Isokinetic and Isometric Assessment of the Knee Joint Extensors and Flexors of Professional Volleyball Players.

PURPOSE: The main objective of this study was to evaluate the level of muscle strength by using isokinetic and isometric measurements-more specifically, the force ratio between the knee flexors and extensors (values of the torques). METHODS: An experimental group of elite volleyball players (n = 14) were compared to a control group (n = 14) of healthy non-athletes of comparable ages. Torque measurements were obtained under three concentric conditions (angular velocities of 60 °/s, 180 °/s, and 300 °/s) and one static condition by utilizing the Biodex System 3. RESULTS: In all trials, the volleyball players achieved significantly higher peak torque (PT) values for both the extensors and flexors (p < 0.05) than those of the control group. However, the strength ratio of the flexors and extensors (H/Q) in the experimental group was only 83% of the standard reported in the literature. The most developed and dominating muscles in the knee joints of the volleyball players were the extensors, which accounted for the low strength ratio and dynamic instability of this joint. CONCLUSION: Based on a proper assessment of the strength ratio of the knee flexors and extensors, properly selected and implemented resistance training can improve the maximum strength and power production and reduce the incidence of injuries in volleyball.

[Analysis of knee joint injuries of competitive volleyball players in selected sports clubs of Poznan city--biomechanical context. Synthesis--proposal for the usage of physiotherapy methods in the prevention of the discussed injuries]. / Analiza urazów stawu kolanowego u trenujacych wyczynowo pilke siatkowa w wybranych klubach poznanskich--kontekst biomechaniczny. Synteza problemu--propozycja wykorzystania metod fizjoterapeutycznych w profilaktyce omawianych urazów.

INTRODUCTION: Volleyball is a source of direct injuries and chronic overloads of the joints, which indirectly results in traumas and permanent dysfunctions. This applies particularly to: knee joints, ankle joints, shoulder joints and small joints of the hand, as well as the joints of the lower spine regions. Each league team should employ a physiotherapist who would be responsible for the implementation of an injury prevention program as well as for choosing the right training loads. PURPOSE: The purpose of this study is to analyze the frequency and the type of knee joint injuries occurring in people practicing Volleyball at competitive level as well as to propose the usage of elements of modern physiotherapy in order to prevent these injuries. MATERIAL AND METHODS: The tests were performed over a group of 19 volleyball players from Poznan. In order to propose measures that would prevent injuries, the authors carried out a review of modern physiotherapy methods and suggested the implementation of certain therapeutic techniques for the region of the knee joint. RESULT ANALYSIS AND DISCUSSION: As much as 79% of the subjects reported having chronic pain and knee joint injuries in the past. All of them, due to their conditions, declared having used various forms of physiotherapy treatment. It seems that in a professional sports club not only the presence of a massage therapist but first of all a qualified physiotherapist is indispensable.