Lower back pain is very common leading to serious effects on individuals worldwide. It is often attributed to uncontrolled movement of the lumbopelvic region which causes strain on the surrounding muscles. From past study, it has been shown that lower back pain can be ameliorated through specific exercises with feedback and instruction. There are multiple types of feedback which have demonstrated effectiveness, but it is still not clear which type of feedback is best during movement of limbs.
One type of exercise for lower back pain is the clam shell exercise which targets the activation of the gluteus maximus, hip abductors and external rotators. Physical therapists from South Korea set out to test two different types of feedback: pressure biofeedback through unit on the outcome of pelvis rotation and gluteus maximus muscle activity, as well as palpation and visual feedback.
The study consisted of young adults suffering from chronic non-specific lower back pain and a group of healthy non-symptomatic individuals. Participants were asked to perform the clam shell movement in which subjects laid on their side with their knees bent and hips in flexion. To complete the movement, each subject was instructed to rotate the top leg, lifting the knee, then returning the leg to so that the knees were touching once again. The participants completed this exercise without feedback, with visual and palpation feedback, and with a pressure biofeedback system in which patients were asked to maintain a certain pressure against an airbag. The visual and palpation feedback method included the patient using tactile feedback by palpating the ASIS and visually monitoring the movement of the pelvis on the horizontal plane for controlled motions.
For the evaluation and comparison between the feedback methods, surface EMG signals were recorded from the key muscles involved in the exercise. Additionally, kinematic data was acquired using a BTS Bioengineering SMART-DX system in which reflective markers were placed on physiological landmarks to facilitate the calculation of pelvic rotation wirelessly and without interfering with the free movement of the participant.
It was found that when the participants experienced the visual and palpation feedback, there was significantly less pelvic rotation demonstrated than the other feedback and control methods. Results also showed significantly more EMG activity of the gluteus maximus and ipsilateral external oblique muscles during the visual and palpation feedback compared to the trials completed without feedback. Less rotation of the pelvis and higher activation of key muscles indicated more control of pelvic movement.
The researchers from the study concluded that from the results, completing the clam shell exercise with visual and tactile feedback was more effective in controlling the movement of the pelvis. While the researchers of the study stated that more studies are needed to confirm the comparison of methods, they recommended the use of visual and tactile feedback during the clam shell exercise to increase control of pelvic movement and thusly decrease the instance of back pain in the lumbosacral region. In this study, the use of non-invasive and advanced devices allowed for quantifiable results to compare methods of exercise. This method can be applied to other exercises and rehabilitation movements to help those suffering from pain and dysfunction.
BTS Bioengineering offers a surface EMG system similar to the device used in this study, the FREEEMG 1000.
This post was based on the following article, referenced:
Koh, E., Park, K., & Jung, D. (2016). Effect of feedback techniques for lower back pain on gluteus maximus and oblique abdominal muscle activity and angle of pelvic rotation during the clam exercise. Physical Therapy in Sport
Image reference: Image created by Freepik (designed by Jcomp)