騎自行車為什麼會有患「跳躍者的膝痛（Jumper’s Knee）」或簡稱「跳躍膝」，明明沒有在進行跳躍？跳躍膝，醫生上稱為「髕骨肌腱炎」，但因為多發生於需要大量跳躍型的運動（如籃球、排球），所以才會有一個跳躍膝的名稱。
在《Performance Cycling: The Science of Success，James Hopker》本書中有提到髕骨肌腱炎與「坐墊高度」的關係：
THE IMPORTANCE OF BIKE FIT IN INJURY PREVENTION（BIKE FIT 在受傷預防的重要性)
Patellar tendonitis（髕骨肌腱炎） is a common overuse injury（過度使用的受傷） in cyclists（自行車） and is usually associated with a low saddle height（較低的座墊高度）. A saddle that is too low can cause over-compression of the knee（膝蓋壓力過大）, resulting in anterior knee pain（膝蓋前側疼痛）. As a result, it has been recommeded that cyclists with patellar tendonitis move their saddle height to create a knee angle close to 25 degrees at the bottom of the pedal stroke.（建議將座墊調高）
Biceps femoris (hamstring) tendonitis（股二頭肌肌腱炎） is another common overuse injury in cyclists and can be caused by a saddle that is too high（座墊太高）. If the saddle is too high, it can cause posterior knee pain by overextension（後側膝蓋過度伸展） in the dead spot at the bottom of pedal stroke, which puts a heavy strain on the biceps femoris（股二頭肌承受很重的壓力）. As a result, it has been recommeded that the saddle height be set for a 25~35 degree knee angle. However, while plausible, no envidence exists to suggest that the 25-35 degree knee angle position actually reduce the risk of injury.
以上整理。