Background: Obesity and mechanical low back pain (MLBP) are two major health problems negatively affecting the human body. Many studies have shown that obesity and MLBP are associated with negative effects on the respiratory system. There are many interventions to treat obesity and MLBP, such as aerobic exercise and diet programs. Moreover, the Inspiratory Muscle Trainer (IMT) significantly improved inspiratory muscle strength in patients with obesity. This study aims to investigate whether adding IMT to aerobic exercise will improve respiratory function, exercise capacity, and pain intensity in patients with obesity and MLBP. Materials and Methods: A total of forty-eight obese patients with MLBP will be equally and randomly assigned to the experimental group and control group. The experimental group will have training on IMT for 6 weeks, three days per week (two sessions daily, thirty breaths per session) using POWERbreathe IMT, starting at 40% of maximal inspiratory pressure with increasing training load at the third week, in addition to having aerobic exercise three times a week for 30 minutes and total body resistance. The control group will have the same training as the experimental group, except for IMT; they will have zero resistance. Main outcome measures: pulmonary function tests and maximal inspiratory pressures to assess respiratory function; VO2 to assess exercise capacity; pain intensity; and Oswestry Disability Index to determine functional disability. All the measurements will be done before and after the intervention in both groups. Paired and independent t-tests will be used to compare within- and between-group differences. A repeated-measures design will be used to determine significant differences before, during, and after the intervention within each group.

The aim of this study is to investigate the effects of inspiratory muscle trainers on respiratory function, exercise capacity, pain intensity, and functional disability in patients with obesity and MLBP. If a significant improvement is found, IMT could be added to the guidelines for exercise prescriptions for obese patients with MLBP. Therefore, this study might provide evidence-based findings to guide clinical decision-making and empower clinicians and healthcare organizations to incorporate IMT into exercise prescription guidelines for obese patients with MLBP. By integrating IMT into guidelines, this study might enhance rehabilitation strategies for obese patients with MLBP.

Hypothesis

• Null Hypothesis: the addition of IMT to aerobic exercise does not result in significant differences in respiratory functions, exercise capacity, pain intensity, and functional disability in patients with obesity and mechanical low back pain.
• Alternative Hypothesis: the addition of IMT to aerobic exercise results in significant differences in respiratory functions, exercise capacity, pain intensity, and functional disability in patients with obesity and mechanical low back pain.

Objectives of the study:

1. To assess the effects of PowerBreathIMT on pulmonary function tests and maximum inspiratory pressure in patients with obesity and mechanical low back pain.
2. To assess the effects of PowerBreathIMT on exercise capacity, pain intensity and functional disability in patients with obesity and mechanical low back pain.

Expected Results The addition of IMT to aerobic exercise results in significant differences in respiratory functions, exercise capacity, pain intensity, and functional disability in patients with obesity and mechanical low back pain.

Material and methods:

o Study setting: The current study will be conducted at King Fahad Hospital of the University, Al Khobar, Saudi Arabia. All participants will be recruited from the orthopedic and neurological clinics after confirming their diagnosis (they suffer from mechanical low back pain & exclude the existence of other causes for back pain). All measurements will be done at the Pulmonary Function Test Lab in the previous week of our intervention and in the next week after the end of our intervention. Participants will practice the supervised sessions at the hospital three times per week for six weeks. During supervised sessions, all participants will follow a dietary regime and perform aerobic exercise and resistance training in addition to IMT training.

NB: Home program: All participants of both groups will also perform aerobic exercise and IMT training two sessions per week at home. The participants from both groups will receive detailed instructions to guide them in performing home sessions. A follow-up with them will be through WhatsApp and Zoom, and I will call them every other day to check their performance. The participants will also have logbooks to document aerobic exercise, resistance training, and IMT training at home and to document the adherence and completeness of the training program.

NB: Diet Program: All participants of both groups will follow an individualized diet program.

• Sample Size Calculation: Sample size was calculated by using data from a previous study that assessed the significant difference between two independent means (intervention and control groups) with a primary outcome measure of Vital Capacity from a Pulmonary Function Test (mean 1 = 4.28 and mean 2 = 4.07, sigma= 0.2) . The parameters used for the calculation included an alpha level of 0.05 and a power of 0.90. This link was used, which is a valid and reliable tool for calculating sample size when comparing two means. The sample size was 20 participants in each group to find out a significant difference with sufficient power. So, the total sample size will be 40. However, to account for a 20% attrition rate and dropouts, the sample size will be adjusted. The adjusted sample size will be calculated as a total of 48 participants, resulting in approximately 24 participants in each group.

  • Ethical considerations: Ethical approval was obtained from the institutional review board of the Dean of Scientific Research at Imam Abdulrahman bin Faisal University. Moreover, approval from the Saudi Food and Drug Administration was obtained. Each patient will sign a consent form to authorize participation. They will be informed that their information and data will be confidential, and the collected data will be published in the future. The participants will be informed that participation is voluntary, and they can withdraw at any time without consequences.

• Recruitment and study population: Participants who meet the inclusion criteria will be recruited from orthopedic and neurologic clinics in the outpatient department of King Fahad Hospital of the University to participate in this study.

Inclusion Criteria:

• Males and females
• Aged between 20 and 50 years
• Obese and experiencing mechanical low back pain (MLBP)
• A body mass index (BMI) between 30 and 40 kg/m²
• low back pain for more than 12 weeks, with pain localized to the lumbar region - A pain score greater than 3 but less than 7 on the Numeric Pain Rating Scale (NPRS).
• Low back pain will be screened using the Mechanical and Inflammatory Low Back Pain (MIL) Index.
• Stable and controlled medical conditions

Exclusion Criteria:

• Medically unstable
• Severe spinal pathology, e.g., infection, tumor, arthritis, inflammation, spine deformity, advanced neurologic diseases, head or spinal surgeries, rheumatic diseases, and respiratory muscle paralysis
• Acute inflammation of the musculoskeletal system
• Pregnancy
• Unable to follow instructions, e.g., those with learning difficulties

Each participant will be stratified and assigned either to a control or experimental group based on age, pain score and BMI.

Blinding & Randomization will be performed by computer-generated numbers from www.randomizer.org. A random number generator will make a serial number for each participant. Both participants and the assessor will be blinded. Participants will be randomized into the experimental group; they will practice an aerobic exercise and resistance training program in addition to IMT with resistance set at 40% of each participant's maximum inspiratory pressure, while all participants of the control group will practice aerobic exercise and resistance training in addition to IMT with no resistance (Ponde et al., 2021 & Medicine, 2014).