Isolated Lumbar Extension Resistance Exercise in Limited Range of Motion for Patients with Lumbar Radiculopathy and Disk Herniation—Clinical Outcome and Influencing Factors

(1) Background: Reconditioning of the paraspinal lumbar extensor muscles by isolated lumbar extension resistance exercises (ILEX) has shown good clinical results for patients with chronic unspecific low back pain. However, the clinical value and safety for patients with specific spine pathologies is unclear. In this study, clinical outcome and influencing factors were retrospectively analyzed for patients with lumbar disk herniation (LDH) and radiculopathy. (2) Methods: 189 consecutive patients (123 men and 66 women; mean age, 36 years) with clinically diagnosed LDH and relative indications for surgery started a 9-week rehabilitation program (2x/week) including ILEX in limited range of motion (ROM) adjusted to patients’ symptoms. Patients diagnosed with advanced levels of spine degeneration were excluded. Pain/radiculopathy (PR), influence on mental health (IOMH), satisfaction rates were measured via Numeric Rating Scales (NRS, 0–10), and overall clinical outcome was stated in % (100% = full recovery). Isometric extension strength was tested before and after the program. (3) Results: 168 patients (88.9%) completed the program. For 162 out of 168 patients (96.4%) there was a significant reduction of clinical symptoms, whereas 6 patients reported no changes in symptoms. Scores (mean) for symptom intensity decreased from 4.2 (±1.5) to 1.9 (±1.5) (p < 0.001), the impact on mental health decreased from 5.9 (±2.3) to 2.4 (±2.0) (p < 0.001). There was a (weak) correlation between lower scores for PR and IOMH before the study and better clinical outcomes; PR also weakly correlated with satisfaction. Other factors such as age, strength increase, level/location and number of LDH did not have a significant impact on the clinical results. (4) Conclusion: The results indicate that ILEX in limited ROM can be an effective treatment for the majority of patients with LDH. For patients with high pain levels, the results are less consistent, and surgery may be considered.