In this cross-over study 25 patients with chronic low back pain (CLBP) were tested for pain relief in 2 conditions: while using the Transcutaneous Electrical Nerve Stimulation (TENS) application and without using it. Primary outcome: Movement-Evoked Pain (MEP). This was measured using the Back Performance Scale (BPS) and a 5-minute walk test (5MWT). Participants performed 5 functional tasks and were asked to rate their pain before, during, and after each movement on a numeric rating score scale. The same principle will be used for the 5MWT: for each walking-minute, 3 pain measurements will be assessed.

Inclusion Criteria:

• chronic nonspecific LBP for at least 3 months' duration: non-specific LBP implies that patients are not allowed to have any evidence of specific spinal pathology (e.g., hernia, spinal stenosis, spondylolisthesis, infection, spinal fracture or malignancy).

Exclusion Criteria:

• spinal surgery in the past 6 months
• severe underlying comorbidity (like diagnosed diabetes, cardiovascular problems, etc.),
• pregnant or given birth in the preceding year,
• having initiated a new LBP treatment in the 6 weeks prior to study participation

There is no plan to make IPD available.