Subjects assigned to the SRT-WBV group were required to stand on the footboard of the SRT-WBV (SR Therapiesysteme GmbH & Co. Lifescience KG, Berlin) device with shoulder width stance, and knees bent at 30 degrees, facing forward. The trim settings progressed from weak (45 seconds with 8 repetitions), to mild (55 seconds with 8 repetitions), average (60 seconds with 6 repetitions), and strong (60 seconds with 6 repetitions), with intensity increased at two-week intervals. Each repetition was separated by a resting period that had the same duration as the trim settings (weak: 45 seconds, mild: 55 seconds, average and strong: 60 seconds).

Subjects were required to stand on the balance board with knees bent at 30 degrees and both hands placed on the chest with eyes opened. The balance board intervention used different durations as its intensity, such as 7.5 minutes, 10 minutes, 12.5 minutes, and 15 minutes continuously without resting period. The intensity of exercise was progressively increased every 2 weeks until completion of the program.

A total of 16 therapeutic exercise sessions were conducted during the intervention where 2 sessions were conducted every week, separated by at least one day. Specifically, subjects assigned to either group, with each session began with standardized warm-up exercises lasting approximately 5-10 minutes, followed by specific therapeutic exercises such as SRT-WBV and Balance Board.

Knee function was assessed using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) questionnaire where pain score, stiffness, and physical function were evaluated on a scale of 0-4, with higher scores indicating worse pain, stiffness, and functional limitations. The questionnaire contains 24 items and the WOMAC Osteoarthritis Index scores were then derived from the sum of the scores for the three subscales It was administered at the beginning and completion of the intervention, as well as every 4 weeks during the intervention.

Balance and mobility will be assessed using the Timed Up and Go Test. The time (in seconds) taken to stand up from a chair, walk 3 meters, turn, return, and sit down will be recorded.

Balance/flexibility will be assessed using the Straight Leg Raise test. The maximum angle (in degrees) achieved during leg elevation will be recorded.

Knee pain will be measured using the Visual Analog Scale ranging from 0 to 10, with higher scores indicating greater pain. Participants will rate their pain at rest while seated.

Quality of life will be assessed using the SF-12. Scores will be calculated according to standard scoring procedures.