Effect of core stability exercises and Russian electrical stimulation on nonspecific low back pain: a single-blinded randomized controlled trial

Abstract Nonspecific low back pain (NSLBP) is a predominant contributor to disability worldwide. Core stability exercises (CSEs) serve as a common intervention; however, their therapeutic effects may be augmented through the incorporation of adjunct modalities such as neuromuscular electrical stimulation. This randomized controlled trial aimed to evaluate whether the addition of Russian current (RC) stimulation to a CSE regimen enhances improvements in pain, functional capacity, muscle thickness, and spinal stability among patients diagnosed with NSLBP compared with a regimen comprising CSE alone. This single-blinded, randomized controlled trial was conducted at the outpatient clinic of Deraya University over a six-week intervention period. A total of fifty patients aged between 20 and 25 years with chronic NSLBP were recruited. The participants were randomly allocated into two groups via a closed-envelope. Group 1 (the study group, n = 25) received CSE and RC three times a week for six weeks, whereas Group 2 (the control group, n = 25) received CSE only. The primary outcomes assessed included pain intensity, measured via the visual analog scale (VAS), and functional disability, evaluated via the Oswestry Disability Index (ODI). The secondary outcomes included the muscle thicknesses of the transversus abdominis (TrA) and lumbar multifidus (LM), which were measured via ultrasonography, and lumbar spine stability, which was assessed via a Spinal Mouse device. The data were analyzed via mixed-model MANOVA for group and time effects, accompanied by post hoc Bonferroni correction. Between-group comparisons were performed via independent t tests, whereas within-group analyses were performed via paired t tests. There was a significant decrease in the VAS score and ODI and a significant increase in the stability score, TrA, and LM thickness, especially in group 1. The demographic characteristics of the groups were comparable at baseline (p > 0.05). Compared with Group 2 (CSE alone), Group 1 (CSE + RC) exhibited significantly greater improvements in the VAS score (MD: -1.04, 95% CI: -1.79–0.29, p = 0.008), ODI (MD: -9.76%, 95% CI: -12.13–7.39, p < 0.001), stability score (MD: 7.53%, 95% CI: 0.95–14.12, p = 0.02), and muscle thickness (e.g., right TrA: MD: 0.08 cm, 95% CI: 0.02–0.12, p = 0.004). There was a significant decrease in the VAS score and ODI and an increase in the stability score, TrA, and LM thickness, especially in group 1. Compared with core stability exercises alone, the Russian current accompanied by core stability exercises results in greater decreases in pain and disability and greater increases in functional ability, TrA and LM thickness, and lumbar spine stability. Trial registration: The study was registered on clinicaltrials.gov (NCT06495099) on 02/07/2024.