High Intensity Training to Improve Diaphragm Functioning in Persons With Chronic Nonspecific Low Back Pain

Hasselt University

Status: Enrolling

Conditions: Chronic Low-back Pain; Chronic Pain; Low Back Pain

Treatments: Other: Moderate intensity training; Other: High intensity training

Study type: Interventional

Funder types: Other

Identifiers

NCT05384457

B1152021000029

Details and patient eligibility

About

This randomized controlled trial aims to investigate 1) the effects of high intensity training (HIT) compared to moderate intensity training (MIT) on diaphragm muscle strength, -endurance, -fatigue and -activation, 2) to which extent these changes in diaphragm functioning are related to changes in cardiorespiratory fitness, postural control, pain and disability after HIT versus MIT, 3) to which extent depressive mood and anxiety moderate the effects of HIT on diaphragm functioning in persons with chronic nonspecific low back pain (CNSLBP). The investigators hypothize that HIT improves diaphragm functioning more compared to MIT in persons with CNSLBP.

Full description

Low back pain is the number one cause of disability worldwide with important socio-economic implications. In Belgium, 7 out of 10 persons will suffer from low back pain during their life, and 29% of all sick leave days are due to it. Chronic low back pain is defined as persistent pain for a period of minimal 12 weeks. In 85-90% of the CLBP cases, the pain cannot be attributed to a definitive underlying pathoanatomical cause, and is therefore labelled as chronic nonspecific low back pain (CNSLBP).

International guidelines recommend exercise therapy as the first-choice treatment for CNSLBP. A crucial factor within this context is exercise intensity. Indeed, multimodal high intensity training (HIT) leads to higher improvements in disability and cardiorespiratory fitness compared to moderate intensity training (MIT) in persons with CNSLBP. However, the underlying mechanisms for the additional value of a HIT approach remain largely unknown. Interestingly, low back pain is associated with impairments in diaphragm function, as the diaphragm is not only a principal inspiratory muscle, but also plays an essential role in postural control. The latter is a key factor in the development and maintenance of CNSLBP.

In this randomized controlled trial, 64 persons with CNSLBP will be recruited through local distribution of flyers and adverts on social media. The sample size calculation is based on (1) the therapeutic effects of a 12-week HIT program (compared to a MIT program) on the maximal oxygen uptake (VO2max) in persons with CNSLBP and (2) the therapeutic effects of a 8-week high-intensity inspiratory muscle training program (compared to a low-intensity inspiratory muscle training program) on the maximal inspiratory pressure (MIP) in persons with CNSLBP. These outcomes were chosen as they relate to the respiratory system and are thus most fitting to indicate possible effects on diaphragm functioning. The sample size calculation is based on the requirement of a minimal clinically important difference of 3-3.5ml/kg/min (VO2max) and 17.2 H2O (MIP). The power calculation resulted in a total of 63 persons. Therefore, the investigators plan to recruit 64 patients.

Participants will be randomly assigned to a HIT program or a MIT program. Primary outcomes are diaphragm muscle strength, -endurance, -fatigue and - activation. Secondary outcomes are cardiorespiratory fitness, postural control, pain, disability, depressive mood and anxiety. Primary and secondary outcomes will be assessed at 5 timepoints (0 weeks, 6 weeks, 12 weeks, 3 months after intervention, 12 months after intervention).

To analyze the data, JMP Pro (15.2 SAS Institute Inc, Cary, USA) will be used. Descriptive statistics will be used to display baseline group characteristics. To evaluate between-group differences (i.e. the effectiveness of the HIT vs MIT intervention), a linear mixed model will be fitted with 'time' and 'group' as covariates, and incorporated random intercepts for the participants to account for the within-subject variation. To evaluate associations between diaphragm functioning and predictors/mediators for therapy success, correlations and multivariate regression analysis will be used.

Enrollment: 64 estimated patients

Sex: All

Ages: 18 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criterian (CNSLBP patients):

• Dutch-speaking
• Adults (age 18-65 years)
• Chronic low back pain (i.e. pain localized below the costal margin and above the inferior gluteal folds, with or without referred leg pain for a period of at least twelve weeks), with a non-specific origin (i.e. pain of a nociceptive mechanical nature, not attributable to a recognizable, known, specific pathology, e.g. infection, tumour, osteoporosis, fracture, structural deformity, inflammatory disorder, radicular syndrome, or cauda equina syndrome)

Exclusion Criteria (CNSLBP patients):

• History of spinal fusion
• A musculoskeletal disorder aside from chronic nonspecific low back pain that could affect the correct execution of the therapy program
• Baseline characteristics that could affect the evaluation of the outcomes (a pacemaker, a chronic obstructive respiratory disorder, or known balance/vestibular problems)
• Severe comorbidities (e.g., paresis or sensory disturbances of neurological origin, diabetes mellitus, rheumatoid arthritis)
• Ongoing compensation claims
• Negative advice from the general practitioner regarding sports medical screening
• Pregnancy
• Persons that are not able to attend regular appointments

Inclusion Criteria (healthy volunteers):

• Dutch-speaking
• Adults (age 18-65 years)
• No acute or chronic complaints

Exclusion Criteria (healthy volunteers):

• History of spinal fusion
• Baseline characteristics that could affect the evaluation of the outcomes (a pacemaker, a chronic obstructive respiratory disorder, or known balance/vestibular problems)
• Severe comorbidities (e.g., paresis or sensory disturbances of neurological origin, diabetes mellitus, rheumatoid arthritis)
• Ongoing compensation claims
• Negative advice from the general practitioner regarding sports medical screening
• Pregnancy

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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64 participants in 2 patient groups

High intensity training (HIT)

Experimental group

Description:

Each participant will follow 24 therapy sessions (2 x 1.5 hours/week). The experimental group will perform a multimodal HIT protocol. Cardiorespiratory training will consist of a high-intensity interval training protocol on a cycle ergometer. After a five-minute warm-up, interval training will start, consisting of five one-minute bouts (110 RPM at 100% VO2max workload), separated by one minute of active rest (75 RPM at 50% VO2max workload). Limb strength training will consist of a circuit of three upper-body (vertical traction, chest press, arm curl) and three lower-body exercises (leg curl, leg press, leg extension) executed at 80% of the one repetition maximum. Core muscle training will consist of a circuit of six static core exercises (glute bridge, glute clam, superman back extension, adapted plank, adapted side plank, shoulder retraction with hip hinge) at 60% of the maximal voluntary contraction.

Treatment:

Other: High intensity training

Moderate intensity training (MIT)

Active Comparator group

Description:

Each participant will follow 24 therapy sessions (2 x 1.5 hours/week). The control group will perform a multimodal MIT protocol. Cardiorespiratory training will consist of a moderate-intensity continuous training protocol on a cycle ergometer. After a five-minute warm up, participants start continuous training comprising of 14 minutes of moderate-intensity cycling (90RPM at 60%VO2max workload). The duration will increase weekly with 1'40'' up to 22'40''. Limb strength training will consist of a circuit of three upper-body (vertical traction, chest press, arm curl) and three lower-body exercises (leg curl, leg press, leg extension) executed at 60% of the one repetition maximum. Core muscle training will be identical to the protocol described in 'Core muscle training HIT' with the exception of the exercise intensity. Only exercises with low relative core muscle activation will be used.

Treatment:

Other: Moderate intensity training