Final answer:
The degrees of flexion at the knee and hip joint when sitting on a stability ball can vary but generally, the knee is flexed at approximately 90 degrees and the hip is flexed at approximately 90-120 degrees.
Step-by-step explanation:
The degrees of flexion at the knee and hip joint when sitting on a stability ball will depend on the individual and their range of motion. Generally, when sitting on a stability ball, the knee joint is flexed at approximately 90 degrees, while the hip joint is flexed at approximately 90-120 degrees.
It's important to note that these angles can vary based on factors such as the size of the stability ball and the individual's comfort level. The goal is to maintain a stable and balanced position on the stability ball to engage the core muscles and promote good posture.