The effect of functional inspiratory muscle training on diaphragm function and core stabilisation in patients with chronic non-specific low back pain: a randomised controlled trial
BMC Musculoskeletal Disorders · 15 Oct 2026
† Impact is the editorial-priority score. All scores are out of 100. Clinical is a stored clinical-importance score from the earlier method; it has not been recalculated.
Why it matters
Chronic low back pain is one of the most common musculoskeletal complaints, and this trial shows how a supervised, exercise-heavy rehabilitation package can outperform minimal home breathing exercises, although this does not prove that the diaphragm-training component itself is the key ingredient.
The evidence
In this single-centre trial, 40 adults with chronic non-specific low back pain were randomised to either a 10-week supervised programme combining inspiratory muscle training with core and functional exercises (F-IMT) or unsupervised home thoracic expansion breathing exercises. After adjusting for baseline values, ultrasound-measured diaphragm thickness was 2.4 mm greater in the F-IMT group (95% CI 1.7 to 3.3), and pain was about 2 points lower on a 0-10 scale; disability (ODI) also favoured F-IMT, more so in patients with worse baseline disability. Because the intervention group got much more supervision and exercise, the benefit cannot be credited to breathing training itself.
Diaphragm thickness measured by ultrasonography at 10 weeks: Mean difference 2.434 (95% CI 1.714 to 3.261; millimetres). The interval favours the first group; the size of the benefit needs clinical interpretation.
Why this rigour score?
RCTDesign starting point: 59.5
Raised the score
- Adequately powered+6
- Concealed allocation+5.1
Lowered the score
- Outdated comparator−8.5
- A positive result from only 40 patients−6.8
Methods at a glance
Recorded assessment- Outcome assessors blindedMet
- Allocation concealedMet
- Random sequence generatedMet
- Intention-to-treat analysisNot reported
- Adequate statistical powerMet
- Prospective registrationMet
Not reported does not mean not done. Checks have different weights; this is not a count of boxes ticked.
See the full score breakdown
- Study design starting point
- 59.5
- Concealed allocation
- +5.1
- Random sequence generation
- +2.5
- Outdated comparator
- −8.5
- Control arm not optimally delivered
- −4.3
- Blinded outcome assessment
- +3.4
- 0% loss to follow-up
- +1.7
- Adequately powered
- +6
- Prospectively registered
- +5.1
- No correction for multiple comparisons
- −3.4
- A positive result from only 40 patients
- −6.8
- A positive result from a single centre
- −4.3
- Final rigour score rounded
- 56 / 100
Study design sets the starting point and a ceiling of 96. Recorded methods then adjust the score. Points are shown to one decimal place; the final score uses unrounded values.
Checklist from the stored appraisal. “Not met” describes the recorded criterion; it does not always produce a deduction. This overview supports reading the full study.
For journal club
1.For a patient with chronic non-specific low back pain referred to physiotherapy, would you add inspiratory muscle loading to a core stabilisation programme, or does supervised core and functional exercise alone likely deliver most of the benefit?
2.How would you counsel a patient with high baseline ODI disability about the expected improvement from a structured 10-week rehabilitation programme, and when would you reassess them to decide on further workup or referral?
Original publication title
The effect of functional inspiratory muscle training on diaphragm function and core stabilisation in patients with chronic non-specific low back pain: a randomised controlled trial