Immediate Effects of Whole-Body versus Local Dynamic Electrostimulation of the Abdominal Muscles in Healthy People Assessed by Ultrasound: A Randomized Controlled Trial

SIMPLE SUMMARY: The muscles of the abdominal wall play a fundamental role in the stabilization of the pelvis and the spinal column, and they must function properly. The simultaneous combination of physical exercise with electrical currents, called dynamic electrostimulation, can have beneficial effects on this musculature in terms of gaining muscle mass and strength. Our research aimed to determine the immediate effects of a single session of dynamic electrostimulation on the thickness of the abdominal musculature and the inter-rectus distance evaluated by ultrasound, as well as on the physiological parameters of heart rate, blood pressure, and body temperature. In addition to the possible differences according to the way of application—local with electrodes placed in the abdominal area or global with whole-body electrostimulation—a total of 120 healthy participants were randomly divided into three groups: WB-EMS, EMS, and control groups. No differences were found in the results of the variables analyzed between the groups, except for heart rate. The EMS group showed a smaller increase in post-intervention heart rate compared to the WB-EMS and control groups. The use of localized dynamic EMS on the abdominal musculature in populations with cardiorespiratory disorders could be of interest, and more research is needed. ABSTRACT: Dynamic electrostimulation consists of the application of local or global electrostimulation together with physical exercise. This study aimed to investigate the immediate effects of a dynamic electrostimulation session on the thickness of the abdominal musculature, inter-rectus distance, heart rate, blood pressure, and body temperature, and to identify possible differences in its form of application. A total of 120 healthy participants were divided into three groups: the whole-body electrostimulation group, the local electrostimulation group, and the control group without electrical stimulation. All groups performed a single session with the same dynamic exercise protocol. Muscle thickness and inter-rectus distance were evaluated ultrasonographically using the Rehabilitative Ultrasound Imaging technique both at rest and in muscle contraction (the active straight leg raise test) to find the post-intervention differences. The results showed significant differences in immediate post-intervention heart rate, with a smaller increase in the local electrostimulation group compared to the control and whole-body electrostimulation groups. No significant differences were identified between the groups after the interventions in the rest of the variables analyzed. Therefore, a local application, with the same effects as a global application on the abdominal musculature, has fewer contraindications, which makes its use more advisable, especially in populations with cardiorespiratory disorders, for which more research is needed.