This randomized, assessor-blinded controlled trial will evaluate the preliminary efficacy and safety of a 12-week supervised intradialytic multimodal exercise program for improving postural abnormalities in adults receiving maintenance hemodialysis. Participants will be randomized to either supervised intradialytic exercise plus usual care or usual care alone. The exercise program will be performed three times per week during scheduled hemodialysis sessions and will include postural correction exercises, resistance-band strengthening, core stabilization, stretching, breathing exercises, and seated aerobic cycling. The primary outcome will be change in thoracic kyphosis angle from baseline to Week 12. Secondary outcomes will include craniovertebral angle, balance, mobility, functional exercise capacity, gait speed, physical activity level, adherence, and adverse events. The findings may provide preliminary evidence on the feasibility, safety, and potential clinical value of incorporating postural correction exercises into routine hemodialysis care.
Falls represent one of the most consequential complications in patients with end-stage renal disease (ESRD), with approximately 25% of dialysis patients experiencing at least one fall annually. Fall-related injuries in this population, including hip fractures, vertebral fractures, and joint dislocations, contribute to significant functional deterioration, diminished quality of life, restricted mobility, and increased healthcare expenditure. Among the many factors driving this fall burden, postural abnormalities have emerged as clinically significant yet persistently underinvestigated contributors. In particular, thoracic hyperkyphosis and forward head posture (FHP) are now recognized as highly prevalent structural deformities in dialysis patients that directly impair postural stability, physical function, and overall safety. The clinical impact of thoracic hyperkyphosis and FHP extends across multiple physiological domains. Hyperkyphosis, characterized by excessive posterior curvature of the thoracic spine, displaces the body's center of gravity anteriorly, impairing postural control and forcing compensatory adaptations in the lumbar spine and hips. When these compensatory mechanisms are overwhelmed, as is common in the context of the sarcopenia and muscle weakness that accompany ESRD, hyperkyphosis leads to impaired gait, reduced walking speed, diminished balance, and substantially heightened fall susceptibility. Beyond its musculoskeletal effects, thoracic hyperkyphosis restricts thoracic cage mobility, reduces vital capacity, and compromises cardiopulmonary function. FHP, defined as anterior displacement of the head relative to the shoulder plumb line in the sagittal plane, generates disproportionate loading of the posterior cervical musculature and disrupts the normal biomechanics of the cervical spine. This misalignment reduces both static and dynamic balance by destabilizing the vestibular and proprioceptive feedback systems that depend on neutral cervical alignment. FHP has been associated with increased postural sway and instability in older adults, as well as altered thoracic shape and impaired respiratory function through weakening of the accessory breathing musculature. Critically, hyperkyphosis and FHP are biomechanically coupled: as thoracic kyphosis increases, compensatory anterior head translation increases proportionally to maintain horizontal gaze, creating a self-reinforcing cycle of progressive postural dysfunction and functional decline. Despite the scale and clinical consequences of this problem, effective corrective strategies for dialysis patients remain largely untested. Evidence from general and older adult populations, however, strongly supports the role of targeted exercise in correcting both hyperkyphosis and FHP. Combined strengthening and stretching exercise programs, specifically targeting the thoracic extensors, scapular stabilizers, and deep cervical flexors while stretching the shortened anterior chain muscles, are found to produce significant reductions in kyphosis angle and improvements in craniovertebral angle across populations with postural deformities. These findings indicate that exercise-based postural correction is not only feasible but reliably effective in older adults with comparable musculoskeletal profiles to dialysis patients, making translation to the ESRD population a logical and clinically justified step. The key challenge lies in delivering such exercise to a population with significant barriers to participation in community or home-based programs, including transportation dependence, fatigue, and medically complex comorbidities. Intradialytic exercise (IDE), supervised physical activity performed during scheduled hemodialysis sessions, offers a uniquely practical solution. By embedding exercise within the unavoidable treatment time of dialysis, IDE eliminates the need for additional healthcare visits, ensures direct professional supervision, and capitalizes on the structure of the dialysis schedule to provide consistent physical stimulation. Despite this accumulating evidence, no published trial has specifically examined the effect of intradialytic exercise on the structural postural abnormalities of thoracic hyperkyphosis and FHP in hemodialysis patients. The present randomized controlled trial therefore aims to determine whether a 12-week supervised, multimodal intradialytic exercise program can improve spinal and cervical postural alignment, dynamic balance, physical function, and health-related quality of life in hemodialysis patients, providing the evidence needed to justify integrating postural correction into standard dialysis care.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
SINGLE
Enrollment
98
Exercises include thoracic extension, scapular retraction, deep cervical flexor activation, pectoral stretching, seated rowing, shoulder external rotation, seated knee extension, hip flexion, ankle pumps, and cycle ergometry. Resistance exercises will be performed for 1-3 sets of 10-15 repetitions and progressed every two weeks according to RPE, tolerance, and absence of adverse symptoms. Exercise will be stopped if the participant develops chest pain, severe dyspnea, dizziness, nausea, muscle cramps, pallor, arrhythmia, systolic blood pressure \>180 mmHg or \<90 mmHg, diastolic blood pressure \>110 mmHg, oxygen saturation \<90%, or any symptom judged unsafe by the supervising clinician.
Pardis specialized wellness institute
Isfahan, Iran
RECRUITINGChange in Thoracic Kyphosis Angle From Baseline to Week 12
Thoracic kyphosis will be assessed using a Debrunner Kyphometer, a validated non-radiographic instrument for measuring thoracic curvature. Participants stand in a relaxed upright position while the device arms are placed over the T2-T3 and T11-T12 spinous processes. Three measurements are obtained and averaged. The outcome is recorded in degrees (°), with higher values indicating greater kyphosis. Hyperkyphosis is defined as ≥53° in women and ≥55° in men. Negative change indicates improvement.
Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)
Change in craniovertebral angle, measured in degrees, from baseline to Week 12
Forward head posture will be measured using digital photogrammetry and craniovertebral angle (CVA) analysis. Reflective markers are placed on the tragus and the C7 spinous process. Standardized lateral photographs are captured at a fixed distance and analyzed using Kinovea software (version 0.9.5 or later). CVA is defined as the angle between a horizontal line passing through C7 and the line connecting C7 to the tragus. Three photographs are obtained and averaged. Larger CVA values indicate improved head posture. A CVA ≥53° is considered normal posture, whereas lower values indicate forward head posture. Positive change indicates improvement.
Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)
Change in Timed Up and Go Test (TUG) From Baseline to Week 12
Participants rise from a standard chair, walk 3 meters, turn, return, and sit down. Time is recorded in seconds from standing initiation to sitting completion. Two measurement trials are performed and averaged. Lower scores indicate better mobility and balance. TUG values ≥12 seconds indicate increased fall risk. The Timed Up and Go (TUG) Test is measured on a continuous scale ranging from 0 seconds to no predefined maximum value, with lower scores indicating better performance and higher scores indicating worse mobility and greater fall risk.
Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)
Change in Berg Balance Scale Score From Baseline to Week 12
Static and dynamic balance will be quantified using the Berg Balance Scale (BBS), a 14-item performance-based assessment. Each item is scored from 0 (unable to perform) to 4 (independent performance), yielding a total score of 0 to 56 points. Higher scores indicate better balance. Established risk thresholds are: 41-56 = low fall risk; 21-40 = medium fall risk; 0-20 = high fall risk. A cut-off of ≤45 has been identified as clinically significant for elevated fall risk in older adults and patients with chronic kidney disease. The Berg Balance Scale total score ranges from 0 to 56, with higher scores indicating better balance and lower scores indicating worse balance performance.
Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)
Change in Six-Minute Walk Distance From Baseline to Week 12
Physical function will be evaluated using the Six-Minute Walk Test (6MWT) according to standardized guidelines. Participants walk as far as possible along a 30-meter corridor during 6 minutes. The total distance walked is recorded in meters. Higher distances indicate better functional exercise capacity. The 6MWT is validated and responsive to exercise interventions in hemodialysis populations. A change of approximately 25-30 meters is considered clinically meaningful. The Six-Minute Walk Test is measured as total walking distance (meters) with a minimum value of 0 meters and no predefined maximum value; higher distances indicate better functional exercise capacity, whereas lower distances indicate poorer physical function.
Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)
Change in Gait Speed From Baseline to Week 12
Habitual gait speed will be assessed over a 4-meter walking course using a stopwatch. Participants are instructed to walk at their comfortable, usual pace. The time elapsed is recorded in seconds and converted to meters per second (m/s). Two trials are performed and averaged. A gait speed \<1.0 m/s is internationally recognized as a threshold associated with increased fall risk, frailty, and adverse health outcomes in older adults and dialysis patients. Gait Speed is recorded in meters per second (m/s), with a minimum value of 0 m/s and no predefined maximum value. Higher gait speed indicates better mobility and physical function, whereas lower gait speed indicates poorer mobility and increased health risk.
Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)
Change in LoPAQ Total Physical Activity Score From Baseline to Week 12
Daily physical activity level will be assessed using the Low Physical Activity Questionnaire (LoPAQ). The questionnaire evaluates occupational, transportation, household, leisure, and sedentary activities. Results are expressed as MET-minutes/week using standardized metabolic equivalent values. Activity levels are categorized as low (\<600 MET-min/week), moderate (600-3000 MET-min/week), or high (\>3000 MET-min/week). Higher scores indicate greater physical activity. The Low Physical Activity Questionnaire does not have a fixed maximum score. Scores range from 0 MET-minutes/week to no predefined upper limit, with higher scores indicating greater physical activity and lower scores indicating lower physical activity levels.
Time frame: Pre-test (Baseline) and 3 Months Later (Post-test, Week 12)
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