Neurodynamic exercises provide no additional benefit to extension-oriented exercises in people with chronic low back-related leg pain and a directional preference: a randomized clinical trial

Key points

1. 01No between-group difference for the primary outcomes (leg pain and function) at 3 weeks
2. 02Extension exercises alone were significantly better than the combined program at 1-month follow-up for leg pain, low back pain, disability, and function (large effect sizes)
3. 03Both groups improved meaningfully within themselves, suggesting extension exercises are effective in this subgroup
4. 04The study was underpowered (statistical power ~60%) and enrolled only 31 participants, limiting confidence in findings
5. 05Neurodynamic therapy protocols vary widely across studies, and the protocol used here (active exercises only, no passive techniques) may not reflect other approaches

How it was conducted

Design

Two-arm, single-blind randomized clinical trial

Participants

31 adults aged 18-65 with chronic low back-related leg pain (at least 3 months), positive SLR test, directional preference for lumbar extension, and leg pain >3/10 on NPRS

Groups

Extension exercises (EE, n=14) vs. extension exercises plus neurodynamic exercises (EEN, n=17)

Treatment duration

7 sessions over 3 weeks (twice weekly), with home exercise program

Primary outcomes

Leg pain intensity (NPRS 0-10) and function (PSFS 0-30) at 3 weeks

Secondary outcomes

Low back pain intensity, disability (RMDQ), global perceived effect (GPE), and quality of life (SF-36) at 3 weeks and 1-month follow-up

What they found

• Leg pain at 3 weeks: EE mean change -2.5 (95% CI -3.9 to -1.0), EEN mean change -4.1 (95% CI -6.3 to -1.8); between-group difference -0.9 (95% CI -2.8 to 0.9), p=0.28, effect size d=0.42
• Function at 3 weeks: no between-group difference (difference -0.4, 95% CI -4.2 to 3.4, p=0.81, d=0.08)
• Disability at 3 weeks: significantly favored EE over EEN (between-group difference 3.6, 95% CI 1.2 to 6.0, p<0.01, d=0.83)
• Leg pain at 1-month follow-up: EE mean change -4.2, EEN mean change -2.2; between-group difference 2.5 (95% CI 0.9 to 4.2), p<0.01, d=1.00, favoring EE
• Low back pain at 1-month follow-up: between-group difference 2.3 (95% CI 0.8 to 3.8), p<0.01, d=1.11, favoring EE
• Disability at 1-month: between-group difference 5.0 (95% CI 2.0 to 8.0), p<0.01, d=1.20, favoring EE
• Function at 1-month: between-group difference -4.3 (95% CI -7.9 to -0.7), p=0.02, d=0.94, favoring EE
• Physical functioning (SF-36) at 1-month: between-group difference -22.0 (95% CI -33.7 to -10.2), p<0.01, d=1.36, favoring EE
• Bodily pain (SF-36) at 1-month: between-group difference -17.8 (95% CI -29.1 to -6.5), p<0.01, d=1.15, favoring EE
• Social functioning (SF-36) at 1-month: between-group difference -13.2 (95% CI -21.9 to -4.6), p<0.01, d=0.99, favoring EE
• GPE was not significantly different between groups at 3 weeks (p=0.12, d=0.53) or 1-month follow-up (p=0.07, d=0.59)
• Retention was 100% (EE) and 94% (EEN) at 3 weeks; 71% (EE) and 76% (EEN) at 1-month follow-up

Limitations

• Small sample size (n=31, achieved ~60% statistical power) instead of the planned 68 participants, substantially reducing confidence in the findings
• No validated neuropathic pain instrument (e.g., LANSS or painDETECT) was used to confirm the presence of neuropathic mechanisms in participants
• High attrition at 1-month follow-up (29% EE, 24% EEN) may bias follow-up comparisons despite intention-to-treat analysis
• Results may not generalize beyond patients with a clear directional preference for extension, limiting applicability to the broader LBLP population

Why it matters

For patients

If you have chronic leg pain from your back and respond to backward-bending exercises, adding nerve-gliding exercises to your program is unlikely to give extra benefit and may actually slow recovery at one month.

For clinicians

For patients with chronic low back-related leg pain and a directional preference for extension, extension-oriented exercises alone appear sufficient and adding neurodynamic exercises confers no short-term benefit and may be inferior at follow-up, though the underpowered sample warrants caution.

For readers

This small RCT challenges the rationale of combining neurodynamic and extension exercises, but the low sample size and specific patient subgroup mean that larger trials are needed before firm conclusions can be drawn.