This randomized, controlled, five-arm, parallel-group trial will evaluate the effects of 8 weeks of supervised resistance training and developmental position-based exercise, with or without real-time non-invasive intra-abdominal pressure biofeedback, in adults aged 40 to 60 years with chronic low back pain. The trial will compare supervised gym-based agonist-antagonist paired set resistance training with OHMTRACK, supervised gym-based resistance training without OHMTRACK, supervised physiotherapy-based developmental exercise with OHMTRACK, home-based developmental exercise with OHMTRACK, and an active control condition. Primary outcomes will assess changes in pain and physical function after the intervention. Secondary outcomes will include neuromuscular coordination, postural stabilization, cardiovascular, respiratory, metabolic, behavioral, feasibility, and follow-up outcomes.
Chronic low back pain is a prevalent and multifactorial condition associated with impaired physical function, reduced quality of life, and substantial socioeconomic burden. Exercise therapy, especially resistance training, is an important non-pharmacological treatment strategy, but the integration of exercise with real-time monitoring of intra-abdominal pressure remains underexplored. This study will examine whether combining exercise with non-invasive intra-abdominal pressure biofeedback can improve trunk stabilization, movement control, pain, and broader health outcomes. The trial includes a 2-week familiarization phase, an 8-week intervention phase, and an 8-week post-intervention follow-up without structured exercise. Participants will be randomly assigned in a 1:1:1:1:1 ratio to one of five parallel groups. The supervised gym-based program uses full-body agonist-antagonist paired set resistance training twice weekly for 60 minutes, with three sets of 10 repetitions at 75 percent of one-repetition maximum, 90-second rest intervals, and a 3-0-2-1 tempo. The supervised physiotherapy and home-based arms use developmental position-based exercise emphasizing trunk stabilization, breathing coordination, support, and movement quality. OHMTRACK biofeedback will be used in selected groups to support real-time regulation of intra-abdominal pressure. Outcome measures will cover pain, trunk muscle function, postural stabilization, body composition, cardiovascular health, respiratory function, metabolic health, strength, functional capacity, adherence, behavioral regulation, and adverse events. Measurements are scheduled at baseline, during the intervention, and through follow-up to examine both immediate and retained effects.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
120
An 8-week supervised full-body resistance training program preceded by a 2-week familiarization phase (4 sessions). During the intervention phase, participants perform training twice weekly for 60 minutes per session. Each session includes a 10-minute warm-up, 40-minute main phase, and 10-minute cool-down. The program consists of 3 sets of 10 repetitions at 75% of 1RM, 90-second rest intervals, and a 3-0-2-1 movement tempo. Training is delivered in a gym setting under professional supervision. Resistance training with or without real-time OHMTRACK biofeedback monitor which support breathing mechanics and trunk stabilization.
An 8-week supervised exercise program based on developmental positions and neurophysiological principles, preceded by a 2-week familiarization phase (4 sessions). Participants exercise twice weekly for 60 minutes per session under physiotherapist supervision. Sessions focus on breathing coordination, deep trunk stabilization, postural control, support function, and movement quality using structured developmental movement sequences.
An 8-week home-based exercise program based on developmental positions and neurophysiological principles, preceded by a 2-week familiarization phase (4 sessions). Participants perform exercises twice weekly for 60 minutes per session using electronic manuals and video instructions. The program emphasizes breathing coordination, deep trunk stabilization, postural control, and self-correction of movement quality in an unsupervised home setting, with the possibility of contacting the research team for support.
Participants continue their usual daily activities without participating in a structured resistance training or developmental position exercise program. Physical activity is monitored throughout the study using a wearable activity tracker to record daily step counts and overall movement behavior.
Faculty of Physical Education and Sport, Chrales University
Prague, Czechia
Change in Trunk Flexor and Extensor Muscle Function
Trunk Flexor Muscle Strength (Isokinetic Peak Torque): Trunk flexor muscle function will be assessed using an isokinetic dynamometer (Cybex NORM or HUMAC NORM system). The primary outcome will be peak torque during trunk flexion, reported in Newton-meters (N·m) (and, if applicable, normalized to body mass as N·m/kg). Higher values indicate greater trunk flexor strength. Trunk Extensor Muscle Strength (Isokinetic Peak Torque): Trunk extensor muscle function will be assessed using an isokinetic dynamometer (Cybex NORM or HUMAC NORM system). The primary outcome will be peak torque during trunk extension, reported in N·m (and, if applicable, normalized to body mass as N·m/kg). Higher values indicate greater trunk extensor strength.
Time frame: Baseline, Week 8, Week 12, and Week 16
Short-Form McGill Pain Questionnaire (SF-MPQ) Total Score
Pain intensity and pain-related characteristics will be assessed using the Short-Form McGill Pain Questionnaire (SF-MPQ). The outcome will be the SF-MPQ total score, calculated as the sum of 15 descriptor items rated on a 0-3 scale (0 = none, 1 = mild, 2 = moderate, 3 = severe). Total score ranges from 0 to 45 points, with higher scores indicating worse pain and lower scores indicating improvement.
Time frame: Baseline to Week 16 (1x every week)
Change in DNS-Based Functional Postural Stabilization Performance
Abdominal wall tension will be measured during the performance of standardized DNS functional tests using a wearable abdominal wall tension monitoring belt (OHMBelt). The device provides continuous, noninvasive, device-derived estimates of abdominal wall tension, which are related to changes in intra-abdominal pressure. Outcomes will include peak abdominal wall tension and mean abdominal wall tension recorded during each DNS test, reported in device-derived units (arbitrary units, a.u.) (and/or as change from baseline, as applicable). Higher values indicate greater abdominal wall tension during task performance.
Time frame: Baseline, Week 8, Week 12, and Week 16
Maximal Oxygen Uptake (VO2max) During Treadmill Graded Exercise Test
Maximal oxygen uptake (VO₂max) will be assessed using a graded exercise test (GXT) on a motorized treadmill with breath-by-breath gas exchange analysis (Metalyzer metabolic cart). VO₂max will be defined as the highest 30-second averaged oxygen uptake achieved during the test and reported in mL/kg/min (and, if applicable, also in L/min). Higher VO₂max values indicate greater aerobic capacity.
Time frame: Baseline, Week 8, Week 12, and Week 16
Quantitative Sensory Testing - Pressure Pain Threshold
Pressure pain threshold will be assessed using quantitative sensory testing with a handheld digital pressure algometer applied at standardized anatomical sites. The outcome will be reported as the pressure at pain threshold in kilopascals (kPa). Higher PPT values indicate lower mechanical pain sensitivity.
Time frame: Baseline, Week 8, Week 12, and Week 16
Isometric Mid-Thigh Pull
Lower-body maximal isometric force production will be assessed using an isometric mid-thigh pull (IMTP) performed on dual force plates (ForceDecks system). The primary outcome will be peak vertical ground reaction force, reported in Newtons (N) (and, if applicable, also normalized to body mass as N/kg). Higher values indicate greater maximal isometric lower-body force.
Time frame: Baseline, Week 8, Week 12, and Week 16
Handgrip Strength
Handgrip (kg) is measured by Takei (TKK 5401, Japan).It will be measured for both hands (left and right). Three trials will be performed on each hand and the mean will be calculated. The standard for men over 40 years of age is 47 (±9.5) kg for the right hand and 45 (±9.3) kg for the left hand. The standard for women over 40 is 29 (±5.7) kg for the right hand and 28 (±5.7) kg for the left hand. Higher values are considered to be better.
Time frame: Baseline, Week 8, Week 12, and Week 16
Behavioral Regulation in Exercise Questionnaire (BREQ-3) Subscale Scores
Exercise motivation and self-regulation will be assessed using the Behavioral Regulation in Exercise Questionnaire-3 (BREQ-3). Items are rated on a 0-4 scale (0 = not true for me, 4 = very true for me). Outcomes will be reported as subscale mean scores (range 0-4 points). Higher scores indicate greater endorsement of the respective motivation/self-regulation construct.
Time frame: Baseline and Week 8
Adverse Events (AEs) and Serious Adverse Events (SAEs)
Adverse events will be monitored and recorded throughout the intervention period. Events of interest include falls, injuries, musculoskeletal complaints, hypoglycemic episodes, major cardiovascular events, and any other events potentially related to study participation. Adverse events will be captured via participant self-report at each weekly contact/session and active investigator monitoring. Each event will be documented by type, onset date, duration, severity (mild/moderate/severe), seriousness (serious vs non-serious), and relatedness to the study intervention (not related/possibly/probably/definitely related). Outcomes will be reported as the number of participants experiencing ≥1 adverse event and the total number of adverse events during the intervention.
Time frame: Throughout the intervention period, Weeks 1-8 (every week)
Body Mass Index (BMI)
Body mass index (BMI) will be calculated as body weight in kilograms (kg) divided by height in meters squared (m²) and reported in kg/m². Higher BMI indicates higher body mass relative to height. The World Health Organization (WHO) adult reference range for normal BMI is 18.5-24.9 kg/m².
Time frame: Baseline, Week 8, Week 12, and Week 16
Total Body Fat Mass
Total body fat mass will be assessed using dual-energy X-ray absorptiometry (DEXA) and/or InBody370S and reported in kilograms (kg).
Time frame: Baseline, Week 8, Week 12, and Week 16
Lean mass
Total body lean mass will be assessed using dual-energy X-ray absorptiometry (DEXA) and/or InBody370S and reported in kilograms (kg).
Time frame: Baseline, Week 8, Week 12, and Week 16
Body Weight
Body weight will be measured using a InBody370S and reported in kilograms (kg).
Time frame: Baseline, Week 8, Week 12, and Week 16
Serum Total Cholesterol Concentration
Serum total cholesterol will be measured from venous blood samples using standard clinical laboratory enzymatic assays. Results will be reported in mmol/L. Laboratory-specific reference ranges will be used for clinical interpretation (e.g., 2.90-5.00 mmol/L).
Time frame: Baseline, Week 8, Week 12, and Week 16
Serum Low-Density Lipoprotein (LDL) Cholesterol Concentration
Serum LDL cholesterol will be measured from venous blood samples using standard clinical laboratory assays. Results will be reported in mmol/L. Laboratory-specific reference ranges will be used for clinical interpretation (e.g., 1.20-3.00 mmol/L).
Time frame: Baseline, Week 8, Week 12, and Week 16
Serum High-Density Lipoprotein (HDL) Cholesterol Concentration
Serum HDL cholesterol will be measured from venous blood samples using standard clinical laboratory assays. Results will be reported in mmol/L. Laboratory-specific reference ranges will be used for clinical interpretation (e.g., 1.00-2.10 mmol/L).
Time frame: Baseline, Week 8, Week 12, and Week 16
Fasting Blood Glucose Concentration
Fasting blood glucose will be measured from venous blood samples using standard clinical laboratory assays (e.g., enzymatic methods). Results will be reported in mmol/L. Laboratory-specific reference ranges will be used for clinical interpretation (e.g., 3.30-5.59 mmol/L).
Time frame: Baseline, Week 8, Week 12, and Week 16
Systolic Blood Pressure (SBP)
Systolic blood pressure (SBP) will be assessed in a seated resting position using a validated oscillometric device with brachial cuff-based measurement (Arteriograph). Results will be reported in millimeters of mercury (mmHg). Higher values indicate higher systolic arterial pressure. For clinical interpretation, commonly used resting thresholds include \<120 mmHg (normal) and ≥140 mmHg (hypertension) (thresholds may vary by guideline and population).
Time frame: Baseline, Week 8, Week 12, and Week 16
Diastolic Blood Pressure (DBP)
Diastolic blood pressure (DBP) will be assessed in a seated resting position using a validated oscillometric device with brachial cuff-based measurement (Arteriograph). Results will be reported in mmHg. Higher values indicate higher diastolic arterial pressure. For clinical interpretation, commonly used resting thresholds include \<80 mmHg (normal) and ≥90 mmHg (hypertension) (thresholds may vary by guideline and population).
Time frame: Baseline, Week 8, Week 12, and Week 16
Aortic Pulse Wave Velocity (aPWV)
Aortic pulse wave velocity (aPWV) will be assessed using oscillometric pulse wave analysis with a brachial cuff-based system (Arteriograph). Results will be reported in meters per second (m/s). Higher aPWV values indicate greater arterial stiffness. For clinical interpretation, \~10 m/s is commonly used as a threshold indicating increased arterial stiffness in adults, although reference values vary by age and blood pressure.
Time frame: Baseline, Week 8, Week 12, and Week 16
Resting Heart Rate (RHR)
Resting heart rate will be assessed during seated rest using a cuff-based oscillometric measurement (Arteriograph). Results will be reported in beats per minute (bpm). Higher values indicate higher resting heart rate. In adults, a commonly cited resting reference range is approximately 60-100 bpm (may vary with fitness level, medications, and clinical status).
Time frame: Baseline, Week 8, Week 12, and Week 16
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