Efectos inmediatos de la electroestimulación dinámica en la musculatura abdominalensayo controlado aleatorizado

Abstract

Electrotherapy is a physiotherapeutic procedure that utilizes electrical currents to elicit specific beneficial physiological effects within the body. One such effect is analgesia, which aims to induce a sense of relief in the patient. Additionally, muscle electrostimulation is employed to enhance strength, endurance, and overall muscle functionality. Muscular electrostimulation can be applied through different methods: localized, where the electrodes are placed in specific areas of the body, or global, which involves simultaneous stimulation of multiple muscle groups. These application techniques can be used individually or in conjunction with physical exercise. The simultaneous combination of physical exercise with excitomotor electrical currents referred to as dynamic electrostimulation, can yield advantageous outcomes for muscle tissue, including increased muscle mass and strength. Based on available evidence, superior results are achieved when both modalities are combined as opposed to when they are used separately. Furthermore, these combined approaches produce similar improvements to conventional training, albeit with lower training intensities required. Consequently, this method may be considered an alternative for individuals facing challenges in performing high-intensity training. The abdominal wall musculature plays a crucial role in stabilizing the pelvis and spine, making proper function essential. It includes the transverse abdominis, anterior rectus abdominis, and the greater and lesser obliques, which work synergistically to maintain the structural and functional integrity of the abdominal region. Despite their importance, there are still gaps in knowledge about their anatomy, their activation mechanisms, and precise functioning. Continued research in this field is essential to improve its understanding and the development of more effective therapeutic strategies, especially in the treatment of conditions and dysfunctions that affect abdominal stability and function. These advancements can have a significant impact on people's health and well-being. Likewise, there is little scientific literature on the immediate effects of dynamic electrostimulation, specifically on the abdominal musculature, and the possible differences between local and global applications. The objectives of this research were to determine the immediate effects of a single session of dynamic electrostimulation on the thickness of the abdominal wall musculature, as well as the distance between the rectus abdominis muscles. In addition to knowing their influence on the physiological parameters corresponding to heart rate, blood pressure (diastolic and systolic) and body temperature. Also, to know the possible differences depending on the form of application, local employing surface electrodes placed in the abdominal area or global through whole-body electrostimulation. The study sample consisted of 120 young, healthy participants aged between 18 and 35 years, randomly divided into three study groups: WB-EMS (global electrostimulation), EMS (local electrostimulation), and control. The intervention consisted of a single 20-minute session of dynamic exercises aimed at stimulating abdominal muscle contraction combined with global electrostimulation, local electrostimulation, or in the case of the control group, with the whole-body electrostimulation turned off. A symmetrical rectangular bipolar electric current was used with specific electrical parameters: 85 Hz stimulation frequency, 350 μs pulse width and 50 % duty cycle (4 s stimulation, 4 s rest). The intensity of the main part of the session ranged from “somewhat strong” to “strong”, depending on each participant's subjective perception of exertion. To evaluate the effects of the intervention, ultrasound was used using the Rehabilitative Ultrasound Imaging technique, a valid procedure to evaluate changes in the morphology and function of the muscles, measuring the thickness of the abdominal musculature and the distance between rectus muscles at rest and during muscle contraction using the extended leg raise test. In addition, physiological parameters such as heart rate, blood pressure and body temperature were recorded. No statistically significant differences were found in the variables analyzed between the study groups, except for heart rate. The EMS group showed a smaller increase in heart rate after the intervention compared to the WB-EMS and control groups. This finding suggests that muscle electrostimulation of the abdominal musculature could be of interest for clinical application in populations with cardiorespiratory disorders. However, further research is needed to investigate this topic in more depth and to find out the effects produced by the application of dynamic electrostimulation in a greater number of sessions.