Isolated lumbar extension exercise alone or in a multimodal program for low back pain and radiculopathy: a non-randomized controlled trial

Isolated lumbar extension resistance exercise (ILEX) has been shown to effectively address chronic low back pain (LBP) and paraspinal deconditioning. However, its role within the widely recommended multimodal management approaches remains unclear. This study aimed to: (1) closely monitor the effects of ILEX throughout the course of a 16-weeks intervention, applied as a stand-alone approach in patients with nociceptive and/or neuropathic pain and (2) to compare this intervention with a multimodal treatment program including general exercise (GE) and manual therapy (MT). Fifty-eight LBP patients were enrolled in this single-center (Wuerzburg, Germany), prospective, non-randomized controlled trial. The ILEX-only group (Powerspine Back [PSB]: n = 29) completed 25 sessions of ILEX, whereas the integrative group (PSB+ : n = 29) also received GE (added to each session) and MT (5 to 7 sessions). Outcome measures were assessed at baseline, 3, 6, 9 and 16 weeks including lumbar multifidus cross-sectional area (CSA), muscle thickness (MT), echointensity (EI) (ultrasound-derived), isometric lumbar strength (isokinetic device) and validated questionnaires (Visual Analog Scale [VAS]; Oswestry Disability Index [ODI]; Short-Form 36). Between-subjects repeated measures ANOVA and correlation analyses were performed. Both groups (PSB: m = 16, f = 15, Ø40.26 (± 13.71) years, BMI 25.16 (± 4.07) kg/m²; PSB+ : m = 16, f = 13, Ø42.00 (± 12.69) years, BMI 25.20 (± 3.29) kg/m²) demonstrated comparable linear improvements in multifidus CSA (PSB: Δ0.59 [95% CI 0.36-0.82] cm²; PSB+ : Δ0.72 [95% CI 0.49-0.96] cm², both p < 0.001; main effect (group): p = 0.52) along with similar strength gains (PSB: Δ96.79 [95% CI 57.64-135.93] Nm; PSB+ : Δ86.88 [95% CI 48.70-125.06] Nm; both p < 0.001; main effect (group): p = 0.91) over time. EI remained unchanged in both groups. No-between group differences were observed for self-reported measures, while all outcomes significantly improved (ODI: PSB: - 15.0 [95% CI - 19.3 to - 10.8], PSB+ : - 11.7 [95% CI - 16.0 to - 7.4]; VAS: PSB: - 29.30 [95% CI - 37.73 to - 20.86], PSB+ : - 29.34 [95% CI - 37.78 to - 20.91], both p < 0.001). Only PSB+ showed correlations between multifidus changes and clinical outcomes. Stand-alone and combined isolated lumbar extension resistance exercise interventions are effective in reversing muscle deconditioning and produce comparable clinical outcomes. The results inform clinical decision-making and support the development of targeted, resource-efficient rehabilitation strategies.ClinicalTrials.gov Identifier NCT06890052 (20/03/2025) ( https://clinicaltrials.gov/study/NCT06890052?cond=NCT06890052%20&rank=1 ).