Transversus Abdominis Thickness at Rest and Exercise in Individuals with Poststroke Hemiparesis

The investigation of ultrasound to assess lateral abdominal wall activation with different types of core exercises

BACKGROUND

Core training is the foundation of physical exercise. The activation of the lateral abdominal wall (LAW) muscles in the core muscles, particularly the transversus abdominal (TrA) muscles, has a stabilizing effect on the chest and abdomen. Therefore, we need to focus on the training effect of the TrA. There are many ways to measure the LAW. Ultrasound can assess the effect of training in real time and intuitively. Therefore, we intend to evaluate the activation of the LAW in different types of core training using ultrasound, to determine the best movements that can activate the TrA and train the core muscles.

METHODS

22 healthy subjects (male 10, female 12, age 22.82 ± 0.98, BMI 20.78 ± 2.27) were included. The subjects were given the following instructions to perform breathing exercises at different positions: calm breathing and deep breathing at 0° hip flexion and 0° knee flexion; calm breathing, deep breathing, abdominal crunches and ball crunches at 45° hip flexion and 90° knee flexion; and calm breathing, deep breathing, abdominal crunches and ball crunches at 90° hip flexion and 90° knee flexion. The muscle thicknesses of the bilateral transversus abdominis (TrA), internal oblique (IO), external oblique (EO), and LAW muscles were measured using ultrasonography at the end of expiration during the above movements.

RESULTS

(1) The action with the greatest contraction ratio of the TrA was deep exhalation, which was significantly greater than crunch and ball crunch; (2) During deep exhalation, the TrA had the greatest contraction ratio, significantly greater than the IO and EO. (3) The TrA was thinnest during deep exhalation at 90°, followed by 45° and 0°.

CONCLUSION

In healthy young people, deep expiration with 90° hip flexion and 90° knee flexion was the optimal action for activating the LAW, especially the TrA.

Comparison of Muscle Activity and Muscle Thickness According to Knee Flexion Angle during Supine Bridge Exercises using the Abdominal Drawing-in Maneuver on an Unstable Surface

This study evaluated changes in deep trunk muscle thickness and lower extremity muscle activities during bridge exercises with the abdominal drawing-in maneuver. Bridge exercises were conducted on an unstable surface at different knee flexion angles (60º, 90º and 120º), with the aim of identifying more effective angles for bridge exercises. This study included 21 healthy adults, aged 20-27 years. Biceps femoris (BF), rectus abdominis, and rectus femoris activity was measured using surface electromyography. The thicknesses of the transverse abdominis (TrA), external oblique (EO) and internal oblique (IO) muscles were measured. BF (p = 0.000, partial η2 = 0.670) activity increased considerably as the knee flexion angle decreased. TrA (p = 0.000, partial η2 = 0.883) and IO (p = 0.000, partial η2 = 0.892) thickness significantly increased, while EO (p = 0.000, partial η2 = 0.893) thickness decreased as the knee flexion angle decreased. When performing bridge exercises using the abdominal drawing-in maneuver on an unstable surface, the knee flexion angles should be at 120º and 60º to increase trunk stability and lower extremity muscle activity, respectively.

Respiratory muscle ultrasonography evaluation and its clinical application in stroke patients: A review

Background

Respiratory muscle ultrasound is a widely available, highly feasible technique that can be used to study the contribution of the individual respiratory muscles related to respiratory dysfunction. Stroke disrupts multiple functions, and the respiratory function is often significantly decreased in stroke patients.

Method

A search of the MEDLINE, Web of Science, and PubMed databases was conducted. We identified studies measuring respiratory muscles in healthy and patients by ultrasonography. Two reviewers independently extracted and documented data regarding to the criteria. Data were extracted including participant demographics, ultrasonography evaluation protocol, subject population, reference values, etc.

Result

A total of 1954 participants from 39 studies were included. Among them, there were 1,135 participants from 19 studies on diaphragm, 259 participants from 6 studies on extra-diaphragmatic inspiratory muscles, and 560 participants from 14 studies on abdominal expiratory muscles. The ultrasonic evaluation of diaphragm and abdominal expiratory muscle thickness had a relatively typically approach, while, extra-diaphragmatic inspiratory muscles were mainly used in ICU that lack of a consistent paradigm.

Conclusion

Diaphragm and expiratory muscle ultrasound has been widely used in the assessment of respiratory muscle function. On the contrary, there is not enough evidence to assess extra-diaphragmatic inspiratory muscles by ultrasound. In addition, the thickness of the diaphragm on the hemiplegic side was lower than that on the non-hemiplegic side in stroke patients. For internal oblique muscle (IO), rectus abdominis muscle (RA), transversus abdominis muscle (TrA), and external oblique muscle (EO), most studies showed that the thickness on the hemiplegic side was lower than that on the non-hemiplegic side.Clinical Trial Registration: The protocol of this review was registered in the PROSPERO database (CRD42022352901).