Effect of real-time ultrasound imaging for biofeedback on trunk muscle contraction in healthy subjects: a preliminary study

Shanshan Lin,Guozhi Huang,Qing Zeng,Yiyi Zheng,Bo Zhu,Chuhuai Wang

doi:10.1186/s12891-021-04006-0

Abstract

BackgroundReal-time ultrasound imaging (RUSI) has been increasingly used as a form of biofeedback when instructing and re-training muscle contraction. However, the effectiveness of the RUSI on a single sustained contraction of the lumbar multifidus (LM) and transversus abdominis (TrA) has rarely been reported. This preliminary study aimed to determine if the use of RUSI, as visual biofeedback, could enhance the ability of activation and continuous contraction of the trunk muscles including LM and TrA.MethodsForty healthy individuals were included and randomly assigned into the experimental group and control group. All subjects performed a preferential activation of the LM and/or TrA (maintained the constraction of LM and/or TrA for 30 s and then relaxed for 2 min), while those in the experimental group also received visual feedback provided by RUSI. The thickness of LM and/or TrA at rest and during contraction (Tc-max, T15s, and T30s) were extracted and recorded. The experiment was repeated three times.ResultsNo significant differences were found in the thickness of LM at rest (P > 0.999), Tc-max (P > 0.999), and T15s (P = 0.414) between the two groups. However, the ability to recruit LM muscle contraction differed between groups at T30s (P = 0.006), with subjects in the experimental group that received visual ultrasound biofeedback maintaining a relative maximum contraction. Besides, no significant differences were found in the TrA muscle thickness at rest (P > 0.999) and Tc-max (P > 0.999) between the two groups. However, significant differences of contraction thickness were found at T15s (P = 0.031) and T30s (P = 0.010) between the two groups during the Abdominal Drawing-in Maneuver (ADIM), with greater TrA muscle contraction thickness in the experimental group.ConclusionsRUSI can be used to provide visual biofeedback, which can promote continuous contraction, and improve the ability to activate the LM and TrA muscles in healthy subjects.

Highlights

Real-time ultrasound imaging (RUSI) has been increasingly used as a form of biofeedback when instructing and re-training muscle contraction
Posthoc analysis showed that there were no significant differences in transversus abdominis (TrA) thickness between the two groups at Trest and The time point of maximum isometric contraction (Tc-max) (P > 0.999 and P > 0.999, respectively)
The results of the present study indicated that real-time ultrasound imaging did not affect the maximum muscle contraction thickness of the TrA or lumbar multifidus (LM) at the beginning

Summary

Introduction

Real-time ultrasound imaging (RUSI) has been increasingly used as a form of biofeedback when instructing and re-training muscle contraction. LM and TrA, which were core stabilizing muscles and acted like a corset of the trunk maintaining the spinal segment’s neutral zone, were helpful to relieve low back pain (LBP) and prevent its recurrence by maintaining segmental stabilization and stiffness once spinal stability was threatened [5,6,7,8] The rehabilitative strategies, such as core stabilizing exercise and sling exercise training, strengthened local muscles around the low back, and were effective in reducing low back pain and alleviating dysfunction caused by lumbopelvic instability [9,10,11]. It appeared to be hard to measure the function of TrA and LM muscles, whose preferentially activation is difficult, causing the dilemma in curing LBP [3]

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Results

Discussion

Conclusion