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Document Type

Abstract

Publication Date

1-14-2026

Abstract

This study examined the immediate effects of modulated medium-frequency electrical stimulation (MMFES) combined with motor control exercise (MCE) on lumbar multifidus (LM) activation, motor control, and pain alleviation in patients with recurrent low back pain (rLBP). This randomized controlled trial (RCT) enrolled 42 participants with rLBP, who were randomly allocated into three intervention groups: the MMFES group (15-minute MMFES), the MCE group (15-minute sham MMFES + 30-minute MCE), and the combined (COMB) group (15-minute MMFES + 30-minute MCE). Electrodes were placed bilaterally 3 cm lateral to L3/L5 spinous processes. The MCE protocol involved quadruped rocking backward exercises performed in sets of 15 repetitions, with 8–12 sets per session and 1-minute rest intervals between sets. Outcome measures, including LM activation, motor performance, and numerical pain rating scale (NPRS), were assessed at baseline and immediately post-intervention. LM activation was quantified via musculoskeletal ultrasound imaging by measuring muscle thickness at rest and during maximal voluntary isometric contraction (MVIC). These measurements were used to calculate the LM activation ratio using the formula： LMACT Rate（%）=(LMMVICLMREST)/ LMREST×100%. Motor performance was operationalized as knee flexion angle during the quadruped rocking backward, with larger angles indicating superior motor control. Intergroup comparisons were analyzed using independent samples t-tests or Kruskal-Wallis tests, while intragroup differences were evaluated via paired samples t-tests or Wilcoxon signed-rank tests. The COMB group exhibited superior outcomes versus the other groups in all measures (P < 0.05), including higher LM activation ratios (vs. MMFES: d = 0.32; vs. MCE: d = 0.79). Post-intervention, the COMB group demonstrated a 61% increase in LM activation (from 13.87% to 22.25%, P < 0.001), 8.5° improvement in motor performance (from 30.9°±3.1° to 39.4°±2.7°, P < 0.01), and 3.2-point NPRS reduction (from 4.5±1.2 to 1.3±0.9, P < 0.001). The MMFES group showed moderate LM activation gains (P < 0.05) with pain relief and unchanged motor, while the MCE group improved motor performance with unchanged LM activation (P > 0.05) and limited pain relief. The integration of MMFES with MCE demonstrated significant improvements in LM activation, motor performance, and pain symptoms in patients with rLBP. These findings support the application of MMFES as an adjunctive neuromodulatory intervention to address LM activation deficits in rLBP, potentially improving lumbar spine stability and reducing recurrence risk. Further research is warranted to validate the long-term therapeutic efficacy and elucidate the mechanistic basis of MMFES-induced neuromuscular adaptations.

DOI

https://doi.org/10.18122/ijpah.5.1.205.boisestate

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