Core stability versus postural control training for pain, disability, and sensorimotor function in chronic non-specific low back pain

Abstract

Chronic non-specific low back pain (CNSLBP) often involves impaired sensorimotor control and functional limitations. This study compared the effects of core stability training (CST) and postural control training (PCT) on pain, functional disability, proprioception, balance, and quality of life (QOL) in middle-aged women with CNSLBP. In a three-arm, assessor-blinded RCT, 51 women were randomized to PCT (n = 17), CST (n = 17), or a control group (n = 17). Pain (VAS), proprioception (goniometric joint repositioning), static balance (Stork test), functional disability (Roland-Morris Disability Questionnaire [RMDQ] and Oswestry Disability Index [ODI]), and QOL (SF-36) were assessed. Between-group differences were analyzed using mean differences and confidence intervals, and analysis of covariance (ANCOVA). The CST group demonstrated significant reductions in ODI (MD = -13.36, 95% CI: -16.63 to -10.10, p < 0.001), RMDQ (MD = -4.82, 95% CI: -5.37 to -4.28, p < 0.001), and pain (MD = -2.48, 95% CI: -3.03 to -1.93, p < 0.001). Similarly, the PCT group showed significant improvements in ODI (MD = -14.05, 95% CI: -17.04 to -11.07, p < 0.001), RMDQ (MD = -4.42, 95% CI: -4.94 to -3.90, p < 0.001), and pain (MD = -2.96, 95% CI: -3.47 to -2.46, p < 0.001). In addition, proprioception improved significantly only in the PCT group, while no significant change was observed in the CST group (p = 0.17) compared with controls. Both CST and PCT effectively reduced pain and disability in women with CNSLBP. PCT demonstrated greater improvements in lumbo-pelvic proprioception compared with control, suggesting potential benefits for sensorimotor function. These findings support a multidimensional approach to CNSLBP rehabilitation targeting both pain and neuromuscular impairments.

Clinical trial registration: This study was a priori registered at IRCT20250519065806N2 on 12 April 2026.

Introduction

Chronic non-specific low back pain (CNSLBP) is a multifactorial musculoskeletal disorder characterized by pain lasting more than three months without identifiable structural pathology on imaging¹. It is particularly prevalent among middle-aged women and is associated with recurrent episodes, reduced functional capacity, and long-term disability². Beyond tissue pathology, evidence indicates that CNSLBP involves neuromuscular alterations, motor control deficits, and impaired sensorimotor integration³. These dysfunctions can sustain symptoms even in the absence of radiographic abnormalities such as X-ray or Magnetic Resonance Imaging⁴.

Patients with CNSLBP often exhibit increased pain intensity, impaired deep lumbar proprioception, reduced postural stability, and functional disability⁵. Proprioceptive deficits in the lumbar-pelvic region may lead to inaccurate joint repositioning and compromised spinal control⁶. Impaired static balance, commonly assessed using single-leg stance tests such as the Stork test, reflects altered neuromuscular coordination⁷. Functional disability, measured with validated tools such as the Oswestry Disability Index (ODI)⁸ and the Roland-Morris Disability Questionnaire (RMDQ)⁹, captures limitations in daily activities. Chronic pain also negatively affects multiple domains of quality of life (QOL), including physical functioning, emotional health, vitality, and social participation, typically assessed using the Short Form-36 (SF-36) questionnaire¹⁰. These interrelated impairments highlight the need for interventions that target both pain reduction and sensorimotor function.

Exercise-based rehabilitation is widely recommended as a primary conservative treatment for CNSLBP. Approaches include general strengthening, flexibility training, stabilization programs, and motor control exercises¹¹. However, not all exercise modalities address underlying sensorimotor deficits¹². Traditional strengthening may increase muscle capacity, but often does not improve proprioception or neuromuscular timing¹³. As a result, interventions targeting motor control and postural regulation have gained attention.

Core stability training (CST) aims to selectively activate deep trunk stabilizers, particularly the transversus abdominis and multifidus, to enhance segmental spinal stability and restore motor control^14,15. In contrast, postural control training (PCT) emphasizes balance-oriented and coordination-based exercises to improve sensorimotor integration and dynamic stability¹⁶. While both approaches target neuromuscular function, CST focuses primarily on deep muscle activation¹⁷, whereas PCT emphasizes whole-body coordination under progressively challenging conditions¹⁸.

CST primarily targets deep trunk muscle activation and spinal segmental control, whereas PCT focuses on balance, coordination, and sensorimotor integration. Although both interventions have shown beneficial effects in chronic low back pain, their comparative effectiveness remains unclear due to differences in underlying mechanisms. To our knowledge, no randomized controlled trial has simultaneously compared the effects of CST and PCT on pain intensity, proprioception, static balance, functional disability, and QOL in middle-aged women with CNSLBP. Given that deficits in neuromuscular control and proprioception contribute to persistent pain and functional limitations, identifying which intervention more effectively targets these underlying impairments is crucial for designing evidence-based rehabilitation programs. Therefore, the present study aimed to determine the comparative effects of CST and PCT on clinical outcomes and sensorimotor function in this population.

Methods

Study design

This study was a three-arm, parallel-group, assessor-blinded randomized controlled trial with a pretest-posttest design. The intervention period lasted eight weeks and targeted clinical outcomes in women with CNSLBP. Participants were randomly assigned to one of three groups: CST, PCT, or control. All outcome measures were collected at baseline and immediately after the intervention. As this was an investigator-initiated academic trial without external funding, the study was not prospectively registered, which should be considered when interpreting the findings. The study protocol was approved by the Research Ethics Committee of the Islamic Azad University, Science and Research Branch, Tehran, under the ethical code identifier IR.IAU.SRB.REC.1403.295. It was conducted in accordance with the ethical standards of the World Medical Association’s Declaration of Helsinki for research involving human subjects. This study was a priori registered at www.irct.behdasht.gov.ir (IRCT20250519065806N2) on 12 April 2026 and reported according to the Consolidated Standards of Reporting Trials (CONSORT) guidelines¹⁹.

Randomization and blinding

After baseline assessments, participants were randomly assigned to one of the three groups using a simple random allocation procedure, ensuring equal probability of allocation. To minimize assessment bias, the outcome assessor remained blinded to group assignments throughout the study. Participants were instructed not to disclose their group allocation during post-intervention testing.

Participants

Following CONSORT guidelines, 68 individuals were initially screened for eligibility. Seventeen participants were excluded due to not meeting the inclusion criteria or declining participation. Fifty-one eligible women were randomly allocated to CST (n = 17), PCT (n = 17), or control (n = 17). All participants completed the eight-week intervention, and no dropouts occurred. Therefore, complete pre- and post-intervention data from 51 participants were included in the final analysis (Fig. 1).

Fig. 1.

Flow diagram of participant recruitment, allocation, follow-up, and analysis.

Inclusion and exclusion criteria

Inclusion criteria were: female sex, middle age, CNSLBP for more than three months, and absence of specific spinal pathology. Exclusion criteria included a history of spinal surgery, radiculopathy, neurological or vestibular disorders, recent lower extremity injury, or participation in structured rehabilitation programs during the study. Written informed consent was obtained from all participants before enrollment.

Sample size calculation

The required sample size was calculated a priori using G*Power software (version 3.1, Heinrich-Heine-University Düsseldorf, Germany). Based on previous studies investigating the effects of stabilization and balance training on pain and disability in chronic low back pain populations, a medium-to-large effect size (f = 0.40) was assumed. With an alpha level of 0.05, statistical power of 0.80, and three groups, the total required sample size was estimated to be 45 participants. To account for potential attrition, 51 participants (17 per group) were recruited.

Procedure and outcome measures

A total of 51 middle-aged women with CNSLBP were recruited as the study sample according to the predefined inclusion criteria. Before enrollment, detailed information regarding the objectives, procedures, and participant responsibilities was provided both verbally and in written form. Written informed consent was obtained from all participants before data collection. Demographic characteristics and medical history were collected through questionnaires and structured interviews. Participants were then randomly allocated into three equal groups (n = 17 per group): PCT, CST, and control. The two intervention groups underwent their respective eight-week exercise protocols, while the control group received no exercise intervention during the study period. All assessments were conducted at baseline before the intervention.

Pain intensity was measured using the Visual Analog Scale (VAS), in which participants rated their perceived pain on a 10-cm horizontal line anchored from 0 (no pain) to 10 (worst imaginable pain)²⁰. Health-related QOL was assessed using the SF-36, which evaluates eight domains including physical functioning, role limitations due to physical health, role limitations due to emotional problems, vitality, emotional well-being, social functioning, bodily pain, and general health. Each domain score ranges from 0 to 100, with higher scores indicating better health status. The validity and reliability of the Persian version have been confirmed in Iran²¹. Functional disability related to low back pain was evaluated using the 18-item RMDQ. Participants marked statements reflecting limitations in daily activities due to low back pain. Total scores range from 0 to 18, with higher scores indicating greater disability. This instrument has demonstrated strong test–retest reliability (r = 0.91) and acceptable internal consistency in Iranian populations (α = 0.88)²².

Functional disability was also assessed using the ODI, which evaluates disability across ten domains, including pain intensity, personal care, lifting, walking, sitting, standing, sleeping, sexual activity, social life, and traveling. Each section is scored from 0 to 5, yielding a total raw score of 0 to 50, which is multiplied by two to obtain a percentage score ranging from 0 to 100. Higher scores indicate greater disability, categorized as minimal (0–25%), moderate (26–50%), severe (51–75%), and very severe disability (76–100%) ²².

Static balance was assessed using the Stork Stand Test²³. Participants stood barefoot on a flat surface with hands placed on the hips and one foot positioned against the medial aspect of the contralateral knee. After a brief preparation period allowing visual focus on a fixed point, timing began when the heel of the supporting foot was lifted from the ground. Timing was terminated if the hands moved away from the hips, the supporting foot rotated, or the lifted foot lost contact with the knee. The test was performed three times, and the longest duration (in seconds) was recorded (Fig. 2A)²³.

Fig. 2.

Assessment procedures for static balance and lumbo-pelvic proprioception. (A) Stork stand test for static balance assessment. (B) Joint position reproduction test for lumbo-pelvic proprioception assessment.

Lumbar-pelvic proprioception was assessed using a joint position reproduction test²⁴. Participants stood barefoot in a relaxed upright posture with hands crossed over the shoulders. To minimize compensatory movements of the trunk and lower extremities, a mini-loop elastic band was used to stabilize the thigh region. Goniometric markers were placed at the superior lateral surface of the arm (movable arm), the superior aspect of the iliac crest (axis, preset at 30°), and the superior lateral aspect of the hip joint (stationary arm positioned vertically). Participants maintained a neutral cervical posture and closed their eyes to eliminate visual input. They were instructed to flex the trunk to 30° at a slow and controlled speed and maintain the position for five seconds. After returning to the starting position and pausing for five seconds, the movement was repeated. Following one practice trial, participants attempted to actively reproduce the 30° trunk flexion angle without verbal feedback. The test was repeated three times, and the absolute angular error (in degrees) was recorded for each trial. The mean error across three repetitions was calculated as the repositioning error. A mean error of less than three degrees was considered indicative of normal lumbar proprioception (Fig. 2B)²⁵.

Intervention protocol

Participants in both intervention groups performed supervised exercise sessions three times per week for eight consecutive weeks, with each session lasting approximately 45 min. All sessions were conducted in a controlled environment under supervision to ensure standardized implementation and safety. Exercise difficulty was progressively increased throughout the intervention.

Core stability training protocol

The core stability training program was implemented over eight consecutive weeks, with three sessions per week and each session lasting 45 min. Each session consisted of a 10-minute warm-up period, including walking, light jogging, and dynamic stretching exercises, followed by 30 min of core stability training and a 5-minute cool-down period. The exercises were structured progressively, such that advancement to higher levels was permitted only after sufficient mastery of the preceding level had been achieved. Progressive overload was applied by gradually increasing the duration of exercise holds based on proper execution and the participant’s tolerance to the training load in the previous session. Before the initiation of the program, participants were instructed on correct postural alignment and the importance of proper breathing technique during exercise performance. A rest interval of 3–5 s was provided between repetitions. Throughout all exercises, participants were required to maintain a neutral spinal alignment, preserve natural posture, and perform abdominal hollowing by drawing the navel inward²⁶.

Each training session consisted of six exercises, with three sets performed for each exercise. The primary progression variable was the duration of isometric contraction. In week one, hold times ranged from 5 to 7 s across the three weekly sessions. This duration increased systematically each week, such that by week eight, hold times ranged from 26 to 28 s per repetition across sessions. Specifically, in each subsequent week, the isometric hold time increased by approximately three seconds per session, ensuring gradual overload while maintaining movement quality and postural control.

The exercise program included prone plank performed with elbows flexed at 90° and aligned under the shoulders, forefeet in contact with the ground, and the entire body maintained in a straight line with abdominal engagement; single-leg bridge performed in the supine position with one knee flexed and the contralateral leg extended while maintaining pelvic alignment and neutral lumbar posture, executed separately for both right and left sides; side plank performed with the elbow flexed at 90°, body aligned laterally in a straight line, and core musculature engaged (Fig. 3A); bilateral glute bridge performed in the supine position with hips flexed to approximately 90° and pelvis elevated without anterior or posterior tilt; and bird dog performed in the quadruped position with contralateral arm and leg elevation while maintaining spinal alignment, in which limb separation occurred during inhalation and controlled approximation during exhalation (Fig. 3B). Emphasis throughout the program was placed on controlled isometric contraction of deep trunk stabilizing musculature, maintenance of neutral spinal alignment, and coordinated breathing patterns²⁶.

Fig. 3.

Core stability training exercises. (A) Side plank exercise. (B) Quadruped arm–leg raise exercise.

.

The set and duration of each week are shown in Table 1.

Table 1.

Sets, repetitions, and duration of the eight-week core stability training program.

CST program	Week 1	Week 2	Week 3	Week 4	Week 5	Week 6	Week 7	Week 8
Session 1	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s
Session 2	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s
Session 3	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s	6 Exercise 3 Sets 8 s

Abbreviation: CST; core stability training.

Postural control training protocol

The postural control training program consisted of three progressive phases implemented over eight weeks. The first phase was conducted for two weeks, followed by a three-week second phase and a three-week third phase. Training sessions were performed three times per week, with each session lasting 45 min. Each session included 10 min of warm-up exercises consisting of walking, light jogging, and dynamic stretching, followed by 30 min of postural control exercises, and concluded with 5 min of cool-down. The principle of progressive overload was applied throughout the intervention, and progression was determined based on correct exercise performance and tolerance to the previously applied training load²⁶. All exercises were performed in 10-second bouts, with a progressive increase in repetitions across sessions beginning at five repetitions and increasing incrementally to thirteen repetitions. A rest interval of 3–5 s was provided between repetitions. During all exercises, participants were instructed to maintain neutral spinal alignment, preserve natural posture, and perform abdominal hollowing by drawing the navel inward.

During the first two weeks, exercises were performed on stable surfaces and included posterior pelvic tilt in the supine position with hips flexed to 90° and knees bent (Fig. 4A); abdominal crunches performed in the supine position with chin-tuck and controlled trunk flexion; glute bridge with pelvic elevation while maintaining spinal alignment (Fig. 4B); bird dog performed in the quadruped position with contralateral limb extension and neutral cervical alignment; bear crawl hold in a quadruped position with knees elevated and core engagement; and contralateral arm lifting in the prone position with maintenance of spinal alignment.

Fig. 4.

Additional core stability training exercises. (A) Posterior pelvic tilt exercise. (B) Abdominal crunch exercise.

During weeks three to five, unstable surfaces were introduced using a gym ball to increase neuromuscular demand. The exercises included posterior pelvic tilt combined with pressure applied to the gym ball; crunches performed while maintaining balance on the gym ball; glute bridge with feet supported on the gym ball and simultaneous balance control; bird dog with controlled contralateral limb elevation; bear crawl performed with balance challenge on the gym ball and the addition of a 5-kg sandbag placed over the lumbar region; and contralateral arm lifting while maintaining balance on the gym ball. Core engagement and neutral spinal alignment were emphasized throughout.

During weeks six to eight, external resistance was incorporated to further increase exercise intensity. Posterior pelvic tilt was performed with both legs extended and elevated; crunches were executed on the gym ball with concurrent resistance using a Pilates elastic band; glute bridge was combined with gym ball support and lateral elastic band resistance; bird dog was performed with simultaneous contralateral limb extension against elastic resistance while maintaining balance on the gym ball; bear crawl was progressed using a gym ball and two 5-kg sandbags to increase loading demand; and contralateral arm lifting was executed with gym ball support and elastic band resistance. Across all phases, strict attention was given to controlled movement execution, maintenance of spinal alignment, and activation of deep trunk stabilizing musculature²⁶.

Control group

Participants in the control group did not receive structured exercise training during the eight weeks and were instructed to continue their usual daily activities.

Statistical analysis

All statistical analyses were performed using SPSS version 26. Normality of data distribution was assessed using the Kolmogorov–Smirnov test, and homogeneity of variances was evaluated using Levene’s test. Between-group differences in post-intervention outcomes were analyzed using analysis of covariance (ANCOVA), controlling for age, height, and weight as covariates. These variables were included as covariates due to their potential influence on physical performance and pain outcomes. When a significant group effect was detected, Tukey post-hoc tests were conducted to determine pairwise differences. Statistical significance was set at p < 0.05.

Results

Preliminary analyses

All statistical analyses were performed using SPSS version 26. The normality of quantitative variables was examined using the Kolmogorov–Smirnov test. Results indicated that all dependent variables were normally distributed (p > 0.05). Further evaluation using skewness and kurtosis indices demonstrated that these variables also met acceptable normality assumptions. Homogeneity of variances was assessed using Levene’s test and was confirmed for all variables (p > 0.05). Therefore, the assumptions for parametric testing, including analysis of covariance (ANCOVA), were satisfied. All analyses were conducted at a 95% confidence level (α = 0.05).

Demographic characteristics

Fifty-one middle-aged women with CNSLBP participated in the study and were equally allocated into three groups (n = 17 per group): PCT, CST, and control. Descriptive statistics for demographic variables are presented in Table 2.

Table 2.

Demographic and baseline characteristics of the participants. Values are presented as mean ± standard deviation or range, where appropriate.

Variable	Index	Control Group	Core stability training group	Postural control group
Height (m)	Mean	1.64	1.62	1.63
	Mi-Max	1.58–1.72	1.58–1.75	1.58–1.70
Weight (kg)	Mean	66.80	66.12	64.69
	Min-Max	58.20–75.60	57.90–75.00	54.00-75.20
Age (years)	Mean	46.47	43.35	45.12
	Min-Max	40–57	40–50	40–51

Baseline demographic characteristics did not differ significantly among the three groups (p > 0.05), indicating successful randomization.

Outcomes

The effects of PCT and CST on pain, functional disability, proprioception, balance, and QOL were analyzed using analysis of covariance (ANCOVA). Adjusted post-test mean differences (MD), standard error (SE), confidence interval (CI), and significance levels are presented in Table 3.

Table 3.

Pairwise comparisons between groups for study outcomes. Values are presented as mean difference (MD), standard error (SE), confidence interval (CI), and p-value.

Variable	Comparison	Mean Difference	SE	95% CI (Lower to Upper)	p-value
Pain	PCT-CST	-0.48	0.25	-0.99 to 0.02	0.06
	PCT-Control	-2.96*	0.24	-3.47 to -2.46	< 0.001
	CST-Control	-2.48*	0.27	-3.03 to -1.93	< 0.001
Static Balance (Right)	PCT-CST	3.19	1.69	-0.22 to 6.61	0.06
	PCT-Control	1.47	1.65	-1.86 to 4.81	0.37
	CST-Control	-1.71	1.81	-5.36 to 1.93	0.34
Static Balance (Left)	PCT-CST	2.41	1.89	-1.39 to 6.22	0.20
	PCT-Control	0.06	1.84	-3.65 to 3.78	0.97
	CST-Control	-2.34	2.02	-6.41 to 1.72	0.25
LP Proprioception	PCT-CST	1.28	1.91	-2.57 to 5.14	0.50
	PCT-Control	4.13*	1.87	0.36 to 7.90	0.03
	CST-Control	2.84	2.04	-1.27 to 6.97	0.17
ODI	PCT-CST	-0.69	1.51	-3.74 to 2.36	0.65
	PCT-Control	14.05*	1.48	-17.04 to -11.07	< 0.001
	CST-Control	-13.36*	1.62	-16.63 to -10.10	< 0.001
RMDQ	PCT-CST	0.40	0.26	-0.13 to 0.94	0.13
	PCT-Control	-4.42*	0.25	-4.94 to -3.90	< 0.001
	CST-Control	-4.82*	0.27	-5.37 to -4.28	< 0.001
SF-36	PCT-CST	0.13	1.84	-3.57 to 3.84	0.94
	PCT-Control	-1.81	1.80	-5.44 to 1.80	0.31
	CST-Control	-1.94	1.96	-3.84 to 3.57	0.32

*P < 0.05 indicates statistical significance. Abbreviations: PCT, postural control training; CST, core stability training; LP, lumbo-pelvic; ODI, Oswestry Disability Index; RMDQ, Roland–Morris Disability Questionnaire; SF-36, Short Form Health Survey; MD, mean difference; SE, standard error; CI, confidence interval.

Both PCT and CST significantly reduced pain and functional disability compared with the control group (p < 0.001), with no significant differences between the two interventions. Moreover, significant group differences were also found for functional disability as measured by the ODI (p < 0.001) and the RMDQ (p < 0.001). According to Table 3, both intervention groups exhibited significantly lower disability scores compared with the control group. However, no significant difference was observed between the PCT and CST groups.

Significant improvements in lumbo-pelvic proprioception were observed only in the PCT group compared with the control (p = 0.03). No significant changes were found for static balance or overall SF-36 scores. Additionally, no significant group differences were detected in static balance performance for either the right or left leg (p > 0.05). As shown in Table 3, although mean values were slightly higher in the PCT group, these differences were not statistically significant.

Overall, as summarized in Table 3, both exercise interventions were effective in reducing pain and functional disability, whereas improvements in proprioception were primarily observed following PCT. No significant effects were found for static balance or overall QOL.

Discussion

The present study investigated the comparative effects of PCT and CST on multiple clinical and sensorimotor outcomes in middle-aged women with CNSLBP. While both interventions were effective in improving pain and disability, only PCT demonstrated superiority in proprioceptive enhancement. No significant between-group differences were detected for static balance or overall QOL. These findings reinforce the multidimensional nature of CNSLBP and suggest that distinct neuromuscular mechanisms may underlie similar clinical improvements.

The analgesic effects observed in both intervention groups can be interpreted beyond purely biomechanical correction. According to Panjabi’s spinal stability framework, dysfunction in CNSLBP arises not only from passive tissue insufficiency but also from impaired neuromuscular control²⁷. CST likely improved segmental stiffness regulation through enhanced activation timing and coordination of deep stabilizing musculature²⁸. Deficits in the anticipatory activation of the transversus abdominis and multifidus have been consistently documented in CNSLBP populations²⁹. Restoration of this feedforward control may reduce excessive neutral zone movement and limit repetitive microtrauma, thereby decreasing peripheral nociceptive input³⁰.

However, mechanical stabilization alone does not fully explain pain reduction³¹. Contemporary pain science emphasizes central sensitization and altered cortical processing in chronic pain states³². PCT, through repeated perturbation exposure and postural adaptation demands, may have contributed to cortical reorganization and improved sensory-motor congruence³³. Tsao et al. demonstrated that CNSLBP is associated with altered motor cortex representation of trunk muscles³⁴. Repetitive sensorimotor engagement may refine cortical mapping, reduce incongruence between intended and actual movement, and subsequently attenuate nociceptive amplification³⁵.

Additionally, both interventions likely elicited exercise-induced hypoalgesia mediated by endogenous opioid and serotonergic pathways³⁶. This neurochemical mechanism provides a systemic explanation for pain reduction independent of local biomechanical change. Thus, the analgesic response observed in both groups likely reflects an interaction between peripheral mechanical stabilization and central pain modulation.

The improvement in disability indices reflects more than symptomatic relief; it likely represents restoration of movement confidence and motor adaptability³⁷. Disability in CNSLBP is likely linked to altered motor strategies characterized by trunk rigidity and excessive co-contraction^38,39. Such protective patterns increase energy expenditure and may perpetuate fatigue and discomfort during daily activities⁴⁰. CST may normalize trunk stiffness modulation, allowing more efficient load transfer across the lumbopelvic region¹⁵. Improved intersegmental coordination reduces compensatory overactivation of superficial musculature, enhancing mechanical economy⁴¹.

PCT, on the other hand, may influence disability through improved adaptability rather than stiffness. Dynamic postural tasks require continuous recalibration of center-of-mass alignment, promoting flexible motor responses instead of rigid stabilization strategies³³. This adaptability may translate into improved functional performance during unpredictable real-world tasks. From a psychosocial perspective, structured exposure to movement inherent in both interventions may disrupt fear-avoidant behavior⁴². Gradual engagement in controlled but progressively challenging tasks can recalibrate threat perception associated with spinal movement⁴³. Therefore, the comparable improvements in disability across both groups likely reflect convergence of mechanical efficiency gains and cognitive-emotional adaptation.

The superiority of PCT in improving lumbo-pelvic proprioception is a critical mechanistic finding. CNSLBP is associated with impaired joint position sense and altered trunk repositioning accuracy, potentially due to degraded muscle spindle sensitivity and altered central integration⁴⁴. PCT directly targets this deficit by repeatedly challenging alignment control under varying sensory conditions. Such tasks require precise discrimination of trunk orientation and continuous updating of afferent feedback⁴⁵. Neuroplastic adaptations may underlie these changes. Repetitive engagement of afferent-efferent coupling strengthens sensorimotor loops and refines cortical somatosensory representation⁴⁶. Studies on cortical “smudging” in chronic pain suggest that reduced representational clarity contributes to impaired motor accuracy⁴⁷. By enhancing sensory resolution, PCT may restore more accurate internal models of trunk position.

In contrast, CST emphasizes co-contraction and stabilization strategies that may increase trunk stiffness but not necessarily enhance fine-grained position sense discrimination⁴⁸. This mechanistic divergence explains why proprioceptive improvement was specific to PCT despite similar reductions in pain and disability.

The absence of significant between-group differences in static balance should not be interpreted as the absence of neuromuscular adaptation. Quiet standing represents a relatively low-demand postural task that relies heavily on ankle strategies rather than trunk-centered control⁴⁹. In individuals without severe baseline balance impairment, ceiling effects may limit detectable improvement. Furthermore, CNSLBP, related instability is more prominent during transitional movements or perturbation challenges rather than during static stance⁵⁰. It is therefore plausible that dynamic balance or reactive postural control would have revealed more substantial between-group differentiation. The selection of the static single-leg stance may have underestimated trunk-specific adaptations induced by the interventions.

Additionally, balance is a multi-system function involving vestibular, visual, and somatosensory integration⁵¹. Improvements localized to trunk control may not significantly influence global balance measures unless task difficulty sufficiently taxes the central integration system.

The lack of significant changes in the overall QOL underscores the complexity of chronic pain beyond physical impairment. Health-related QOL encompasses emotional well-being, social participation, and role limitations, domains not exclusively driven by biomechanical improvement⁵². Although pain reduction contributes to improved perception of health, psychosocial factors such as depression, catastrophizing, occupational stress, and social support play substantial roles⁵³.

Exercise-based interventions primarily targeting neuromuscular function may not sufficiently modify cognitive-emotional constructs within an eight-week timeframe⁵⁴. Integration of behavioral therapy or pain education components might be necessary to produce measurable shifts in broader QOL domains. Therefore, the findings suggest that while motor rehabilitation is essential, it may be insufficient as a standalone strategy for comprehensive biopsychosocial recovery.

The present findings advocate for impairment-based rehabilitation rather than protocol-driven prescription. CST appears particularly suitable in individuals exhibiting deficits in deep trunk activation and segmental stiffness control. PCT may be more appropriate for patients presenting with impaired joint position sense or altered postural adaptability.

Importantly, since both interventions effectively reduced pain and disability, clinicians may tailor programs based on individual motor phenotype, patient preference, and resource availability. Combining both approaches sequentially or concurrently may potentially target complementary subsystems of spinal stability and yield additive effects.

This study has some limitations. First, the sample was limited to middle-aged women with CNSLBP, which may restrict generalizability. Second, the absence of long-term follow-up prevents assessment of sustained treatment effects. Third, no objective neurophysiological measures such as electromyography or motion analysis were used, limiting mechanistic interpretation. Fourth, psychological factors influencing pain and motor control were not evaluated. Fifth, intervention adherence and session attendance rates were not formally quantified, which may influence the interpretation of the findings. The absence of an active control group may also limit the ability to control for placebo or attention effects. Furthermore, participant blinding was not feasible due to the nature of exercise interventions, which may introduce performance bias despite assessor blinding. Finally, the sensitivity of the static balance assessment may have been insufficient to detect subtle between-group differences.

Future research should employ dynamic perturbation testing, incorporate neurophysiological measurements, and examine long-term retention of motor adaptations. Stratified randomized trials based on baseline proprioceptive or motor control deficits could further refine personalized intervention strategies.

In conclusion, both CST and PCT were associated with improvements in pain and disability in women with CNSLBP. PCT demonstrated greater improvements in lumbo-pelvic proprioception compared with the control group. These findings suggest that CST and PCT may have differential effects on aspects of neuromuscular function. Rehabilitation programs for CNSLBP may benefit from incorporating both stabilization- and sensorimotor-oriented exercises tailored to functional impairments.

Abbreviations

CNSLBP

Chronic non-specific low back pain

CST

Core stability training

CI

Confidence interval

LP

Lumbo-pelvic

MD

Mean difference

ODI

Oswestry Disability Index

PCT

Postural control training

RMDQ

Roland–Morris Disability Questionnaire

SF

Short form

SE

Standard error

VAS

Visual Analog Scale

Author contributions

Mohammad Ali Seyed Hosseini did Conceptualizing, Methodology, Software, Validation, Investigation, Data Curation, Writing Original Draft, Review & Editing, Supervision, and Project Administration. Shaghayegh Bozorgzad Fahadan did Conceptualizing, Software, Methodology, Validation, Formal analysis, Investigation, Data Curation, Writing Original Draft, and Project Administration. Hamid Tabatabaei did Conceptualizing, Software, Methodology, Validation, Formal analysis, Investigation, Data Curation, and Project Administration. Mostafa Jalili Bafrouei did Methodology, Validation, Investigation, Data Curation, Writing Original Draft, Review & Editing, and Supervision.

Data availability

All relevant data are included in the article.

Declarations

Competing interests

The authors declare no competing interests.

Ethics statement and consent to participate

All participants in the study were assured that their information would remain confidential and be safeguarded by the researcher. Additionally, they were informed that they could withdraw from the study at any stage if they so wished. The study adhered to the ethical guidelines set by the Research Ethics Committee of the Islamic Azad University, Science and Research Branch, Tehran, under the ethical code identifier IR.IAU.SRB.REC.1403.295. Before the commencement of the research and measurements, participants were requested to provide informed consent by completing a consent form. The research procedures were clearly explained to them. Key ethical principles observed during the study included obtaining informed consent, maintaining the confidentiality of questionnaire data, and ensuring that no costs were imposed on the participants. Furthermore, participants retained the right to withdraw from the study at any time.

Patient consent statement

Written informed consent was obtained from all participants before participation in the study.