Valoración funcional de la fuerza muscular de cadera mediante dinamometría electromecánica y su relación con rendimiento deportivo y riesgo de lesión en futbolistas

Abstract

Muscular strength is the most important fitness component of any training and rehabilitation program. It has been shown that having optimal levels of muscle strength improves key aspects of athletic performance such as acceleration, deceleration, linear velocity, jumping and changes of direction, and on the contrary, having strength deficits or muscle imbalances not only diminish these aspects of performance, but also cause injury, mainly to the structures of the lower extremity. In this sense, the hip joint is considered the structure that initiates the lower extremity, allowing movements in three planes (sagittal, frontal, and transverse) and playing an important role of stability during each sporting gesture. For this reason, it is necessary to objectively know the levels of hip muscle strength, and for this purpose isokinetic dynamometers are the gold standard for the evaluation of muscle strength, in turn, are also considered an effective means to rehabilitate and condition muscle function. However, the isokinetic measurement process must be valid and reliable to be meaningful and interpretable; the more reliable the measurement, the greater the likelihood of adequate sensitivity to track clinically important changes. Isokinetic measurements are known to be reproducible for the shoulder, knee, and spine joints, however, there is a lack of clarity in hip studies, mainly due to methodological fragility of the investigations, which is a consequence of studies with small numbers of participants, and differences in the type of population. Due to the above, the first topic of the Doctoral Thesis was "Determining the reliability of hip isokinetic measurements in healthy subjects and athletes", which, for its better interpretation was divided into two studies (i) reliability of isokinetic measurements of hip flexors and extensors in healthy subjects and athletes", (ii) reliability of isokinetic measurements of hip abduction and adduction in healthy subjects and athletes". Soccer is the most practiced sport worldwide, and its performance is determined by technical, tactical, physiological, biomechanical, and psychological factors. During ninety minutes the soccer player must perform activities at high speed, and for this, it is necessary to have high levels of muscular strength. Therefore, it is important to know these values, since they will allow us to establish reference parameters per player and per position, which are important to generate prevention, rehabilitation, and specific sports training guidelines for each athlete. Existing studies on muscle strength parameters and profiles have been developed at the knee level, evaluating concentric and eccentric action of quadriceps and hamstrings, however, it is also necessary to know these values at the hip level, due to the great influence they have on sports performance and lower extremity injuries. Although it is true that isokinetic dynamometry is the gold standard for muscle assessment, it is not free from questioning, since its lack of functionality is criticized, at the same time, there are valid dynamometers that allow a reliable isokinetic assessment, respecting the functional and natural movement of the athlete. In this context, the second topic of the Doctoral Thesis was "Determining the hip dynamometric profile in soccer players". On the other hand, knowing the values of hip strength, we will be able to relate them to aspects of sports performance, due to this, the third topic of the Doctoral Thesis was "To determine the influence of hip muscle strength with aspects of sports performance in young soccer players". Based on the above, the main objective of the Doctoral Thesis was "To determine the levels of hip muscle strength and its relationship with sports performance and lower extremity injuries in soccer players through a functional electromechanical dynamometer", and for this, we have the publication of three scientific articles that allow us to give part of the answer to this objective; (I) reliability of isokinetic measurements of hip flexors and extensors in healthy subjects and athletes: A systematic review and meta-analysis", (II) reliability of isokinetic measurements of hip abduction and adduction in healthy subjects and athletes: A systematic review and meta-analysis", (III) dynamometric profile of hip muscle strength in young soccer players. The correlation of hip muscle strength with aspects of sports performance are presented in the fourth study of the Doctoral Thesis, whose data have not yet been published. The correlation of hip muscle strength and lower extremity injuries will be performed through the research project "Validity and Reliability of the Hip Muscle Strength Ratio: A Proposal for Health and Performance of the Lower Extremity (S10/20)" awarded and funded by the Universidad de los Lagos, Puerto Montt, Chile which is currently under development.