Maximal vs. explosive knee extensor strength in professional soccer players: inter-limb asymmetries and relationship with knee function.

The main aims of this study were to compare the magnitude of inter-limb asymmetry (ILA) and the relation with self-reported knee function between maximal and explosive knee extensor strength outcomes in professional soccer players. Forty-six male soccer players completed different maximal isokinetic and isometric contractions of the knee extensors for the assessment of maximal strength (peak torque and maximal voluntary contraction (MVC) torque) and explosive strength (early, intermediate, late, and peak rate of torque development (RTD)). Self-reported knee function was assessed with the International Knee Documentation Committee (IKDC) and Lysholm knee scoring scales. Peak torque and MVC torque showed comparable ILAs (8-9%), both being significantly lower than all RTD ILAs (16% on average; p < 0.001). ILAs for early RTD (21%) and peak RTD (19%) were significantly higher than all the other variables (p < 0.05). Only early and intermediate RTD were significantly correlated - though weakly - with both IKDC (rho = 0.32 for both) and Lysholm (rho = 0.36 and 0.30, respectively) scores. We conclude that explosive knee extensor strength - early RTD in particular - exhibited larger ILAs and better relations with self-reported knee function than peak torque and MVC torque in professional soccer players. These results confirm the validity and functional relevance of early RTD and the need for its inclusion in routine performance testing for soccer players.Highlights Professional soccer players exhibited larger inter-limb deficits in knee extension strength for explosive actions than for the widely-used isokinetic test.Self-reported knee function was significantly correlated with explosive strength of the knee extensor muscles but not with maximal strength.The first 50 ms of an explosive knee extension seem to be crucial for self-perceived sport performance and possibly for injury prevention.

Repercussions of the COVID-19 pandemic on athletes: a cross-sectional study.

The COVID-19 pandemic has presented significant challenges and implications for the sports community. Thus, this study aimed to describe the prevalence of COVID-19 in Brazilian athletes and identify the epidemiological, clinical, athletic, life and health factors associated with the disease in these individuals. A cross-sectional study was performed involving 414 athletes from 22 different sports using an online questionnaire from August to November 2020. The association between the athletes' characteristics and COVID-19 was evaluated using a logistic regression model. The prevalence of COVID-19 was 8.5%, although only 40% of athletes reported having been tested. Being under 27 years of age (3-fold), having children (~5-fold), having a teammate test positive for COVID-19 (2.5-fold), and smoking (14-fold) were associated with a possible higher risk of disease. Almost 20% of athletes self-reported musculoskeletal injuries during the period of the pandemic that was studied. Athletes with a university education (P = 0.02), a profession other than sports (P < 0.001), those from a low-income family (P = 0.01), and public health system users (P = 0.04) were significantly less frequently tested for COVID-19, whereas international competitors, athletes who received a wage, and athletes who had a teammate who tested positive for COVID-19 were 2-, 3-, and 15-fold more likely to be tested for COVID-19, respectively. Approximately 26% of the athletes who tested negative or were untested reported more than three characteristic COVID-19 symptoms, and 11% of athletes who tested positive for COVID-19 were asymptomatic. The identification of modifiable (have children, smoking, and teammates positively tested) and non-modifiable (age under 27 years) factors related to COVID-19 in athletes can contribute to implementing surveillance programmes to decrease the incidence of COVID-19 in athletes and its negative impacts in sports.

Return to play after anterior cruciate ligament reconstruction / Retorno ao esporte após a reconstrução do ligamento cruzado anterior / Retorno al deporte después de reconstrucción del ligamento cruzado anterior

ABSTRACT The anterior cruciate ligament (ACL) tear represents more than half of all knee injuries in sports that involve body rotations and sudden changes of direction. Discharging the athlete for return to play (RTP) post-ACL reconstruction (ACLR) is a difficult task with multidisciplinary responsibility. For many years, a six-month period post-ACLR was adopted as the only criterion for RTP. However, it is now suggested that RTP should not be exclusively time-based, but to clinical data and systematic assessments. Despite the importance of post-ACLR factors for RTP, pre- and peri-ACLR factors must also be considered. Historically, ACLR is performed with the hamstring or autologous patellar tendons, although the choice of graft is still an open and constantly evolving theme. Anterolateral ligament reconstruction and repair of meniscal ramp tear associated with ACLR have recently been suggested as strategies for improving knee joint stability. Subjective questionnaires are easy to apply, and help identify physical or psychological factors that can hamper RTP. Functional tests, such as hop tests and strength assessment by means of isokinetic dynamometers, are fundamental tools for decision making when associated with clinical evaluation and magnetic resonance imaging. Recently, the capacity to generate force explosively has been incorporated into the muscle strength assessment. This is quantified through the rate of torque development (RTD). Due to characteristics inherent to the practice of sport, there is an extremely short time available for produce strength. Thus, RTD seems to better represent athletic demands than the maximum strength assessment alone. This review investigates the pre-, peri- and post-ACLR factors established in the literature, and shares our clinical practice, which we consider to be best practice for RTP. Level of evidence V; Specialist opinion.

RESUMO A ruptura do ligamento cruzado anterior (LCA) representa mais da metade das lesões do joelho em esportes que envolvem rotações e mudanças repentinas de direção. A liberação do atleta para o retorno ao esporte (RAE) depois da reconstrução do LCA (RLCA) é uma tarefa difícil, de responsabilidade multidisciplinar. Por muitos anos, o período de seis meses pós-RLCA foi utilizado como único critério para RAE. Contudo, atualmente, sugere-se que o RAE não deve estar atrelado exclusivamente ao tempo, mas a dados clínicos e avaliações sistemáticas. Apesar da importância dos fatores pós-RLCA para o RAE, os fatores pré- e peri-RLCA também devem ser contemplados. Historicamente, a RLCA é realizada com tendões isquiotibiais ou patelares autólogos, apesar da escolha do enxerto ainda ser um tema em aberto e em constante evolução. Recentemente, a reconstrução do ligamento anterolateral e o reparo da lesão na rampa meniscal associadas à RLCA têm sido sugeridas como estratégias para melhorar a estabilidade articular do joelho. Questionários subjetivos são de fácil aplicação e ajudam a identificar fatores físicos ou psicológicos que possam dificultar o RAE. Testes funcionais como os hop tests e a avaliação de força com dinamômetros isocinéticos são ferramentas fundamentais na decisão quando aliadas à avaliação clínica e de ressonância magnética. Recentemente, tem-se incorporado ao escopo de avaliação da força muscular a capacidade de gerar força de maneira explosiva, mensurada através da taxa de desenvolvimento de torque (TDT). Devido a características inerentes a prática esportiva os tempos disponíveis para produção de força são demasiadamente pequenos e, sendo assim, a TDT parece representar melhor as demandas esportivas do que a avaliação isolada de força máxima. Nesta revisão, foram reunidos fatores pré, peri e pós-RLCA estabelecidos na literatura, assim como foi compartilhada nossa prática clínica, que consideramos ser a melhor para o RAE. Nível de evidência V; Opinião do especialista.

RESUMEN La ruptura del ligamento cruzado anterior (LCA) representa más de la mitad de las lesiones de rodilla en deportes que involucran rotaciones y cambios repentinos de dirección. La liberación del atleta para el retorno al deporte (RAD) después de la reconstrucción del LCA (RLCA) es una tarea difícil, de responsabilidad multidisciplinaria. Durante muchos años, el período de seis meses post-RLCA fue usado como único criterio para RAD. Sin embargo, actualmente, se sugiere que el RAD no debe estar vinculado exclusivamente al tiempo, sino a datos clínicos y evaluaciones sistemáticas. A pesar de la importancia de los factores post-RLCA para el RAD, también deben ser contemplados los factores pre y peri-RLCA. Históricamente, la RLCA es realizada con tendones isquiotibiales o patelares autólogos, a pesar de que la elección del injerto aún sea un tema abierto y en constante evolución. Recientemente, la reconstrucción del ligamento anterolateral y la reparación de la lesión en la rampa meniscal asociadas a la RLCA han sido sugeridas como estrategias para mejorar la estabilidad articular de la rodilla. Los cuestionarios subjetivos son de fácil aplicación y ayudan a identificar los factores físicos o psicológicos que pueden dificultar el RAD. Los tests funcionales como los hop tests y la evaluación de fuerza con dinamómetros isocinéticos son herramientas fundamentales en la decisión cuando se combinan a la evaluación clínica y de resonancia magnética. Recientemente, se ha incorporado al alcance de evaluación de la fuerza muscular, la capacidad de generar fuerza de manera explosiva, medida a través de la tasa de desarrollo de torque (TDT). Debido a características inherentes a la práctica deportiva, los tiempos disponibles para producción de fuerza son demasiado pequeños y, siendo así, la TDT parece representar mejor las demandas deportivas que la evaluación aislada de fuerza máxima. En esta revisión fueron reunidos factores pre, peri y post-RLCA establecidos en la literatura, así como fue compartida nuestra práctica clínica, que consideramos la mejor para el RAD. Nivel de evidencia V; Opinión del especialista.

Ramp Lesions: An Unrecognized Posteromedial Instability?

Meniscal ramp lesions occur much more frequently than was previously considered, and particularly so in ACL-injured knees. The historically high rate of missed diagnoses is a result of unfamiliarity with this injury pattern within the orthopedic community, and also the difficulty in diagnosis. A systematic exploration of the posteromedial compartment of the knee is mandatory to reliably identify ramp lesions. Failure to recognize and repair these injuries is associated with persistent anterior and posteromedial instability. Understanding their nature, biomechanics, and epidemiology is essential in allowing orthopedic surgeons to suspect their presence and adequately treat these lesions.