The sample size was determined based on prior YBT studies,1,2 (link) which showed a large effect size of 1.25 between individuals with LBP and asymptomatic individuals. Using a more conservative approach, an effect size of 1.0 was used to estimate the sample size for this study. A power analysis performed with G*Power version 3.1.9. indicated that at least 24 participants would be needed to ensure an adequate power level of 0.80 for an independent t-test at an alpha level of 0.05. To allow for attrition, 30 participants, 15 in each group, were planned for the study.
Thirty 18- to 40-year-old young adults, 15 individuals with CLBP and 15 age- and gender-matched asymptomatic participants, were recruited and completed the study. Age and gender were matched between groups to reduce the possible influence of these variables on dynamic balance. Asymptomatic participants were individuals who had not experienced LBP within a year before the testing and no known LBP-related injury in their lives. Participants in the CLBP group were individuals who had experienced repeated episodes of persistent or recurrent LBP of musculoskeletal origin for a duration of over 12 weeks and an average pain intensity score ≥ 2/10 on the Numeric Pain Rating Scale (NPRS) in the past week.
Participants were excluded from the study if they reported or demonstrated any of the following: (1) pregnancy, (2) systemic joint disease (e.g., neurological or rheumatologic disorders), (3) serious spinal conditions, such as tumor, infection, or fracture, (4) signs of nerve root compression, (5) a history of hip, knee, or ankle pain in the previous two years, (6) previous surgery to the lower extremity or lumbar spine, (7) a concussion within the previous three months, (8) vestibular or other balance disorders, (9) ongoing treatment for inner ear, sinus, or upper respiratory infection, and (10) a need for any form of walking aid, such as a cane or walker. In addition, participants were excluded were they receiving medical care from a physician or other practitioner at the time of the study. Each participant was informed of the study procedures, benefits, and possible risks and then signed a written informed consent form. Potential participants were screened with a neurological examination (e.g., strength, sensation, and reflexes) performed by one investigator to determine their eligibility for the study.
Thirty 18- to 40-year-old young adults, 15 individuals with CLBP and 15 age- and gender-matched asymptomatic participants, were recruited and completed the study. Age and gender were matched between groups to reduce the possible influence of these variables on dynamic balance. Asymptomatic participants were individuals who had not experienced LBP within a year before the testing and no known LBP-related injury in their lives. Participants in the CLBP group were individuals who had experienced repeated episodes of persistent or recurrent LBP of musculoskeletal origin for a duration of over 12 weeks and an average pain intensity score ≥ 2/10 on the Numeric Pain Rating Scale (NPRS) in the past week.
Participants were excluded from the study if they reported or demonstrated any of the following: (1) pregnancy, (2) systemic joint disease (e.g., neurological or rheumatologic disorders), (3) serious spinal conditions, such as tumor, infection, or fracture, (4) signs of nerve root compression, (5) a history of hip, knee, or ankle pain in the previous two years, (6) previous surgery to the lower extremity or lumbar spine, (7) a concussion within the previous three months, (8) vestibular or other balance disorders, (9) ongoing treatment for inner ear, sinus, or upper respiratory infection, and (10) a need for any form of walking aid, such as a cane or walker. In addition, participants were excluded were they receiving medical care from a physician or other practitioner at the time of the study. Each participant was informed of the study procedures, benefits, and possible risks and then signed a written informed consent form. Potential participants were screened with a neurological examination (e.g., strength, sensation, and reflexes) performed by one investigator to determine their eligibility for the study.
