Background:

Low back pain (LBP) is highly prevalent globally, affecting people of all ages(Wu et al., 2020). In China, LBP is a leading cause of disease burden(Wu et al., 2019). Exercise therapy such as core stability training(CST), Tai Chi(TC) and education are commonly recommended treatments, but research on optimal protocols has been limited. Blood flow restriction(BFR) is beneficial for inducing muscle hypertrophy and promoting muscle strength (Hughes et al., 2019). Combined approaches using multiple modalities may provide added benefits but are understudied.

Research objectives:

1. To determine the effects of combined CST, BFR and Tai Chi on muscle physiology (muscle activation, muscle fatigue, back extensor strength, and transverses abdominus control) among working adults with LBP.
2. To determine the effects of combined CST+ BFR+Tai Chi on functional performance (gait speed, balance, proprioception, and postural sway) among working adults with LBP.
3. To determine the effects of combined CST+BFR+Tai Chi on pain intensity among working adults with LBP.
4. To determine the effects of combined CST+BFR+Tai Chi on fear among working adults with LBP.

Location of research:

Qianxinan Wutong Orthopedic Hospital, Guizhou Province, China

Instrumentations:

1. Demographic Data
2. Surface Electromyography (S-EMG)
3. Pressure Biofeedback Unit (PBU)
4. Back Extensor Strength Test (BEST)
5. Joint Repositioning Error(JRE)
6. APECS app
7. Y-Balance Test(YBT)

8.10-Meter Walk Test(10MWT)

9.Visual Analogue Scale (VAS)

10.Chinese version of the Fear-Avoidance Beliefs Questionnaire(FABQ-CHI)

Interventions:

Group A: CST+BFR+Tai Chi+Education;

Group B: CST+BFR+Education;

Group C: Tai Chi +BFR+Education;

Group D: CST+Education.

Sample size:

Considering 30% drop out. 52 participants. 13 participants in each group

Statistical analysis:

Data were processed using SPSS version 25.0 and Microsoft Excel 2010 software.

1. Demographic data = descriptive analytics.
2. All objectives = repeated measure ANCOVA (within-between interactions) for all variables.
3. The significant level is P < 0.05.

Research objectives:

1. To determine the effects of combined CST, BFR and Tai Chi on muscle physiology (muscle activation, muscle fatigue, back extensor strength, and transverses abdominus control) among working adults with LBP.
2. To determine the effects of combined CST+ BFR+Tai Chi on functional performance (gait speed, balance, proprioception, and postural sway) among working adults with LBP.
3. To determine the effects of combined CST+BFR+Tai Chi on pain intensity among working adults with LBP.
4. To determine the effects of combined CST+BFR+Tai Chi on fear among working adults with LBP.

Test methods for each indicator:

1. The RMS and MF value test by S-EMG

   For each muscle, double electrode sheets are put to the belly. The electrode placement site is as follows: ①Erecter spinae: Open 2cm lateral to the midline of the trunk, between the spinous process of the twelfth thoracic vertebra and the first lumbar vertebra. ②Multifidus: 2cm next to the L4-5 interspinous. ③Rectus abdominis: On both sides of the midline of the abdomen, 3cm away from the navel. ④Transversus abdominis: Approximately 2 cm medial to the intersection of the vertical line traversing the anterior superior iliac spine and the lower border of the costal arch.

   Test action: Back Bridge, Side Bridge, Abdominal Bridge. Each action lasts 10 seconds, and there is a 2-minute break between two adjacent actions to ensure that muscle weariness from the previous measurement does not interfere with the following measurement.

   S-EMG analysis: It is the recording of electrical activity in muscles utilizing the BioForce surface electromyography tester model JE-TB1610 and the accompanying wireless data collection equipment. The sampling frequency was 2000Hz, the above three exercise groups lasted 10 seconds each, and the original EMG signal was recorded for 10 seconds. Use the InstallShield Wizard operating software to execute 10-500Hz noise processing on the original muscle electrical data(Perchthaler et al., 2015). Then, from the 3rd to the 7th second, extract the data, remove the baseline, demodulate and smooth the original signal, take the absolute value of the signal during the demodulation process, and acquire the average value of the EMG data from the 3rd to the 7th second (RMS value, MF value).

2. Transverses abdominus control test

   In the case of muscle control, which is quantified by PBU. In the prone position, the transversus abdominis will be tested. The inflated cuff will be placed beneath the abdomen at the anterior superior iliac spine level. The patient will be asked to draw in the lower abdomen without moving the upper stomach, back, or pelvis once the PBU has been inflated to 70 mm Hg. Readings will be taken at the end of a 10-second contraction. Two submaximal force tests will be performed to familiarise participants with each test position, followed by two repeats of maximum isometric contraction. For analysis, the average of the two greatest contractions will be used(Cairns et al., 2000).

3. Back extensor strength test

   The participant will be seated on the treatment table with their head in the midline, trunk straight, arms along their body, palms facing upwards, and feet over the table's edge. The dynamometer will be placed at the inferior angle of the scapulae, in the center of the back between the shoulder blades. The therapist will be above and to the side of the patient. The test will be executed by the guidelines of Yang et al. (2020). After obtaining the proper starting posture, the participant will be asked to relax their arms, lift their head and chest, and push back against the dynamometer for 5 seconds with maximal force (N) .

4. Lumbar proprioception test

   The procedure utilized for the proprioception test was reported by Puntumetakul(2018). "The participant was seated (90° hips and knees) with feet on the ground and hands on thighs, and the examiner guided the participant into the neutral lumbar spine position." The center of the 10-centimeter tape measure was placed on sacral segment 1 (S1) as the measurement's starting point. The start point was marked by a laser pointer with a stable foundation. The examiner advised the participant to "remember the target position, then perform the maximum anterior and posterior pelvic tilt twice, holding each position for five seconds," before returning to the neutral target position. As a combined repositioning error, deviation from the starting location was assessed in centimeters. The participant received no feedback regarding any errors. The participants practiced the relocation test twice before the evaluation. This examination process was repeated three times with one-minute rest intervals in between. For analysis, the mean values will be employed.

5. Trunk postural sway test

   According to Trovato et al.(2020), APECS will record the participants in a standing stance for the 30s, and participants will be asked to wear little clothes to reduce biases associated with incorrect landmark positioning during the postural analysis; for the same reason, trained clinicians will place markers on the participants' bodies in correlation to the app's specified landmarks. One video will be taken for the sagittal plane (left). Participants will be told to keep their feet the same width as their shoulders. Finally, the videos that meet the regulations will be imported into the video analysis system in APECS for analysis. The maximum angle of the torso wobbles will be recorded and used for analysis.

6. Standing dynamic balance test

   While standing on one leg (barefoot) in a central location on the Y-Balance Test instrument, with hands on the wing of the ilium, the subjects will be asked to move the pointer as far as possible in three directions - anterior, posteromedial, and posterolateral. All Y-Balance Test efforts will be made in the same order: first in the anterior direction, then in the posterolateral direction, and finally in the posteromedial direction. Participants moved the pointer with their dominant leg first. The following is the measuring protocol (Linek et al., 2017): 1. A training effort consists of four replications of the right and left lower limbs in each of three directions: anterior, posteromedial, and posterolateral. 2. Execution of the proper test, which consisted of three attempts in each direction, measuring the distance between the pointer's closest location and the central plate. Only when the individual tested was able to return to the starting location while fully controlling the movement was the result of each attempt saved. During the performance of an attempt, the following will be considered irregularities: support using the movement-performing limb on the surface of the pointer to maintain balance, pushing the pointer to achieve a better result, changing the starting position (taking the upper limbs off the iliac wing). In such a case, the participant repeated the attempt until three properly accomplished repetitions were obtained (Linek et al., 2017). For the analysis, the maximum reach distance in each direction and the composite score are employed (Picot et al., 2021)

7. Gait speed test

   For gait speed, a 10-meter walk test was used, which required the participant to walk for 10 meters in a straight line at their normal speed, with a 1-meter start-up before starting timing and a 1-meter stop-time timing. It is permissible to employ an assistance walking device. For the walking test, each participant completed three consecutive trials. The participants are told to "walk at your normal, comfortable pace" until they reach the end of the indicated course. The duration is recorded using a stopwatch, which is started when the participant's lead leg (or assistive device) crosses the first marker and stopped when the participant's lead leg (or assistive device) crosses the second marker. By dividing the distance of 8 m by the time recorded, the recorded time is translated into walking speed (m/s).

8. Fear avoidance belief test

   The subject will next be allowed 3-5 minutes to respond to the FABQ-CHI. Those who are unable to read will receive assistance.

9. Pain test

Finally, the subject will be allowed 2-3 minutes to respond to the VAS. The following is the specific evaluation method: Choose a 10 cm ruler and face the experimenter with it marked with a complete digital scale from 0 to 10. The patient only sees scales at both ends of the ruler, and the 0 end is blank. "No pain" implies no pain at all, "14" means mild pain, "56" means moderate discomfort, "7" or more means severe pain, and "10" signifies agonizing pain(Langley & Sheppard, 1985). When the low back pain arises on the 0 scale, the patient begins to picture his pain state, and the experimenter notes the ultimate number, which can be immediately recorded as the patient's pain intensity score(Wewers & Lowe, 1990).

Rest for 30-60 seconds between tests to remove the confounding impact of weariness.

Procedure

This study will screen subjects according to inclusion and exclusion criteria. Before the evaluation and examination, the physiotherapist will tell the participants the purpose and methods, and the participants need to sign the consent form. The demographic data, which includes biographical information, short questions concerning the occurrence of LBP, and past medical history, will then be recorded. The subjects must then complete the anthropometric data, such as weight, height, and BMI. All patients require blood pressure and heart rate measurements before and after treatment.

For all subjects, the measurement indicators will be measured before the intervention, six weeks after the treatment, and 12 weeks after the treatment. In addition, all the subjects need to perform a warm-up before each exercise intervention and a cooldown after the exercise intervention. Warm up includes walking (5 min) and dynamic stretching (5 mins). Cooldown includes static stretching (5 min).

For group A, subjects will receive education from a qualified physiotherapist before the first treatment. Subsequent treatment begins with a warm-up. After the warm up, the physical therapist will install the BFR device for the subject as required. Then, the patients will receive CST for 15 minutes. Then, they will receive Tai Chi practice for 15 minutes. Finally, complete a 5-minute cooldown. The above treatments are performed 3 times a week for 12 weeks(Zou, Zhang, Liu, et al., 2019).

For group B, subjects will receive education from a qualified physiotherapist before the first treatment. Subsequent treatment begins with a warm-up. After the warm up, the physical therapist will install the BFR device for the subject as required. Then, the patients will receive CST for 30 minutes. Finally, complete a 5-minute cooldown. The above treatments are performed 3 times a week for 12 weeks(Nipa et al., 2022).

For group C, subjects will receive education from a qualified physiotherapist before the first treatment. Subsequent treatment begins with a warm-up. After the warm up, the physical therapist will install the BFR device for the subject as required. Then, the patients will receive Tai Chi for 30 minutes. Finally, complete a 5-minute cooldown. The above treatments are performed 3 times a week for 12 weeks(Qin et al., 2019).

For group D, subjects will receive education from a qualified physiotherapist before the first treatment. Subsequent treatment begins with a warm-up. Then, the patients will receive CST for 30 minutes. Finally, complete a 5-minute cooldown. The above treatments are performed 3 times a week for 12 weeks(Nipa et al., 2022).

Statistical analysis:

Data were processed using SPSS version 25.0 and Microsoft Excel 2010 software.

1. Demographic data = descriptive analytics.
2. All objectives = repeated measure ANCOVA (within-between interactions) for all variables.
3. The significant level is P < 0.05.

Inclusion Criteria:

• All participants had stable vital signs, were cognizant, and had no cognitive impairment.
• Aged 18-60 years old, able to understand Mandarin Chinese, and willing to cooperate.
• LBP duration ≥ 3 months.
• Be diagnosed as NLBP.
• VAS score ≤ 5 points.

Exclusion Criteria:

• Patients with severe heart disease, liver disease, renal disease, pulmonary insufficiency, tumors, and postoperative dysfunction.
• Patients who are unconscious and unable to cooperate.
• Spinal fractures, severe arthritis, bony spinal stenosis, ankylosing spondylitis, open fractures, or unhealed traumatic wounds.
• Patients who have not been diagnosed with NLBP.
• Unable to communicate and read in Chinese.
• Age <18 & >60 years old.
• LBP duration < 3 months.
• Patients with high blood pressure and abnormal heartbeat.
• VAS score > 5 points.