The experimental 1 group perform self-myofascial release and Pilates exercises.

The experimental 2 group perform pilates exercise using reformer.

The self-myofascial release combined reformer Pilates group performs 10 minutes of self-myofascial release using the BALLance© method before beginning 20 minutes of Reformer Pilates. The 6-week program includes warm-up and breathing, main supine exercises 1 and 2, and movements targeting the sacroiliac and hip joints.

All Pilates exercises are designed in a variety of positions including supine, prone, sitting and standing. All participants attend twice a week for 6 weeks, for a total of 12 sessions.

And all participants performed home exercise program follows the guidelines of Geroge et al (2021) and includes myofascial release and Pilates Reformer exercises, as well as stretching exercises beneficial for chronic low back pain. The home exercises are performed three times a week for 15 minutes, and exercise materials are distributed.

Pain severity is measured using a visual analogue scale, where participants mark the level of back pain they feel on a line between 0 mm and 100 mm(0: no pain, 10: worst pain imaginable).

Measurement unit is in mm, with higher scores considered more painful

The Korean version of the Oswestry Disability Index (KODI) is used to assess functional impairment due to low back pain. This assessment consists of 10 items, including pain intensity, personal care, lifting, walking, sitting, standing, sleeping, sexual life, social life, and travel, with each item scored on a scale of 0 to 5 for a total of 50 points. The KODI score is given as a percentage (%) of the total score. Scores are categorised as mild disability (0-20%), moderate disability (21-40%), severe disability (40-60%) and disability affecting all aspects of life (>60%), with high test-retest reliability (r=0.92).

Flexibility is measured using the sit-to-stand reach test (SRT), which assesses the flexibility of the lower back and hamstrings. The score is the most distant point (cm) reached with the fingertips. The best of three trials should be recorded. Participants sit with their feet on a box, knees straight, and reach as far forward as possible. The posture is maintained for five seconds and the reach distance is recorded over three trials and averaged. The longer the distance in centimeters, the more flexible it is.