When motorcyclists ride in the same position for long periods of time, they may be at risk for Deep Vein Thrombosis and Edema.  When riding you may or may not be able to straighten or move your knees and hips. And riding in this limited position for hours on end as well as wearing snug fitting riding pants increases the risk. Dr Liza Thomas, an emergency physician, explains what DVT and Edema are, as well as how these medical conditions happen and what factors put you at higher risk of developing them.