Effect of Adding Diaphragmatic Breathing Exercises to Core Stabilization Exercises on Pain, Muscle Activity, Disability, and Sleep Quality in Patients With Chronic Low Back Pain: A Randomized Control Trial

Abstract

Objective

The purpose of this study was to test the effect of adding diaphragmatic breathing exercises (DBEs) to core stabilization exercises (CSEs) for patients with chronic low back pain (CLPB).

Methods

Twenty-two patients with CLPB were randomly allocated to the experimental (DBE + CSE) or control group (CSE only). They were given 12 treatment sessions 3 times a week for 4 weeks. Patients were evaluated before and after the 12 sessions. Surface electromyography of transverse abdominis, Oswestry Disability Index, Fear Avoidance Belief Questionnaire, Pittsburgh Sleep Quality Index, Numeric Pain Rating Scale, and chest expansion were used as outcome measures for pain, muscle activity, disability, and sleep quality.

Results

The outcome measure scores showed statistical significance of (P = .01) in time effect on muscle activity, sleep quality, disability score, pain score, fear-avoidance belief of patients and chest expansion; and group effect on Fear Avoidance Belief Questionnaire and physical activity parameter (P = .05). An interaction effect (time x group) on muscle activity for right transverse abdominus during tuck in (P = .01) and chest expansion (P = .01) was also found; however, no significant difference was found related to other parameters.

Conclusion

The combination of DBE and CSE interventions compared to CSE alone showed improvement in the measured parameters for patients with CLBP. Incorporating DBE with CSE also improved muscle activation and chest expansion.

Introduction

Low back pain (LBP) is a common health problem that has become a substantial economic burden worldwide.¹ The reported recurrence rate of LBP is 80%.² Chronic LBP (CLBP) is described as pain that persists for over 3 months.^2,3 The etiological factors for CLBP include spinal instability,⁴ impaired postural control,⁵ altered lumbosacral proprioceptive acuities,⁶ altered patterns of activation of abdominal and extensor muscles,⁷ fatigability of the back extensors, and alteration in the somatosensory system.⁸ A sedentary lifestyle is also associated with weakness, which compromises the stability of the trunk.⁹

Chronic low back pain is etiologically related to the core trunk musculature, a box-like structure surrounded by the abdominal, paraspinal, diaphragm, and pelvic floor muscles,¹⁰ which provides primary stability to the lumbar spine. Core trunk muscles have been classified into global and local according to location and function.¹¹

Core stabilization exercises (CSEs) have been included in the management of patients with CLBP.¹² During this training, the local muscles are activated through isometric contraction of the transverse abdominis (TrA), co-contraction of TrA, and lumbar multifidus in order to gain segmental control over primary stabilizers.⁴ The diaphragm is the primary inspiratory muscle that affects the stability of the lumbar spine during postural activity.¹³ The proper activation of the diaphragm during normal breathing expands the lower ribs from inside to outside. This expansion provides space for increased intra-abdominal pressure. The TrA acts like a corset by providing stretching forces on the fascia, which builds up the intra-abdominal pressure that stabilizes and unloads the lumbar spine.⁴ Studies have revealed that diaphragm fatigability is common among individuals who have recurrent LBP, thus reducing the pulling forces of TrA on the fascia, which compromises the stability of the lumbar spine.¹⁴

Chronic low back pain initiates a cascade of cognitive-behavioral processes that affect the somatic, cognitive, emotional, and behavioral domains,¹⁵ which causes functional changes in the neural system that affect the quality and quantity of sleep.¹⁶ According to one study, CLBP has a significant relationship with sleep, with 55% of participants reporting restless/light sleep following the onset of CLBP.¹⁷ Chronic pain is known to alter the microstructure of sleep, which leads to increased perception of pain after sleep deprivation.¹⁸ Thus, pain and poor sleep create a repetitive cycle in which one factor worsens the other.¹⁹

It is believed that pain intensity, strain, and muscle spasms can lead to reduced chest expansion (CE).²⁰ Low back pain is known to cause respiratory problems; for example, CE was significantly reduced among patients with LBP.²¹ A previous study has reported physiotherapy programs, including massage, hot pack, and interferential current, has improved CE in patients with LBP.²² Also, patients with LBP may enhance their respiratory function, including CE, by respiratory exercises.²¹

Patients with LBP frequently report high levels of fear-avoidance,²³ which is the fear of physical activities that could elicit pain.²⁴ Behaviors manifested by fear-avoidance have been associated with increased levels of disability and pain intensity in patients with chronic musculoskeletal pain.²⁵ Previous studies have provided evidence that patients with LBP who had high levels of pain-related fear showed greater levels of disability.²⁶

Although trials have shown that core training improves pain and disability in patients with CLBP, to the best of our knowledge, the effect of incorporating diaphragmatic breathing exercises (DBEs) with CSE in improving respiratory parameters and influencing the lumbar stability in patients with CLBP has not been explored. Thus, this study aimed to evaluate the effect of incorporating DBE with CSE on pain, muscle activity, disability, and sleep quality in patients with CLBP.

Methods

Participants

A sample size of 22 participants was achieved using Software G. Power 3.1.9.2 (Kiel University) based on a previous study.⁹ The configuration error was set at α = .05, power was .95 with the effect size of 1.67. The sample size was increased to 25 to compensate for any dropouts (12% of the achieved sample size). Twenty-five patients with CLBP were chosen by convenience sampling method from the outpatient physiotherapy clinic of Jamia Millia Islamia University, New Delhi, India, for this single-blinded, randomized controlled trial. Three participants dropped out after the initial assessment as they were unwilling to comply with the treatment protocol period of 4 weeks, leaving a total of 22 participants. The study was conducted from December 2018 to April 2019.

The inclusion criteria were as follows: patients with CLBP (>3 months) between the 12th rib and inferior gluteal fold without leg pain or neurological symptoms, both men and women aged between 20 and 60 years, and with an average pain score between 2 to 7 on a numerical pain rating scale (NPRS). Exclusion criteria included the presence of any limiting condition that would make diaphragmatic breathing contraindicated, cardiopulmonary disease or disorder, history of any surgery in the past year, history of any major injury in the past 3 months, osteoporosis, patients on any medication that affected sleep directly, cancer and orthopedic problems -limiting physical activity or exercise capacity, and a body mass index higher than 30. Pregnant women or patients who had taken any physiotherapy treatment in the past 3 months were also excluded.

Chit-based randomization was used to allocate the patient into 2 groups. An independent researcher who was not involved in treatment sessions performed the randomization. The envelope was opened only at the time of treatment by the researcher responsible for implementing the exercise program. We also requested that the patients not discuss their treatment protocol with others so that they were self-blinded.

Ethics

The study was approved by the institutional ethical committee of Jamia Millia Islamia (Proposal 31/10/183/JMI/IEC/2018) before the commencement. It was prospectively registered in the Clinical Trials Registry - India (REF/2019/04/025420 AU). We followed the Consolidated Standards of Reporting Trials guidelines to conduct this study.²⁷ The clinical practice guidelines as prescribed by the European medicine agency (2016)²⁸ and the Declaration of Helsinki²⁹ were also followed. The written consent form was given to all the patients. They were informed about the nature of the exercises, and a signed consent was obtained from all the patients.

Study Procedure

A total of 22 patients were randomized into 2 equal groups (experimental and control group). The flowchart of the study is presented in Figure 1. The patients were submitted to 4 weeks of treatment sessions, which were held 3 times a week and lasted around 45 minutes per session. The treatment program was done under the supervision of either of the researchers. The interventions proposed for the experimental group (DBE + CSE) and control group (CSE only) are described as follows:

Fig 1.

Study flowchart. EMG, electromyography; FABQ, Fear-Avoidance Belief Questionnaire; NPRS, Numerical Pain Rating Scale; ODI, Oswestry Disability Index; PSQI, Pittsburgh Sleep Quality Index.

Core Stabilization Exercise

The session included 5 minutes of stationary cycling warm-up, 20 minutes of CSE involving 10-second holds, 10 repetitions, 3 to 4 seconds of rest between each contraction, and doing 3 sets. The session was wound up with 5 minutes of cool-down by stationary cycling. The exercise for core stabilization was incorporated into 6 stages (Table 1). The progression of the stages was not quantified; it was made when the patient could comfortably do the previous stage exercise without fatigue.³⁰

Table 1.

Description of Core Stabilization Exercise Used in the Study

Stages	Description of Exercises
Stage 1	In the supine position, the PBU was used to activate the transverse abdominis as the patient drew their navel in towards the spine, and pressure in the PBU rose from 40 mmHg to 42 mmHg. Secondly, an abdominal draw-in maneuver was performed in a 4-point kneeling position. And lastly, in this stage, the arm lift maneuver was performed in a sitting position.
Stage 2	The co-contraction of transverse abdominis and lumbar multifidus was achieved by alternating arm leg lift in crook lying position and posterior pelvic tilt.
Stage 3	Patients sat on a stable surface with feet on the ground and were asked to lift their heel from the ground, hip abduction as doing clamshell while sitting, and horizontal arm abduction while maintaining abdominal tuck-in throughout the exercise.
Stage 4	Patients were asked to do heel slide and clamshell in the supine position, hip abduction, and hip and knee flexion in the side-lying position while maintaining abdominal tuck-in throughout the exercise.
Stage 5	Patients sat on an unstable surface and maintained balance while moving the trunk from the hip joint forward and backward. They then rotated the lumbar spine to both sides and maintained the position to improve control over their movement while doing a diagonal pattern (chopping) on each side. Lastly, they lifted the knee while maintaining balance and abdominal tuck-in throughout the exercise.
Stage 6	Patients were asked to do bridging, leg cycling, and leg lift in a quadruped position.

PBU, pressure biofeedback unit.

Diaphragmatic Breathing Exercises

The DBE included 2 sets of 6 repetitions of diaphragmatic breathing in 4 unique positions. The inspiration was quiet and normal through the nose, and the abdomen rose with inspiration. Exhalations were done through the mouth, and while exhaling patients were instructed to lift the pelvic floor. The TrA, internal and external oblique, pelvic floor muscles, and diaphragm share the connection with thoracolumbar fascia. During exhalation, the diaphragm relaxes and returns to the cupule position, and the contraction of the abdomen favors this breathing mechanism. The lift had to be maintained by the patient in the exhalation phase. The breathing exercise sequence was as follows: (1) in the supine lying position, an upward stretch of the arm incorporated inhalation, maintaining the spine neutral and lifting the pelvis during exhalation; (2) in the long sitting position, lower limb was straightened, and arms extended in front of the chest; the spine elongated more vertically and lifted the pelvic floor during the exhalation phase of breathing; (3) in the kneeling position, exhalation was accompanied by lateral bending of the trunk while lifting the pelvic floor; and (4) in the kneeling position, one of the patient's arms was bent in front of the eyes, and the other was resting on the floor. The trunk was rotated to the right during the inhalation phase of breathing, keeping the body rotated and stretched while lifting the pelvic floor during exhalation.

Outcome Measures

There were 3 primary outcome measures in this study—surface electromyography (sEMG) for TrA during abdominal tuck-in maneuver and curling up against therapist resistance; the Oswestry Disability Index (ODI) was used to measure functional disability; and the Pittsburgh Sleep Quality Index (PSQI) was used to measure the quality of sleep.

There were 3 secondary outcomes in this study—the NPRS was used to measure the pain intensity; the Fear-Avoidance Belief Questionnaire (FABQ) was used to measure the avoidance of physical activity and work-related activity, and CE was used to assess the expansion of the chest. We measured the primary and secondary outcomes at the baseline and the end of the intervention (Week 4).

Primary Outcomes

The muscle activity of TrA was recorded by sEMG. Disposable silver-silver chloride sEMG electrodes with bipolar configuration, rectangular-shaped strong adhesive fixation, and a dimension 4.4 × 1.2 cm (Medico Electrodes International Ltd) were used. The Surface ElectroMyoGraphy for the Non-Invasive Assessment of Muscles recommendations were followed for the sEMG testing.³¹ The skin was shaved, abraded, and cleaned with a 2% alcohol swab before the electrode placement. This preparation was done to reduce the skin impedance to less than 5 kΏ.³² Electrodes were placed approximately 2 cm medial and inferior to the anterior superior iliac spine, with an inter-electrode distance of 20 mm for TrA. The right and left TrA muscle activity was measured during the abdominal draw-in maneuver (sEMG R1 and sEMG L1, respectively), and right and left TrA muscle activity was measured during curl-up against therapist resistance (sEMG R2 and sEMG L2, respectively). The isometric contractions were performed 3 times for 5 seconds, with a 30-second rest period between each effort.⁹ The mean of 3 contractions was taken for evaluation. The sEMG data was collected through adhesive surface electrodes (Powerlab 15T, AD Instruments, Australia). The activity of the TrA muscle was recorded in the form of root mean square value.³³ A Butterworth bandpass filter with a cut-off frequency between 20 to 500 Hz, and a sampling rate of 1000 Hz was used. The maximal voluntary contraction (MVC) was calculated for the center for 3 seconds, and the mean of 3 trials of the MVC was used for further calculation. The same procedure was repeated after a 48-hour interval to determine the test-retest reliability of MVC for each muscle. For the normalization purpose, the MVC of the first test was used to provide %MVC of both testing conditions.

The ODI is a self-administered questionnaire developed by Fairbank in 1980. This index is considered the gold standard amongst functional outcome tools of CLBP. The questionnaire has questions related to functional activities of pain intensity, personal care, walking, sitting, lifting, standing, sleeping, sex life, traveling, and social life. A score of 2% to 20% indicates minimal disability, 21% to 40% indicates moderate disability, 41% to 60% for severe disability, 61% to 80% for the physically disabled, and 81% to 100% indicates a patient who is bed-bound.³⁴

The PSQI was used to measure sleep quality. It is a self-rating questionnaire developed by Buysse et al, in 1988,³⁵ to measure the quality of sleep over the past month. It contains 19 self-rated questions set into the following 7 components: patientive sleep quality, sleep latency (time to fall asleep), sleep duration, habitual sleep efficiency (ratio of hours slept as compared to hours spent in bed), sleep disturbances, use of sleeping medications, and daytime dysfunction. The total of the 7-component score gives the global PSQI score, ranging from 0 to 21. A score of more than 5 shows poor sleep quality. The overall reliability coefficient (Cronbach's alpha) of 0.736 indicated that the PSQI has an acceptable consistency in the Indian population.³⁶

Secondary Outcomes

The NPRS is an 11-point numeric scale ranging from 0 to 10 in which 0 indicates no pain, 1 to 3 represents mild pain that interferes in the activities of daily living (ADLs), 4 to 6 represents moderate pain that interferes significantly with ADLs, and 7 to 10 indicate the worst pain that makes a person unable to perform ADLs.¹¹ Waddell's FABQ has 16 statements related to work (FABQ-W) and physical activity (FABQ-PA). These statements are graded on a 0 to 6 Likert scale. The scoring of subclasses for FABQ-W ranges from 0 to 42, and for FABQ-PA ranges from 0 to 24. The internal consistency has been reported to be 0.88 and 0.77 for FABQ-W and FABQ-PA, respectively.³⁷

Chest expansion was measured using a non-elastic, flexible measuring tape at full inhalation (patient felt as big as possible) and full exhalation (patient felt as small as possible). The lower thoracic expansion was measured at the level of the xiphoid process.³⁸ The normal chest excursion was reported as 8.48 ± 0.64 cm in a group whose mean age was 24.5 ± 2.9 years.³⁹

Statistical Analysis

All the data were analyzed by using SPSS software version 21 (IBM Corp, Armonk, New York). The normality of data was evaluated by the Shapiro-Wilk test. One-way analysis of variance was used at baseline to test the variables. The results found that all data (NPRS, sEMG R1, sEMG L1, sEMG R2, sEMG L2, ODI, PSQI, FABQ-PA, FABQ-W, and CE) were equal at baseline (P > .05), which made both groups equal at baseline (Table 2). Also, the assumption of homogeneity was met for all the variables (P > .05), as shown in Table 3. A repeated measure analysis of variance was employed to test the main effect for the group (experimental and control group), time (pre and post), and interaction effect (time x group) outcome measure. The mean difference with their CI at 95% was also calculated for the analysis of differences between variables. The significant level was set at 5%.

Table 2.

Summary of One-Way ANOVA to Test the Variables at Baseline

Variables		Mean Square	F	Significance
NPRS	Between-groups	0	0	1
	Within-groups	1.055
sEMG R1	Between-groups	0.002	0.4	0.534
	Within-groups	0.005
sEMG L1	Between-groups	0.001	0.168	0.686
	Within-groups	0.004
sEMG R2	Between-groups	0	0.014	0.906
	Within-groups	0.006
	Total
sEMG L2	Between-groups	0	0.057	0.814
	Within-groups	0.007
ODI	Between-groups	89.607	0.541	0.471
	Within-groups	165.635
GPSQI	Between-groups	18.182	1.953	0.178
	Within-groups	9.309
FABQ-PA	Between-groups	18.182	0.586	0.453
	Within-groups	31.045
FABQ-W	Between-groups	6.545	0.088	0.77
	Within-groups	74.191
CE (cm)	Between-groups	0.293	0.19	0.668
	Within-groups	1.544

ANOVA, analysis variance; CE, chest expansion (in cm); FABQ-PA, Fear-Avoidance Belief Questionnaire physical activity; FABQ-W, Fear-Avoidance Belief Questionnaire work score; GPSQI, Global Pittsburgh Sleep Quality Index score; NPRS, numerical pain rating scale; ODI, Oswestry Disability Index score; sEMG R1, L1, R2, and L2, surface electromyography for right and left transverse abdominus during tuck in (1) and curl up against maximal resistance (2), respectively.

Table 3.

Test of Homogeneity of Variances

Variables	Levene Statistic	Significance
NPRS	0.732	.402
sEMG R1	0.152	.7
sEMG L1	0.512	.482
sEMG R2	0.2	.659
sEMG L2	0.12	.732
ODI	0.054	.819
GPSQI	2.9	.104
FABQ-PA	0.004	.948
FABQ-W	0.018	.896
CE (cm)	3.491	.076

CE, chest expansion (in cm); FABQ-PA, Fear-Avoidance Belief Questionnaire physical activity; FABQ-W, Fear-Avoidance Belief Questionnaire work score; GPSQI, Global Pittsburgh Sleep Quality Index score; NPRS, numerical pain rating scale; ODI, Oswestry Disability Index score; sEMG R1, L1, R2, and L2, surface electromyography for right and left transverse abdominus during tuck in (1) and curl up against maximal resistance (2), respectively.

Results

The characteristics and features of the patients are given in Table 4. The demographic data showed no statistically significant difference between the groups at the baseline. The mean and SD of pre-and post-intervention muscle activity, disability, sleep quality, fear avoidance belief of the patients, pain intensity, and CE for both the groups are reported in Table 5.

Table 4.

Baseline Characteristics

Measures	DBE + CSE	CSE Only	P Value
Age (y)—mean (SD)	25.3 (3.4)	25.6 (4.2)	.898
Weight (kg)—mean (SD)	63.6 (5.1)	61.6 (13.3)	.17
Height (cm)—mean (SD)	162.6 (7.8)	161.6 (11.1)	.221
BMI (kg/m²)—mean (SD)	24.1 (2.6)	23.3 (3.3)	.249

BMI, body mass index; CSE, core stabilization exercises; DBE, diaphragmatic breathing exercises.

Table 5.

Mean ± SD of Outcome Measures of Both the Groups

Variables	(DBE + CSE)		(CSE Only)
	Pre	Post	Pre	Post
Primary outcome
sEMG R1	0.07 (0.06)	0.164 (0.1)	0.09 (0.07)	0.11 (0.08)
sEMG L1	0.76 (0.07)	0.163 (0.12)	0.06 (0.04)	0.094 (0.05)
sEMG R2	0.11 (0.06)	0.16 (0.08)	0.11 (0.08)	0.15 (0.08)
sEMG L2	0.1 (0.07)	0.16 (0.07)	0.11 (0.09)	0.13 (0.08)
ODI	29.4 (13.9)	8.17 (10.2)	25.4 (11.6)	10.6 (13.02)
GPSQI	9.1 (3.7)	4.64 (3.1)	7.3 (2.1)	3.73 (1.8)
Secondary outcome
NPRS	5.6 (1.1)	1.00 (1.26)	5.64 (0.9)	2.81 (1.53)
FABQ-PA	14.7 (5.8)	4.36 (4.5)	16.5 (5.2)	9.0 (8.0)
FABQ-W	24.8 (8.9)	9.36 (10.9)	23.7 (8.3)	15.0 (12.4)
CE (cm)	3.1 (1.4)	5.74 (1.6)	3.3 (0.9)	4.73 (1.2)

CE, chest expansion; CSE, core stabilization exercises; DBE, diaphragmatic breathing exercises; FABQ-PA, Fear-Avoidance Belief Questionnaire physical activity; FABQ-W, Fear-Avoidance Belief Questionnaire work score respectively; GPSQI, Global Pittsburgh Sleep Quality Index score; NPRS, numerical pain rating scale; ODI, Oswestry Disability Index score; sEMG R1, L1, R2, and L2, surface electromyography for right and left transverse abdominus during tuck in (1) and curl up against maximal resistance (2), respectively.

There was statistically significant main effect for time for sEMG R1, sEMG L1, sEMG R2, sEMG L2, ODI, global quality sleep quality index (GPSQI), NPRS, FABQ-PA, FABQ-W, and CE. There was statistically significant group effect for FABQ physical activity (P = .05). There was no significant difference in sEMG R1, sEMG L1, sEMG R2, sEMG L2, ODI, GPSQI, NPRS, FABQ-W, and CE (Table 6).

Table 6.

Summary of Repeated Measure ANOVA

Variables	Main Effect (time)		Main Effect (group)		Main Effect (time × group)
	P	Partial Eta Squared (Effect Size)	P	Partial Eta Squared (Effect Size)	P	Partial Eta Squared (Effect Size)
Primary outcome
sEMG R1	.01	0.491	.716	0.007	.01	0.289
sEMG L1	.01	0.469	.287	0.056	.144	0.103
sEMG R2	.01	0.567	.816	0.003	.637	0.011
sEMG L2	.01	0.531	.692	0.008	.087	0.139
ODI	.01	0.734	.413	0.042	.069	0.192
GPSQI	.01	0.630	.699	0.008	.413	0.036
Secondary outcome
NPRS	.01	0.837	.388	0.057	.09	0.199
FABQ-PA	.01	0.591	.055	0.225	.149	0.134
FABQ-W	.01	0.589	.487	0.026	.265	0.065
CE	.01	0.803	.474	0.026	.01	0.286

ANOVA, analysis of variance; CE, chest expansion in centimeter; FABQ-PA, fear-avoidance belief questionnaire physical activity FABQ-W, fear-avoidance belief questionnaire work score respectively; GPSQI, Global Pittsburgh Sleep Quality Index score; NPRS, numerical pain rating scale; ODI, Oswestry Disability Index score; sEMG R1, L1, R2, and L2, surface electromyography for right and left transverse abdominus during (1) tuck in and (2) curl up against maximal resistance, respectively.

There was a statistically significant interaction effect (time x group) for sEMG R1 and CE. There was no significant change shown in ODI. There was no significant difference in sEMG L1, sEMG R2, sEMG L2, GPSQI, FABQ-PA, FABQ-W, and NPRS (Table 6). No patients reported any adverse effects during the exercise period.

Discussion

This study examined the effects of deep breathing exercises in addition to CSE on pain, muscle activity, disability, and sleep quality in patients with CLPB. We found that the DBE and core stabilization program effectively improved the TrA muscle of the right side when performed with a tuck-in maneuver and in the CE in patients with CLBP. The results of this study suggest that DBE increased the TrA muscle activity during an abdominal draw-in maneuver to a greater extent when compared to CSE alone in CLBP rehabilitation.

The results of the present study for TrA muscle activity are in line with the findings of a former study that showed improved TrA muscle activity after administering forced exhalation exercises in CLBP.⁴⁰ Regarding the lability of the lumbar spine, the extension pattern of the spine causes excessive contraction of the erector spinal muscle, which, in turn, increases lumbar lordosis, hindering the mutual contractility of TrA and spinal multifidus and decreasing the diaphragm function. The breathing exercises have been shown to decrease the extension angle, which, in turn, enhanced the breathing pattern and stimulated the abdominal muscles including the TrA.⁴⁰ Our results support previous research by concluding that the activities of the TrA, rectus abdominis, and other muscles increased significantly after participation in the breathing exercises program. Interestingly, there was a significant and meaningful difference in the TrA alone with respect to the changes in trunk muscle activities.⁹

The present study also showed significant improvement in CE. A possible mechanism for this could have been that diaphragmatic breathing enhanced the diaphragmatic neural drive, which may have led to a greater contraction of the diaphragm, thereby improving the CE of the lower ribs.⁴¹ Therefore, these results showed that DBE was more effective in improving CE compared to core stabilization alone. In this study, CE significantly improved compared with those of the core stabilization group. Our findings are similar to previous findings in which the respiratory muscle exercises improved CE capabilities.^9,40,42 In summary, the use of diaphragmatic breathing combined with CSE may yield better results in terms of muscle activation, CE, and functional improvement in an individual with CLBP.

Limitations and Future Studies

The sample of participants for this study was small, and thus the findings are limited; larger studies should be performed in the future. The breathing patterns were not assessed during the initial assessment in this study. Since there may be a correlation between LBP and breathing pattern disorders, this should have been considered. The absence of a control group so that we could observe the treatment groups compared to natural progression during the same time makes it challenging to determine if the pre/post changes are due to time effect or not. The study did not conduct a prolonged follow-up; therefore, we do not know if there are lasting or long-term effects of the interventions.

Further studies are needed to investigate the long-term effect of DBE along with CSE. Future studies with follow-ups are also recommended. We could not study the difference between men and women, which might be an interesting area for future research. Evaluation of other sleep parameters could be incorporated to make the results more generalized. A study that can establish a definite activation of the diaphragm and its effect on the lumbar spine is also recommended.

Conclusion

The results of this study suggest that diaphragmatic breathing and a combination of diaphragmatic breathing and CSE helped in improving the condition in patients with CLBP. Incorporating DBEs with traditional core exercises had additional benefits of improving muscle activation and CE.

Funding Sources and Conflicts of Interest

No funding sources or conflicts of interest were reported for this study.

Contributorship Information

Concept development (provided idea for the research): S.M.

Design (planned the methods to generate the results): S.M., Z.V.

Supervision (provided oversight, responsible for organization and implementation, writing of the manuscript): T.T., I.I., Z.V.

Data collection/processing (responsible for experiments, patient management, organization, or reporting data): S.M.

Analysis/interpretation (responsible for statistical analysis, evaluation, and presentation of the results): S.M., M.A.

Literature search (performed the literature search): S.M.

Writing (responsible for writing a substantive part of the manuscript): S.M., T.T.

Critical review (revised manuscript for intellectual content, this does not relate to spelling and grammar checking): T.T., M.A., I.I., Z.V.

Practical Applications.

• •This study was performed on 22 people with chronic low back pain.
• •Diaphragmatic breathing exercises with traditional core exercises improved muscle activation and chest expansion.
• •Diaphragmatic breathing pattern improved overall abdominal fitness and pulmonary functions.

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