Badminton Knee Muscle Imbalance in Elite Players

Summer

Unilateral movements repetitions put the sport at risk of imbalance, that is, asymmetry between the same muscle groups on the opposite side of the body (lateral asymmetry) and the opposite interfunctional structures between the opposite parts of the body (functional asymmetry). Tensiomiography, a non -invasive method to evaluate the contractile characteristics of muscle fibers, allows a vision of the current state of sports and provides a great opportunity to improve both in the current process and in the process of maintenance of sports. The objective of this work is to examine the lateral and functional asymmetries of the muscles that surround the knee joint in the elite bádminton players and compare them with the standard recommended values ​​in practice.

The sample of respondents that were tested and analyzed the contractile characteristics of the muscles using the TMG method consisted of elite bádminton players of the Serbian national team, with many years of experience in that sport. The assumption was that the pronounced asymmetry is the result of the constant commitment of the musculature of the dominant side during the specific technique of moving and hitting the ball in the bádminton. An independent T test was used to process the results, and the estimated values ​​indicate the support of the hypothesis on the present imbalance.

The functional asymmetry, that is, the imbalance of the extensor muscles in relation to the flexors of the knee joint, is represented at a level of 25%± 1, which does not represent a great risk and danger for athletes, and is present to a greater extent in the deficiency of the legs. The size of the radial deformation of the biceps femoral and the vast side is greater in the non -dominant leg than in the dominant leg. The contraction time of the extensor muscles of the dominant leg knee is shorter than that of the non -dominant leg. The contraction time of the flexor muscles in the knee of the non -dominant leg is not shorter than that of the dominant leg.

Introduction

Badminton is a sport in which the goal is to reach a Shuttlecock on the network on the opponent’s court and score points in this way. It is extremely popular as recreational activity and is favored by people of all ages. The game is played on a field of specific dimensions and requires a particular technique of movement and transport blow using a racket. The game that involves a feathered Shuttlecock is very old. In India, there are paintings of caves over two thousand years that represent this game. In China, he was known as Di Jian-Zi and was especially popular between girls and women (Wikipedia).

Inca and Azteca civilizations in the Americas were also familiar with a game based on Shuttlecock, and it was not uncommon in European royal courts during feudalism. A painting by French artist Jean-Baptiste-Siméon Chardin (1699-1779), currently housed in the Uffizi gallery, represents a girl who holds a racket in her right hand and a feathered transfer to the left. The painting is titled The Fillette Au Volant. The Bádminton as a modern sport developed in the early fourteenth century since the old Indian Poona game, which was brought to England by British officers in 1873. They demonstrated it in a castle in the south of England in the property of the Duke of Beaufort, after which the game was appointed. In 1877, the first Bádminton club (Bath Badminton Club) was established, and in 1893, the first national association, the Badminton Association of England was founded, in which the first official rules were published. These rules are very similar to the rules in force today. The Bádminton International Federation (IBF) was established in 1934 and continues to rule the sport and organize competitions. Bádminton was later included in the Olympic Games (Wikipedia).

At the elite level, the bádminton is characterized by dynamics, speed and agility. The timely positioning of the athlete’s body in the most efficient position for a technically precise and tactically planned shot is crucial to obtain an advantage over the opponent and winning points, the games and, ultimately, the medals in the championship tournaments. A shot in the badminton is done through the simultaneous movement towards the trajectory of the ferry with a dominant leg lunge, on the same side as the racket arm (Figures 2–6). The repeated unilateral movement puts the athlete at risk of muscle imbalances, which leads to the lateral and functional asymmetry of the body.

Theoretical framework

Definition of basic concepts

The main objective of any training process and the fundamental prerequisite to improve human skills in any form of physical activity should be the balance and synchronization of neuromuscular function.

Muscle and muscle group imbalance

The term muscle imbalance in skeletal muscles can refer to asymmetry in the following contexts:

Bilateral muscle couplesthat is, imbalance between the muscles on one side of the body compared to the corresponding muscle on the opposite side (left vs. right and vice versa)

Lateral asymmetry

• Pares of agonist muscles (synergistic)That is, an imbalance between the muscles that act from different angles to perform the same joint movement or fulfill the same function (for example, the internal and external heads of the Quadriceps Femoris muscle, which together perform an extension of the knee)

Functional asymmetry

• Couples or muscle groups antagoniststhat is, an imbalance between the muscles located on opposite sides of the same joint that are involved in the same movement, but in opposite directions (for example, the muscles of the previous versus rear thigh, which perform flexion and extension of the knee, respectively)

Functional asymmetry

• Muscle imbalances can be observed between different muscle pairs or muscle groups when describing several properties of skeletal muscles:

Figure 1 – Obtained from Dynamicmedicalfitness.com

The pairs of bilateral, agonist or antagonistic muscles in the imbalance can cause asymmetry in the execution of the technique, asynchrony in isolated or combined movements, and consequently lead to a reduced efficiency of movement or a greater risk of injuries to the locomotor system. When evaluating healthy individuals, an imbalance of less than 10% can be considered normal, between 10% and 20% possibly abnormal, and more than 20% probably abnormal. However, in individuals with an injury, damage, disease or postoperative condition, where an imbalance is expected, an asymmetry from 10% to 20% can already be considered as probable abnormal, and more than 20% as almost surely abnormal. The most commonly applied criteria of 80% to 90% capacity of the injured, deteriorated, affected or operated compared to the healthy limb is considered the minimum standard to return an individual to the sport (Baltzopoulos and Brodie, 1989; Kannus, 1994). When applying selective strengthening techniques or several recovery methods (for example, stretching, cryotherapy, physiotherapy, etc.), potential imbalances or dysfunctions can be corrected for any parameter of an individual TMG signal, either in relation to the average, minimum or absolute values ​​for a given population, or compared to another selected muscle or muscle head.

Due to the characteristics of the method itself, TMG can be used at any time during a training or competitive cycle. Without evidence and a detailed analysis of the results, it is impossible to accurately identify critical muscles and muscle groups, and thus determine an appropriate corrective training program to address the identified imbalances. The properly performed tests with the TMG system do not induce any form of fatigue that can affect maximum human performance. A large amount of practically applicable data is obtained by comparing the results of the tests with reference values ​​determined by sex, age and occupation. In other words, the higher the database (number of tests performed), the greater the quality of the individual test report.

Figure 2 – Viktor Petrović doing a net shot

Figures 3–6: Viktor Petrović in the situational game in court

Application and importance of the TMG method

Tensiomiography isolates the muscle of interest by excluding the central confusion variables that can influence the measurement. It allows the evaluation of muscle contraction through electrical stimulation alone. The level of induced contraction is relatively low (in the case of knee flexors, only about 10% of the maximum voluntary contraction). Electrical stimulation can be applied to the motor nerve or the muscle surface at the motor nerve point. In both cases, stimulation travels through nerve fiber and reaches muscle fiber. A muscle contraction can be defined as the contractile response to a single electrical impulse. The factors that affect the muscle response depending on the intensity of the electrical stimulus include: recruitment threshold of the motor unit, skin conductivity, subcutaneous fat thickness, water and temperature retention level.

Tensiomiography can provide information on muscle composition, functional muscle characteristics, local muscle fatigue, atrophy, muscle inhibition, spasticity, tone and more. For these reasons, TMG applies to the monitoring of mechanical adaptations of muscles, fatigue and damage, recovery, prevention of injury, evaluation of muscle characteristics with respect to the proportion of fibers of rapid and slow contraction or muscle stiffness, and to determine the balance (symmetry by several parameters) between the muscles and the muscle groups that can alter the movement or the sports technique in any type of activity. It is also useful for tracking the effects of rehabilitation processes. Due to all these applications, the TMG method is also used for the evaluation and/or monitoring of sports and non -athletic populations. It is based on registering different indicators of the functional capacity of muscle fiber in response to stimulation.

Through adapted software, the results of the tests can be easily applied in the training, monitoring, design and evaluation control processes, with the objective of the prevention and performance of the lesions …