Isokinetic performance of ankle evertor and invertor muscles in adolescent female volleyball athletes

Abstract

Introduction Volleyball is one of the most practiced sport worldwide and is characterized by short, intense, and explosive movements; such as jumps, attack hits, blocks, services, passes, and lateral shuffling 1. However, the most important actions observed during the volleyball practice are the offensive movements (services, blocks, and attack hits) which requires many muscle and joint demands 2. Since it is a sport with no physical contact and the opponents are separated by a net, volleyball is considered to be a safe sport, and, consequently, there is a low incidence of musculoskeletal injuries when compared to other sports 3-4. Nevertheless, previous studies have shown that the most frequent injury which affect volleyball players is the ankle sprain 2-3, 5 and that according to a recent meta-analysis by Doherty, Delahunt, Caulfield, Hertel, Ryan, Bleakley 6 and females have higher chances of ankle sprains. The main factor related to ankle sprains is the high impact after a vertical jump, which is a fundamental movement and is considered a differential for better performance by the athletes during services, blocks and attack hits 7. Nevertheless, just the impact intensity alone does not justify the occurrence of these injuries, and the malfunctioning of the structures that comprise this joint, such as the ankle muscles, also justify the high occurrence of ankle sprains 8. The study of the ankle muscles is of great importance as it is related to the good performance during volleyball practice and since it is involved in the mechanism of jumping and landing on a single foot, making the ankle one of the most injured joints 9. The comparison between limbs' strength is important to determine muscular balance because bilateral asymmetries indicates a higher risk of musculoskeletal injuries 10. Thus, the isokinetic testing, which is an assessment method of high effectivity and trustworthiness, can be used to compare bilateral and agonist/ antagonist muscle strength of the athletes 11. Although many studies have used the isokinetic testing in the muscular study of different sports populations, and joints, there are few studies directed to adolescent volleyball athletes, and, especially, to the ankle joint. Therefore, this study aimed to analyze, through information from a database, the muscular performance and differences between the dominant and nondominant limbs of the evertor and invertor muscles of the ankle in adolescent female volleyball players.

Avaliação isocinética de extensores e flexores de joelho de ciclistas amadores

“…Após, foi realizada a avaliação de desempenho muscular, através da avaliação isocinética, realizada no dinamômetro isocinético do Centro Clínico da Universidade de Caxias do Sul (Biodex System 4®, Biodex Medical Systems, Shieley, Nova Iorque, EUA). Foram avaliados os extensores e flexores dos joelhos, utilizando-se protocolos baseados nos estudos de Stedile et al 27 e Bonetti et al 28 . Primeiramente, os ciclistas realizaram exercício de aquecimento em uma bicicleta ergométrica vertical (BiocycleMagnetic 2500®, Moviment, São Paulo, Brasil), por 8 minutos, com velocidade moderada (70-80 rotações por minuto) e sem resistência.…”

Effects of Robot-assisted Gait With Body Weight Support on Torque, Work, and Power of Quadriceps and Hamstring Muscles in Healthy Subjects

“…Both legs were tested and the participants' dominant side was always tested first. For isokinetic testing, the participants performed five maximal contractions of the knee flexion and extension at a velocity of 60°/s and then fifteen maximal contractions at a velocity of 180°/s [27]. The subjects were allowed a 20-second rest between the angular velocity conditions.…”