When I first got my bike, I had the saddle too low and I experienced some pain in my right knee while riding. I seem to have "fixed" this problem by raising it some. However, that got me thinking... what would happen if I raised it even more so that my legs would be straight (not bent at the knee) when the pedal was at the bottom? Would this give me increased power? Have power tests been done to verify what level of leg extension produces the most power? Are there any problems allowing your leg to fully extend (straighten)? I may try this sometime but wanted to get some info here first. I asked someone at the local bikeshop and they told me there is a chance of hyperextending if I do that but I asked myself how if the position is fixed? I think the general rule is to have a little bit of knee flex while the pedal is at the bottom but maybe that is a guideline and not a "hard" rule.
I wanted to add that I don't use any fancy riding shoes or any clips. Just regular "street" shoes. Also, my typical longest ride in a single day is only about 10 miles max. That translates into about a little over 1 hour at an average speed of less than 10 MPH.
Also, I am not sure why some people might say it is "bad" to straighten your leg totally when riding cuz when we walk we have alternating straight legs so why not the same when we ride a bike? When we lift a heavy object off of the floor, the hardest part is when our legs are bent the most, indicating that is the most inefficient position. When our legs are nearly straight it is much easier for us to lift weight such as a heavy box that is already at waist height for us.