We tested this unit with many different adults with different body shapes and proportions. Women, men, dancers, gymnasts, aerialists, yoga teachers. All of them had exactly the same problem with this unit with many reporting knee joint pain after first use!!This unit has a major design flaw in that the point at which it applies maximum pressure to spread the legs is almost perfectly centered on the medical meniscus (part of knee joint), which is the absolute worst place you can possibly apply force to.We are not testing this on disproportionately tall people. The picture shown is representitive of almost every person over 5' tall. The only possibility we can think of is this was designed exclusively for children or an adult user under 5' tall.The point of contact where spreading force is applied is supposed to be on either the thigh above the knee joint or on the lower leg between knee and ankle joints. Concentrated force should NEVER be applied directly perpendicular to any joint.From our testing, the only users that this would be suitable for are children, or users under 4'11" average (or those with dispropotionately short legs).We tried some other versions "designed for western users" and ALL of them had this issue. Some other units had longer leg boards that go on bottom of the lower legs, but the problem with all of these units is the location of the short pads that apply the spreading force.We are not even talking about weak gears, quality issues, etc. This is a MUCH more serious risk of using this unit than losing some money when it breaks.Let us know if you found this information useful, and if it would be helpful to you if we share our modification for these units that fixes this particular issue.
JARJAX 
