Ultrasound biofeedback can help increase activation and timing of the core muscles, which is important both for sport performance and for reducing risk of injuries like low back pain. A main advantage of using ultrasound for biofeedback is that it provides a real-time image. This image, along with verbal cues, can help patients use their muscles properly.
This method can also be applied directly to other rotational movements, like a baseball or softball swing, or a tennis forehand. To begin, open and turn on the ultrasound device using the on/off button. Then press the patient button on the keyboard to add a new patient, and select New Patient on the left side of the screen.
Enter the desired patient ID number, ensure MSK is selected as the exam type, and click on Register. Exit to begin the exam, and enter B-mode. Position the linear array transducer in the elastic belt by placing the head of the linear transducer through a horizontal slit in the middle of the belt.
Next, apply one to two foam blocks to secure the transducer in its place. Apply ultrasound gel to the linear transducer. Position the transducer on the lateral abdominal wall, approximately 10 centimeters lateral to the umbilicus.
Secure the belt to the participant using the hook and loop fasteners, ensuring that the belt is tight enough so that the transducer is secured perpendicular to the lateral abdominal wall. Adjust the depth and gain of the ultrasound if necessary to obtain a clear image of the fascia borders and muscle thickness of the external oblique, internal oblique, and transverse abdominis, ensuring that the fascia border of the transverse abdominis is visible on the edge of the screen in this longitudinal view. Once the image is clear, position the patient in a manner that mirrors the task they will complete, such as make them stand in their set-up position if they perform a golf swing.
Then press Freeze, then Store to capture a static image. Save it to the patient's exam and measure in real-time or access it later to measure the resting muscle thickness. Select Freeze again to return to live imaging.
Press Store to begin recording in B-mode video. Provide the verbal cuing or instruction following each attempt, while adjusting the cuing as needed. On the bottom right corner of the screen, check that a timer begins and is highlighted in bright green, indicating that a video is being captured.
Press Store again to end the video and save it to their exam. If the image becomes blurry, adjust the positioning of the ultrasound probe within the foam block as needed. After each trial, review the video for image clarity and if the image becomes anechoic at any point, it indicates that the ultrasound probe moved during the swing.
Exclude the trial and re-measure. Following each swing have the patient positioned where they can view the ultrasound screen. Open the first resting image to measure.
Using the cursor, hover over the desired image from the library below the active image and click on Enter. Click on Measure once to open the measurement tool and then click on Enter when the cursor is over the superior fascia border of the muscle of interest. Click on Enter again once the cursor is over the inferior fascia border.
Once the desired number of videos have been captured, open the first video to be processed. Using the cursor, hover over the desired image from the library below the active image and click on the Enter button. Adjust the viewing frame within the B-mode video until the first frame is reached and determine the desired sampling rate.
Once there is the desired frame open, use the Measure tool by clicking the button once to open the tool. Place the cursor on the superior fascia border of the muscle of interest and click on Enter to place the first end of the measurement. Drag the measurement line to the inferior fascia border of the muscle of interest and click on Enter again to complete the measurement.
Then press Store to save the measured image. Record the measurement in a spreadsheet organized to include participant or patient name/number, frame number, and thickness measurements. Return to the original B-mode video frame and scroll to the next frame to be analyzed.
Repeat the measurement steps until all the desired frames are measured. To determine the activation ratio at a specific time point, measure the thickness as demonstrated previously and divide this value by the resting image thickness. To determine whether the combined oblique thickness increased at the 50%time point when biofeedback was provided, activation ratios were calculated.
The non-bio feedback trial shows a thickness of 1.685, while biofeedback has a value of 1.739. Thus it can be inferred that the biofeedback led to a small increase in oblique muscle activation at the 50%duration of the golf swing. With ultrasound biofeedback, it's important to be able to use lay terms to help the patient understand the image.
Explain that the goal is to rotate through their core to produce power. Following this procedure, we can also look at muscle thickness of the transverse abdominis. This can show us a patient's deep core muscle activity and spinal stability during dynamic movements.
