation and physical fitness programs, but little is known of the effects of this training in the balance between knee antagonistic muscles. Torque ratios allow determining such balance. The purpose of this study was to assess the effect of a 12-week eccentric training program on the eccentric torque ratio between hamstring and quadriceps muscles (Hecc:Qecc). Twenty-four healthy male subjects were assigned to either a control group (CG, n=13, aged 27.7±4.6 years) or an experimental group (EG, n=11, aged 28.5±9.5 years). An isokinetic dinamometer was used (angular velocity -60º/s) for both the eccentric training and the assessments, performed every four weeks. Torque ratios measured were statistically compared between groups and intragroups between assessments, with (significance level set at p<0.05. In EG a reduction in torque ratios was found from the initial assessment (AS1) to the other three ones: AS1x AS2, p=0.005; AS1x AS3, p=0.001; and AS1x AS4, p<0.001. At the last evaluation, EG torque ratios were lower than those of CG's (p=0.041). Eccentric training hence changes balance between knee flexor and extensor muscles: a 12-week training program leads to lower Hecc:Qecc ratio and to extensor torque increase, with no significant change in flexor torque, being thus suitable for rehabilitation aimed at strengthening knee extensor muscles

Comparação das variáveis eletromiográficas e cinemáticas entre uma corrida do "triathlon" e uma corrida prolongada

A corrida e o ciclismo realizados com uma mesma duração e intensidade podem apresentar diferentes respostas biomecânicas e metabólicas durante um protocolo de fadiga devido à sobrecarga mecânica e à especificidade técnica de cada modalidade. O objetivo do presente estudo foi avaliar os efeitos da fadiga proveniente de uma corrida de 10 km, precedida por ciclismo ou corrida, no padrão de passada e no sinal eletromiográfico (EMG). Nove triatletas do sexo masculino com tempo de prática superior a dois anos participaram do estudo. Os testes foram realizados em duas etapas: corrida do "triathlon" (40 km de ciclismo seguidos de 10 km de corrida) e corrida prolongada (corrida com duração igual ao tempo que o atleta levou para percorrer os 40 km de ciclismo, seguidos de mais 10 km de corrida). Uma análise cinemática (frequência e amplitude de passada) e eletromiográfica correspondentes às 10 passadas registradas no 5º km de cada corrida foi realizada. As curvas de EMG foram retificadas e filtradas para cálculo das curvas de RMS. A partir da média das curvas de EMG foram obtidos os valores de pico de RMS para os músculos reto femoral, vasto lateral e bíceps femoral. Maiores valores de frequência de passada e do sinal EMG do músculo bíceps femoral foram obtidos na corrida prolongada quando comparada com a corrida do "triathlon". Esses resultados parecem estar relacionados a maior fadiga proveniente da corrida prolongada devido às maiores exigências mecânicas

Effects of neck-specific exercise with or without a behavioural approach in addition to prescribed physical activity for individuals with chronic whiplash-associated disorders: A prospective randomised study

Background: Up to 50% of chronic whiplash associated disorders (WAD) patients experience considerable pain and disability and remain on sick-leave. No evidence supports the use of physiotherapy treatment of chronic WAD, although exercise is recommended. Previous randomised controlled studies did not evaluate the value of adding a behavioural therapy intervention to neck-specific exercises, nor did they compare these treatments to prescription of general physical activity. Few exercise studies focus on patients with chronic WAD, and few have looked at patients' ability to return to work and the cost-effectiveness of treatments. Thus, there is a great need to develop successful evidence-based rehabilitation models. The study aim is to investigate whether neck-specific exercise with or without a behavioural approach (facilitated by a single caregiver per patient) improves functioning compared to prescription of general physical activity for individuals with chronic WAD. Methods/Design. The study is a prospective, randomised, controlled, multi-centre study with a 2-year follow-up that includes 216 patients with chronic WAD (> 6 months and < 3 years). The patients (aged 18 to 63) must be classified as WAD grade 2 or 3. Eligibility will be determined with a questionnaire, telephone interview and clinical examination. The participants will be randomised into one of three treatments: (A) neck-specific exercise followed by prescription of physical activity; (B) neck-specific exercise with a behavioural approach followed by prescription of physical activity; or (C) prescription of physical activity alone without neck-specific exercises. Treatments will be performed for 3 months. We will examine physical and psychological function, pain intensity, health care consumption, the ability to resume work and economic health benefits. An independent, blinded investigator will perform the measurements at baseline and 3, 6, 12 and 24 months after inclusion. The main study outcome will be improvement in neck-specific disability as measured with the Neck Disability Index. All treatments will be recorded in treatment diaries and medical records. Discussion. The study findings will help improve the treatment of patients with chronic WAD. Trials registration. ClinicalTrials.gov identifier: NCT01528579