IJCRR

Introduction

Mechanical low back pain refers to pain caused by abnormal stress and strain on vertebral column muscles which can be due to poor posture, ill-designed ergonomics or incorrect bending and lifting motions. It is the common representative muscular disorder and consists of spinal instability which further can lead to malfunctioning neuromuscular control.¹Chronic low back pain (CLBP) is normally continuous back pain lasting more than 3 months.²It is widely seen in 70-85% of the population with up to 80% of patients described at least one episode in their life.³According to the world health organization low back pain constituted 37% of all occupational hazards which occupy the first rank among all the diseases.⁴

To provide stability of the lumbar spine, core muscles strengthening and stabilization exercises are important, and Core muscles mainly consist of deep stabilizer muscles are transverse abdominis, multifidus, pelvic floor muscles etc and global muscles are erector spinae, rectus abdominis, latissimus dorsi etc.⁵ Core training emphasis strengthening and reconditioning of local and global muscles that work together to stabilize the spine.⁶ The local muscles are slow-twitch fibres while global muscles are torque-producing muscles. The inter-segmental local muscle groups provide stabilization and control over supine position with lower force production.⁷

The major problem is the weakness, lack of motor control and delayed speed of muscles contraction of deep trunk muscles such as multifidus and Transverse Abdominis muscles.⁸ Deep stabilizer muscles in chronic low back pain patients become weak and imbalanced leading to reduced proprioceptive sense which further leads to stability problems in the spine and recurrence of back pain.⁹Therefore to treat LPB, deep stabilizer muscles exercise is required to balance the muscle control and counteract muscle atrophy. Unstable training equipment, such as Swiss balls, tend to increase the difficulty of performing exercises using complete bodyweight and resistance using free weights.¹⁰ Exercises done using Swiss balls employ all body regions and extensively activities can be done in comparison with exercises done on fixed floors. Using balls for performing exercises therefore can enhance the ability of dynamic balance, stability and the flexibility of the spine and improve the sense of balance to prevent injuries.¹¹So exercises were done on a stable and unstable surface to examine its effects and measures using NPRS scale, MODI scale and surface EMG of core muscles.

Recently a study was done to see the correlation between the effects of trunk stability and LBP It has been suggested that to stabilize the trunk, correlation of deep and superficial muscles are needed as they are directly attached to the spine and stabilization exercises helps in improving the function on of neuromuscular system and hence support as well protect the spine.¹²LSE also helps in maintaining the neutral position of the spine, which is best for unloading of the spine. But no study shows the effectiveness of LSE on stable and unstable surfaces and their impact on global and local core muscle activation patterns in CLBP.¹³

Therefore, the study aimed to determine effective treatment protocol for chronic low back patients by performing LSE on the stable or unstable surface and to find out which exercise is best for reduction of pain, improving the core muscles activities and decreasing the functioning disability in chronic low back pain.

Materials and methods

Design

Pre-test and post-test experimental design.

Participants and Procedure

A total of 24 male and female subjects having chronic non-specific low back pain were recruited based on inclusion and exclusion criteria. Participants were informed about the purpose, procedure and effects of the treatment before the experiment and written consent was taken from them. Ethical clearance was taken from Institutional Ethical Committee Jamia Millia Islamia.

Inclusion Criteria

Non-specific low back pain experienced at least from last 3 months, age 18- 45 years, NPRS score from 3 to 6, MODI score from 20% to 60% (minimal disability to moderate disability), able to attend the hospital for treatment over 6 weeks, Prone instability test positive, Extensor endurance test positive, Aberrant movement pattern present.¹⁰

Exclusion criteria

 Patients who have infectious pathology or injury received surgical interventions for their back pain or were awaiting surgery, diagnosis of clinical depression or other specific psychiatric pathology, contradicted to do exercises.¹⁰

All the participants were advised to avoid any other treatment interventions and they were recruited for a 6-week training program.

Measures and Interventions

Demographic data of subjects age (2.1346±4.475), height (1.676±7.471.), weight (62.130±0.113) and BMI (21.922±0.610) were taken along with the pre-test outcome measures which include pain level, functional disability and EMG of transverse abdominis and erector spinae. To measure the pain, Numerical Pain Rating Scale (NPRS) was used with an 0-10 integral rating scale. Modified Oswestry Disability Index (MODI) was used to assess the functional disability in CLBP.¹⁴The coefficient of Cronbach’s alpha was 0.92 and test-retest correlation reliability was 0.93.¹⁰

Surface EMG of erector spinae and transverse abdominis were taken by attaching disposable bipolar electrodes with a diameter of 1 cm attached parallel to muscle fibres. Skin preparation was done before the experiment to reduce impedance. Muscle activity of Transverse Abdominis was recorded by attaching surface electrode 2 cm away from the anterior superior iliac spine anteromedially while the activation pattern of the Erector spinae was recorded by attaching electrodes at 3 cm apart from the spinous process at the lateral side.¹²Ground electrode was attached over the superior aspect of the iliac crest of the same side.¹⁵ Every second time of the isometric phase of each exercise the root mean square (RMS) of EMG amplitude was calculated and then mean RMS obtained from three Maximum Voluntary Contraction trials for each muscle was used to provide a basis for EMG amplitudes normalization of data obtained during the experimental exercises (%MVC). The static phase of the experimental exercise was analysed, using means of three trials. The root means square (RMS) for the 3 repetitions of TA and ES muscles were normalised using 100 (%MVC). ¹⁶

Treatments

Participants are randomly assigned into two groups by using computer randomization Group A (n=12) and Group B (n=12).In Group A patients performed  Lumbar Stabilization exercises on a stable surface along with hot fomentation for 10 min while Group B received hot packs for 10 min along with lumbar stabilization exercises on an unstable surface i.e Swiss ball. Equilibrium is maintained for 10 sec with a break of 3 seconds between repetitions for 40 min a day. Exercise protocol for both the groups was Back Bridging Exercise, Prone on Elbow, Posterior Pelvic Tilt, Abdominal Crunches and abdominal hollowing. Patients were instructed to maintain the final position for 10 sec then return to the initial position.¹⁰

Before initiation of each exercise program patients were given detailed verbal commands and visual clues or illustrations of exercise to patients emphasizing the starting and ending position. The selection of appropriate Swiss balls was based on demographic data given earlier. Group B was advised that the hip region must be parallel to the floor and the patient knee must maintain an angle of 90°while sitting on the Swiss ball .¹⁷

Duration of treatment: Both groups received treatment for 3 days a week × 6 weeks, 10 times/set, 3 sets .¹⁰

Data analysis

Data were assessed by SPSS version 17.0.Shapiro -Wilk test for the normality of the distribution scores. The demographic characteristic and the baseline criterion measure were compared between the two experimental groups at the study evaluated by an independent t-test. Then a paired t-test was applied to analyze the effect of intervention in two groups for the measures of pain (NPRS), functional disability (MODI) and muscle activation of TA and ES muscles using EMG.

Results

Patients Demographic

To prove the homogeneity between the two groups contrasting baseline criterion measurement was done using an independent t-test. No significant difference seen in baseline value of (p>0.05), Table 1

Analysis of data within groups

Paired t-test was used to distinguish the comparison between outcome variables at the baseline and Post-test measures in Group A and Group B. There was a significant difference in NPRS as pre mean of pain was 4.58(0.996) and post mean was 0.50(0.07)* in Group A and Group B pre mean was 4.75(1.138) and post mean was 0.00(0.00)*which shows the significant reduction of pain after 6 weeks of intervention. Similarly, there were significant reductions in MODI and EMG shown in figures 1A, 1B, 1C.

Analysis of data between the two groups

An independent t-test was used to compare post-test criterion measurement between Group-A and Group-B. A significant difference was seen between the groups in Pain (NPRS) and EMG activity of transverse abdominal muscle but there was no significant difference in Functional Disability (MODI) and EMG activity of Erector Spinae as shown in table 2. This reveals that lumbar stabilisation exercises done on Swiss balls were effective in decreasing chronic pain and increasing muscle activity patterns of local core muscles.