This study is conducted as a single-blinded, randomized control trial to compare the effectiveness of telerehabilitation-based and clinic-based methods to deliver CSE with ADIM on pain intensity, functional ability, quality of life, and satisfaction in chronic low back pain patients with lumbar instability. Participants will be non-specific chronic low back pain patients with lumbar instability, which will be screened by history and physical examination. Lumbar instability will be diagnosed using the Screening Tool for Patients with Lumbar Instability Questionnaire, 14 items were yes-or-no questions. If "yes" answers are more than 6/14, this score represents lumbar instability and will be diagnosed by special tests with at least two positive signs from three special tests consisting of: 1) Painful catch sign; 2) Aberrant movement sign; and 3) Prone instability test.

The estimation of the sample is based on a previous study of Chalermsan et al. (2016. Based on this study, a standard deviation of pain intensity after treatment for both groups were used to calculate the sample size for a power of 80% at 5% significance, and a dropout rate of 30% allowed for estimating the final sample. Therefore, the sample size will be 15 participants per group, and the total number of participants will be 30. The allocation sequence will be generated using the random number function in Excel. All participants will be randomly allocated to either the telerehabilitation-based group or the clinic-based group using stratified random allocation by age groups and gender.

The data collection process in this study. After participants receive a screen test and sign the informed consent form, a baseline assessment will be conducted by the assessor before randomization. The outcome measurement includes pain level assessment using the numerical rating scale (NRS), participation restriction using the Oswestry disability index (ODI), activity limitation using the Roland Morris Disability Questionnaire (RMDQ), quality of life using the 36-item Short Form Survey (SF-36), and lumbar joint repositioning sense to measure proprioception. Regarding lumbar joint repositioning sense measurement, participants will be asked to sit with their hips and knees at 90 degrees, feet supported, and arms resting on their thighs. The assessor will guide the participant's lumbar spine into a mid-range position between a posterior and anterior pelvic tilt. The assessor then uses a 10-centimeter tape measure on the participant's lumbar, with the center of the tape marking sacral segment 1 (S1) as the measurement start point. A laser pointer placed on a stable base and adjusted to be level is in a in a position to have the mark line directly on the start point. The participant will be instructed to remember this position before moving the pelvis twice from maximum anterior to maximum posterior tilt for approximately five seconds before returning to neutral position. The distance from the starting point will be measured in centimeters using the laser line on the tape measure. This protocol will be conducted by an assessor (researcher number 1) who is a licensed physical therapist and blinded to group allocation. Then participants will be randomly allocated into one of two groups in this study: either the telerehabilitation-based group or the clinic-based group, by the assistant researcher. All outcome measures will be reassessed after completing the seven-week intervention. Furthermore, a satisfaction questionnaire will be used to determine satisfaction, and then the satisfaction of participants will be determined using a 5-point Likert scale questionnaire.

The intervention of this study is a 7-week core stabilization exercise with abdominal drawing-in maneuver technique, or CSE with ADIM. All participants received a 7-week CSE with ADIM. However, the method of receiving the exercise program in the experimental group (telerehabilitation-based group) will be telerehabilitation via video call with the main researcher. At the first session of each week, the researcher will provide supervision via video call with the participant for the exercise program. The participants will perform the exercise by following the video demonstration. In this session, the main researcher will supervise the participants as they do the exercise. The session will start with the participant and the main researcher watching the video demonstrating the exercise program together. After watching the video, the participants can ask a question in case they have any doubts about how to do the exercise. Then the participants will be asked to perform the exercise, and the main researcher will observe and advise or correct in case the participant cannot perform the exercise correctly. For the rest of the week, the participants will perform the exercise by themselves. In case they want to ask any questions, they can contact the main researcher via line application. In the control group (clinic-based group), at the first session of each week, an appointment with the main researcher will be set, and then the specific exercise for each week will be delivered and trained by the main researcher at the clinic. After completing weekly training, participants will perform their exercise routine as part of a daily home program.

The statistical analysis will be performed using SPSS version 22.0 for Windows (IBM Corporation, Armonk, NY, USA). The Shapiro-Wilk test will be used to test the normality of the data. All data analysis will be performed with an intention-to-treat analysis. The data will be presented as means, standard deviations (SD), 95% CI, percentage, ratio, or mode, and interquartile as appropriate. The analysis of comparisons within the pre- and post-intervention in each group will use a pair T-test. The analysis of comparative data between the telerehabilitation-based group and the clinic-based group will use an analysis of covariance (ANCOVA). Because the randomization process does not ensure that the groups have identical baseline characteristics, the researchers conducted an ANCOVA to compare the differences in outcome measures between the groups. In this analysis, the pre-test scores of each outcome will be used as a covariate to estimate the adjusted mean differences and 95% confidence intervals for each outcome measure in each group. The researcher will interpret Partial Eta Squared effect sizes as either large (≥ 0.80), medium (0.50-0.79), or small (0.20-0.49) (Richardson et al., 2011), and the level of significance will be set at a p-value less than 0.05.