Muscle Function Obtained with Motion Mode Ultrasound and Surface Electromyography during Core Endurance Exercise

This protocol uses motion mode ultrasound and surface electromyography simultaneously to measure muscle function of the core. Muscle thickness and activation of the local stabilizers (e.g., transverse abdominis, internal oblique) and global movers (e.g., external oblique) is achievable during specific time points of the side plank and dead bug exercises.

This protocol provides insight into how dynamic ultrasound can be implemented in a clinical setting to assess musculature during core exercise. The main advantage of this technique is that both instruments can be used simultaneously during core exercise. To begin, turn on the ultrasound machine, press Patient, and add a new patient.

Click New Patient and enter the patient identification number. Select MSK exam type then click abdominal preset and press Register. Press Exit.

Turn on the tablet and click the EMG recording application. Click the menu button in the top left screen and scan for sensors. Take the sensor out of the base and hover over the activation button.

Once the sensor is connected with the application, create a new folder with the participant's identification number. Determine the external oblique sensor location by palpating the right iliac crest and right inferior rib while the participant is supine hook lying. Shave, clean, and debris the area of the skin where the sensor will be placed.

Add adhesive to the sensor and secure onto skin. Place the sensor three centimeters anterior from the midway point between the lower rib and the iliac crest parallel to the muscle fibers. In a standing position, place the transducer through the elastic belt and foam block.

Add gel to the transducer and place the transducer 10 centimeters lateral to the umbilicus. Adjust until the lateral abdominal wall is visible on the screen. Ensure that the transducer is tightly secured to the lateral abdominal wall.

Secure the belt with the Velcro straps. Adjust the depth to obtain optimal image quality in B mode. On a yoga mat, instruct the participant to lay on their right side with their elbow in 90 degrees of flexion so their trunk and upper extremity is raised off the ground.

The participant's feet should be stacked on each other with the knees fully extended. The legs should be parallel, touching the yoga mat. Press Freeze then Store for each image to capture three static ultrasound images of the lateral abdominal wall.

In the SEMG menu in the top left screen of the EMG recording application, select Settings and select the bicep icon. Press Click Play to begin. There will be a five second countdown.

During this period, instruct the patient to assume the testing position. Record the maximum voluntary contraction, as this will be used for normalization calculation. Next, instruct the participant to complete the side plank for 60 seconds, maintaining the correct form.

Press the M on the ultrasound machine to turn on M mode. Press the Play button on the EMG application. Once the five second countdown commences, press Store on the ultrasound to begin the ultrasound recording.

To save the recorded M mode video, press Store once the exercise has stopped and the Stop button on the SEMG application. Click Save File As and type in a file name to save the output which will appear on the screen when the recording is stopped. On the yoga mat, instruct the participant to lay supine with their legs in a hook lying position.

Press Freeze and then Store for each image to capture three static images of the lateral abdominal wall via ultrasound. Saved images will be located below the active image screen. Next, instruct the participant to complete the dead bug for 60 seconds, maintaining the correct form.

Press the M on the ultrasound machine to turn on M mode. Instruct the participant to maximally extend their right shoulder while maximally extending their left hip and knee while also maintaining the starting position of the contralateral extremities. Instruct the participant to then flex their shoulder, hip, and knee to return to the starting position.

The contralateral extremities will then perform the same motion. Ask the participant to perform the exercise to a metronome set to 45 beats per minute. This results in 22 repetitions of the dead bug in 60 seconds.

Press the Play button on the EMG application. Once the five second countdown commences, press Store on the ultrasound to begin the ultrasound recording. Click enter when the first static image you want to measure is selected.

Press Measure to open the measurement tool. Measure the maximal muscle thickness during the static positions in centimeters from the superior inferior facial border to the inferior superior facial border. Click Enter at the superior inferior border and Enter again at the inferior superior border.

Repeat the ultrasound static measurement procedure for side plank and dead bug static measurements. Average the measurements of the three static images. Measure the maximal thickness of the external oblique, internal oblique, and transverse abdominal thickness during the first five seconds and the last five seconds of the exercise.

Additionally, record the maximal thickness over the entire 60 seconds. Press Measure to open the measurement tool. Measure the maximal muscle thickness during the static positions in centimeters from the superior interior facial border to the inferior superior facial border.

Divide each of the three thickness measurements obtained during the exercises by the averaged static position to obtain an activation ratio. Press the home icon on the EMG data recording page. Select the folder icon in the top right corner of the screen.

The saved output from the static and exercise trials will be saved here. Convert each file to a XLSX file. Export the XLSX file.

In a spreadsheet, obtain the maximum values during the first and last five seconds and the overall maximum value. Divide the static SEMG output obtained from static side plank SEMG and dead bug SEMG by the output during the exercises respectively. The table here represents measurements of both ultrasound and SEMG during the static exercise starting position.

These numbers are used as the denominator when calculating the activation ratio. The thickness values of the external oblique, internal oblique, and transverse abdominous during the first five seconds, last five seconds, and total duration of 60 seconds show higher values of dead bug. The SEMG values normalized to static exercise starting position during the first five seconds, last five seconds, and peak activity show lower values of dead bug.

The activation ratios for the external oblique, internal oblique, and transverse abdominous also show lower dead bug values. Make sure the location of the transducer is accurate with the muscles visible on the screen with and without the securing belt and foam. Additional methods include obtaining the onset of muscle activation visually through ultrasound and electrically through surface electromyography.

Researchers can use both instruments and healthy and pathological individuals to observe muscle function of the core. Additionally, these instruments can be used with other muscles within the body.